Rheumatology
Rheumatol Int DOI 10.1007/s00296-014-3128-6
INTERNATIONAL
ORIGINAL ARTICLE - VALIDATION STUDIES
Validity and reliability of the Persian version of Behçet’s disease quality‑of‑life (BD‑QoL) questionnaire: a cross‑cultural adaptation Mahdi Vojdanian · Seyedeh Tahereh Faezi · Alan Tennant · Ann W. Morgan · Pedram Paragomi · Mostafa Qorbani · Maryam Mattaji · Fereydoun Davatchi
Received: 13 June 2014 / Accepted: 3 September 2014 © Springer-Verlag Berlin Heidelberg 2014
Abstract The Leeds Behçet’s disease quality-of-life (BDQoL) questionnaire is a specific and valid measure which is applied in English-speaking patients. We conducted Persian adaptation of BD-QoL questionnaire. Between June and December 2012, 220 Iranian patients fulfilling International Study Group criteria for the diagnosis of BD attending the rheumatology clinics at Tehran University of Medical Sciences were enrolled. Bilingual translators undertook the forward translation and cross-cultural adaptation of the BD-QoL questionnaire. Back-translation was conducted, and this version was sent to the designer of the questionnaire and revised accordingly. SF-36 health survey, Iranian Behçet’s disease dynamic activity measure (IBDDAM), and Behçet’s Disease Current Activity Form (BDCAF) were other administered measures. The Varimax rotation
M. Vojdanian · S. T. Faezi (*) · M. Mattaji · F. Davatchi Rheumatology Research Center, Shariati Hospital, Tehran University of Medical Sciences, North Kargar Avenue, Tehran, Iran e-mail: [email protected] A. Tennant Leeds Institute Rheumatic and Musculoskeletal Medicine, St. James’s University Hospital, Leeds, UK A. W. Morgan Department of Rehabilitation Medicine, Faculty of Medicine and Health, The University of Leeds, Leeds, UK P. Paragomi Rheumatology Research Center, Tehran University of Medical Sciences, Tehran, Iran M. Qorbani Non‑Communicable Diseases Research Center, Endocrinology and Metabolism Population Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran
method with Kaiser normalization defined 5 factors with eigenvalues greater than 1.0. Studied cases were comprised of 118 males (53.6 %) and 102 females (46.4 %). Mean age of the patients was 38.3 ± 11.3 years (range 16–73). The mean BD-QoL score was 10.3 ± 8.8. Test–retest reliability was high, and two time points were significantly correlated (Spearman’s correlation coefficient of 0.75–0.84). Cronbach’s α coefficient of 0.949 demonstrated the excellent internal consistency. These factors cumulatively explained 58.74 % of total variance. The ratio of first to second eigenvalue was 7.08, which underlined the undimensionality. The results revealed adapted BD-QoL scores had significant correlation with IBDDAM (correlation coefficient = 0.19, P value = 0.005) and BDCAF (correlation coefficient = 0.21, P value = 0.002). Conversely, no significant correlation between BD-QoL and SF-36 results was detected (P value = 0.078). The Persian version of BDQoL was shown to be unidimensional, highly reliable, and adequate construct validity. Keywords Behçet’s disease · Quality of life
Introduction Behçet’s disease (BD) is a multisystemic vasculitide, which is encountered along the ancient Silk Road especially in Middle East and Far Eastern countries [1, 2]. Turkey has the highest reported prevalence ranging from 80 to 370 per 100,000 [3]. Iran has the second highest prevalence with 80 per 100,000 [4]. The main manifestations include mucocutaneous, ophthalmological, and CNS lesions [5]. The chronic course of Behçet’s disease and complexity of clinical scenario leads to various degrees of functional impairment, activity limitation, and restricted participation
13
