ORIGINAL RESEARCH
Health literacy, self-efficacy, and self-care behaviors in patients with type 2 diabetes mellitus Walton Bohanny, MSN, RN (Lecturer)1 , Shu-Fang Vivienne Wu, PhD, RN (Associate Professor)2 , Chieh-Yu Liu, PhD (Associate Professor)2 , Shu-Hui Yeh, PhD, RN (Professor)3 , Shiow-Luan Tsay, PhD, RN (Professor)2 , & Tsae-Jyy Wang, PhD, RN (Associate Professor)2 1
Department of Nursing, College of Marshall Islands, Majuro Atoll, Marshall Islands Department of Nursing, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan 3 Department of Medical Research and Development, Show Chwan Memorial Hospital in Chang Bing & Department of Nursing, Central Taiwan University, Taichung, Taiwan 2
Keywords Diabetes mellitus; health literacy; self-care behavior; self-efficacy; vulnerable populations. Correspondence Tsae-Jyy Wang, PhD, RN, Department of Nursing, National Taipei University of Nursing and Health Science, Taipei, Taiwan. Tel: 886-2-28227101; Fax: 886-2-28213233; E-mail: [email protected] Received: May 2011; accepted: August 2011 doi: 10.1111/1745-7599.12017
Abstract Purpose: The study purpose was to explore the relationships among health literacy, self-efficacy, and self-care behaviors of patients with type 2 diabetes. Data sources: A cross-sectional study with a descriptive correlational design was conducted. Patients (N = 150) with type 2 diabetes were recruited from diabetes clinics in the Marshall Islands. Levels of health literacy, self-efficacy, and self-care behaviors were assessed by a questionnaire. Conclusions: Health literacy, receiving diabetes education, and employment status together explained 11.8% of the variance in self-efficacy (F(3,147) = 7.58, p < .001). Patients who had higher health literacy, received more diabetesrelated education, were currently employed and had better self-efficacy. Selfefficacy and marital status together explained 16.7% of the variance in selfcare behaviors (F(2,148) = 15.96, p < .001). Patients who had higher self-efficacy and who were married had better self-care behaviors. Implications for practice:: Strategies are needed to incorporate the concept of self-efficacy in the design of diabetes education to promote patients’ self-care behaviors, with an emphasis on dealing with hyper- or hypoglycemia, following the diet plan, and checking blood sugar levels as recommended. Diabetes education material that requires a lower literacy level may be needed for older or unemployed adult populations.
Introduction Type 2 diabetes is an epidemic that affects close to 285 million people worldwide (International Diabetes Federation, 2009). Without appropriate management, type 2 diabetes can cause serious complications such as cardiovascular diseases, neuropathy, retinopathy, and neuropathy. Self-care behaviors are essential for controlling type 2 diabetes’ progression and for preventing long-term complications (American Diabetes Association, 2010). Because patients are expected to integrate a complex set of selfcare behaviors into their daily routines (Chatterjee, 2006; Funnell et al., 2010), it is essential to know the factors that influence type 2 diabetes patients’ performance in these self-care behaviors. Therefore, the purpose of this study was to explore the factors related to the self-care
behaviors of patients with type 2 diabetes. Specifically, we sought to explore the relationships among health literacy, self-efficacy, and self-care behaviors in an urban, diverse population of type 2 diabetes patients. The results of the study are relevant to the understanding of preconditions that enable type 2 diabetes patients to successfully cope with the disease and its diverse consequences.
Background Self-care behavior refers to “decisions and actions that an individual can take to cope with a health problem or to improve his or her health” (Breslow, 2002, p. 1). Self-care behaviors that individuals must learn or modify to effectively cope with their type 2 diabetes include
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eating healthily, exercising regularly, adhering to medical treatments, self-monitoring of blood glucose levels, and developing healthy coping skills (Funnell et al., 2010). Self-efficacy is “the belief in one’s capabilities to organize and execute the courses of action required to manage prospective situation” (Bandura, 1995, p. 2). How people behave can often be better predicted by the beliefs that they hold about their capabilities than by what they are actually capable of accomplishing because self-efficacy perceptions help determine what individuals do with the knowledge and skills that they have (Bandura, 1997). Self-efficacy was found to be an important predictor of self-care behaviors in type 2 diabetes patients (Sarkar, Fisher, & Schillinger, 2006; Wu et al., 2007; Xu, Toobert, Savage, Pan, & Whitmer, 2008). The correlations between self-efficacy and self-care behaviors of type 2 diabetes were 0.45 (p < 0.01) and 0.50 (p < 0.01) in Wu et al. (2007) and Xu et al. (2008), respectively. The Sarkar et al. (2006) study showed that, with each 10% increase in the self-efficacy score, patients were more likely to report a more optimal diet 0.14 day/week, more exercise 0.09 day/week, and an odds ratio of 1.16 for self-monitoring blood glucose and 1.22 for foot care after adjusting for duration of diabetes, insulin use, race/ethnicity, and literacy score. Another factor that seems to affect self-care behaviors is health literacy. Health literacy is “the degree to which individuals have the capacity to obtain, process and understand basic health information and services needed to make appropriate health decisions” (U.S. Department of Health and Human Services, 2000, p. 2). These are skills that all people need, for instance, to find their way to the right place in a hospital, fill out medical and insurance forms, and communicate with healthcare providers. Poor literacy and numeracy skills can result in difficulties in interpreting glucose reading, adjusting medication, calculating carbohydrate intake, and performing other self-care activities among type 2 diabetes patients (Wolff et al., 2009). Limited health literacy was associated with lower diabetes knowledge and awareness of complications (Kim, Love, Quistberg, & Shea, 2004; Powell, Hill, & Clancy, 2007), poor glycemic control (Ishikawa & Yano, 2011; Powell et al. 2007; Schillinger, Barton, Karter, Wang, & Adler, 2006; Tang, Pang, Chan, Yeung, & Yeung, 2008), and more diabetes-related complications (Schillinger et al., 2002). The findings from previous studies support that health literacy is associated with diabetes outcomes. The unique contributions of health literacy on self-efficacy and self-care behaviors, however, are not as well understood. Patients with higher health literacy may feel more confident in their ability to perform self-care behaviors and may be more likely to actually perform them. Additional work is needed to explore the relation496
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ships among health literacy, self-efficacy, and self-care behaviors in patients with type 2 diabetes.
Method Design We used a cross-sectional descriptive correlational design to explore the factors influencing self-care behaviors of type 2 diabetes patients, including demographics, disease characteristics, health literacy, and self-efficacy.
Participants and setting A convenience sample of 150 type 2 diabetes patients was recruited from a public diabetes clinic on Majuro Atoll, the Marshall Islands. Inclusion criteria were having (a) age above 25, (b) diagnosis of type 2 diabetes, and (c) ability to speak and understand Marshallese. Exclusion criteria were having (a) impaired vision or (b) a psychiatric illness. Initially, 155 eligible type 2 diabetes patients were recruited. Of these, five dropped out because of time constraints (n = 2) or difficulty in completing the study questionnaire (n = 3).
Sample size The desired sample size was estimated based on a multiple linear regression model, by using G*power software (version 3.1; Faul, Erdfelder, Lang, & Buchner, 2007). Taking into account the number of possible predictors (n = 10) in this study, a sample size of 118 was required to have approximately 80% power to detect a medium effect size of F2 = 0.15 with a 0.05 significant level. A medium effect size was estimated based a 0.45 correlation between self-efficacy and self-care behaviors as reported by Wu et al. (2007). A total of 150 participants was recruited and completed the study questionnaire.
Data collection Data were collected between October 2008 and March 2009 by 25 trained data collectors, including researchers, nurses, and senior nursing students. The data collection took place either at a diabetes clinic or at the participants’ residences. After obtaining informed consent, participants answered the study questionnaires, which included demographic and disease questions, the Shortform Test of Functional Health Literacy in Adults (S-TOFHLA), the Diabetes Management Self-Efficacy Scale (DMSES), and the Summary of Diabetes Self-Care Activities (SDSCA). The S-TOFHLA, DMSES, and SDSCA were translated and back-translated until the concordance in meaning between the English and Marshallese
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versions was achieved. To establish the stability of the study questionnaires, the first 30 participants were asked to complete the study questions twice, 2 weeks apart.
