METHODS AND METHODOLOGIES
doi: 10.1111/scs.12186
Validation of the Test of Functional Health Literacy in Adults in a Danish population Lisa Korsbakke Emtekær Hæsum PhD (Student)1, Lars Ehlers (Professor)2 and Ole K. Hejlesen (Professor)1,3 1
Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark, 2Danish Center for Healthcare Improvements, Faculty of Social Sciences and Faculty of Health Sciences, Aalborg University, Aalborg,Denmark and 3Department of Computer Science, University of Tromsø, Tromsø, Norway
Scand J Caring Sci; 2015; 29; 573–581 Validation of the Test of Functional Health Literacy in Adults in a Danish population
Objective: To describe how the original American fulllength version of the Test of Functional Health Literacy in Adults (TOFHLA) was translated and adapted for use in the Danish setting and culture. A reliable Danish version of the TOFHLA was created and pretested using patients diagnosed with chronic obstructive pulmonary disease (COPD) as case group. Methods: Forty-two patients with COPD completed the Danish TOFHLA and participated in a face-to-face interview concerning their basic demographics. Statistical analyses were conducted to explore the demographic data provided by the participants and to determine the internal consistency and reliability of the Danish TOFHLA. Results: The mean age of sample was 68.7 years (range 34–86). The face validity, internal consistency and item to scale correlations of the Danish TOFHLA were
Introduction Health literacy has become a rather vibrant area of research over the past decade (1). The interest in health literacy has evolved from being mainly concentrated in the United States and Canada to become more internationalised (2). Research in health literacy has been conducted in Korea (3), Australia (4, 5), Japan (6), Switzerland (7), the Netherlands (8) and the UK (9). During 1991–2005, less than one-third of the global research within the field of health literacy was conducted in Europe (10). In recent years, health literacy has Correspondence to: Lisa Korsbakke Emtekær Hæsum, Department of Health Science and Technology, Faculty of Medicine, Fredrik Bajers Vej 7, building C1, Aalborg University, 9220 Aalborg East, Denmark. E-mail: [email protected] © 2015 Nordic College of Caring Science
determined and found to fulfil well-established criteria; on this basis, we found the reliability and consistency of the Danish TOFHLA to be satisfying. Conclusion: The Danish TOFHLA is now ready for application in future research projects, which test levels of functional health literacy in an elderly Danish population at risk of chronic diseases. The evolvement in the measurement of health literacy is still ongoing, as there is a need to refine existing methods. Until recently, there has been a total lack of instruments for assessing health literacy in Scandinavia; it is hoped that this development of the Danish TOFHLA will promote further research within the field of health literacy in Scandinavia and other European countries. Keywords: health literacy, Test of Functional Health Literacy in Adults, reliability, chronic disease, chronic obstructive pulmonary disease, communication, Denmark. Submitted 27 May 2014, Accepted 16 September 2014
started to receive increased attention in European politics and legislation, which indicates that it is in the process of becoming recognised as a problem also in Europe. The importance of health literacy is mentioned as a focus area in the European Commission’s Health Strategy 2008– 2013 (11).In spite of the increasing interest in health literacy, there is still no consensus in the existing literature regarding its definition and conceptualisation (12). The definitions from the World Health Organisation (WHO) (13), the American Medical Association (AMA) (14) and the Institute of Medicine (15) are the most acknowledged ones and therefore also the ones most frequently cited in relevant literature (12). These definitions vary slightly in content, but they still hold very similar characteristic in terms of their focus on the individual ability to access, evaluate and use health-related information to maintain good health and make appropriate health decisions (12). Health literacy is a very broad and complex concept that 573
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includes multiple levels and different sets of skills. As an attempt to kind of frame the complexity of health literacy, Don Nutbeam has divided it into three levels (16): • The functional level of health literacy: The basic skills of writing, reading and numeracy that allow an individual to function effectively with regards to their health (16). • The interactive level of health literacy: A more advanced level of literacy, cognitive and social skills that make an individual capable of retrieving health information and active engage in dialogue/discussion with healthcare professionals (16). • The critical level of health literacy: An advanced set of skills that includes critical analysis of health information retrieved independently or from the healthcare system and the ability to actively act on this information (16). Common to all three levels is that basic literacy skills, defined as basic reading, writing and numeracy skills, constitute the foundation of health literacy; it is not possible to retrieve and critically analyse health information without the ability to read and write (16). Don Nutbeam has also stated that health literacy can be viewed as either a personal ‘asset’ or clinical ‘risk’ factor (17). Health literacy as a clinical risk factor includes identification and proper management of it in clinical care – something that begins with assessment using proper screening instruments (17). Health literacy viewed as a personal asset is more complex, as it comprises the ability of individuals to exert more control over their general health and environmental, personal and social determinants of health (17). Health literacy can either be defined in a complex approach (the interactive and critical levels defined by Don Nutbeam), where multiple levels, skills, views etc. are included or in a more simple tangible way where it only comprises the basic individual skills needed to navigate the healthcare system and to understand health-related information (18). The authors of this paper have taken the simple approach when defining and assessing health literacy. Elderly people with a chronic disease like for instance chronic obstructive pulmonary disease (COPD) are at risk of having a low level of health literacy and of not receiving the health care they need (19). The literature describing the connection between COPD and health literacy is rather limited. Three very recent studies have investigated the connection between health literacy and various health outcomes among patients with COPD; one study found that a low level of health literacy seems to be associated with poorer health outcomes, including a high rate of hospitalisations, among patients with COPD (20). The other study found that patients with COPD, whose health literacy level is low often have less knowledge of their condition, are less well managed and have a poorer overall health status than
more health-literate patients with COPD (21). The third study emphasises that health literacy seems to play a crucial role in chronic disease self-management, and good doctor–patient communication is essential to support self-management among patients with COPD (22). The same study points out that to achieve better health outcomes among patients with COPD requires recognition of the nature and extent of the problem and proper screening instruments for identifying those whose health literacy level need to be heightened (22). This is, however, a challenging task, as the lack of consensus about the definition of health literacy causes disagreement about how it should be measured (1). Objective screening instruments to measure health literacy have been developed, but are criticised for not capturing the complexity of the concept of health literacy (1, 15); therefore, the development of more recent screening instruments have focused on assessing the higher, more complex level of health literacy in a more subjective manner (23, 24). To date the instruments most widely used to measure health literacy are the Test of Functional Health Literacy in Adults (TOFHLA) (25) and the Rapid Estimate of Adult Literacy in Medicine (REALM) (26). In 1995, the TOFHLA was developed as a screening instrument to measure the level of functional health literacy (25). Functional health literacy, as measured in the TOFHLA, is defined as basic reading, writing, and numeracy skills applied in a healthcare setting, and it constitutes the foundation for health literacy on which a variety of complementary and advanced skills can be built (17). However, the TOFHLA is only available in an American and Spanish version, and there is no standardised way to measure health literacy in most European countries (10). As a result, the research into functional health literacy among the Danish population is also in an infant stage. It is important to identify people vulnerable to low health literacy, so that medical counselling and education efforts regarding medications and chronic disease management can be tailored to their needs (27). The full-length American standardised version of the TOFHLA is well described in the existing literature and has been used on various populations and health conditions to assess the ability to read healthrelated materials; therefore, this paper describes how this original version was translated and adapted for use in a Danish population based on a sample of patients diagnosed with COPD.
