Application of World Health Organization Quality of Life Instrument, Short Form (WHOQOL-BREF) in measuring quality of life in patients with cataract

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1 Application of World Health Organization Quality of Life Instrument, Short Form (WHOQOL-BREF) in measuring quality of life in patients with cataract Ali Gholami 1, 2, Mahmood Tavakoli Araghi 3, Fatemeh Shamsabadi 3, Mahdiye Bayat 3, Fatemeh Dabirkhani 3, Farhad Moradpour 5, Kamyar Mansori 4, Yosef Moradi 2, Abdolhalim Rajabi 2* 1 Department of Public Health, School of Public Health, Neyshabur University of Medical Sciences, Neyshabur, Iran 2 Department of Epidemiology, school of public health, Iran University of Medical Sciences, Tehran, Iran 3 Students Research Committee, Neyshabur University of Medical Sciences, Neyshabur, IR Iran 4 Department of Epidemiology, school of public health, Shahid Beheshti University of Medical Sciences, Tehran, Iran 5 Department of Epidemiology, School of Public Health, Sanandaj University of Medical Sciences, Sanandaj, Iran * Corresponding author: Abdolhalim Rajabi Tel: rajabiepid@gmail.com Running title: Quality of life in patients with cataract

2 Application of World Health Organization Quality of Life Instrument, Short Form (WHOQOL-BREF) in measuring quality of life in patients with cataract Abstract Objectives: Cataract is a prevalent disease in senile persons and has some negative influence on patients quality of life. This study conducted to study the application of WHOQoL-Bref in determining quality of life in patients with cataract. Methods: In this cross-sectional study, an entire of 300 patients with cataract were studied in Neyshabur from July to October The Iranian version of the WHOQoL-BREF questionnaire was used to measure quality of life. Cronbach s alpha coefficient, Pearson s correlation coefficient, Paired t-test, t-independent test and Linear Regression Model were used for analyzing data. Data were analyzed using SPSS software ver16. Results: The mean age of the contributors was 68.11±11.98 yr and the majority of them were female (53%). The overall observed Cronbach s alpha coefficient for WHOQoL- BREF was and for each domain ranged from to The total mean score of WHOQoL-BREF was The highest and lowest mean scores were observed in Social relationship domain (14.11) and physical health domain (12.29), respectively. Backward multiple linear regression model displayed that duration of disease and marital status are associated with total WHOQoL, age, duration of disease, marital status and income level are associated with Domain1, Domain2, Domain3 and Domain4, respectively (p<0.05). Conclusion: Reliability analysis in this study indicated an acceptable internal consistency of WHOQOL-BREF scale to measure quality of life in patients with cataract. Also, it appears that surveyed patients with cataract have relatively moderate quality of life. Keywords: Cataract, Quality of life, Reproducibility of Results, Iran 1

3 Introduction Cataract is a common disease in senile persons and is especially prevalent in those older than 65 years. Cataract manifests itself as double or distorted vision, halo or glare vision, blurry vision, colors appearing differently, and gradual worsening of vision (1). Surgical and non-surgical managements are two strategies for treatment of cataract. Non-surgical strategy is typically performed during early cataract development, and operative strategy is generally performed when a cataract affects patients daily activities (2). Snellen visual acuity has been widely used in clinical practice for measurement of a patient s visual function. Vision problems due to cataract have some negative effect on patients quality of life. Quality of life is defined by World Health Organization (WHO) as an individual's perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards and concerns (3). Evaluation of the prevalence of cataract and its problems cannot convey the full meaning of the impact of it on the physical, mental and social well-being of individuals. Quality of life measures allow for a more comprehensive view of the problems due to cataract. To study quality of life, we must be able to measure it. The World Health Organization QoL-BREF (WHOQoL-BREF) questionnaire is a commonly utilized generic measure of quality of life and is used to measure quality of life in healthy people and different patients groups(4-20). The WHOQoL-BREF questionnaire is available in many languages (21), and also it has been translated into Persian and then validated in Iran by Nedjat (21). So this study conducted to study the utility of WHOQoL-Bref in assessing quality of life in patients with cataract. 2