Validity and reliability of instruments The S-TOFHLA (Baker, William, Parker, Gazmarmarian, & Nurss, 1999) was used to measure patients’ health literacy. The scale consists of four numerical items and 36 reading comprehension items, assessed by a cloze technique. Seven points and two points are given for each correctly answered numerical item and reading comprehension item, respectively. Scores are summed to give a total range from 0 to 100; higher scores represent greater health literacy. The cutoff points were 0–53 for inadequate, 54–66 for marginal, and 67–100 for adequate health literacy. The original scale showed adequate internal consistency and convergent validity. Cronbach’s alphas were 0.68 and 0.97 for the four numeric items and the 36 cloze items, respectively. The correlation (Spearman) between the S-TOFHLA and the Rapid Estimate of Adult Literacy in Medicine was 0.80 (Baker et al., 1999). For the Chinese version, Cronbach’s alphas were 0.68 for the four numeric items and 0.97 for the 36 cloze items (Tang et al., 2008). In the current study, Cronbach’s alphas were 0.83 for the overall scale, 0.67 for the four numeric items, and 0.81 for the 36 cloze items. The test–retest reliability coefficient was 0.83 (p < 0.01). The DMSES assesses the extent to which respondents are confident in managing their blood sugar, diet, and exercise (Stanford Patient Education Research Center, 2008). Each item is responded to on a 10-point Likert scale. Scores are averaged to present a total score of the scale ranged from 0 to 10. Higher scores indicate better self-efficacy in diabetes self-management. The instrument has demonstrated good internal consistency and test–retest reliability in previous studies. For the Australia/English version, the Cronbach’s alpha was 0.91, and the test–retest reliability coefficient was 0.76 (McDowell, Courtney, Edward, & Shortridge, 2005). For the Chinese version, the Cronbach’s alpha was 0.93, and the test–retest reliability was 0.86 (Wu et al., 2007). The Cronbach’s alpha was 0.84 in the current study. The test– retest reliability was 0.86 (p < 0.01). The SDSCA consists of 12 items to assess the frequency of performing diabetes self-care tasks in the following five regimen areas: diet, exercise, blood glucose testing, foot care, and smoking status (Toobert, Hampson, & Glasgow, 2000). Participants were asked to report on how many of the last 7 days were spent in performing the self-care activity as indicated by the item. A mean score was cal-
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culated for each of the five areas of self-care behaviors, except smoking, with a possible range from 0 to 7. Participants were also asked to indicate whether they were a smoker and the number of cigarettes that they smoked per day. The original scale showed adequate internal consistency and test–retest reliability. The Cronbach’s alphas were 0.75 for the overall scale, 0.65 for diet, 0.84 for exercise, and 0.84 for blood testing subscales. The test– retest reliability coefficient was 0.70 for the overall measure of self-care (Johnson-Brooks, Lewis, & Garg, 2002). In the present study, the Cronbach’s alphas were 0.63 for the overall scale and 0.79, 0.67, 0.72, and 0.80 for the diet, exercise, blood testing, and foot-care subscales, respectively. The test–retest reliability coefficient was 0.73 (p < 0.01) for the overall scale.
Ethical considerations The study was approved by the National Taipei University Institutional Review Board (IRB No. 97A166) and the Secretary of the Ministry of Health, Marshall Islands. Each participant received an oral explanation of the research and signed a consent form before participation.
Data analysis Data were analyzed using the SPSS Version 17.0 software statistical package (SPSS, Inc., Chicago, IL, 2008). Percentages, means, and standard deviations (SDs) were used to describe the participants’ demographics and study variables. Independent t-tests, one-way analysis of variance (ANOVA), and Pearson product moment correlations were used to examine the relationships among demographics, disease variables, health literacy, selfefficacy, and self-care behaviors. Stepwise multiple regressions were used to determine the important predictive factors of self-efficacy and self-care behaviors. In the first regression model, demographics (age, gender, marital status, education level, employment status, and living arrangement), disease characteristics (years of diabetes and diabetes education), and health literacy were entered as the dependent variables for predicting self-efficacy. In the second regression model, demographics, disease characteristics, health literacy, and self-efficacy were entered as the dependent variables for predicting self-care behaviors. Gender, marital status, education level, employment status, and living arrangement were measured categorically, these variables were dummy coded prior to analysis. Normality and independent assumptions of the regression analysis were examined through standardized residual plots and collinearity statistics, and neither assumption was violated.
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Table 1 Demographic characteristics of the sample and comparisons of health literacy, self-efficacy, and self-care behavior among different characteristics (N = 150) Health literacy n (%)
Mean(SD)
80(53.3) 70(46.7)
78.1(12.8) 75.2(15.9)
45(30.0) 105(70.0)
73.8(16.2) 78.0(13.3)
4(2.7) 62(41.3) 66(44.0) 18(12.0)
68.3(16.8) 76.7(13.3) 76.7(13.6) 79.0(19.6)
86(57.3) 64(42.7)
74.1(15.1) 80.4(12.5)
126(84.0) 24(16.0)
77.4(14.2) 73.4(15.1)
Characteristic Gender Female Male Marital status Single Married Education level Never attend school Elementary (1–8 years) High school (9–12 years) College and above Employment status Unemployed Employed Living arrangement Living with someone Living alone
Self-efficacy t/F
Mean(SD)
1.21
Self-care behavior t/F
Mean(SD)
0.23 7.7(2.2) 7.6(2.3)
− 1.53
0.55 3.8(1.1) 3.791.1)
− 1.50 7.2(2.6) 7.9(2.0)
0.61
−2.55* 3.4(1.1) 3.9(1.1)
1.44 7.4(2.2) 7.2(2.5) 7.9(1.9) 8.2(2.4)
− 2.69**
0.34 3.5(1.2) 3.7(1.2) 3.8(1.1) 3.6(0.9)
− 3.03** 7.2(2.4) 8.3(1.7)
1.26
−1.77 3.6(1.2) 3.9(0.9)
1.83 7.8(2.1) 6.9(2.5)
t/F
0.54 3.7(1.1) 3.6(1.1)
SD, standard deviation, * p-value < .05, ** p-value < .01.
Results Participant characteristics The demographics and disease variables of the sample are presented in Table 1. Participants were mainly female (53.3%, n = 80), married (70.0%, n = 105), unemployed (57.3%, n = 88), living with family (84.0%, n = 126). The mean age of participants was 52.7 years (SD = 10.5; range = 37–79). The educational level ranged from never attended school to post-college. The majority (44%, n = 66) of participants had a high school education level. Mean length of time diagnosed with type 2 diabetes was 7.8 years (SD = 5.8; range = 0–30). Thirtythree (22%) participants had diabetes for more than 10 years. Most participants were treated with oral hypoglycemic agents (OHAs; 63.3%) and combined OHAs with insulin injections (24.7%); few received diet-only treatments (12%). Frequency (times per year) of having diabetes education ranged from 0 to 48, with a mean 8.2 (SD = 9.7). Of the participants, 29 (19.3%) indicated that they never received or gained information about diabetes complications or risk factors from either doctors or nurses.