Methods Procedures The original Spanish version of TOFHLA was translated and adapted for the setting and culture of Puerto Rico in a study from 2010 (28). The Puerto Rican study conducted © 2015 Nordic College of Caring Science
Validation of TOFHLA the cross-cultural adaptation process according to international guidelines defined by Beaton et al. (29), so the authors of this paper chose to translate and adapt the original American version of the TOFHLA for the Danish setting and culture, also by following the guidelines for cross-cultural adaptation as defined by Beaton et al. (29). The American TOFHLA consists of two parts with a total of 67 items; the first part comprises 17 items concerned with numeracy skills and the second part comprises 50 items concerned with reading comprehension skills. The reading comprehension part is divided into three passages: passage A concerned with x-ray preparation, passage B concerned with Medicaid rights and responsibilities and passage C concerned with a hospital consent form. The structure, content and intent of these 67 items in the American TOFHLA were maintained in the Danish TOFHLA, which also made it possible to maintain the scoring system of the American TOFHLA in the Danish TOFHLA. The total score for the American TOFHLA is divided into three levels: inadequate (score: 0–59), marginal (score: 60–74) and adequate (score 75–100) (25). The cross-cultural adaptation process and evaluation of cultural equivalence should be carried out according to the following six stages defined by Beaton et al. (29): Stage I: Two forward translations of the instrument from the original language into the target language. Stage II: Synthesis of the two translations produced in stage I. Stage III: Two back-translations from target language back to original language. Stage IV: Expert committee and production of prefinal version. Stage V: Pretest of prefinal version. Stage VI: Consistency and reliability. In the following, it will be described how the American TOFHLA was translated and adapted into a Danish version by following the six stages defined by Beaton et al. (29). Stage I in our study. The American TOFHLA was translated from its original language (English) into the target language (Danish) by two different translators – producing two different Danish versions of the TOFHLA: T1 and T2. The two translators were selected on the criteria suggested by Beaton et al. (29). Time estimation–1–2 working days (considered to be 8– 10 hours) per translator depending on the amount of modifications made, and how easy it is to find solutions to cultural challenges. Stage I also depends on the correspondence between the American healthcare system and the healthcare system at the target location. Stage II in our study. The two different Danish versions of the TOFHLA, T1 & T2, produced in stage I, were © 2015 Nordic College of Caring Science
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synthesised into one joint translation T12. A written report that thoroughly documents the synthesis process was developed. The written report addresses each difference between T1 and T2 and the reasons for the solution used in the T12 joint version of the Danish TOFHLA. Time estimation–1 work day per translator. Stage III in our study. The T12 joint Danish version of the TOFHLA was translated from the target language (Danish) back to the original language (English) by two different translators – producing two different back-translations BT1 and BT2. The two back-translators were selected on the criteria suggested by Beaton et al. (29). Time estimation–½–1 work day per translator. Stage IV in our study. The expert committee consisted of: A methodologist, a healthcare professional, all the translators and the researcher. The expert committee reviewed following material from previous stages: the American TOFHLA, each translation (T1, T2, T12, BT1 and BT2) together with the corresponding written reports (explaining the rationale behind decisions made at earlier stages). The primary objective of the expert committee was to explore the idiomatic, semantic, conceptual and experiential equivalence between the American and the Danish version of the TOFHLA. The expert committee compared the American TOFHLA with the T12 joint version of the Danish TOFHLA to evaluate if the intention in the American TOFHLA has been preserved in the Danish TOFHLA. Furthermore, they also compared the back-translations BT1 and BT2 with the American TOFHLA to ensure that the Danish TOFHLA is reflecting the same item content as the American TOFHLA. The main task of the expert committee was to reach consensus on discrepancies and produce a prefinal version of the Danish TOFHLA. Time estimation–The expert committee should expect to meet for ½–1 work day to discuss the translations and to reach a prefinal version (this is without accounting for preparation time prior to the expert committee meeting). Stage V in our study. The prefinal Danish version of TOFHLA was pretested on 42 patients with COPD to ensure reliability and consistency of the instrument. Time estimation–5–6 patients with COPD per work day. Stage VI in our study. Face validity was assessed entirely based on observations made during the pretest in stage V. The Cronbach’s alpha coefficient was calculated to
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analyse the internal consistency and reliability of the Danish TOFHLA, based on the data collected in the pretest. Finally, item to scale correlations of all 67 items was explored by Pearson’s correlation coefficient.
Participants in the pretest A consecutive sample of 42 Danish participants with COPD were selected from the pulmonary outpatient clinic at Aalborg Hospital (Aalborg Municipality) and the Health Centre in Hjørring (Hjørring Municipality), which are both located in the area of Northern Jutland, Denmark. This area serves almost 45 000 people with COPD (30), which represent a broad socio-demographic range. The participants were selected using consecutive sampling, which seeks to include all accessible subjects at multiple data collection sites, in this case the outpatient clinic at Aalborg Hospital and the Health Centre in Hjørring. At each site, a healthcare professional initiated contact with all accessible subjects and provided them with a short written description (developed by the researcher) explaining the process as well as the requirements of participants should they agree to participate in the pretest of the Danish TOFHLA. The healthcare professionals were instructed to consider the following criteria when inviting potential subjects to participate in the pretest. Inclusion criteria. Diagnosis of COPD (based on the selection by the two healthcare professionals and afterwards confirmed by self-report by the participant to the researcher), adult, both men and women, pregnant or nonpregnant and able to read and understand Danish as judged by the researcher. Exclusion criteria. Diagnosis of dementia (based on the selection by the two healthcare professionals and afterwards on observation by the researcher), blindness or being too ill to participate, unable to understand the informed consent procedure as judged by the researcher, unable to read or understand Danish also as judged by the researcher. If a subject agreed to participate, the researcher initiated the actual data collection process by ensuring that the participant was suitable for inclusion in the pretest. All participants were orally informed about the purpose of the study and about their rights to withdraw from the study at any time during the study. The collection of relevant data was carried out at the most convenient times for the participants either at the setting where they received health services or in their own homes. Confidentiality and privacy conditions were assured at all times during the data collection process.
Data collection in the pretest Two types of methods were used to collect relevant data for statistical analysis in the pretest (stage VI in our study): 1 The researcher conducted a face-to-face interview with each patient with COPD to collect the following demographic data: sex, age, marital status, living situation, education level, employment and COPD status. 2 Each patient with COPD completed the Danish TOFHLA. The Danish TOFHLA consists of a 17-item numeracy part and 50-item reading comprehension part–constructed just like the American TOFHLA (25). The numeracy part of the Danish TOFHLA assesses the participant’s ability to understand financial assistance, keep a clinical appointment, understand instructions for taking medication, etc. A participant could, for example, be asked to read an appointment reminder card or prescription medication instructions, and subsequently, he/she could be asked about what had been read. In the Danish TOFHLA, the test of reading comprehension is conducted as a modified cloze procedure in which random words are deleted from a reading passage (31). In this case, every fifth to seventh word is deleted in healthrelated reading passages, and the participant then selects the most fitting word from a list of four possible words. The total scores for the Danish TOFHLA test are divided into three levels: inadequate (score: 0–59), marginal (score: 60–74) and adequate (score 75–100)–just like the American TOFHLA (25).
