Reliability and validity of the Malay version of the Health-Related Quality of Life instrument in a Malaysian population

OBJECTIVE: To validate the Malay version of the Health-Related Quality of Life (Mal-HRQOL-20) questionnaire in patients with and without urinary symptoms in a Malaysian population. PATIENTS AND METHODS: The validity and reliability of the Mal-HRQOL-20 were assessed in patients with and without lower urinary tract symptoms (LUTS). The reliability was evaluated using the test-retest method and the internal consistency using Cronbach's alpha. Sensitivity to change was expressed as the effect size in the score before and after intervention in additional patients with LUTS who underwent transurethral resection of the prostate. RESULTS: The internal consistency was excellent; there was a high degree of internal consistency for each of the 20 items and for the overall score (Cronbach's alpha > or = 0.57 and 0.79, respectively) in the population study. The test-retest correlation coefficient for the 20 item scores was highly significant. The intra-class correlation coefficient was high (> or = 0.55). The sensitivity and specificity were high for the effects of treatment. There was a very significant agreement between scores before and after treatment across all domains in the treatment cohort, but not in the control group. CONCLUSION: The Mal-HRQOL-20 is suitable, reliable, valid and sensitive to clinical change in the Malaysian population.