Health literacy, self-efficacy, and self-care behaviors The participants’ S-TOFHLA scores ranged from 27 to 96, with a mean 76.78 (SD = 14.3). Using the cutoff points (0–53, inadequate; 54–66, marginal; and 67–100, adequate) to categorize participants’ literacy levels re498
sulted in 114 (76%) participants having adequate health literacy, 26 (17%) having marginal health literacy, and only 10 (7%) participants having inadequate health literacy. Participants, on average, answered correctly three (SD = 1.2) out of the four numeracy items of S-TOFLA. The most common mistakes were made in item 2 (regarding whether a blood sugar level of 160 mg/dL was normal) and item 4 (regarding the correct time for taking the medication as prescribed), with incorrect rates of 34% and 33.3%, respectively. As for the 36 reading comprehension items, participants, on average, answered 28 (SD = 5.1) items correctly. The rate for correctly answered individual items ranged from 54% to 96%. The mean score of participants’ DMSES was 7.7 (SD = 2.2; range, 0–10), indicating a high level of self-efficacy in managing diabetes. Of the participants, 24 (16%) had a self-efficacy score below 5 (possible score of 0–7), meaning that those participants were lacking in confidence in managing their diabetes. Participants reported to be least confident in dealing with hyper- or hypoglycemia, followed by a lack of confidence in following the diet plan when having to prepare or share food with others. The mean score of the SDSCA was 3.7 (SD = 1.1; range, 1–6.4), indicating that participants performed most of the self-care tasks about 4 days a week. The mean scores for the general diet, specific diet, exercise, blood sugar testing, and foot care were 4.5 (SD = 1.9), 3.9 (SD = 1.6), 4.2 (SD = 2.2), 1.4 (SD = 1.1), and 4.6 (SD = 2.8), respectively. These indicated that, during the previous week,
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Table 2 Person product moment correlation coefficients among study variables (N = 150)
Age
Years of Diabetes Health Self- Self-care diabetes education literacy efficacy behavior
Age 1 Years of diabetes 0.58*** 1 Diabetes 0.15 0.10 education Health literacy − 0.23** − 0.11 Self-efficacy 0.05 0.02 Self-care behavior 0.15 0.13
1 − 0.04 1 0.20* 0.24** 1 0.19* 0.06 0.39**
1
Diabetes education: number of diabetes related teaching classes received in the past 12 months, *p-value < .05, ** p-value < .01.
participants followed the healthy eating plan in general, ate five or more servings of fruits or vegetables, and did exercise and foot care for about 4 days. On average, the participants also did blood testing once during the last 7 days.
Relationships among demographics, disease variables, health literacy, self-efficacy, and self-care behavior factors associated with health literacy Level of health literacy (t = −2.69, p = .008) were found to be significantly higher in participants who were holding a job at the time of interview as compared to those who were unemployed (Table 1). Age was negatively associated with health literacy (r = −0.23, p = .004; Table 2). Gender, marital status, education level, living arrangement, years of diabetes, and receiving diabetes education were not related to health literacy. Factors associated with self-efficacy. Selfefficacy (t = −3.03, p = .003) was significantly higher in employed participants than unemployed participants (Table 1). Diabetes education (r = 0.20, p = .015) and health literacy (r = 0.24, p = .003) were both positively correlated with self-efficacy (Table 2). The results of stepwise regression showed that health literacy, receiving diabetes education, and employment status together explained 11.8% of the variance in self-efficacy (F(3,147) = 7.58, p < .001; Table 3). Patients who had higher health literacy, received more diabetes-related education, and who were currently employed had better self-efficacy than those who had less health literacy and diabetesrelated education and were unemployed. Among these variables, health literacy (5.0%) explained the most variance in self-efficacy, followed by diabetes-related education (3.7%) and employment status (3.1%). Age, gender, marital status, education level, living arrangement, and years of diabetes were excluded from the regression model.
Factors associated with self-care behaviors. Self-care behavior scores were found to be significantly higher in married participants than in unmarried participants (t = −2.55, p = .012; Table 1). Self-efficacy was positively correlated with self-care behaviors (r = 0.39, p < .001; Table 2). The results of stepwise regression showed that self-efficacy and marital status together explained 16.7% of the variance in self-care behaviors (F(2,148) = 15.96, p < .001; Table 3). Patients who had higher selfefficacy and who were married had better self-care behaviors than those who had lower self-efficacy and who were not married. Self-efficacy and marital status each explained 14.9% and 1.8% of the variance in self-care behaviors, respectively. Age, gender, education level, employment status, living arrangement, years of diabetes, diabetes education, and health literacy were excluded from the regression model. Figure 1 presents the relationships among demographics, disease characteristics, health literacy, self-efficacy, and self-care behaviors with their perspective standardized regression coefficients (ß).
Discussion Health literacy, self-efficacy, and self-care behaviors Similar to what was found (8% marginal and 15% inadequate health literacy) in a previous study (Kim et al., 2004), 24% of our study participants had limited health literacy (17% marginal and 7% inadequate). Over 30% of the study participants made mistakes in judging their blood sugar levels and in knowing the correct time for taking their medication. They also reported being least confident in dealing with hyper- or hypoglycemia and following the diet plan when having to prepare or share food with others. As for self-care behaviors, participants reported checking their blood sugar levels less often than recommended. During the prior 7 days, they checked their blood sugar on only 1.5 (SD = 1.8) days and did it as recommended by their healthcare providers on only 1.2 (SD = 1.5) days. These results indicate that checking and judging blood glucose levels, taking diabetes medications correctly, dealing with hyper- or hypoglycemia, and following the diabetic diet plan are areas that need to be reinforced in future diabetes education.
Relationships among demographics, disease variables, health literacy, self-efficacy, and self-care behavior factors associated with health literacy Our result supports a previous finding that older patients had lower health literacy (Kim et al., 2004; Schillinger et al., 2006). Age is a factor that needs to be considered when reading comprehension is required for 499
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Table 3 Results of stepwise regressions on self-efficacy and self-care behavior (N = 150) Model
Dependent variables
1
Self-efficacy
2
Self-care behavior
*
Independent variables
ß
R2
Adjusted R2
F
VIF
Health literacy Diabetes education Employment Employed versus unemployed Self-efficacy Marital status Married versus single
0.20** 0.21**
0.136
0.118
7.58***
1.05 1.00
0.178
0.167
15.96***
0.19* 0.37*** 0.15*
1.05 1.02 1.02
p-value < .05, ** p-value < .01, *** p-value < .001.
0.15* Marital status
Health literacy
0.20*
0.21** Diabetes education
0.37*** Self-efficacy
Self-care behavior
0.19* Employment status
* p < .05, ** p < 0.01, *** p < 0.001
Figure 1 Relationships among demographics, health literacy, selfefficacy, and self-care behavior in patients with type 2 diabetes mellitus.
certain health or medical tasks. In a busy clinic, healthcare providers often rely on pamphlets or written materials to provide patient education. This may leave the older patients with poor health literacy at a substantial disadvantage. Moreover, we found that unemployed participants had lower health literacy and less confidence in managing their diabetes than those who were employed. This might be because outreach health programs and diabetes screening activities in Marshall Islands often target the working population because of its accessibility and leaves out unemployed diabetes patients. In contrast to what was reported in previous studies (Berkman et al., 2004; Kim et al., 2004; Schillinger et al., 2006), we found no statistically significant differences in levels of health literacy among participants of different educational levels. This may be because of the lack of variation in the education levels of the current sample. The inconsistent findings need to be further investigated. Factors associated with self-efficacy. We found that health literacy is positively associated with selfefficacy in diabetes self-care. This has also been reported in previous studies (Cavanaugh et al., 2008; DeWalt, Boone, & Pignone, 2007). Additionally, health literacy, diabetes education, and employment status were impor500
tant predictors of diabetic patients’ self-efficacy. This result suggests that clinicians who try to enhance diabetes patients’ self-efficacy should take patients’ literacy levels, received diabetes-related health education, and employment status into consideration. Proper patient education will often bring positive outcomes because of better understanding and cooperation with both preventive and treatment interventions among individuals with diabetes. Our results, however, showed that there was still a large proportion (20%) of patients who did not receive any information regarding diabetes complications and risk factors from their healthcare providers. This reminds us that extra efforts are needed to provide basic patient education in a more systemic way.
Factors associated with self-care behaviors. Our results also support the strong positive relationship between self-efficacy and self-care behaviors found in previous studies (Sarkar et al., 2006; Sousa, Zauszniewski, Musil, Lea, & Davis, 2005; Wu et al., 2007). Self-efficacy together with marital status explained 16.7% of the variance in self-care behaviors. Therefore, strategies to increase patients’ self-efficacy should be developed in the design of diabetic patients’ education for enhancing proper diabetes self-care behaviors among type 2 diabetes patients. Similar to the results of the Kim et al. (2004) study, we found no direct relationship between health literacy and self-care behaviors. Although health literacy was positively associated with self-efficacy, and self-efficacy was positively associated with self-care behaviors, the correlation between health literacy and self-care behaviors was statistically insignificant. These results indicate that health literacy is an antecedent to self-efficacy and that the influence of health literacy on self-care behaviors may be completely mediated through self-efficacy. However, evidence to date is still too sparse to enable a definite conclusion. The specific pathway between health literacy and self-care behaviors should be further investigated. Additionally, our study participants were generally well educated and with high health literacy. Perhaps, in a follow-up study, proportionally representing different
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levels of education and health literacy may offer some more insight to the relationships among health literacy, self-efficacy, and self-care behaviors in diabetics.
