Performance of an Asthma Quality of Life Questionnaire in an Outpatient Setting

Abstract

The objectives of this study were to assess the validity, reliability, and responsiveness of a disease-specific quality of life questionnaire (AQLQ) in asthma patients presenting for assessment and treatment in an emergency department (ED). Fifty-two patients 18 to 64 yrs of age were surveyed in three EDs. Admitted and discharged patients with stable and unstable asthma were included. Patients were interviewed prior to discharge from the ED. They completed a self-report asthma questionnaire, the self-administered Sickness Impact Profile (SIP) and AQLQ, a global assessment of asthma severity, a symptom questionnaire, and pulmonary function testing. Forty-three (83%) patients were available for follow-up at 7 to 10 days, and they completed a similar series of tests. Moderate correlations were found between total SIP and AQLQ measurements (r = 0.49; p < 0.001). Correlations were high between physical domain scores of the SIP and AQLQ symptoms (r = 0.58; p < 0.0001) and activity limitations (r = 0.50; p < 0.0001). Low correlations were found between pulmonary function results and AQLQ domains, except activity limitations (r = 0.44; p < 0.001). High correlations were found between symptoms or global assessments and AQLQ (r > 0.6; p < 0.0001). The instrument is highly responsive to small changes in patient status and outperforms pulmonary function tests and symptom scores in this setting. Test-retest reliability in patients who were stable was substantial (intraclass correlation coefficients > 0.9) on all aspects of the AQLQ. The AQLQ has been shown to be a reliable, valid, and responsive instrument for use in outpatient studies of patients who present with exacerbations of asthma and are discharged from the ED setting. Its use should be encouraged in future studies of asthmatic patients.