Data analysis Results obtained from the basic demographic interview were entered into the statistical software SPSS version 21 (32). Various statistics were performed on these results to describe the study group in terms of mean, standard deviations, frequency, percent, etc. The face validity was assessed during the pretest based on observations made by the researcher. The internal consistency of the Danish TOFHLA was analysed using the Cronbach’s alpha coefficient. This consisted of an overall analysis as well as analysis on the two subcategories (reading comprehension and numeracy). Following the criteria for reliability set by Houser (33), an instrument is considered reliable if Cronbach’s alpha exceeds a value of 0.7. Finally, item to scale correlations of all 67 items was assessed using Pearson’s (Point-Biserial) correlation coefficient. This also consisted of an overall analysis as well as analysis on the two subcategories (reading comprehension and numeracy). Pearson values of 0–0.2 were considered weak correlations, 0.2–0.5 medium correlations and 0.5–1 high correlations (34).
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Validation of TOFHLA
Results Our sample comprised 42 Danish patients with COPD of whom 22 were women and 20 were men. The mean age in the sample was 68.7 years (range 34–86 years) with a standard deviation of 11.49. Of the 42 participants, 42.8% had completed 9th or 10th grade or less, whereas 14.3% had a high school education and 4.8% reported having education above high school. Of all the participants, 38.1% reported being skilled workers. The basic demographics of the 42 participants are shown in Table 1. The basic demographics are relatively balanced among the participants with 22 women and 20 men, 19 participants reported not having a partner and 23 reported having a partner. 57.1% of the participants were recruited from Aalborg Hospital, and 42.9% were recruited from Hjørring Health Centre. However, only 28.6% of the participants reported living in the city, in this case the city of Aalborg or Hjørring, and 71.4% of the participants reported living outside the city, in this case defined as smaller villages situated in the area surrounding Aalborg and Hjørring. Furthermore, the distribution of educational levels is skewed as only approximately 19% had completed high school or had a higher education. It should be noted that the participants were asked about their COPD stage, and only four of the 42 participants could provide a correct answer to this question. Table 1 Basic demographics of the 42 participants Number of participants Age
42 Mean = 68.7 (range 34–86 years)
Sex Men Women Recruitment Hospital Health Centre Living situation In the city In rural area Civil status Married or living with a partner Living alone Level of employment Full-time employment Less than 37 hours per week No job (Including those who have retired) Level of education 9th or 10th grade or less (some only completed 7th grade) High school Higher education Skilled worker (trade, industry, office, etc.) Correct answer to question about COPD stage
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Frequency
Percent
20 22
47.6 52.4
24 18
57.1 42.9
12 30
28.6 71.4
23 19
54.8 45.2
3 2 37
7.1 4.8 88.1
18
42.8
6 2 16 4
14.3 4.8 38.1 9.5
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As seen in Table 2, 11 patients with COPD were categorised as having an inadequate level of health literacy with a mean health literacy score of 47.09, 8 were categorised as having a marginal level of health literacy with a mean health literacy score of 67.38, and 23 were categorised as having an adequate level of health literacy with a mean health literacy score of 86.30. The mean response time for the completion of the entire Danish TOFHLA was 18 minutes and 23 seconds (17 minutes 28 seconds; 19 minutes 18 sec). In the reading comprehension component, the mean response time was 10 minutes and 44 seconds (10 minutes 10 seconds; 11 minutes 18 seconds); and for the numeracy component, it was 7 minutes and 39 seconds (7 minutes 5 seconsds; 8 minutes 12 seconds). As the American healthcare system is very different from the Danish system, passage B in the American TOFHLA, which concerns the American Medicaid insurance system, had to be modified to fit the structure of the Danish healthcare system in the Danish version. In order to translate and adapt the instrument for the Danish language and culture, passage B in the Danish version of TOFHLA concerns the Danish health insurance system called ‘health insurance Denmark’. It was possible to maintain the structure and intent of passage B, in spite of this change from the American Medicaid insurance system to the Danish ‘health insurance Denmark’; sentences and lists of words were constructed in a manner almost identical to that in the American TOFHLA. Moreover, item 16 and 17 in the numeracy part, concerning financial support in the American healthcare system, were modified to fit the Danish healthcare system. The first 15 items in the numeracy part and passage A and C in the reading comprehension part of the American TOFHLA were almost directly translated into Danish, only with some minor alterations of words and construction of sentences suitable to the Danish language. The expert committee found that all 67 items in the Danish TOFHLA measured health literacy in the same manner as the 67 items in the American TOFHLA (conceptual equivalence). They also found that the
Table 2 Distribution of health literacy score Obs (n) Total HL Score 42 HL score numeracy part 42 HL score reading 42 comprehension part HL score by health literacy category Inadequate 11 Marginal 8 Adequate 23
Mean HL
SD
Min
Max
72.43 38.12 34.31
18.14 9.29 10.63
29 18 2
95 50 48
47.09 67.38 86.30
8.84 3.54 6.47
29 62 76
59 73 95
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experience and knowledge of health literacy (experiential equivalence) did not differ much between the Danish and the American culture prior to completing the TOFHLA. The American TOFHLA does not contain any words or phrases specific or distinct to the American language only – all items could be translated into Danish without altering their intent – so the expert committee found that the intent of words and sentences is the same in the TOFHLA regardless of the language being American or Danish in their evaluation of the translation and adaptation process. The face validity of the Danish TOFHLA was satisfying, subjectively judged by the researcher. The internal consistency of the Danish TOFHLA was determined to 0.943 by the Cronbach’s alpha coefficient. This indicates that the criterion for reliability of the Danish version is fulfilled (>0.7 as set by Houser (33)). When calculated for the two subcategories, the following reliabilities were observed: numeracyalpha = 0.750 and reading comprehensionalpha = 0.940. Item to scale correlations were assessed for all 67 items individually in the Danish TOFHLA using the Pearson’s (Point-Biserial) correlation coefficient; 62 items showed a medium or high correlation with values > 0.2 and 5 items in the reading comprehension part showed a weak correlation with values < 0.2. The average (mean) strength of correlation for all 67 items combined was determined to 0.4 by Pearson’s coefficient. When calculated for the two subcategories, the following average strength of correlations was observed: numeracyPearson= 0.4 and reading comprehensionPearson= 0.5.
Discussion In our study, we translated and adapted the full-length American standardised version of the TOFHLA into a Danish version. The Danish TOFHLA was pretested on 42 patients with COPD to ensure reliability and consistency of the instrument. We assessed the face validity, internal consistency, and item to scale correlations of the Danish TOFHLA, and based on this, we found the reliability and consistency of the instrument to be satisfying.