Study limitations Limitations of the study include the use of a convenience sample, a cross-sectional design, and 25 data collectors. Because nonprobability sampling was used, the results of the study cannot be generalized to all diabetic patients. Specifically, our participants were younger and more educated than participants in previous studies (Redmond et al., 2006; Tang et al., 2008; Wu et al., 2007). Thus, the conclusions and recommendations may not be applicable to patients who are older and who are less educated. In addition, the causal relationships among study variables are difficult to establish through cross-sectional observational data. Finally, because of the geographic distance, we had to use 25 trained personnel to collect data from the participants’ homes. The large number of data collectors may introduce some inconsistency in data collection.
Conclusion and relevance to clinical practice Our results showed that type 2 diabetes patients who had the worst health literacy and received less diabetesrelated education had the worst self-efficacy in self-care. Therefore, interventions to boost self-efficacy should take the patients’ health literacy into consideration. Unemployed older adults were at the greatest risk for inadequate health literacy. Diabetes education material that requires lower literacy levels may be needed for older or unemployed adult populations. In addition, outreach health activities and diabetes screening programs should be extended from working populations to a broader community to reach unemployed individuals. Regarding health literacy, patients showed the most difficulties in accurately interpreting glucose reading and knowing the correct times for taking medication. Therefore, when working with type 2 diabetes patients, nurses should place an emphasis on teaching glucose reading interpretations and the correct times for taking medication. Moreover, our results showed that self-efficacy is an important predictor of self-care behaviors. Nurses should consider incorporating the concept of self-efficacy in designing self-care behavior-enhancing interventions and diabetes education programs. Special attention should be paid to boosting patients’ confidence in dealing with hyper- or hypoglycemic situations, preparing food according to diabetes dietary plans, and checking blood sugar levels as recommended.
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Acknowledgments Funded by the National Science Council, Taiwan ROC (99–2511-S-227–011). The authors thank all the participants in this study.
References American Diabetes Association. (2010). Standards of medical care in diabetes—2010. Diabetes Care, 33, S11–S61. Baker, D. W., William, M. V., Parker, R. M., Gazmarmarian, J. A., & Nurss, J. (1999). Development of a brief test to measure functional health literacy. Patient Education and Counseling, 38, 33–42. Bandura, A. (1995). Self-efficacy in changing societies (p. 2). Cambridge, UK: Cambridge University Press. Bandura, A. (1997). Self-efficacy: The exercise of control. New York, NY: W.H. Freeman. Berkman, N. D., DeWalt, D. A., Pignone, M. P., Sheridan, S. L., Lohr, K. N., Lux, L., . . . Bonito, A. J. (2004). Literacy and health outcomes. Evidence report/technology assessment. Rockville, MD: Agency for Healthcare Research and Quality. Retrieved from http://www.ahrq.gov/clinic/ epcsums/litsum.pdf Breslow, L. (2002). Self-care behavior. Encyclopedia of Public Health. Farmington Hills, MI: Gale Group. Retrieved from http://www.enotes.com/ public-health-encyclopedia/self-care-behavior Cavanaugh, K., Huizinga, M. M., Wallston, K. A., Gerbretsadik, T., Shintani, A., Davis, D., . . . Rothman, R. L. (2008). Association of numeracy and diabetes control. Annals of Internal Medicine, 10, 737–746. Chatterjee, J. S. (2006). From compliance to concordance in diabetes. Journal of Medical Ethics, 32, 507–510. DeWalt, D. A., Boone, R. S., & Pignone, M. P. (2007). Literacy and its relationship with self-efficacy, trust, and participation in medical decision making. American Journal of Behavior, 31, 27–35. Faul, F., Erdfelder, E., Lang, A.-G., & Buchner, A. (2007). G*Power 3: A flexible statistical power analysis program for the social, behavioral and biomedical sciences. Behavior Research Methods, 39, 175–191. Funnell, M. M., Brown, T. L., Childs, B. P., Haas, L. B., Hosey, G. M., Jensen, B., . . . Weiss, M. A. (2010). National standards for diabetes self-management education. Diabetes Care, 33, S89–S96. International Diabetes Federation. (2009). Latest diabetes figures paint grim global picture. Retrieved from http://www.idf.org/latest-diabetes-figures-paintgrim-global-picture Ishikawa, H., & Yano, E. (2011). The relationship of patient participation and diabetes outcomes for patients with high vs. low health literacy. Patient Education and Counseling, 84, 393–7. doi: 10.1016/j.pec.2011.01.029 Johnson-Brooks, C. H., Lewis, M. A., & Garg, S. (2002). Self-efficacy impacts self-care and HbA1c in young adults with type 1 diabetes. Psychosomatic Medicine, 64, 43–51. Kim, S., Love, F., Quistberg, D., & Shea, J. A. (2004). Association of health literacy with self-management behavior in patients with diabetes. Diabetes Care, 27, 2980–2982. McDowell, J., Courtney, M., Edward, H., & Shortridge, L. (2005). Validation of Australian/English version of the Diabetes Management Self-Efficacy Scale. International Journal of Nursing Practice, 11, 177–184. Powell, C. K., Hill, E. G., & Clancy, D. E. (2007). The relationship between health literacy and diabetes knowledge and readiness to take health actions. The Diabetes Educator, 33, 144–151. Redmond, E. H., Burnett, S. M., Johnson, M. A., Park, S., Fischer, J. G., & Johnson, T. (2006). Improvement in A1 C levels and diabetes self-management activities following a nutrition and diabetes education program in older adults. Nutrition for the Elderly, 26, 83–101. Sarkar, U., Fisher, L., & Schillinger, D. (2006). Is self-efficacy associated with diabetes self-management across race/ethnicity and health literacy? Diabetes Care, 29, 823–829. Schillinger, D., Barton, L. R., Karter, A. J., Wang, F., & Adler, N. (2006). Does literacy mediate the relationship between education and health outcomes?
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A study of a low-income population with diabetes. Public Health Report, 121, 245–254. Schillinger, D., Grumbach, K., Piette, J., Wang, R., Osmond, D., Daher, C., . . . Bindman, A. B. (2002). Association of health literacy with diabetes outcomes. Journal of the American Medical Association, 288, 475–482. Sousa, V. D., Zauszniewski, J. A., Musil, C. M., Lea, P. J. P., & Davis, S. A. (2005). Relationships among self-care agency, self-efficacy, self-care, and glycemic control. Research and Theory for Nursing Practice, 19, 217–230. Stanford Patient Education Research Center. (2008). Diabetes Self-efficacy Scale. Retrieved from http://patienteducation.stanford. edu/research/sediabetes.html Tang, Y. H., Pang, S. M., Chan, M. F., Yeung, G. S., & Yeung, V. T. (2008). Health literacy, complication awareness and diabetic control in patients with type 2 diabetes mellitus. Journal of Advance Nursing, 62, 74–83. Toobert, D. J., Hampson, S. E., & Glasgow, R. E. (2000). The summary of diabetes self-care activities measure. Diabetic Care, 23, 943–950.
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U.S. Department of Health and Human Services, Office of Disease Prevention and Health Promotion. (2000). Quick guide to health literacy. Retrieved from http://www.health.gov/communication/literacy/quickguide/quickguide.pdf Wolff, K., Cavanaugh, K., Malone, R., Hawk, V., Gregory B. P., Davis, D., . . . Rothman, R. L. (2009). The diabetes literacy and numeracy education toolkit (DLNET) materials to facilitate diabetes education and management in patients with low literacy and numeracy skills. The Diabetes Educator, 35, 233–245. Wu, S. V., Courtney, M., Edwards, H., McDowell, J., Shortridge, B. L., & Chang, P. (2007). Self-efficacy, outcome expectations and self-care behaviour in people with type 2 diabetes in Taiwan. Journal of Nursing and Healthcare of Chronic Illness in Association with Journal of Clinical Nursing, 16(11c), 250–257. Xu, Y., Toobert, D., Savage, C., Pan, W., & Whitmer, K. (2008). Factors influencing diabetes self-management in Chinese people with type 2 diabetes. Research in Nursing & Health, 31, 613–625.