(collectively health status) in those with the condition, and can also adversely affect quality of life [6–9]. Furthermore, some of the therapeutic interventions in rheumatologic conditions can also affect the patients’ quality of life [10]. Thus, a number of previous studies have addressed the health status and quality of life in the Behçet’s population [8, 11, 12]. Some of these studies focused upon the effect of a specific feature of BD such as mucocutaneous or ocular symptoms [6, 8, 9], while other studies investigated the relationship between BD activity level and quality-of-life parameters (e.g., life satisfaction) [12, 13]. Two methodologies have been described in the literature to assess the health status and quality of life in patients with chronic disease. One is the generic health status instrument that provides a concise overview of health-related qualityof-life issues (HRQOL). The main advantage of a generic instrument is that it provides opportunity to assess various aspects of health status that are expected to impact quality of life across different conditions. The second method employs specific instruments, which targets single-disease states (disease-specific), but also patient groups or areas of function [14]. Specific instruments can investigate the impact of the condition on quality of life, and are reported to be a more suitable approach in the evaluation of treatment effects and the follow-up of patients [15, 16]. Currently, the only specific instrument to study quality of life in Behçet’s disease is the Leeds BD quality-of-life (Leeds BD-QoL) questionnaire [7]. The Leeds BD-QoL is a self-administered questionnaire consisting of 30 questions with two-option answers, true [1] or not true (0), thus total score ranges between 0 and 30 [7]. The original development process involved identifying potential items from qualitative interviews with patients, so leading to a draft questionnaire that was posted to a wider sample in order to examine its validity, reliability, and internal consistency. After a short interval of 30 days, the questionnaire was resent to patients to check its test–retest reliability. Initially, 71 items were selected, which were deemed to reflect the impact of the condition upon quality of life, and these included themes were related to the patients’ communication, emotions, life limitations, and self-perception. Rasch analysis revealed 30 BD-related items that were invariant for age and sex. The BD-QoL was shown to be a reliable and valid instrument with appropriate psychometric properties [7]. As the original version of BD-QoL was developed in the English language, and as the most prevalent regions are located in non-English-speaking countries, the issue of cross-cultural adaptation became paramount. To date, only two other language adaptations have been developed. Thouma et al. confirmed validity, reliability, and internal consistency of adapted Arabic version of BD-QoL [17]. Another adaptation was conducted by Yi et al. [18] who
13
Rheumatol Int
translated BD-QoL questionnaire into Korean. The adapted Korean questionnaire revealed a significant correlation with the Clinical Activity Form for Korean Patients with BD (BDCAF-K) and the Center for Epidemiologic StudiesDepression (CES-D) scales. Moreover, the Korean adaptation had acceptable internal consistency and test–retest reliability. Given the considerable prevalence of BD in Iran and the need to evaluate patients’ health status and its impact upon QoL, a Persian translation of QoL questionnaire was deemed necessary. Thus, the Behçet’s unit of the rheumatology research center in TUMS, which is considered the referral center in the country for BD population, set out to adapt the BD-QoL into the Persian language, and to test its validity and reliability.