Strengths and limitations of using consecutive sampling as a data collection method The baseline characteristics, of the 42 patients with COPD included in our study, were compared with factual information on risk factors in COPD to assess if our sample is representative of patients with COPD in Denmark. This comparison shows identical patterns: slightly more women are diagnosed with COPD, patients are > 60 years, and have a low educational level (35–37). The sample of 42 patients with COPD is a moderately small, but considering that the purpose of this paper was to
pretest a screening instrument already widely used and acknowledged in the literature, we argue that it is reasonable to assume that the sample is sufficiently representative to state that the Danish TOFHLA is ready for application in future research projects which test levels of functional health literacy in an elderly Danish population at risk of chronic diseases.
Strengths and limitations of the actual translating and adaptation process An important advantage of translating and adapting the original American TOFHLA into a Danish version instead of developing a new screening instrument is that the American TOFHLA is already acknowledged in the existing literature, and it has been used numerous times on the assumption that it enjoys sufficient validity and reliability; thus making it easier to create a reliable Danish version compared to developing a completely new instrument from scratch. It would also be very time-consuming to produce a new reliable screening instrument applicable for assessing health literacy in a Danish research project. Additionally, as the original TOFHLA is the screening instrument primarily used to measure health literacy, using a translated and adapted version of the American TOFHLA will make it possible to more accurately compare the results obtained with the Danish version with the results in the literature. The translation and adaptation of the American TOFHLA into a Danish version was challenging in terms of accounting for linguistic and cultural nuances of the Danish language and the application in two very different healthcare systems. It was not possible to just do a direct translation of the American TOFHLA into the Danish version; some of the questions had to be modified in the translation and adaptation process to suit the Danish context. These modifications were discussed very carefully by the expert panel to avoid losing the original intention of the questions in the translation and modification process. Even though these modifications were made with much caution, it remains a question whether such a modification of the American TOFHLA results in reduced validity and reliability of the new Danish TOFHLA. This is why Beaton et al. (29) recommend an assessment of face validity, internal consistency, item to scale correlations etc. with the purpose of accounting for cross-cultural differences when translating and adapting an instrument from one setting and culture to another. We found the Danish TOFHLA to have sufficient face validity, internal consistency and 62 of the 67 items showed a medium or high correlation with the scale. In spite of this, however, it is still important to remember that the American setting and culture is very different from the Danish in terms of the structure and access to © 2015 Nordic College of Caring Science
Validation of TOFHLA education and health care. The Danish healthcare system emphasises equity in health with equality in (free) access to various health services, whereas health services are not free of charge in America. Some Americans are able to pay these charges, and some are not (in this case, they are offered the social healthcare program Medicaid), which produces inequity in access to health care in the American healthcare system. Moreover, there is equality in the free Danish educational system and inequity in the American educational system that is not free of charge. These differences should be considered when using the Danish TOFHLA, as the American TOFHLA is originally designed for a system with inequities in access to education and health care – very different from the Danish system. If the translation and adaptation process is conducted properly according to international guidelines and modifications are made without changing the original intention of the questions, then it is reasonable to assume that a relatively reliable screening instrument for measuring the level of functional health literacy among Danish patients with COPD has been developed. It should be noted that the construct validity of the Danish TOFHLA was not assessed. Existing objective screening instruments like the TOFHLA are criticised for not capturing the complexity of health literacy (1, 15); therefore, the development of more recent screening instruments have focused on assessing the higher, more complex level of health literacy in a more subjective manner (23, 24). The subjective instruments provide valuable information on the participants’ experiences and overall points of view related to navigating and interacting with the healthcare system. A low level of health literacy is often associated with shame and embarrassment, and objective screening instruments can make the participants’ feel very uncomfortable (15). The subjective screening instruments can be considered more ‘user-friendly’, as they focus on the participants’ subjective evaluation of access to health-related information, ability to navigate the healthcare system etc. However, the reliability of these subjective screening instruments can be questioned, as there is a risk that participants with a low level of health literacy will try to hide it, because they feel ashamed and embarrassed. Overall, the measures of health literacy still need refinement, and a next step could be use of the available objective screening instruments in synergy with the subjective ones; the results should provide the same picture, for example a participant that subjectively finds it easy to find and understand health-related information would assumingly also achieve a high score in an objective test. The very first step to truly refine the measurement of health literacy is to reach consensus on the definition and conceptualisation of this concept.
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Conclusion In this study, the full-length Danish TOFHLA demonstrates strong consistency with the original American TOFHLA. Based on the cross-cultural transformation process and satisfying results in terms of face validity, internal consistency, and item to scale correlations, a reliable Danish version of the original American TOFHLA has been successfully developed for use in the Danish setting and culture. The Danish TOFHLA is now ready for application in future research projects, which test levels of functional health literacy in an elderly Danish population at risk of chronic diseases. The evolvement in the measurement of health literacy is still ongoing, as there is a need to refine existing methods. Until recently, there has been a total lack of instruments for assessing health literacy in Scandinavia; hopefully, this development of the Danish TOFHLA will promote further research within the field of health literacy in Scandinavia and other European countries.
Acknowledgements The authors thank the pulmonary outpatient clinic at Aalborg Hospital and Hjørring Health Centre for their collaboration. The authors especially wish to thank the two healthcare professionals, Carl Nielsen and Lone Jessen, for establishing the initial contact with the patients with COPD.
Author contributions Lisa Hæsum was responsible for data collection, data analysis and wrote the manuscript as first author. Lars Ehlers primarily provided feedback on the selection of statistical analyses, and also critically revised the manuscript. Ole Hejlesen primarily contributed as a discussion partner during the design of the study and analysis process. He also had the role of a critical reviser of the manuscript.
Ethical approval The present study is conducted in accordance with the Helsinki Declaration. The study is a part of a Ph.D. study on the influence of health literacy in telehomecare, which is conducted as a part of a large scale telehomecare project, TeleCare North. The TeleCare North project has been presented to the Regional Ethical Committee for Medical Research in the North Denmark Region where it was determined that no ethical approval was necessary.
Funding No funding was sought for the study.
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disease. J Gen Intern Med 2013; 28: 74–81. Sadeghi S, Brooks D, Stagg-Peterson S, Goldstein R. Growing awareness of the importance of health literacy in individuals with COPD. COPD 2013; 10: 72–8. Roberts NJ, Ghiassi R, Partridge MR. Health literacy in COPD. Int J Chron Obstruct Pulmon Dis 2008; 3: 499. HLS-EU Consortium. Comparative report of health literacy in eight EU member states. The European Health Literacy Survey HLS-EU 2012. Ishikawa H, Takeuchi T, Yano E. Measuring functional, communicative, and critical health literacy among diabetic patients. Diabetes Care 2008 May; 31: 874–9. Parker RM, Baker DW, Williams MV. The test of functional health literacy in adults. J Gen Intern Med 1995; 10: 537–41. Davis TC, Crouch M, Long SW, Jackson RH, Bates P, George RB, Bairnsfather LE. Rapid assessment of literacy levels of adult primary care patients. Fam Med 1991; 23: 433–5. Baker DW, Williams MV, Parker RM, Gazmararian JA, Nurss J. Development of a brief test to measure functional health literacy. Patient Educ Couns 1999; 38: 33–42. Rivero-Mendez M, Suarez E, SolısBaez SS, Hernandez G, Cordero W, Vazquez I, Medina Z, Padilla R, Flores A, Bonilla JL. Internal consistency of the Spanish health literacy test (TOFHLA-SPR) for Puerto Rico. P R Health Sci J 2010; 29: 49. Beaton DE, Bombardier C, Guillemin F, Ferraz MB. Guidelines for the process of cross-cultural adaptation of self-report measures. Spine 2000; 25: 3186–91. Jungersen DR. 4.500 nordjyske KOLpatienter tilbydes behandling i eget hjem (4.500 COPD patients in Northern Jutland are offered treatment in their own homes). 2013; Available at: ugeskriftet.dk/nyhed/45 00-nordjyske-kol-patienter-tilbydesbehandling-i-eget-hjem (last accessed 29 September 2014). Sadeghi K. Measuring reading comprehension: The judgmental validity
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Validation of TOFHLA of cloze procedure. Int J Am Linguist 2008; 11: 115–130. 32 IBM Corp. IBM SPSS Statistics for Windows, Version 21.0. 2012. 33 Houser J. Nursing research Reading, Using and Creating Evidence, 2nd edn, 2011, Jones & Barlett Publishers, Boston. 34 Everitt BS. The Cambridge Dictionary of Statistics, 2002, Cambridge, Cambridge.