Health literacy, self-efficacy, and self-care behaviors in patients with type 2 diabetes mellitus Walton Bohanny, MSN, RN (Lecturer)1 , Shu-Fang Vivienne Wu, PhD, RN (Associate Professor)2 , Chieh-Yu Liu, PhD (Associate Professor)2 , Shu-Hui Yeh, PhD, RN (Professor)3 , Shiow-Luan Tsay, PhD, RN (Professor)2 , & Tsae-Jyy Wang, PhD, RN (Associate Professor)2 1
Department of Nursing, College of Marshall Islands, Majuro Atoll, Marshall Islands Department of Nursing, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan 3 Department of Medical Research and Development, Show Chwan Memorial Hospital in Chang Bing & Department of Nursing, Central Taiwan University, Taichung, Taiwan 2
Keywords Diabetes mellitus; health literacy; self-care behavior; self-efficacy; vulnerable populations. Correspondence Tsae-Jyy Wang, PhD, RN, Department of Nursing, National Taipei University of Nursing and Health Science, Taipei, Taiwan. Tel: 886-2-28227101; Fax: 886-2-28213233; E-mail: [email protected] Received: May 2011; accepted: August 2011 doi: 10.1111/1745-7599.12017
Abstract Purpose: The study purpose was to explore the relationships among health literacy, self-efficacy, and self-care behaviors of patients with type 2 diabetes. Data sources: A cross-sectional study with a descriptive correlational design was conducted. Patients (N = 150) with type 2 diabetes were recruited from diabetes clinics in the Marshall Islands. Levels of health literacy, self-efficacy, and self-care behaviors were assessed by a questionnaire. Conclusions: Health literacy, receiving diabetes education, and employment status together explained 11.8% of the variance in self-efficacy (F(3,147) = 7.58, p < .001). Patients who had higher health literacy, received more diabetesrelated education, were currently employed and had better self-efficacy. Selfefficacy and marital status together explained 16.7% of the variance in selfcare behaviors (F(2,148) = 15.96, p < .001). Patients who had higher self-efficacy and who were married had better self-care behaviors. Implications for practice:: Strategies are needed to incorporate the concept of self-efficacy in the design of diabetes education to promote patients’ self-care behaviors, with an emphasis on dealing with hyper- or hypoglycemia, following the diet plan, and checking blood sugar levels as recommended. Diabetes education material that requires a lower literacy level may be needed for older or unemployed adult populations.
Introduction Type 2 diabetes is an epidemic that affects close to 285 million people worldwide (International Diabetes Federation, 2009). Without appropriate management, type 2 diabetes can cause serious complications such as cardiovascular diseases, neuropathy, retinopathy, and neuropathy. Self-care behaviors are essential for controlling type 2 diabetes’ progression and for preventing long-term complications (American Diabetes Association, 2010). Because patients are expected to integrate a complex set of selfcare behaviors into their daily routines (Chatterjee, 2006; Funnell et al., 2010), it is essential to know the factors that influence type 2 diabetes patients’ performance in these self-care behaviors. Therefore, the purpose of this study was to explore the factors related to the self-care
behaviors of patients with type 2 diabetes. Specifically, we sought to explore the relationships among health literacy, self-efficacy, and self-care behaviors in an urban, diverse population of type 2 diabetes patients. The results of the study are relevant to the understanding of preconditions that enable type 2 diabetes patients to successfully cope with the disease and its diverse consequences.
Background Self-care behavior refers to “decisions and actions that an individual can take to cope with a health problem or to improve his or her health” (Breslow, 2002, p. 1). Self-care behaviors that individuals must learn or modify to effectively cope with their type 2 diabetes include
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eating healthily, exercising regularly, adhering to medical treatments, self-monitoring of blood glucose levels, and developing healthy coping skills (Funnell et al., 2010). Self-efficacy is “the belief in one’s capabilities to organize and execute the courses of action required to manage prospective situation” (Bandura, 1995, p. 2). How people behave can often be better predicted by the beliefs that they hold about their capabilities than by what they are actually capable of accomplishing because self-efficacy perceptions help determine what individuals do with the knowledge and skills that they have (Bandura, 1997). Self-efficacy was found to be an important predictor of self-care behaviors in type 2 diabetes patients (Sarkar, Fisher, & Schillinger, 2006; Wu et al., 2007; Xu, Toobert, Savage, Pan, & Whitmer, 2008). The correlations between self-efficacy and self-care behaviors of type 2 diabetes were 0.45 (p < 0.01) and 0.50 (p < 0.01) in Wu et al. (2007) and Xu et al. (2008), respectively. The Sarkar et al. (2006) study showed that, with each 10% increase in the self-efficacy score, patients were more likely to report a more optimal diet 0.14 day/week, more exercise 0.09 day/week, and an odds ratio of 1.16 for self-monitoring blood glucose and 1.22 for foot care after adjusting for duration of diabetes, insulin use, race/ethnicity, and literacy score. Another factor that seems to affect self-care behaviors is health literacy. Health literacy is “the degree to which individuals have the capacity to obtain, process and understand basic health information and services needed to make appropriate health decisions” (U.S. Department of Health and Human Services, 2000, p. 2). These are skills that all people need, for instance, to find their way to the right place in a hospital, fill out medical and insurance forms, and communicate with healthcare providers. Poor literacy and numeracy skills can result in difficulties in interpreting glucose reading, adjusting medication, calculating carbohydrate intake, and performing other self-care activities among type 2 diabetes patients (Wolff et al., 2009). Limited health literacy was associated with lower diabetes knowledge and awareness of complications (Kim, Love, Quistberg, & Shea, 2004; Powell, Hill, & Clancy, 2007), poor glycemic control (Ishikawa & Yano, 2011; Powell et al. 2007; Schillinger, Barton, Karter, Wang, & Adler, 2006; Tang, Pang, Chan, Yeung, & Yeung, 2008), and more diabetes-related complications (Schillinger et al., 2002). The findings from previous studies support that health literacy is associated with diabetes outcomes. The unique contributions of health literacy on self-efficacy and self-care behaviors, however, are not as well understood. Patients with higher health literacy may feel more confident in their ability to perform self-care behaviors and may be more likely to actually perform them. Additional work is needed to explore the relation496
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ships among health literacy, self-efficacy, and self-care behaviors in patients with type 2 diabetes.
Method Design We used a cross-sectional descriptive correlational design to explore the factors influencing self-care behaviors of type 2 diabetes patients, including demographics, disease characteristics, health literacy, and self-efficacy.
Participants and setting A convenience sample of 150 type 2 diabetes patients was recruited from a public diabetes clinic on Majuro Atoll, the Marshall Islands. Inclusion criteria were having (a) age above 25, (b) diagnosis of type 2 diabetes, and (c) ability to speak and understand Marshallese. Exclusion criteria were having (a) impaired vision or (b) a psychiatric illness. Initially, 155 eligible type 2 diabetes patients were recruited. Of these, five dropped out because of time constraints (n = 2) or difficulty in completing the study questionnaire (n = 3).
Sample size The desired sample size was estimated based on a multiple linear regression model, by using G*power software (version 3.1; Faul, Erdfelder, Lang, & Buchner, 2007). Taking into account the number of possible predictors (n = 10) in this study, a sample size of 118 was required to have approximately 80% power to detect a medium effect size of F2 = 0.15 with a 0.05 significant level. A medium effect size was estimated based a 0.45 correlation between self-efficacy and self-care behaviors as reported by Wu et al. (2007). A total of 150 participants was recruited and completed the study questionnaire.
Data collection Data were collected between October 2008 and March 2009 by 25 trained data collectors, including researchers, nurses, and senior nursing students. The data collection took place either at a diabetes clinic or at the participants’ residences. After obtaining informed consent, participants answered the study questionnaires, which included demographic and disease questions, the Shortform Test of Functional Health Literacy in Adults (S-TOFHLA), the Diabetes Management Self-Efficacy Scale (DMSES), and the Summary of Diabetes Self-Care Activities (SDSCA). The S-TOFHLA, DMSES, and SDSCA were translated and back-translated until the concordance in meaning between the English and Marshallese
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versions was achieved. To establish the stability of the study questionnaires, the first 30 participants were asked to complete the study questions twice, 2 weeks apart.
