We in this study aimed to evaluate internal consistency of transculturally adapted WHOQOL‑BREF questionnaire in patients with CLBP. Results of our study suggest that Hi-WHOQOL-BREF is reliable and valid tool for assessing QOL in Hindi speaking patients with CLBP. Hi-WHOQOL-BREF in our study showed excellent internal consistency. (Cronbach-α 0.869 - 0.938) The test retest reliability was good (ICC 0.768-0.883). Maximum positive correlation was found between domain 2 (PS) of and vitality (VT) of SF-36. Confirmatory factor analysis showed that approximately all three models were fitted well and similarly.
The WHOQOL-100 allows detailed assessment of each individual facet relating to QOL. In certain instances however, the WHOQOL-100 may be too lengthy for practical use. The WHOQOL-BREF Field Trial Version has therefore been developed to provide a short form of QOL assessment questionnaire that looks at domain level profiles. WHOQOL-BREF has been widely translated and validated in several languages and in many chronic disorders.19 Hindi version used in the present study was obtained from WHO organisation online.
Previous literature suggests that Hindi version of the questionnaire possess good internal consistency with high Cronbach alpha range in different settings.20 Hi-WHOQOL-BREF in our study showed excellent internal consistency with cronbach’s-α reaching 0.869 and 0.938 in patients of CLBP. This is more than all other versions validated for respective populations in other languages: Krio 0.55-0.7221, Amharic >0.722, Kazakh 0.7-0.7823, Chichewa >0.724, Libras 0.6-0.87325, Odia 0.65-0.77, and Malayalam 0.28-0.4826. Lower internal consistency was found in social domain. This can be attributed to the small number of questions (3 items) in social relationships domain. Further, domain enquires into the sexual life and social support which are perceived and answered in a different way in Indian society. This domain showed similar results in validation studies in different countries.7,23,26
The correlation between the SF-36 and Hi-WHOQOL-BREF has been examined previously in different fields with contradictory results. While some studies have shown strong correlation between both questionnaires, others have reported weak correlation. This suggests that the reliability and validity of these two questionnaires for the evaluation of QoL may be different. In a national survey on 11,440 civilian residents of Taiwan, Huang et al indicated that the correlations were weak among the subscales of both instruments and concluded that both SF-36 and WHOQOL-BREF appeared to measure different constructs.27 Another study by Hsiung et al on patients with HIV infection reported that both the questionnaires were reliable and valid health-related QoL instruments.28 Our study found good construct validity of WHOQOL-BREF in patients with CLBP. (Pearson coefficient 0.206 - 0.702).
93.6% patients completed the questionnaires on day 3 indicating good acceptability.. There was no confusion in reporting of any of the domains. The scale was easily understandable and acceptable, and could be completed by patients in about 8 (1.4) minutes. This confirms that the meaning of the original items was not changed during translation done by WHO.
In our study there was a significant difference in response to item 15 of physical health (p-value 0.000) “Aap kitni achi tarah idhar udhar aa ja pate hain”( How well are you able to get around?) and item 5 of psychological domain (p value 0.023) “Aap jeevan mai kitna aanand lete hain”( How much do you enjoy life?) between day 0 and day 3. CLBP is a dynamic state and variation in mobility is dependent on pain. This might have led to variation in response creating a bias in reporting of this question. Overall state of the person, especially when in pain can be a confounding factor while filling the questionnaire.
CFA done in our study showed that the proposed model 2 captured the covariance between all the items in the model 1. WHOQOL-BREF is an acceptable model as seen by the absolute indices, where RMSEA value of .06 or less and GFI value of over .9 is indicative of acceptable model fit. The relative fit indices (also called “incremental fit indices” and “comparative fit indices” too ensured that misspecified models are deemed acceptable by achieving a value greater than .90.
Though there are many published QOL measures, there is still a lack of consensus amongst researchers about its definition as seen in the choice of items for their instruments while assessing QOL. SF-36 is a sufficient measure of health status and functioning of patients with LBP29 and hence we decided to use it as a reference scale. However, it is a more objective questionnaire when compared to WHOQOL-BREF and requires more time to fill. On the other hand, WHOQOL-BREF is a completely subjective questionnaire.
WHO-QOL assessment scale is a valuable tool for patients with CLBP where prognosis is likely to involve only partial recovery or remission. Countries where no validated QoL measures currently exist can be confident that data yielded by work involving the WHOQOL assessments will be genuinely sensitive to their setting. This study shall make multi-centre QoL research possible and comparable.
One of the advantages of this study is the use of a sample from one of the largest government hospitals in North India for the validation of the Hindi version of a patient satisfaction questionnaire. This sample may overcome any cultural and environmental factors that could lead to differences in the instrument’s ability to measure an object of interest. The high response rate to the questionnaire can be explained by its design, which takes into consideration the deficiencies observed in other questionnaires, such as a large number of questions, including all the activities performed in daily living of a common person, which may discourage participants from completing the questionnaire.
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STUDY LIMITATIONS
The present study has certain limitations. Even though explained, an intention to aggravate ones condition for the above reason and thus creating a test retest reliability bias cannot be ruled out. Also, investigators did not undergo any formal training to conduct cognitive debriefing. Another limitation was the short test–retest time interval (3 days). This was selected assuming no change in disease state within such a short span of time. However, the chance of the memory effect for an observed effect of good test–retest reliability cannot be ruled out. Finally, the generalizability of the Hi-WHOQOL-BREF to other musculoskeletal disorders apart from CLBP cannot be assured from the results of the present study.