Validation and clinical interpretation of the St George’s respiratory questionnaire for COPD (SGRQ-C) after adaptation to Malaysian language and culture, in patients with COPD
Anees ur Rehman, Mohamed Azmi Hassali, Sabariah Noor Harun, Sameen Abbas, Jaya Muneswarao, Irfhan Ali Bin Hyder Ali, Rabia Hussain
Abstract
BACKGROUND: Cultural differences affect the administration and results of health status questionnaires. "Cross cultural adaptation" ensures retention of psychometric properties such as validity and reliability at an item and/or scale level. OBJECTIVE: To develop a Malaysian version of St George's respiratory COPD specific questionnaire (SGRQ-CM), to evaluate the full spectrum of psychometric properties (reliability, validity and responsiveness), to test the factor structure and to assess minimum clinically important difference for the SGRQ-CM, to be used in population of Malaysia. METHODOLOGY: SGRQ-C was translated to Bahasa Malaysia using a standard protocol. 240 COPD patients were included in the study. All patients were followed-up for six months. Construct validity, internal consistency, item convergent validity, test-retest ability, responsiveness, factor analysis and MCID of the Malaysian version of SGRQ-C to be used in population of Malaysia were evaluated. RESULTS: %predicted were reported as 0.86, - 0.82, 0.72 and - 0.42 respectively. Correlation coefficient between the subscales and other clinical and health status measures ranged from r = - 0.35 to r = - 0.87. The MCID was reported as 5.07 (- 2.54-12.67). CONCLUSION: The Malaysian version of SGRQ-C has a good psychometric property comparable to those of the original version and has a strong evidence of validity, reliability and responsiveness towards disease severity in Malaysian COPD patients. It can be recommended as a reliable quality of life measure for future research.