Methods Patient enrollment Between June and December 2012, 220 Iranian patients were enrolled into the study who fulfilled the International Study Group (ISG) criteria for the diagnosis of BD [19] and who attended the BD Research Unit at the Rheumatology Research Center, Shariati Hospital, Tehran University of Medical Sciences(TUMS), Tehran, Iran. Recruited patients were required to have no history of psychiatric disorders. The Leeds BD-QoL, SF-36 health survey, Iranian Behçet’s disease dynamic activity measure (IBDDAM), and Behçet’s Disease Current Activity Form (BDCAF) were administered concurrently. A thorough history of each patient was recorded, and physical examination was performed by a rheumatologist. Informed consent form was signed by volunteer participants. SF‑36 Questionnaire The SF-36 consists of 8 major health-related concepts that address individual’s physical and psychological well-being. The major items include limitations in physical activities because of health problems; limitations in social activities due to physical or emotional problems; limitations in usual role activities because of physical health problems; bodily pain; general mental health (psychological distress and well-being); limitations in usual role activities because of emotional problems; vitality (energy and fatigue); and general health perceptions [20]. IBDDAM and BDCAF The IBDDAM is based on interval scale and summarizes disease status based on the accurate history of clinical
Rheumatol Int
manifestations over the preceding 4 weeks. An average activity score/month is calculated for each patient. Scores are proportionate to the severity and duration of each sign [21, 22]. The BDCAF evaluates the BD-related symptoms in the 4-week period of time prior to the visit. One point is given to the presence of different organ involvements including headache, oral ulcers, genital ulcers, skin lesions (pustules, erythema nodosum, or superficial thrombophlebitis), joint involvement (arthralgia or arthritis), gastrointestinal symptoms, ocular lesions, nervous system involvement, and major vessel involvement. Rheumatologist infers the items relation to BD from clinical assessment of patient. The total score will range between 0 and 12 [23]. Cross‑cultural adaptation of BD‑QoL Questionnaire The translation was conducted in rheumatology research center, TUMS, in accordance with the guidelines outlined by Beaton et al. [24] regarding cross-cultural adaptation. Two bilingual translators undertook the forward translation and cross-cultural adaptation of the questionnaire. A second stage involved the synthesis of the Persian translation where the conceptual, idiomatic, and semantic equivalence of translated version was re-evaluated by a committee consisting of rheumatologists, professional translators, and methodologists. True or false answer format did not convey the exact meaning to Persian patients; therefore, the answers were changed to yes or no options. The synthesized Persian questionnaire was back-translated to English by another professional translator. This back-translated version was sent to the original designer of the questionnaire who sent back the draft with comments and amendments on some items to make it closer to the original concept. After performing the suggested amendments, the revised questionnaire was resent to the designer of questionnaire, which was approved. Statistical analysis Data were entered in our data base and analyzed by SPSS 20.0 software (SPSS Inc., Chicago, IL, USA). P value
Rheumatol Int DOI 10.1007/s00296-014-3128-6
INTERNATIONAL
ORIGINAL ARTICLE - VALIDATION STUDIES
Validity and reliability of the Persian version of Behçet’s disease quality‑of‑life (BD‑QoL) questionnaire: a cross‑cultural adaptation Mahdi Vojdanian · Seyedeh Tahereh Faezi · Alan Tennant · Ann W. Morgan · Pedram Paragomi · Mostafa Qorbani · Maryam Mattaji · Fereydoun Davatchi
Received: 13 June 2014 / Accepted: 3 September 2014 © Springer-Verlag Berlin Heidelberg 2014
Abstract The Leeds Behçet’s disease quality-of-life (BDQoL) questionnaire is a specific and valid measure which is applied in English-speaking patients. We conducted Persian adaptation of BD-QoL questionnaire. Between June and December 2012, 220 Iranian patients fulfilling International Study Group criteria for the diagnosis of BD attending the rheumatology clinics at Tehran University of Medical Sciences were enrolled. Bilingual translators undertook the forward translation and cross-cultural adaptation of the BD-QoL questionnaire. Back-translation was conducted, and this version was sent to the designer of the questionnaire and revised accordingly. SF-36 health survey, Iranian Behçet’s disease dynamic activity measure (IBDDAM), and Behçet’s Disease Current Activity Form (BDCAF) were other administered measures. The Varimax rotation
M. Vojdanian · S. T. Faezi (*) · M. Mattaji · F. Davatchi Rheumatology Research Center, Shariati Hospital, Tehran University of Medical Sciences, North Kargar Avenue, Tehran, Iran e-mail: [email protected] A. Tennant Leeds Institute Rheumatic and Musculoskeletal Medicine, St. James’s University Hospital, Leeds, UK A. W. Morgan Department of Rehabilitation Medicine, Faculty of Medicine and Health, The University of Leeds, Leeds, UK P. Paragomi Rheumatology Research Center, Tehran University of Medical Sciences, Tehran, Iran M. Qorbani Non‑Communicable Diseases Research Center, Endocrinology and Metabolism Population Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran
