Validation of the Persian work productivity and activity impairment questionnaire in asthmatic patients

Abstract

ABSTRACT Background The work productivity and activity impairment (WPAI) questionnaire is a fine linguistic validated tool to measure work productivity and activity impairment. Considering its capability, this study aimed to evaluate the validity of the Persian version of WPAI-AQ in asthmatics. Methods The standard forward-backward process was used to translate the English version of WPAI-AQ into Persian. The convergent validity and responsiveness were evaluated by analyzing the correlations between the Persian WPAI-AQ and the health outcomes, and its longitudinal change score with the change in SGRQ score, respectively. Additionally, the stability was estimated according to test-retest scores. Results There was a significant correlation between the Persian WPAI-AQ related outcomes and symptoms, activities, and impacts of disease (r = 0.41–0.89, p < 0.04). Desirable stability was observed by the test-retest analysis; 0.90 (95%CI: 0.89–0.95) for overall impairment, 0.90 (95%CI: 0.86–0.93) for work time missed, 0.72 (95%CI: 0.54–0.83) for activity impairment; 0.79 (95%CI: 0.71–0.86) for student class time missed, and 0.76 (95%CI: 0.66–0.81) for school impairment. Response to the change scores strongly supported the longitudinal responsiveness of the Persian WPAI-AQ (r = 0.37 to 0.63, p < 0.05). Conclusion The Persian WPAI-AQ is a feasible valid tool to estimate work productivity and activity impairment in Persian-speaking asthmatic patients.