Reliability and Validity of the Persian Version of the European Quality of life Questionnaire (EQ-5D-3L) in Patients with Meniscus and Knee Ligaments Injury

Given the growing importance of evaluating and improving the quality of life as an important factor in determining the therapeutic outcomes, it is essential to validate the instrument that measures this category. This study was designed to evaluate the validity and reliability of the Persian version of the European Quality of Life questionnaire (EQ-5D-3L) in Iranian patients with meniscus and knee ligaments injury. After obtaining permission and receiving the Persian version of the EQ-5D-3L questionnaire from Euro QOL group, this questionnaire was completed with SF-36 and KOOS questionnaires by 143 patients suffering from meniscus and knee ligaments injury (92 patients before and 51 patients after the surgery). Construct validity was tested by apriori hypotheses and discriminative validity was tested by known group method. To evaluate the test-retest reliability, 65 patients who did not report a significant change in their status after one week re-completed the EQ-5D-3L questionnaire. According to the findings, the total score of the EQ-5D-3L questionnaire with the total scores of SF-36 a valid generic instruments (r= 0.445) and dimensions of EQ-5D-3L questionnaire with related dimensions from SF-36 questionnaires (r= 0.37-0.45) and KOOS (r= 0.30-0.45) had a moderate correlation. The EQ-5DIndex score was able to differentiate patients according to the severity of the disease based on the EQ-5DVAS (p=0.000). The intra class correlation coefficients for EQ-5DIndex and EQ-5DVAS were 0.753 and 0.896, respectively. The results showed that the Persian version of the EQ-5D-3L questionnaire has acceptable reliability and validity for measurement of the health-related quality of life in patients with meniscus and knee ligaments injury.