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35 Decramer M, Vestbo J, Bourbeau J, Celli BR, Hui DSC, Varela MVL, Nishimura M, Roisin RR, Stockley RA, Vogelmeier C. Global initiative for Chronic Obstructive Pulmonary Disease - Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Pulmonary Disease. The Gold report. Updated version 2013. 2013. 36 Eisner MD, Blanc PD, Omachi TA, Yelin EH, Sidney S, Katz PP,
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doi: 10.1111/scs.12186
Validation of the Test of Functional Health Literacy in Adults in a Danish population Lisa Korsbakke Emtekær Hæsum PhD (Student)1, Lars Ehlers (Professor)2 and Ole K. Hejlesen (Professor)1,3 1
Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark, 2Danish Center for Healthcare Improvements, Faculty of Social Sciences and Faculty of Health Sciences, Aalborg University, Aalborg,Denmark and 3Department of Computer Science, University of Tromsø, Tromsø, Norway
Scand J Caring Sci; 2015; 29; 573–581 Validation of the Test of Functional Health Literacy in Adults in a Danish population
Objective: To describe how the original American fulllength version of the Test of Functional Health Literacy in Adults (TOFHLA) was translated and adapted for use in the Danish setting and culture. A reliable Danish version of the TOFHLA was created and pretested using patients diagnosed with chronic obstructive pulmonary disease (COPD) as case group. Methods: Forty-two patients with COPD completed the Danish TOFHLA and participated in a face-to-face interview concerning their basic demographics. Statistical analyses were conducted to explore the demographic data provided by the participants and to determine the internal consistency and reliability of the Danish TOFHLA. Results: The mean age of sample was 68.7 years (range 34–86). The face validity, internal consistency and item to scale correlations of the Danish TOFHLA were
Introduction Health literacy has become a rather vibrant area of research over the past decade (1). The interest in health literacy has evolved from being mainly concentrated in the United States and Canada to become more internationalised (2). Research in health literacy has been conducted in Korea (3), Australia (4, 5), Japan (6), Switzerland (7), the Netherlands (8) and the UK (9). During 1991–2005, less than one-third of the global research within the field of health literacy was conducted in Europe (10). In recent years, health literacy has Correspondence to: Lisa Korsbakke Emtekær Hæsum, Department of Health Science and Technology, Faculty of Medicine, Fredrik Bajers Vej 7, building C1, Aalborg University, 9220 Aalborg East, Denmark. E-mail: [email protected] © 2015 Nordic College of Caring Science
determined and found to fulfil well-established criteria; on this basis, we found the reliability and consistency of the Danish TOFHLA to be satisfying. Conclusion: The Danish TOFHLA is now ready for application in future research projects, which test levels of functional health literacy in an elderly Danish population at risk of chronic diseases. The evolvement in the measurement of health literacy is still ongoing, as there is a need to refine existing methods. Until recently, there has been a total lack of instruments for assessing health literacy in Scandinavia; it is hoped that this development of the Danish TOFHLA will promote further research within the field of health literacy in Scandinavia and other European countries. Keywords: health literacy, Test of Functional Health Literacy in Adults, reliability, chronic disease, chronic obstructive pulmonary disease, communication, Denmark. Submitted 27 May 2014, Accepted 16 September 2014
started to receive increased attention in European politics and legislation, which indicates that it is in the process of becoming recognised as a problem also in Europe. The importance of health literacy is mentioned as a focus area in the European Commission’s Health Strategy 2008– 2013 (11).In spite of the increasing interest in health literacy, there is still no consensus in the existing literature regarding its definition and conceptualisation (12). The definitions from the World Health Organisation (WHO) (13), the American Medical Association (AMA) (14) and the Institute of Medicine (15) are the most acknowledged ones and therefore also the ones most frequently cited in relevant literature (12). These definitions vary slightly in content, but they still hold very similar characteristic in terms of their focus on the individual ability to access, evaluate and use health-related information to maintain good health and make appropriate health decisions (12). Health literacy is a very broad and complex concept that 573
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includes multiple levels and different sets of skills. As an attempt to kind of frame the complexity of health literacy, Don Nutbeam has divided it into three levels (16): • The functional level of health literacy: The basic skills of writing, reading and numeracy that allow an individual to function effectively with regards to their health (16). • The interactive level of health literacy: A more advanced level of literacy, cognitive and social skills that make an individual capable of retrieving health information and active engage in dialogue/discussion with healthcare professionals (16). • The critical level of health literacy: An advanced set of skills that includes critical analysis of health information retrieved independently or from the healthcare system and the ability to actively act on this information (16). Common to all three levels is that basic literacy skills, defined as basic reading, writing and numeracy skills, constitute the foundation of health literacy; it is not possible to retrieve and critically analyse health information without the ability to read and write (16). Don Nutbeam has also stated that health literacy can be viewed as either a personal ‘asset’ or clinical ‘risk’ factor (17). Health literacy as a clinical risk factor includes identification and proper management of it in clinical care – something that begins with assessment using proper screening instruments (17). Health literacy viewed as a personal asset is more complex, as it comprises the ability of individuals to exert more control over their general health and environmental, personal and social determinants of health (17). Health literacy can either be defined in a complex approach (the interactive and critical levels defined by Don Nutbeam), where multiple levels, skills, views etc. are included or in a more simple tangible way where it only comprises the basic individual skills needed to navigate the healthcare system and to understand health-related information (18). The authors of this paper have taken the simple approach when defining and assessing health literacy. Elderly people with a chronic disease like for instance chronic obstructive pulmonary disease (COPD) are at risk of having a low level of health literacy and of not receiving the health care they need (19). The literature describing the connection between COPD and health literacy is rather limited. Three very recent studies have investigated the connection between health literacy and various health outcomes among patients with COPD; one study found that a low level of health literacy seems to be associated with poorer health outcomes, including a high rate of hospitalisations, among patients with COPD (20). The other study found that patients with COPD, whose health literacy level is low often have less knowledge of their condition, are less well managed and have a poorer overall health status than
more health-literate patients with COPD (21). The third study emphasises that health literacy seems to play a crucial role in chronic disease self-management, and good doctor–patient communication is essential to support self-management among patients with COPD (22). The same study points out that to achieve better health outcomes among patients with COPD requires recognition of the nature and extent of the problem and proper screening instruments for identifying those whose health literacy level need to be heightened (22). This is, however, a challenging task, as the lack of consensus about the definition of health literacy causes disagreement about how it should be measured (1). Objective screening instruments to measure health literacy have been developed, but are criticised for not capturing the complexity of the concept of health literacy (1, 15); therefore, the development of more recent screening instruments have focused on assessing the higher, more complex level of health literacy in a more subjective manner (23, 24). To date the instruments most widely used to measure health literacy are the Test of Functional Health Literacy in Adults (TOFHLA) (25) and the Rapid Estimate of Adult Literacy in Medicine (REALM) (26). In 1995, the TOFHLA was developed as a screening instrument to measure the level of functional health literacy (25). Functional health literacy, as measured in the TOFHLA, is defined as basic reading, writing, and numeracy skills applied in a healthcare setting, and it constitutes the foundation for health literacy on which a variety of complementary and advanced skills can be built (17). However, the TOFHLA is only available in an American and Spanish version, and there is no standardised way to measure health literacy in most European countries (10). As a result, the research into functional health literacy among the Danish population is also in an infant stage. It is important to identify people vulnerable to low health literacy, so that medical counselling and education efforts regarding medications and chronic disease management can be tailored to their needs (27). The full-length American standardised version of the TOFHLA is well described in the existing literature and has been used on various populations and health conditions to assess the ability to read healthrelated materials; therefore, this paper describes how this original version was translated and adapted for use in a Danish population based on a sample of patients diagnosed with COPD.