Validity and reliability of instruments The S-TOFHLA (Baker, William, Parker, Gazmarmarian, & Nurss, 1999) was used to measure patients’ health literacy. The scale consists of four numerical items and 36 reading comprehension items, assessed by a cloze technique. Seven points and two points are given for each correctly answered numerical item and reading comprehension item, respectively. Scores are summed to give a total range from 0 to 100; higher scores represent greater health literacy. The cutoff points were 0–53 for inadequate, 54–66 for marginal, and 67–100 for adequate health literacy. The original scale showed adequate internal consistency and convergent validity. Cronbach’s alphas were 0.68 and 0.97 for the four numeric items and the 36 cloze items, respectively. The correlation (Spearman) between the S-TOFHLA and the Rapid Estimate of Adult Literacy in Medicine was 0.80 (Baker et al., 1999). For the Chinese version, Cronbach’s alphas were 0.68 for the four numeric items and 0.97 for the 36 cloze items (Tang et al., 2008). In the current study, Cronbach’s alphas were 0.83 for the overall scale, 0.67 for the four numeric items, and 0.81 for the 36 cloze items. The test–retest reliability coefficient was 0.83 (p < 0.01). The DMSES assesses the extent to which respondents are confident in managing their blood sugar, diet, and exercise (Stanford Patient Education Research Center, 2008). Each item is responded to on a 10-point Likert scale. Scores are averaged to present a total score of the scale ranged from 0 to 10. Higher scores indicate better self-efficacy in diabetes self-management. The instrument has demonstrated good internal consistency and test–retest reliability in previous studies. For the Australia/English version, the Cronbach’s alpha was 0.91, and the test–retest reliability coefficient was 0.76 (McDowell, Courtney, Edward, & Shortridge, 2005). For the Chinese version, the Cronbach’s alpha was 0.93, and the test–retest reliability was 0.86 (Wu et al., 2007). The Cronbach’s alpha was 0.84 in the current study. The test– retest reliability was 0.86 (p < 0.01). The SDSCA consists of 12 items to assess the frequency of performing diabetes self-care tasks in the following five regimen areas: diet, exercise, blood glucose testing, foot care, and smoking status (Toobert, Hampson, & Glasgow, 2000). Participants were asked to report on how many of the last 7 days were spent in performing the self-care activity as indicated by the item. A mean score was cal-
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culated for each of the five areas of self-care behaviors, except smoking, with a possible range from 0 to 7. Participants were also asked to indicate whether they were a smoker and the number of cigarettes that they smoked per day. The original scale showed adequate internal consistency and test–retest reliability. The Cronbach’s alphas were 0.75 for the overall scale, 0.65 for diet, 0.84 for exercise, and 0.84 for blood testing subscales. The test– retest reliability coefficient was 0.70 for the overall measure of self-care (Johnson-Brooks, Lewis, & Garg, 2002). In the present study, the Cronbach’s alphas were 0.63 for the overall scale and 0.79, 0.67, 0.72, and 0.80 for the diet, exercise, blood testing, and foot-care subscales, respectively. The test–retest reliability coefficient was 0.73 (p < 0.01) for the overall scale.
Ethical considerations The study was approved by the National Taipei University Institutional Review Board (IRB No. 97A166) and the Secretary of the Ministry of Health, Marshall Islands. Each participant received an oral explanation of the research and signed a consent form before participation.
Data analysis Data were analyzed using the SPSS Version 17.0 software statistical package (SPSS, Inc., Chicago, IL, 2008). Percentages, means, and standard deviations (SDs) were used to describe the participants’ demographics and study variables. Independent t-tests, one-way analysis of variance (ANOVA), and Pearson product moment correlations were used to examine the relationships among demographics, disease variables, health literacy, selfefficacy, and self-care behaviors. Stepwise multiple regressions were used to determine the important predictive factors of self-efficacy and self-care behaviors. In the first regression model, demographics (age, gender, marital status, education level, employment status, and living arrangement), disease characteristics (years of diabetes and diabetes education), and health literacy were entered as the dependent variables for predicting self-efficacy. In the second regression model, demographics, disease characteristics, health literacy, and self-efficacy were entered as the dependent variables for predicting self-care behaviors. Gender, marital status, education level, employment status, and living arrangement were measured categorically, these variables were dummy coded prior to analysis. Normality and independent assumptions of the regression analysis were examined through standardized residual plots and collinearity statistics, and neither assumption was violated.
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Table 1 Demographic characteristics of the sample and comparisons of health literacy, self-efficacy, and self-care behavior among different characteristics (N = 150) Health literacy n (%)
Mean(SD)
80(53.3) 70(46.7)
78.1(12.8) 75.2(15.9)
45(30.0) 105(70.0)
73.8(16.2) 78.0(13.3)
4(2.7) 62(41.3) 66(44.0) 18(12.0)
68.3(16.8) 76.7(13.3) 76.7(13.6) 79.0(19.6)
86(57.3) 64(42.7)
74.1(15.1) 80.4(12.5)
126(84.0) 24(16.0)
77.4(14.2) 73.4(15.1)
Characteristic Gender Female Male Marital status Single Married Education level Never attend school Elementary (1–8 years) High school (9–12 years) College and above Employment status Unemployed Employed Living arrangement Living with someone Living alone
Self-efficacy t/F
Mean(SD)
1.21
Self-care behavior t/F
Mean(SD)
0.23 7.7(2.2) 7.6(2.3)
− 1.53
0.55 3.8(1.1) 3.791.1)
− 1.50 7.2(2.6) 7.9(2.0)
0.61
−2.55* 3.4(1.1) 3.9(1.1)
1.44 7.4(2.2) 7.2(2.5) 7.9(1.9) 8.2(2.4)
− 2.69**
0.34 3.5(1.2) 3.7(1.2) 3.8(1.1) 3.6(0.9)
− 3.03** 7.2(2.4) 8.3(1.7)
1.26
−1.77 3.6(1.2) 3.9(0.9)
1.83 7.8(2.1) 6.9(2.5)
t/F
0.54 3.7(1.1) 3.6(1.1)
SD, standard deviation, * p-value < .05, ** p-value < .01.
Results Participant characteristics The demographics and disease variables of the sample are presented in Table 1. Participants were mainly female (53.3%, n = 80), married (70.0%, n = 105), unemployed (57.3%, n = 88), living with family (84.0%, n = 126). The mean age of participants was 52.7 years (SD = 10.5; range = 37–79). The educational level ranged from never attended school to post-college. The majority (44%, n = 66) of participants had a high school education level. Mean length of time diagnosed with type 2 diabetes was 7.8 years (SD = 5.8; range = 0–30). Thirtythree (22%) participants had diabetes for more than 10 years. Most participants were treated with oral hypoglycemic agents (OHAs; 63.3%) and combined OHAs with insulin injections (24.7%); few received diet-only treatments (12%). Frequency (times per year) of having diabetes education ranged from 0 to 48, with a mean 8.2 (SD = 9.7). Of the participants, 29 (19.3%) indicated that they never received or gained information about diabetes complications or risk factors from either doctors or nurses.
Health literacy, self-efficacy, and self-care behaviors The participants’ S-TOFHLA scores ranged from 27 to 96, with a mean 76.78 (SD = 14.3). Using the cutoff points (0–53, inadequate; 54–66, marginal; and 67–100, adequate) to categorize participants’ literacy levels re498
sulted in 114 (76%) participants having adequate health literacy, 26 (17%) having marginal health literacy, and only 10 (7%) participants having inadequate health literacy. Participants, on average, answered correctly three (SD = 1.2) out of the four numeracy items of S-TOFLA. The most common mistakes were made in item 2 (regarding whether a blood sugar level of 160 mg/dL was normal) and item 4 (regarding the correct time for taking the medication as prescribed), with incorrect rates of 34% and 33.3%, respectively. As for the 36 reading comprehension items, participants, on average, answered 28 (SD = 5.1) items correctly. The rate for correctly answered individual items ranged from 54% to 96%. The mean score of participants’ DMSES was 7.7 (SD = 2.2; range, 0–10), indicating a high level of self-efficacy in managing diabetes. Of the participants, 24 (16%) had a self-efficacy score below 5 (possible score of 0–7), meaning that those participants were lacking in confidence in managing their diabetes. Participants reported to be least confident in dealing with hyper- or hypoglycemia, followed by a lack of confidence in following the diet plan when having to prepare or share food with others. The mean score of the SDSCA was 3.7 (SD = 1.1; range, 1–6.4), indicating that participants performed most of the self-care tasks about 4 days a week. The mean scores for the general diet, specific diet, exercise, blood sugar testing, and foot care were 4.5 (SD = 1.9), 3.9 (SD = 1.6), 4.2 (SD = 2.2), 1.4 (SD = 1.1), and 4.6 (SD = 2.8), respectively. These indicated that, during the previous week,
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Table 2 Person product moment correlation coefficients among study variables (N = 150)
Age
Years of Diabetes Health Self- Self-care diabetes education literacy efficacy behavior
Age 1 Years of diabetes 0.58*** 1 Diabetes 0.15 0.10 education Health literacy − 0.23** − 0.11 Self-efficacy 0.05 0.02 Self-care behavior 0.15 0.13
1 − 0.04 1 0.20* 0.24** 1 0.19* 0.06 0.39**
1
Diabetes education: number of diabetes related teaching classes received in the past 12 months, *p-value < .05, ** p-value < .01.
