Acute exacerbations of chronic obstructive pulmonary disease and the effect of existing psychiatric comorbidity on subsequent mortality.

Objectives: Studies investigating associations between chronic obstructive pulmonary disease (COPD) outcomes and psychiatric comorbidity have yielded mixed findings. We examined a national sample of hospitalized COPD patients to evaluate the impact of three psychiatric conditions on mortality and readmission.

Methods: Department of Veterans Affairs (VA) administrative and laboratory data were used to identify 26,591 consecutive patients admitted for COPD during October 2006 to September 2008. Associations between psychiatric comorbidity and both 30-day mortality and readmission were examined using generalized estimating equations and Cox proportional hazards regression, respectively, with adjustments for patient demographics, medical comorbidities, illness severity, and clustering within hospitals.

Results: Unadjusted 30-day mortality was higher in patients with anxiety (5.3% vs. 3.8% [P < 0.001]) and depression (6.2% vs. 3.8% [<0.001]). In multivariable analyses, adjusted odds of 30-day mortality were higher for patients with depression (OR, 1.53; 95% CI, 1.28-1.82) and anxiety (OR, 1.72; 1.42 -2.10), but not for patients with PTSD (OR, 1.19; 0.92-1.55). Unadjusted 30-day readmission rates also varied by diagnosis; depression and PTSD were associated with lower rates of readmission (10.4% vs. 11.6% [<0.05] and 8.6% vs. 11.6% [<0.001], respectively), whereas anxiety was not (11.3% vs. 11.5% [NS]). However, after covariate adjustment using multivariable models, anxiety and depression (but not PTSD) were associated with increased risk for readmission (HR, 1.22; 1.03 -1.43 and HR, 1.35; 1.18 -1.54, respectively).

Conclusion: Comorbid anxiety and depression may have an adverse impact on COPD hospital prognosis or may be indicative of more severe illness.