Methods Procedures The original Spanish version of TOFHLA was translated and adapted for the setting and culture of Puerto Rico in a study from 2010 (28). The Puerto Rican study conducted © 2015 Nordic College of Caring Science
Validation of TOFHLA the cross-cultural adaptation process according to international guidelines defined by Beaton et al. (29), so the authors of this paper chose to translate and adapt the original American version of the TOFHLA for the Danish setting and culture, also by following the guidelines for cross-cultural adaptation as defined by Beaton et al. (29). The American TOFHLA consists of two parts with a total of 67 items; the first part comprises 17 items concerned with numeracy skills and the second part comprises 50 items concerned with reading comprehension skills. The reading comprehension part is divided into three passages: passage A concerned with x-ray preparation, passage B concerned with Medicaid rights and responsibilities and passage C concerned with a hospital consent form. The structure, content and intent of these 67 items in the American TOFHLA were maintained in the Danish TOFHLA, which also made it possible to maintain the scoring system of the American TOFHLA in the Danish TOFHLA. The total score for the American TOFHLA is divided into three levels: inadequate (score: 0–59), marginal (score: 60–74) and adequate (score 75–100) (25). The cross-cultural adaptation process and evaluation of cultural equivalence should be carried out according to the following six stages defined by Beaton et al. (29): Stage I: Two forward translations of the instrument from the original language into the target language. Stage II: Synthesis of the two translations produced in stage I. Stage III: Two back-translations from target language back to original language. Stage IV: Expert committee and production of prefinal version. Stage V: Pretest of prefinal version. Stage VI: Consistency and reliability. In the following, it will be described how the American TOFHLA was translated and adapted into a Danish version by following the six stages defined by Beaton et al. (29). Stage I in our study. The American TOFHLA was translated from its original language (English) into the target language (Danish) by two different translators – producing two different Danish versions of the TOFHLA: T1 and T2. The two translators were selected on the criteria suggested by Beaton et al. (29). Time estimation–1–2 working days (considered to be 8– 10 hours) per translator depending on the amount of modifications made, and how easy it is to find solutions to cultural challenges. Stage I also depends on the correspondence between the American healthcare system and the healthcare system at the target location. Stage II in our study. The two different Danish versions of the TOFHLA, T1 & T2, produced in stage I, were © 2015 Nordic College of Caring Science
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synthesised into one joint translation T12. A written report that thoroughly documents the synthesis process was developed. The written report addresses each difference between T1 and T2 and the reasons for the solution used in the T12 joint version of the Danish TOFHLA. Time estimation–1 work day per translator. Stage III in our study. The T12 joint Danish version of the TOFHLA was translated from the target language (Danish) back to the original language (English) by two different translators – producing two different back-translations BT1 and BT2. The two back-translators were selected on the criteria suggested by Beaton et al. (29). Time estimation–½–1 work day per translator. Stage IV in our study. The expert committee consisted of: A methodologist, a healthcare professional, all the translators and the researcher. The expert committee reviewed following material from previous stages: the American TOFHLA, each translation (T1, T2, T12, BT1 and BT2) together with the corresponding written reports (explaining the rationale behind decisions made at earlier stages). The primary objective of the expert committee was to explore the idiomatic, semantic, conceptual and experiential equivalence between the American and the Danish version of the TOFHLA. The expert committee compared the American TOFHLA with the T12 joint version of the Danish TOFHLA to evaluate if the intention in the American TOFHLA has been preserved in the Danish TOFHLA. Furthermore, they also compared the back-translations BT1 and BT2 with the American TOFHLA to ensure that the Danish TOFHLA is reflecting the same item content as the American TOFHLA. The main task of the expert committee was to reach consensus on discrepancies and produce a prefinal version of the Danish TOFHLA. Time estimation–The expert committee should expect to meet for ½–1 work day to discuss the translations and to reach a prefinal version (this is without accounting for preparation time prior to the expert committee meeting). Stage V in our study. The prefinal Danish version of TOFHLA was pretested on 42 patients with COPD to ensure reliability and consistency of the instrument. Time estimation–5–6 patients with COPD per work day. Stage VI in our study. Face validity was assessed entirely based on observations made during the pretest in stage V. The Cronbach’s alpha coefficient was calculated to
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analyse the internal consistency and reliability of the Danish TOFHLA, based on the data collected in the pretest. Finally, item to scale correlations of all 67 items was explored by Pearson’s correlation coefficient.
Participants in the pretest A consecutive sample of 42 Danish participants with COPD were selected from the pulmonary outpatient clinic at Aalborg Hospital (Aalborg Municipality) and the Health Centre in Hjørring (Hjørring Municipality), which are both located in the area of Northern Jutland, Denmark. This area serves almost 45 000 people with COPD (30), which represent a broad socio-demographic range. The participants were selected using consecutive sampling, which seeks to include all accessible subjects at multiple data collection sites, in this case the outpatient clinic at Aalborg Hospital and the Health Centre in Hjørring. At each site, a healthcare professional initiated contact with all accessible subjects and provided them with a short written description (developed by the researcher) explaining the process as well as the requirements of participants should they agree to participate in the pretest of the Danish TOFHLA. The healthcare professionals were instructed to consider the following criteria when inviting potential subjects to participate in the pretest. Inclusion criteria. Diagnosis of COPD (based on the selection by the two healthcare professionals and afterwards confirmed by self-report by the participant to the researcher), adult, both men and women, pregnant or nonpregnant and able to read and understand Danish as judged by the researcher. Exclusion criteria. Diagnosis of dementia (based on the selection by the two healthcare professionals and afterwards on observation by the researcher), blindness or being too ill to participate, unable to understand the informed consent procedure as judged by the researcher, unable to read or understand Danish also as judged by the researcher. If a subject agreed to participate, the researcher initiated the actual data collection process by ensuring that the participant was suitable for inclusion in the pretest. All participants were orally informed about the purpose of the study and about their rights to withdraw from the study at any time during the study. The collection of relevant data was carried out at the most convenient times for the participants either at the setting where they received health services or in their own homes. Confidentiality and privacy conditions were assured at all times during the data collection process.