participants followed the healthy eating plan in general, ate five or more servings of fruits or vegetables, and did exercise and foot care for about 4 days. On average, the participants also did blood testing once during the last 7 days.
Relationships among demographics, disease variables, health literacy, self-efficacy, and self-care behavior factors associated with health literacy Level of health literacy (t = −2.69, p = .008) were found to be significantly higher in participants who were holding a job at the time of interview as compared to those who were unemployed (Table 1). Age was negatively associated with health literacy (r = −0.23, p = .004; Table 2). Gender, marital status, education level, living arrangement, years of diabetes, and receiving diabetes education were not related to health literacy. Factors associated with self-efficacy. Selfefficacy (t = −3.03, p = .003) was significantly higher in employed participants than unemployed participants (Table 1). Diabetes education (r = 0.20, p = .015) and health literacy (r = 0.24, p = .003) were both positively correlated with self-efficacy (Table 2). The results of stepwise regression showed that health literacy, receiving diabetes education, and employment status together explained 11.8% of the variance in self-efficacy (F(3,147) = 7.58, p < .001; Table 3). Patients who had higher health literacy, received more diabetes-related education, and who were currently employed had better self-efficacy than those who had less health literacy and diabetesrelated education and were unemployed. Among these variables, health literacy (5.0%) explained the most variance in self-efficacy, followed by diabetes-related education (3.7%) and employment status (3.1%). Age, gender, marital status, education level, living arrangement, and years of diabetes were excluded from the regression model.
Factors associated with self-care behaviors. Self-care behavior scores were found to be significantly higher in married participants than in unmarried participants (t = −2.55, p = .012; Table 1). Self-efficacy was positively correlated with self-care behaviors (r = 0.39, p < .001; Table 2). The results of stepwise regression showed that self-efficacy and marital status together explained 16.7% of the variance in self-care behaviors (F(2,148) = 15.96, p < .001; Table 3). Patients who had higher selfefficacy and who were married had better self-care behaviors than those who had lower self-efficacy and who were not married. Self-efficacy and marital status each explained 14.9% and 1.8% of the variance in self-care behaviors, respectively. Age, gender, education level, employment status, living arrangement, years of diabetes, diabetes education, and health literacy were excluded from the regression model. Figure 1 presents the relationships among demographics, disease characteristics, health literacy, self-efficacy, and self-care behaviors with their perspective standardized regression coefficients (ß).
Discussion Health literacy, self-efficacy, and self-care behaviors Similar to what was found (8% marginal and 15% inadequate health literacy) in a previous study (Kim et al., 2004), 24% of our study participants had limited health literacy (17% marginal and 7% inadequate). Over 30% of the study participants made mistakes in judging their blood sugar levels and in knowing the correct time for taking their medication. They also reported being least confident in dealing with hyper- or hypoglycemia and following the diet plan when having to prepare or share food with others. As for self-care behaviors, participants reported checking their blood sugar levels less often than recommended. During the prior 7 days, they checked their blood sugar on only 1.5 (SD = 1.8) days and did it as recommended by their healthcare providers on only 1.2 (SD = 1.5) days. These results indicate that checking and judging blood glucose levels, taking diabetes medications correctly, dealing with hyper- or hypoglycemia, and following the diabetic diet plan are areas that need to be reinforced in future diabetes education.
Relationships among demographics, disease variables, health literacy, self-efficacy, and self-care behavior factors associated with health literacy Our result supports a previous finding that older patients had lower health literacy (Kim et al., 2004; Schillinger et al., 2006). Age is a factor that needs to be considered when reading comprehension is required for 499
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Table 3 Results of stepwise regressions on self-efficacy and self-care behavior (N = 150) Model
Dependent variables
1
Self-efficacy
2
Self-care behavior
*
Independent variables
ß
R2
Adjusted R2
F
VIF
Health literacy Diabetes education Employment Employed versus unemployed Self-efficacy Marital status Married versus single
0.20** 0.21**
0.136
0.118
7.58***
1.05 1.00
0.178
0.167
15.96***
0.19* 0.37*** 0.15*
1.05 1.02 1.02
p-value < .05, ** p-value < .01, *** p-value < .001.
0.15* Marital status
Health literacy
0.20*
0.21** Diabetes education
0.37*** Self-efficacy
Self-care behavior
0.19* Employment status
* p < .05, ** p < 0.01, *** p < 0.001
Figure 1 Relationships among demographics, health literacy, selfefficacy, and self-care behavior in patients with type 2 diabetes mellitus.
certain health or medical tasks. In a busy clinic, healthcare providers often rely on pamphlets or written materials to provide patient education. This may leave the older patients with poor health literacy at a substantial disadvantage. Moreover, we found that unemployed participants had lower health literacy and less confidence in managing their diabetes than those who were employed. This might be because outreach health programs and diabetes screening activities in Marshall Islands often target the working population because of its accessibility and leaves out unemployed diabetes patients. In contrast to what was reported in previous studies (Berkman et al., 2004; Kim et al., 2004; Schillinger et al., 2006), we found no statistically significant differences in levels of health literacy among participants of different educational levels. This may be because of the lack of variation in the education levels of the current sample. The inconsistent findings need to be further investigated. Factors associated with self-efficacy. We found that health literacy is positively associated with selfefficacy in diabetes self-care. This has also been reported in previous studies (Cavanaugh et al., 2008; DeWalt, Boone, & Pignone, 2007). Additionally, health literacy, diabetes education, and employment status were impor500
tant predictors of diabetic patients’ self-efficacy. This result suggests that clinicians who try to enhance diabetes patients’ self-efficacy should take patients’ literacy levels, received diabetes-related health education, and employment status into consideration. Proper patient education will often bring positive outcomes because of better understanding and cooperation with both preventive and treatment interventions among individuals with diabetes. Our results, however, showed that there was still a large proportion (20%) of patients who did not receive any information regarding diabetes complications and risk factors from their healthcare providers. This reminds us that extra efforts are needed to provide basic patient education in a more systemic way.
Factors associated with self-care behaviors. Our results also support the strong positive relationship between self-efficacy and self-care behaviors found in previous studies (Sarkar et al., 2006; Sousa, Zauszniewski, Musil, Lea, & Davis, 2005; Wu et al., 2007). Self-efficacy together with marital status explained 16.7% of the variance in self-care behaviors. Therefore, strategies to increase patients’ self-efficacy should be developed in the design of diabetic patients’ education for enhancing proper diabetes self-care behaviors among type 2 diabetes patients. Similar to the results of the Kim et al. (2004) study, we found no direct relationship between health literacy and self-care behaviors. Although health literacy was positively associated with self-efficacy, and self-efficacy was positively associated with self-care behaviors, the correlation between health literacy and self-care behaviors was statistically insignificant. These results indicate that health literacy is an antecedent to self-efficacy and that the influence of health literacy on self-care behaviors may be completely mediated through self-efficacy. However, evidence to date is still too sparse to enable a definite conclusion. The specific pathway between health literacy and self-care behaviors should be further investigated. Additionally, our study participants were generally well educated and with high health literacy. Perhaps, in a follow-up study, proportionally representing different
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levels of education and health literacy may offer some more insight to the relationships among health literacy, self-efficacy, and self-care behaviors in diabetics.
