Psychometric validation of a Hindi version of a chronic obstructive pulmonary disease (COPD) assessment test in patients in northern India

Background. We aimed to validate a Hindi version of a chronic obstructive pulmonary disease (COPD) assessment test (CAT) for assessing the health status of patients in northern India. Methods. Of the 178 patients studied, 171 with COPD self-completed CAT twice at a 4-week interval. The patients also self-completed the Hindi versions of the abbreviated World Health Organization Quality of Life questionnaire (WHOQOL-Bref) and St George's Respiratory Questionnaire (SGRQ) at the initial assessment. Baseline clinical details and spirometric data were recorded. Acceptability, validity, internal consistency, test-retest reproducibility and responsiveness were assessed using standard tools. Results. The study population of 178 had 167 (93.8%) males and 159 (89.3%) smokers. One hundred and twenty-seven (71.3%) patients completed the second assessment, of whom the condition of 19 had worsened. Each of the eight CAT items correlated strongly with the total CAT score (Pearson coefficients 0.59-0.73). The total CAT score correlated well with the dyspnoea grade, SGRQ domain scores and the physical domain score of WHOQOL-Bref. Cronbach's alpha coefficient had a high value of 0.83. The intraclass correlation coefficient for 101 patients with stable disease between the two assessments was high (0.83), but the effect size in the 19 patients who recovered from an exacerbation was moderate (0.45). Conclusion. The Hindi version of CAT has good validity and reliability and can be used to quantify the health impact of COPD among patients in northern India.