4 Materials and Methods In this cross-sectional study, the data were collected between July and October 2014, from all cataractous patients whom they conferred to two hospitals in the city of Neyshabur (A city in Northeastern of Iran) for surgery. From all patients provided informed consent after being acquainted with the purpose of study. Procedure and Study Instrument In this study, questionnaires have been filled by personally interview, but before the interview, all participants were informed that their responses would remain confidential. The Persian validated brief version of the WHO's QOL scale (WHOQOL-BREF) was used in this study. This questionnaire contains two items from the Overall QOL and General Health and 24 items of satisfaction that divided into four domains: physical health with 7 items (Domain1), psychological health with 6 items (Domain2), social relationships with 3 items (Domain3) and environmental health with 8 items (Domain4). Each item is rated on a 5-point Likert scale and scored from 1 to 5 on a response scale. According to guidelines, raw domain scores for the WHOQOL were transformed to a 4 20 scores (22). Scores of each domain are scaled in a positive direction (i.e., lower scores denote lower QOL). The mean score of items in each domain is used to calculate the domain score, and finally they transformed linearly to a scale(23, 24). Inclusion criteria applied in the study included: 1. having cataract, 2. residence in Neyshabur, 3. agreement to participate in the study. Dependent and Independent variables In this study, four domains of WHOQOL-BREF questionnaire were considered as dependent variables and the other data (age, sex, education level, marital status, income level (per month), local residence and duration of disease) were considered as independent variables. The age of participants was represented by two categories of 65 yr and > 65 yr. Education level was categorized into two groups: illiterate and literacy. Marital status was categorized into two categories, including single/divorced and married. Income level was divided into two categories including 5 million rial and >5million Rial per month. Local residence was categorized into two categories, including urban and rural. Time duration from detection of cataract was divided into two categories including 30 days and >30 days. 3

5 Statistical Analyses In this study, data were analyzed with the use of SPSS16 software. Descriptive analyses executed including frequencies, percentages, ranges, means, and standard deviations (SD). The reliability of the WHOQoL- BREF domains and overall QOL were assessed using Cronbach's Alpha (0.70 and over were deemed acceptable)(25). We used of Pearson s correlation coefficient to determine the level of agreement between four domains of WHOQOL-BREF. Paired t-test was used to compare the mean scores of different domains of WHOQOL-BREF. T-independent test and linear regression model were used to investigate the relationship between patients' QoL and their characteristics. Transformed scores were used for statistical analyses in all domains and the level of significance was set at p < 0.05 for all analyses. 4

6 Results In total, 300 patients with cataract filled out the WHOQOL-BREF questionnaire in this study. The characteristics of study population are shown in Table 1. The mean age of study population was ± year. Of all participants who contributed in this study, 158 persons (53%) were female, and 142 persons (47%) were male. Table 2 presents the missing, mean score, standard deviation, floor and ceiling effects for each item. The highest and lowest mean score observed in personal relationship (3.99) and leisure activity (2.09) items respectively. The percentage of respondents scoring at the highest level (ceiling effect) ranged from 2.3 to 35.3 while the percentage of respondents scoring at the lowest level (floor effect) ranged from 1 to In this study, Cronbach s alpha coefficient was applied to examine the internal consistency of WHOQOL-BREF scale (24 items) as well as the four domains of it. The Cronbach s alpha coefficient of WHOQOL-BREF was adequate (0.889) for all 24 questions and for each domain the values are: Domain1 (0.810), Domain2 (0.765), Domain3 (0.731) and Domain4 (0.714). As table 3 shows, there are statistically significant correlations between all domains of WHOQOL-BREF. Also, statistically significant correlation was observed between overall QOL (Q1) and scores of different domains in table 3. In this study in order to compare the mean scores of four domains of WHOQOL-BREF, the paired t-tests were used. As table 4 shows, there were significant differences between all different domains of WHOQOL-BREF (except difference between domain2 and domain4). The total mean score of WHOQoL-BREF was (65.95%). Among the different domains of WHOQOL-BREF, the lowest and highest mean and percentage of satisfaction were found for Domain1 (Mean = 12.29; percentage = 51.95) and Domain3 (Mean = 14.11; percentage=63.20) respectively (table 5). The mean score of four domains and total of WHOQOL-BREF according to independent variables (sex, age, education years, marital status, income, duration of disease, and local residence) are displayed in Table 5. As seen in table 5, mean and percentage of satisfaction rating in total and also in Domain1, Domain2 and Domain3 were lower in males than females but this is reversed in DOM4. Also, mean and percentage of satisfaction rating in all domains in married persons were higher than single (table 5). As Table 5 illustrates, there were differences between different states of some variables (age, sex, education level, marital 5

