Depression is associated with poor prognosis in patients with chronic obstructive pulmonary disease - a systematic review

INTRODUCTION: Patients with depression have significantly increased mortality from somatic disease. The purpose of this article was to review studies that investigate if there is a prognostic association with depression as co-morbidity in patients with chronic obstructive pulmonary disease (COPD). We chose the following outcomes: mortality, suicide behaviour, risk of COPD exacerbation, use of primary care and prescription data.

METHODS: A literature review was performed on 16 December 2014 in PubMed, Embase, OVID Medline and Cochrane for cohort studies. Only studies with mortality and exacerbation/hospital admissions were found. Studies failing to meet relevant criteria in terms of design or/and outcome, and studies with significant methodological faults were excluded.

RESULTS: A total of 22 cohort studies were included. Of these studies, 20 were prospective, one retrospective and one was a combined retro- and prospective study. There was a tendency for studies with more patients and higher methodological quality to show a positive correlation. Sixteen of the studies showed that depression was associated with increased mortality (relative risk (RR): 1.02-3.6) and more COPD exacerbations (RR: 1.3-7.0).

CONCLUSIONS: The results showed that not only is depression a debilitating disease on its own, it also predisposes to COPD exacerbations and increased mortality in patients with COPD. Depression in patients with COPD is under-diagnosed and undertreated, and a stronger focus on the clinical significance of depression as co-morbidity is warranted.