Depression and chronic obstructive pulmonary disease (COPD). Impact on survival

To determine if the presence of depression in patients suffering from chronic obstructive pulmonary disease (COPD) would have an independent impact on mortality. Prospective evaluation of the impact of depression according to the ICD-10 criteria for depression. Cox proportional hazards regression was used to evaluate the independent impact of depression after controlling for significant univariate clinical predictors in the data set. Consenting out-patients (n = 49) who meet the criteria for COPD between September 1997 and September 1998. There were no age limits (range: 53-90 years). The sample was 67% female. Survival status at follow-up after a mean of 803 days was measured. At follow-up, 16 patients had died. Depression significantly reduced the mortality risk at follow-up (hazard ratio, 0.30; 95% confidence interval, 0.10-0.93; P = 0.037). The impact of depression remained after control for forced expiratory volume during the first second (FEV1), the only multivariate significant predictor of mortality in the data set (hazard ratio, 0.27; 95% confidence interval, 0.09-0.84; P = 0.024). Depression in out-patients suffering from COPD appears to be an independent protector for mortality. Additional studies in larger samples are needed to replicate this finding and to determine possible underlying pathogenetic mechanisms.