7 status, income level (per month), local residence and duration of disease) in total or in four domains of WHOQOL at significant level of P<0.2. Table 6 displays the results of Backward Multiple Linear Regression; it is obvious that duration of disease and marital status are significantly associated with total WHOQOL. Age is associated with Domain1, duration of disease associated with Domain2, marital status associated with Domain3 and income associated with Domain4. 6

8 Discussion In this study, we evaluated the reliability (internal consistency) of WHOQOL-BREF questionnaire in patients with cataract. The findings from this study confirm that WHOQOL-BREF questionnaire has good internal consistency (α=0.889) and for each of its domains were satisfactory (α>0.7). Reliability analysis of Skevington (26), Nedjat (27), Gholami (28, 29), Asnani (6) and Mazaheri(12) studies indicated an acceptable internal consistency of WHOQOL-BREF scale (α>0.7), however, Cronbach's Alpha value for social relationship domain was partly low (α <0.7) in these studies. In this study, a positive correlation between all domains of WHOQOL-BREF was observed. All correlations were found statistically significant. In Gholami and Mazaheri studies, also a positive correlation between all domains of WHOQOL-BREF was observed (6, 28, 29). According to table 4, mean scores of four domains were different (except a difference between domain2 and domain4), and the most difference was observed between Domain1 and Domain3. In Gholami and Mazaheri studies found that mean scores of four domains were different, and the most difference was observed between Domain1 and Domain4 (6, 28, 29). In this study, among the four domains of WHOQOL- BREF, the lowest mean satisfaction rating was found for Domain1 (physical health, Mean = 12.19), implying relatively low activities of daily living, more dependence on medicinal substances and medical aids, lack of enough energy and mobility, more pain and discomfort, lack of sufficient sleep and rest and bad work capacity. Moreover, the highest mean score was observed in domain3 (social relationships, 14.11), implying that study population had fairly more satisfaction of their personal relationships and sexual activity and also social support. In this study, maximum SD from mean (SD=3.45) was observed in Domain3 (Social Relationships). In some studies that used of WHOQOL- BREF questionnaire, it also was observed that Domain3 had highest SD from the mean (6, 12, 27-29). Maximum SD of mean observed in Domain3 may be associated with different interpretations of the items used in this domain and also small number of items. In the present study, after the use of multiple linear regression model, it was observed that duration of disease, and marital status are significantly associated with total WHOQOL, so that patients with duration of disease lower than 30 days had lower quality of life and also 7

9 single patients had a lower quality of life. Age was associated with Domain1; therefore, patients with age lesser than 65 years old had higher physical health. Duration of disease was associated with Domain2; hence patients with duration of disease lesser than 30 days had lower psychological health. Marital status associated with Domain3, therefore, married patients had higher social relationships. Income level associated with Domain4, so that patients with high income had higher environmental health. According to result from multiple linear regression model, it was observed that different variables were associated with four domains of WHOQOL- BREF. There are a number of limitations to this study. First, as this was a cross-sectional study, causality between the compared variables cannot be concluded. Second, the surveyed population in this study was relatively small. 8

