Effects of depressive symptoms on health-related quality of life in asthmapatients

OBJECTIVE: To assess the effects of depressive symptoms on asthma patients' reports of functional status and health-related quality of life. DESIGN: Cross-sectional study. SETTING: Primary care internal medicine practice at a tertiary care center in New Pork City. PATIENTS: We studied 230 outpatients between the ages of 18 and 62 years wi th moderate asthma. MEASUREMENTS AND MAIN RESULTS: Patients were interviewed in person in Engli sh or Spanish with two health-related quality-of-life measures, the disease -specific Asthma Quality of Life Questionnaire (AQLQ) (possible score range , 1 to 7; higher scores reflect better function) and the generic Medical Ou tcomes Study SF-36 (general population mean is 50 for both the Physical Com ponent Summary [PCS] score and Mental Component Summary [MCS] score). Patie nts also completed a screen for depressive symptoms, the Geriatric Depressi on Scale (GDS), and a global question regarding current disease activity. S tepwise multivariate analyses were conducted with the AQLQ and SF-36 scores as the dependent variables and depressive symptoms, comorbidity, asthma, a nd demographic characteristics as independent variables. The mean age of pa tients was 41 +/- SD 11 years and 83% were women. The mean GDS score was 11 +/- SD 8 (possible range, 0 to 30; higher scores reflect more depressive s ymptoms), and a large percentage of patients, 45%, scored above the thresho ld considered positive for depression screening. Compared with patients wit h a negative screen for depressive symptoms, patients with a positive scree n had worse composite AQLQ scores (3.9 +/- SD 1.3 vs 2.8 +/- SD 0.8, P < .0 001) and worse PCS scores (40 +/- SD 11 vs 34 +/- SD 8, P < .0001) and wors e MCS scores (48 +/- SD 11 vs 32 +/- SD 10, P < .0001) scores. In stepwise analyses, current asthma activity and GDS scores had the greatest effects o n patient-reported health-related quality of life, accounting for 36% and 1 1% of the variance. respectively, for the composite AQLQ, and 11% and 38% o f the variance, respectively, for the MCS in multivariate analyses. CONCLUSIONS: Nearly half of asthma patients in this study had a positive sc reen for depressive symptoms. Asthma patients with more depressive symptoms reported worse health-related quality of life than asthma patients with si milar disease activity but fewer depressive symptoms. Given the new emphasi s on functional status and health-related quality of life measured by disea se-specific and general health scales, we conclude that psychological statu s indicators should also be considered when patient-derived measures are us ed to assess outcomes in asthma.