ABSTRACT
BACKGROUND: The Asthma Quality of Life Questionnaire (AQLQ) has been shown to have strong measurement properties. Quality of life instruments need to be validated under local conditions before these can be accepted for application in that community. The AQLQ has not been formally validated in India. OBJECTIVES: To measure the evaluative and discriminative properties of the AQLQ (UK English version) in Indian asthmatics. METHODOLOGY: Thirty-eight adult patients with asthma underwent spirometry and completed the AQLQ and the Asthma Control Questionnaire (ACQ), administered by an interviewer. Standard treatment was given for four weeks during which daytime and nocturnal symptoms of asthma, and use of rescue medication were recorded in diaries. The questionnaires were administered again at the end of four weeks and spirometry was repeated. RESULTS: The total and domain-wise scores of AQLQ improved in patients whose control of asthma improved during treatment. It had good reproducibility with no changes in scores in patients whose condition remained stable, and also high intraclass correlation coefficients for the total and domain-wise scores in these patients. Significant correlations were found between the changes in AQLQ scores and in ACQ scores confirming the longitudinal construct validity. The symptoms domain score of the AQLQ was related significantly to the patient diary-recorded scores of cough, sputum and nocturnal asthma. Cross-sectional construct validity of AQLQ was established by demonstrating significant correlation of total, and symptoms and emotions domain scores with the ACQ scores. CONCLUSIONS: It was concluded that the AQLQ (UK English version) has sufficiently acceptable evaluative and discriminatory properties in Indian subjects and is therefore a valid instrument for quality of life measurements in clinical and research studies in asthmatics in Indian patients.