method with Kaiser normalization defined 5 factors with eigenvalues greater than 1.0. Studied cases were comprised of 118 males (53.6 %) and 102 females (46.4 %). Mean age of the patients was 38.3 ± 11.3 years (range 16–73). The mean BD-QoL score was 10.3 ± 8.8. Test–retest reliability was high, and two time points were significantly correlated (Spearman’s correlation coefficient of 0.75–0.84). Cronbach’s α coefficient of 0.949 demonstrated the excellent internal consistency. These factors cumulatively explained 58.74 % of total variance. The ratio of first to second eigenvalue was 7.08, which underlined the undimensionality. The results revealed adapted BD-QoL scores had significant correlation with IBDDAM (correlation coefficient = 0.19, P value = 0.005) and BDCAF (correlation coefficient = 0.21, P value = 0.002). Conversely, no significant correlation between BD-QoL and SF-36 results was detected (P value = 0.078). The Persian version of BDQoL was shown to be unidimensional, highly reliable, and adequate construct validity. Keywords Behçet’s disease · Quality of life
Introduction Behçet’s disease (BD) is a multisystemic vasculitide, which is encountered along the ancient Silk Road especially in Middle East and Far Eastern countries [1, 2]. Turkey has the highest reported prevalence ranging from 80 to 370 per 100,000 [3]. Iran has the second highest prevalence with 80 per 100,000 [4]. The main manifestations include mucocutaneous, ophthalmological, and CNS lesions [5]. The chronic course of Behçet’s disease and complexity of clinical scenario leads to various degrees of functional impairment, activity limitation, and restricted participation
13
(collectively health status) in those with the condition, and can also adversely affect quality of life [6–9]. Furthermore, some of the therapeutic interventions in rheumatologic conditions can also affect the patients’ quality of life [10]. Thus, a number of previous studies have addressed the health status and quality of life in the Behçet’s population [8, 11, 12]. Some of these studies focused upon the effect of a specific feature of BD such as mucocutaneous or ocular symptoms [6, 8, 9], while other studies investigated the relationship between BD activity level and quality-of-life parameters (e.g., life satisfaction) [12, 13]. Two methodologies have been described in the literature to assess the health status and quality of life in patients with chronic disease. One is the generic health status instrument that provides a concise overview of health-related qualityof-life issues (HRQOL). The main advantage of a generic instrument is that it provides opportunity to assess various aspects of health status that are expected to impact quality of life across different conditions. The second method employs specific instruments, which targets single-disease states (disease-specific), but also patient groups or areas of function [14]. Specific instruments can investigate the impact of the condition on quality of life, and are reported to be a more suitable approach in the evaluation of treatment effects and the follow-up of patients [15, 16]. Currently, the only specific instrument to study quality of life in Behçet’s disease is the Leeds BD quality-of-life (Leeds BD-QoL) questionnaire [7]. The Leeds BD-QoL is a self-administered questionnaire consisting of 30 questions with two-option answers, true [1] or not true (0), thus total score ranges between 0 and 30 [7]. The original development process involved identifying potential items from qualitative interviews with patients, so leading to a draft questionnaire that was posted to a wider sample in order to examine its validity, reliability, and internal consistency. After a short interval of 30 days, the questionnaire was resent to patients to check its test–retest reliability. Initially, 71 items were selected, which were deemed to reflect the impact of the condition upon quality of life, and these included themes were related to the patients’ communication, emotions, life limitations, and self-perception. Rasch analysis revealed 30 BD-related items that were invariant for age and sex. The BD-QoL was shown to be a reliable and valid instrument with appropriate psychometric properties [7]. As the original version of BD-QoL was developed in the English language, and as the most prevalent regions are located in non-English-speaking countries, the issue of cross-cultural adaptation became paramount. To date, only two other language adaptations have been developed. Thouma et al. confirmed validity, reliability, and internal consistency of adapted Arabic version of BD-QoL [17]. Another adaptation was conducted by Yi et al. [18] who
13
Rheumatol Int
translated BD-QoL questionnaire into Korean. The adapted Korean questionnaire revealed a significant correlation with the Clinical Activity Form for Korean Patients with BD (BDCAF-K) and the Center for Epidemiologic StudiesDepression (CES-D) scales. Moreover, the Korean adaptation had acceptable internal consistency and test–retest reliability. Given the considerable prevalence of BD in Iran and the need to evaluate patients’ health status and its impact upon QoL, a Persian translation of QoL questionnaire was deemed necessary. Thus, the Behçet’s unit of the rheumatology research center in TUMS, which is considered the referral center in the country for BD population, set out to adapt the BD-QoL into the Persian language, and to test its validity and reliability.