Study limitations Limitations of the study include the use of a convenience sample, a cross-sectional design, and 25 data collectors. Because nonprobability sampling was used, the results of the study cannot be generalized to all diabetic patients. Specifically, our participants were younger and more educated than participants in previous studies (Redmond et al., 2006; Tang et al., 2008; Wu et al., 2007). Thus, the conclusions and recommendations may not be applicable to patients who are older and who are less educated. In addition, the causal relationships among study variables are difficult to establish through cross-sectional observational data. Finally, because of the geographic distance, we had to use 25 trained personnel to collect data from the participants’ homes. The large number of data collectors may introduce some inconsistency in data collection.
Conclusion and relevance to clinical practice Our results showed that type 2 diabetes patients who had the worst health literacy and received less diabetesrelated education had the worst self-efficacy in self-care. Therefore, interventions to boost self-efficacy should take the patients’ health literacy into consideration. Unemployed older adults were at the greatest risk for inadequate health literacy. Diabetes education material that requires lower literacy levels may be needed for older or unemployed adult populations. In addition, outreach health activities and diabetes screening programs should be extended from working populations to a broader community to reach unemployed individuals. Regarding health literacy, patients showed the most difficulties in accurately interpreting glucose reading and knowing the correct times for taking medication. Therefore, when working with type 2 diabetes patients, nurses should place an emphasis on teaching glucose reading interpretations and the correct times for taking medication. Moreover, our results showed that self-efficacy is an important predictor of self-care behaviors. Nurses should consider incorporating the concept of self-efficacy in designing self-care behavior-enhancing interventions and diabetes education programs. Special attention should be paid to boosting patients’ confidence in dealing with hyper- or hypoglycemic situations, preparing food according to diabetes dietary plans, and checking blood sugar levels as recommended.
Health literacy, self-efficacy, and self-care in diabetes
Acknowledgments Funded by the National Science Council, Taiwan ROC (99–2511-S-227–011). The authors thank all the participants in this study.
References American Diabetes Association. (2010). Standards of medical care in diabetes—2010. Diabetes Care, 33, S11–S61. Baker, D. W., William, M. V., Parker, R. M., Gazmarmarian, J. A., & Nurss, J. (1999). Development of a brief test to measure functional health literacy. Patient Education and Counseling, 38, 33–42. Bandura, A. (1995). Self-efficacy in changing societies (p. 2). Cambridge, UK: Cambridge University Press. Bandura, A. (1997). Self-efficacy: The exercise of control. New York, NY: W.H. Freeman. Berkman, N. D., DeWalt, D. A., Pignone, M. P., Sheridan, S. L., Lohr, K. N., Lux, L., . . . Bonito, A. J. (2004). Literacy and health outcomes. Evidence report/technology assessment. Rockville, MD: Agency for Healthcare Research and Quality. Retrieved from http://www.ahrq.gov/clinic/ epcsums/litsum.pdf Breslow, L. (2002). Self-care behavior. Encyclopedia of Public Health. Farmington Hills, MI: Gale Group. Retrieved from http://www.enotes.com/ public-health-encyclopedia/self-care-behavior Cavanaugh, K., Huizinga, M. M., Wallston, K. A., Gerbretsadik, T., Shintani, A., Davis, D., . . . Rothman, R. L. (2008). Association of numeracy and diabetes control. Annals of Internal Medicine, 10, 737–746. Chatterjee, J. S. (2006). From compliance to concordance in diabetes. Journal of Medical Ethics, 32, 507–510. DeWalt, D. A., Boone, R. S., & Pignone, M. P. (2007). Literacy and its relationship with self-efficacy, trust, and participation in medical decision making. American Journal of Behavior, 31, 27–35. Faul, F., Erdfelder, E., Lang, A.-G., & Buchner, A. (2007). G*Power 3: A flexible statistical power analysis program for the social, behavioral and biomedical sciences. Behavior Research Methods, 39, 175–191. Funnell, M. M., Brown, T. L., Childs, B. P., Haas, L. B., Hosey, G. M., Jensen, B., . . . Weiss, M. A. (2010). National standards for diabetes self-management education. Diabetes Care, 33, S89–S96. International Diabetes Federation. (2009). Latest diabetes figures paint grim global picture. Retrieved from http://www.idf.org/latest-diabetes-figures-paintgrim-global-picture Ishikawa, H., & Yano, E. (2011). The relationship of patient participation and diabetes outcomes for patients with high vs. low health literacy. Patient Education and Counseling, 84, 393–7. doi: 10.1016/j.pec.2011.01.029 Johnson-Brooks, C. H., Lewis, M. A., & Garg, S. (2002). Self-efficacy impacts self-care and HbA1c in young adults with type 1 diabetes. Psychosomatic Medicine, 64, 43–51. Kim, S., Love, F., Quistberg, D., & Shea, J. A. (2004). Association of health literacy with self-management behavior in patients with diabetes. Diabetes Care, 27, 2980–2982. McDowell, J., Courtney, M., Edward, H., & Shortridge, L. (2005). Validation of Australian/English version of the Diabetes Management Self-Efficacy Scale. International Journal of Nursing Practice, 11, 177–184. Powell, C. K., Hill, E. G., & Clancy, D. E. (2007). The relationship between health literacy and diabetes knowledge and readiness to take health actions. The Diabetes Educator, 33, 144–151. Redmond, E. H., Burnett, S. M., Johnson, M. A., Park, S., Fischer, J. G., & Johnson, T. (2006). Improvement in A1 C levels and diabetes self-management activities following a nutrition and diabetes education program in older adults. Nutrition for the Elderly, 26, 83–101. Sarkar, U., Fisher, L., & Schillinger, D. (2006). Is self-efficacy associated with diabetes self-management across race/ethnicity and health literacy? Diabetes Care, 29, 823–829. Schillinger, D., Barton, L. R., Karter, A. J., Wang, F., & Adler, N. (2006). Does literacy mediate the relationship between education and health outcomes?
501
Health literacy, self-efficacy, and self-care in diabetes
A study of a low-income population with diabetes. Public Health Report, 121, 245–254. Schillinger, D., Grumbach, K., Piette, J., Wang, R., Osmond, D., Daher, C., . . . Bindman, A. B. (2002). Association of health literacy with diabetes outcomes. Journal of the American Medical Association, 288, 475–482. Sousa, V. D., Zauszniewski, J. A., Musil, C. M., Lea, P. J. P., & Davis, S. A. (2005). Relationships among self-care agency, self-efficacy, self-care, and glycemic control. Research and Theory for Nursing Practice, 19, 217–230. Stanford Patient Education Research Center. (2008). Diabetes Self-efficacy Scale. Retrieved from http://patienteducation.stanford. edu/research/sediabetes.html Tang, Y. H., Pang, S. M., Chan, M. F., Yeung, G. S., & Yeung, V. T. (2008). Health literacy, complication awareness and diabetic control in patients with type 2 diabetes mellitus. Journal of Advance Nursing, 62, 74–83. Toobert, D. J., Hampson, S. E., & Glasgow, R. E. (2000). The summary of diabetes self-care activities measure. Diabetic Care, 23, 943–950.
502
W. Bohanny et al.
U.S. Department of Health and Human Services, Office of Disease Prevention and Health Promotion. (2000). Quick guide to health literacy. Retrieved from http://www.health.gov/communication/literacy/quickguide/quickguide.pdf Wolff, K., Cavanaugh, K., Malone, R., Hawk, V., Gregory B. P., Davis, D., . . . Rothman, R. L. (2009). The diabetes literacy and numeracy education toolkit (DLNET) materials to facilitate diabetes education and management in patients with low literacy and numeracy skills. The Diabetes Educator, 35, 233–245. Wu, S. V., Courtney, M., Edwards, H., McDowell, J., Shortridge, B. L., & Chang, P. (2007). Self-efficacy, outcome expectations and self-care behaviour in people with type 2 diabetes in Taiwan. Journal of Nursing and Healthcare of Chronic Illness in Association with Journal of Clinical Nursing, 16(11c), 250–257. Xu, Y., Toobert, D., Savage, C., Pan, W., & Whitmer, K. (2008). Factors influencing diabetes self-management in Chinese people with type 2 diabetes. Research in Nursing & Health, 31, 613–625.
