What Predicts Change in Pulmonary Function and Quality of Life in Asthma or COPD?

Abstract

Information about predictors of decline in pulmonary function (forced expiratory volume in 1 second [FEV₁]) or health-related quality of life (HRQoL) in patients with asthma or (chronic obstructive pulmonary disease [COPD]) might help to determine those who need additional care. A 2-year prospective cohort study was conducted among 380 asthma and 120 COPD patients. In both asthma and COPD patients, a 2-year change in FEV₁ was only weakly associated with a 2-year change in HRQoL (r =. 0.19 and 0.24, respectively). In both groups, older age, living in an urban environment, and a lower peak expiratory flow rate (PEFR) at baseline were associated with a decline in FEV₁. Additional predictors of FEV₁ decline were greater body weight, less chronic cough or sputum production, and less respiratory symptoms in asthma patients and current smoking in COPD patients. A decline in HRQoL was associated with older age, non-compliance with medication, more dyspnea, and a lower PEFR in asthma patients and with male gender, lower education, lower body weight, more dyspnea, and more respiratory symptoms in COPD patients. Our results show that FEV₁ and HRQoL appear to represent different disease aspects influenced by different predictors.