Data collection in the pretest Two types of methods were used to collect relevant data for statistical analysis in the pretest (stage VI in our study): 1 The researcher conducted a face-to-face interview with each patient with COPD to collect the following demographic data: sex, age, marital status, living situation, education level, employment and COPD status. 2 Each patient with COPD completed the Danish TOFHLA. The Danish TOFHLA consists of a 17-item numeracy part and 50-item reading comprehension part–constructed just like the American TOFHLA (25). The numeracy part of the Danish TOFHLA assesses the participant’s ability to understand financial assistance, keep a clinical appointment, understand instructions for taking medication, etc. A participant could, for example, be asked to read an appointment reminder card or prescription medication instructions, and subsequently, he/she could be asked about what had been read. In the Danish TOFHLA, the test of reading comprehension is conducted as a modified cloze procedure in which random words are deleted from a reading passage (31). In this case, every fifth to seventh word is deleted in healthrelated reading passages, and the participant then selects the most fitting word from a list of four possible words. The total scores for the Danish TOFHLA test are divided into three levels: inadequate (score: 0–59), marginal (score: 60–74) and adequate (score 75–100)–just like the American TOFHLA (25).
Data analysis Results obtained from the basic demographic interview were entered into the statistical software SPSS version 21 (32). Various statistics were performed on these results to describe the study group in terms of mean, standard deviations, frequency, percent, etc. The face validity was assessed during the pretest based on observations made by the researcher. The internal consistency of the Danish TOFHLA was analysed using the Cronbach’s alpha coefficient. This consisted of an overall analysis as well as analysis on the two subcategories (reading comprehension and numeracy). Following the criteria for reliability set by Houser (33), an instrument is considered reliable if Cronbach’s alpha exceeds a value of 0.7. Finally, item to scale correlations of all 67 items was assessed using Pearson’s (Point-Biserial) correlation coefficient. This also consisted of an overall analysis as well as analysis on the two subcategories (reading comprehension and numeracy). Pearson values of 0–0.2 were considered weak correlations, 0.2–0.5 medium correlations and 0.5–1 high correlations (34).
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Validation of TOFHLA
Results Our sample comprised 42 Danish patients with COPD of whom 22 were women and 20 were men. The mean age in the sample was 68.7 years (range 34–86 years) with a standard deviation of 11.49. Of the 42 participants, 42.8% had completed 9th or 10th grade or less, whereas 14.3% had a high school education and 4.8% reported having education above high school. Of all the participants, 38.1% reported being skilled workers. The basic demographics of the 42 participants are shown in Table 1. The basic demographics are relatively balanced among the participants with 22 women and 20 men, 19 participants reported not having a partner and 23 reported having a partner. 57.1% of the participants were recruited from Aalborg Hospital, and 42.9% were recruited from Hjørring Health Centre. However, only 28.6% of the participants reported living in the city, in this case the city of Aalborg or Hjørring, and 71.4% of the participants reported living outside the city, in this case defined as smaller villages situated in the area surrounding Aalborg and Hjørring. Furthermore, the distribution of educational levels is skewed as only approximately 19% had completed high school or had a higher education. It should be noted that the participants were asked about their COPD stage, and only four of the 42 participants could provide a correct answer to this question. Table 1 Basic demographics of the 42 participants Number of participants Age
42 Mean = 68.7 (range 34–86 years)
Sex Men Women Recruitment Hospital Health Centre Living situation In the city In rural area Civil status Married or living with a partner Living alone Level of employment Full-time employment Less than 37 hours per week No job (Including those who have retired) Level of education 9th or 10th grade or less (some only completed 7th grade) High school Higher education Skilled worker (trade, industry, office, etc.) Correct answer to question about COPD stage
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Frequency
Percent
20 22
47.6 52.4
24 18
57.1 42.9
12 30
28.6 71.4
23 19
54.8 45.2
3 2 37
7.1 4.8 88.1
18
42.8
6 2 16 4
14.3 4.8 38.1 9.5
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As seen in Table 2, 11 patients with COPD were categorised as having an inadequate level of health literacy with a mean health literacy score of 47.09, 8 were categorised as having a marginal level of health literacy with a mean health literacy score of 67.38, and 23 were categorised as having an adequate level of health literacy with a mean health literacy score of 86.30. The mean response time for the completion of the entire Danish TOFHLA was 18 minutes and 23 seconds (17 minutes 28 seconds; 19 minutes 18 sec). In the reading comprehension component, the mean response time was 10 minutes and 44 seconds (10 minutes 10 seconds; 11 minutes 18 seconds); and for the numeracy component, it was 7 minutes and 39 seconds (7 minutes 5 seconsds; 8 minutes 12 seconds). As the American healthcare system is very different from the Danish system, passage B in the American TOFHLA, which concerns the American Medicaid insurance system, had to be modified to fit the structure of the Danish healthcare system in the Danish version. In order to translate and adapt the instrument for the Danish language and culture, passage B in the Danish version of TOFHLA concerns the Danish health insurance system called ‘health insurance Denmark’. It was possible to maintain the structure and intent of passage B, in spite of this change from the American Medicaid insurance system to the Danish ‘health insurance Denmark’; sentences and lists of words were constructed in a manner almost identical to that in the American TOFHLA. Moreover, item 16 and 17 in the numeracy part, concerning financial support in the American healthcare system, were modified to fit the Danish healthcare system. The first 15 items in the numeracy part and passage A and C in the reading comprehension part of the American TOFHLA were almost directly translated into Danish, only with some minor alterations of words and construction of sentences suitable to the Danish language. The expert committee found that all 67 items in the Danish TOFHLA measured health literacy in the same manner as the 67 items in the American TOFHLA (conceptual equivalence). They also found that the
Table 2 Distribution of health literacy score Obs (n) Total HL Score 42 HL score numeracy part 42 HL score reading 42 comprehension part HL score by health literacy category Inadequate 11 Marginal 8 Adequate 23
Mean HL
SD
Min
Max
72.43 38.12 34.31
18.14 9.29 10.63
29 18 2
95 50 48
47.09 67.38 86.30
8.84 3.54 6.47
29 62 76
59 73 95
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experience and knowledge of health literacy (experiential equivalence) did not differ much between the Danish and the American culture prior to completing the TOFHLA. The American TOFHLA does not contain any words or phrases specific or distinct to the American language only – all items could be translated into Danish without altering their intent – so the expert committee found that the intent of words and sentences is the same in the TOFHLA regardless of the language being American or Danish in their evaluation of the translation and adaptation process. The face validity of the Danish TOFHLA was satisfying, subjectively judged by the researcher. The internal consistency of the Danish TOFHLA was determined to 0.943 by the Cronbach’s alpha coefficient. This indicates that the criterion for reliability of the Danish version is fulfilled (>0.7 as set by Houser (33)). When calculated for the two subcategories, the following reliabilities were observed: numeracyalpha = 0.750 and reading comprehensionalpha = 0.940. Item to scale correlations were assessed for all 67 items individually in the Danish TOFHLA using the Pearson’s (Point-Biserial) correlation coefficient; 62 items showed a medium or high correlation with values > 0.2 and 5 items in the reading comprehension part showed a weak correlation with values < 0.2. The average (mean) strength of correlation for all 67 items combined was determined to 0.4 by Pearson’s coefficient. When calculated for the two subcategories, the following average strength of correlations was observed: numeracyPearson= 0.4 and reading comprehensionPearson= 0.5.