Methods Patient enrollment Between June and December 2012, 220 Iranian patients were enrolled into the study who fulfilled the International Study Group (ISG) criteria for the diagnosis of BD [19] and who attended the BD Research Unit at the Rheumatology Research Center, Shariati Hospital, Tehran University of Medical Sciences(TUMS), Tehran, Iran. Recruited patients were required to have no history of psychiatric disorders. The Leeds BD-QoL, SF-36 health survey, Iranian Behçet’s disease dynamic activity measure (IBDDAM), and Behçet’s Disease Current Activity Form (BDCAF) were administered concurrently. A thorough history of each patient was recorded, and physical examination was performed by a rheumatologist. Informed consent form was signed by volunteer participants. SF‑36 Questionnaire The SF-36 consists of 8 major health-related concepts that address individual’s physical and psychological well-being. The major items include limitations in physical activities because of health problems; limitations in social activities due to physical or emotional problems; limitations in usual role activities because of physical health problems; bodily pain; general mental health (psychological distress and well-being); limitations in usual role activities because of emotional problems; vitality (energy and fatigue); and general health perceptions [20]. IBDDAM and BDCAF The IBDDAM is based on interval scale and summarizes disease status based on the accurate history of clinical
Rheumatol Int
manifestations over the preceding 4 weeks. An average activity score/month is calculated for each patient. Scores are proportionate to the severity and duration of each sign [21, 22]. The BDCAF evaluates the BD-related symptoms in the 4-week period of time prior to the visit. One point is given to the presence of different organ involvements including headache, oral ulcers, genital ulcers, skin lesions (pustules, erythema nodosum, or superficial thrombophlebitis), joint involvement (arthralgia or arthritis), gastrointestinal symptoms, ocular lesions, nervous system involvement, and major vessel involvement. Rheumatologist infers the items relation to BD from clinical assessment of patient. The total score will range between 0 and 12 [23]. Cross‑cultural adaptation of BD‑QoL Questionnaire The translation was conducted in rheumatology research center, TUMS, in accordance with the guidelines outlined by Beaton et al. [24] regarding cross-cultural adaptation. Two bilingual translators undertook the forward translation and cross-cultural adaptation of the questionnaire. A second stage involved the synthesis of the Persian translation where the conceptual, idiomatic, and semantic equivalence of translated version was re-evaluated by a committee consisting of rheumatologists, professional translators, and methodologists. True or false answer format did not convey the exact meaning to Persian patients; therefore, the answers were changed to yes or no options. The synthesized Persian questionnaire was back-translated to English by another professional translator. This back-translated version was sent to the original designer of the questionnaire who sent back the draft with comments and amendments on some items to make it closer to the original concept. After performing the suggested amendments, the revised questionnaire was resent to the designer of questionnaire, which was approved. Statistical analysis Data were entered in our data base and analyzed by SPSS 20.0 software (SPSS Inc., Chicago, IL, USA). P value