10 Conclusion: This study has shown good reliability of the WHOQOL-Bref questionnaire in determining quality of life in patients with cataract. Also, from the data it appears that surveyed cataract patients have relatively moderate quality of life. In this study observed that age, marital status, income level (per month), and duration of disease are important variables influencing quality of life of patients with cataract. Conflict of interest statement The authors have no conflicts of interest. Acknowledgments The author gratefully acknowledges the patients with cataract who willingly contribute in this study. Financial Disclosure This study was funded by Students Research Committee of Neyshabur University of Medical Sciences. 9

11 Table 1: Characteristics of study population (n=300) Characteristics n % Age 65 yr >65 yr sex Female Male Education level Illiterate Literacy Marital Status Single/ Divorced Married Income Level (per month) 5 million rial >5 million rial Local Residence Urban Rural Duration of disease 30 day >30 day

12 Table 2: Response pattern and missing items for each item (n = 300) Missing Mean Floor ceiling SD Items (items numbers) n (%) Score n (%) n (%) Overall QOL (1) 0 (0) (4.3) 20 (6.7) Overall Health (2) 0 (0) (7.3) 33 (11) Pain (3) 0 (0) (15.3) 66 (22) Dependence of medical aids (4) 0 (0) (7) 55 (18.3) Positive feeling (5) 0 (0) (11.7) 36 (12) Personal belief (6) 0 (0) (4.7) 48 (16) Concentration (7) 0 (0) (4.3) 32 (10.7) Security (8) 0 (0) (1.7) 70 (23.3) Physical environment (9) 0 (0) (1) 62 (20.7) Energy (10) 0 (0) (8) 18 (6) Bodily image (11) 0 (0) (1.7) Financial support (12) 0 (0) Accessibility of information (13) 40 (13.3) 61 (20.3) 7 (2.3) 0 (0) (6.7) 7 (2.3) Leisure activity (14) 0 (0) (32.3) Mobility (15) 0 (0) (11) 5 (1.7) 35 (11.7) Sleep and rest (16) 0 (0) (4.7) 51 (17) Activities of daily living (17) 0 (0) (7.6) 22 (7.3) Work capacity (18) 0 (0) (3) 16 (5.3) Self-esteem (19) 0 (0) (1.3) Personal relationship (20) 0 (0) (2) Sexual activity (21) 55 (18.3) (3.3) 91 (30.3) 106 (35.3) 59 (19.7.7) Social support (22) 0 (0) (5.3) 57 (19) Home environment (23) 0 (0) (2) 45 (15) Health care (24) 0 (0) (3.3) 42 (14) Transport (25) 0 (0) (2.7) 28 (9.3) Negative feeling (26) 0 (0) (11) 100 (33) 11

13 Table 3: Correlation coefficients in two overall questions and four domains of WHOQOL-BREF Q1 Q2 Domain1 Domain2 Domain3 Domain4 Q1 CC P.value Q2 CC P.value Domain1 CC P.value Domain2 CC P.value Domain3 CC Domain4 P.value CC P.value 1 Pair 1 Pair 2 Pair 3 Pair 4 Pair 5 Pair 6 Table 4: Paired t-test for the four domains of WHOQOL-BREF Paired Differences Sig. 95% CI of the Std. t-test df (2- Mean Difference Deviation tailed) Lower Upper DOM1- DOM DOM1- DOM DOM1- DOM DOM2- DOM DOM2- DOM DOM3- DOM

14 Table 5: Comparison of the WHOQOL-BREF mean scores in four domains according to independent variables Domain1 Domain2 Domain3 Domain4 Total Mean±SD Mean±SD Mean±SD Mean±SD Mean±SD Total 12.29± ± ± ± ±1.81 Age ( year ) 65 y >65 y P value Sex Female Male P value Education level Illiterate Literacy P value Marital status Married Single P value Income level (per month) Rial > Rial P value Local residence Urban Rural P value Duration of disease 30 day >30 day P value 12.84± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± Table 6: Backward multiple linear regression analyses of significant factors associated with QOL QOL Unstandardized Standardized Variables domains coefficients coefficients t P value B SE Beta Domain 1 Age Domain 2 duration of disease Domain 3 marital status

15 Domain 4 Income level marital status Total duration of disease 14

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