Discussion In our study, we translated and adapted the full-length American standardised version of the TOFHLA into a Danish version. The Danish TOFHLA was pretested on 42 patients with COPD to ensure reliability and consistency of the instrument. We assessed the face validity, internal consistency, and item to scale correlations of the Danish TOFHLA, and based on this, we found the reliability and consistency of the instrument to be satisfying.
Strengths and limitations of using consecutive sampling as a data collection method The baseline characteristics, of the 42 patients with COPD included in our study, were compared with factual information on risk factors in COPD to assess if our sample is representative of patients with COPD in Denmark. This comparison shows identical patterns: slightly more women are diagnosed with COPD, patients are > 60 years, and have a low educational level (35–37). The sample of 42 patients with COPD is a moderately small, but considering that the purpose of this paper was to
pretest a screening instrument already widely used and acknowledged in the literature, we argue that it is reasonable to assume that the sample is sufficiently representative to state that the Danish TOFHLA is ready for application in future research projects which test levels of functional health literacy in an elderly Danish population at risk of chronic diseases.
Strengths and limitations of the actual translating and adaptation process An important advantage of translating and adapting the original American TOFHLA into a Danish version instead of developing a new screening instrument is that the American TOFHLA is already acknowledged in the existing literature, and it has been used numerous times on the assumption that it enjoys sufficient validity and reliability; thus making it easier to create a reliable Danish version compared to developing a completely new instrument from scratch. It would also be very time-consuming to produce a new reliable screening instrument applicable for assessing health literacy in a Danish research project. Additionally, as the original TOFHLA is the screening instrument primarily used to measure health literacy, using a translated and adapted version of the American TOFHLA will make it possible to more accurately compare the results obtained with the Danish version with the results in the literature. The translation and adaptation of the American TOFHLA into a Danish version was challenging in terms of accounting for linguistic and cultural nuances of the Danish language and the application in two very different healthcare systems. It was not possible to just do a direct translation of the American TOFHLA into the Danish version; some of the questions had to be modified in the translation and adaptation process to suit the Danish context. These modifications were discussed very carefully by the expert panel to avoid losing the original intention of the questions in the translation and modification process. Even though these modifications were made with much caution, it remains a question whether such a modification of the American TOFHLA results in reduced validity and reliability of the new Danish TOFHLA. This is why Beaton et al. (29) recommend an assessment of face validity, internal consistency, item to scale correlations etc. with the purpose of accounting for cross-cultural differences when translating and adapting an instrument from one setting and culture to another. We found the Danish TOFHLA to have sufficient face validity, internal consistency and 62 of the 67 items showed a medium or high correlation with the scale. In spite of this, however, it is still important to remember that the American setting and culture is very different from the Danish in terms of the structure and access to © 2015 Nordic College of Caring Science
Validation of TOFHLA education and health care. The Danish healthcare system emphasises equity in health with equality in (free) access to various health services, whereas health services are not free of charge in America. Some Americans are able to pay these charges, and some are not (in this case, they are offered the social healthcare program Medicaid), which produces inequity in access to health care in the American healthcare system. Moreover, there is equality in the free Danish educational system and inequity in the American educational system that is not free of charge. These differences should be considered when using the Danish TOFHLA, as the American TOFHLA is originally designed for a system with inequities in access to education and health care – very different from the Danish system. If the translation and adaptation process is conducted properly according to international guidelines and modifications are made without changing the original intention of the questions, then it is reasonable to assume that a relatively reliable screening instrument for measuring the level of functional health literacy among Danish patients with COPD has been developed. It should be noted that the construct validity of the Danish TOFHLA was not assessed. Existing objective screening instruments like the TOFHLA are criticised for not capturing the complexity of health literacy (1, 15); therefore, the development of more recent screening instruments have focused on assessing the higher, more complex level of health literacy in a more subjective manner (23, 24). The subjective instruments provide valuable information on the participants’ experiences and overall points of view related to navigating and interacting with the healthcare system. A low level of health literacy is often associated with shame and embarrassment, and objective screening instruments can make the participants’ feel very uncomfortable (15). The subjective screening instruments can be considered more ‘user-friendly’, as they focus on the participants’ subjective evaluation of access to health-related information, ability to navigate the healthcare system etc. However, the reliability of these subjective screening instruments can be questioned, as there is a risk that participants with a low level of health literacy will try to hide it, because they feel ashamed and embarrassed. Overall, the measures of health literacy still need refinement, and a next step could be use of the available objective screening instruments in synergy with the subjective ones; the results should provide the same picture, for example a participant that subjectively finds it easy to find and understand health-related information would assumingly also achieve a high score in an objective test. The very first step to truly refine the measurement of health literacy is to reach consensus on the definition and conceptualisation of this concept.
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Conclusion In this study, the full-length Danish TOFHLA demonstrates strong consistency with the original American TOFHLA. Based on the cross-cultural transformation process and satisfying results in terms of face validity, internal consistency, and item to scale correlations, a reliable Danish version of the original American TOFHLA has been successfully developed for use in the Danish setting and culture. The Danish TOFHLA is now ready for application in future research projects, which test levels of functional health literacy in an elderly Danish population at risk of chronic diseases. The evolvement in the measurement of health literacy is still ongoing, as there is a need to refine existing methods. Until recently, there has been a total lack of instruments for assessing health literacy in Scandinavia; hopefully, this development of the Danish TOFHLA will promote further research within the field of health literacy in Scandinavia and other European countries.
Acknowledgements The authors thank the pulmonary outpatient clinic at Aalborg Hospital and Hjørring Health Centre for their collaboration. The authors especially wish to thank the two healthcare professionals, Carl Nielsen and Lone Jessen, for establishing the initial contact with the patients with COPD.
Author contributions Lisa Hæsum was responsible for data collection, data analysis and wrote the manuscript as first author. Lars Ehlers primarily provided feedback on the selection of statistical analyses, and also critically revised the manuscript. Ole Hejlesen primarily contributed as a discussion partner during the design of the study and analysis process. He also had the role of a critical reviser of the manuscript.
Ethical approval The present study is conducted in accordance with the Helsinki Declaration. The study is a part of a Ph.D. study on the influence of health literacy in telehomecare, which is conducted as a part of a large scale telehomecare project, TeleCare North. The TeleCare North project has been presented to the Regional Ethical Committee for Medical Research in the North Denmark Region where it was determined that no ethical approval was necessary.
Funding No funding was sought for the study.
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