Prevalence of sub-threshold depression in elderly patients with chronic obstructive pulmonary disease

Abstract

Objectives: We hypothesized that COPD patients with sub-threshold depression would have levels of disability and impaired quality of life approaching that for major depression and significantly greater than for non-depressed COPD patients.

Setting: A university teaching hospital

Method: 137 outpatients (69 men), with a mean age of 73 years (range 60-89 years) with symptomatic irreversible, moderate to severe COPD were recruited. Subjects were interviewed using the Geriatric Mental State Schedule (GMS), a structured psychiatric interview schedule, along with its diagnostic algorithm AGECAT. A GMS/AGECAT score of 3 or more is indicative of a case-level of depression, a GMS/AGECAT score of 1-2 indicates sub-threshold depression and GMS/AGECAT of 0, no depression. Physical disability was measured by the Manchester Respiratory Activities of Daily Living questionnaire (MRADL) and quality of life was assessed by the Breathing Problems Questionnaire (BPQ).

Results: Mean (SD) one second forced expiratory volume was 0.89 (0.33) litres. The prevalence of GMS/AGECAT case-level depression (>or= 3) was 57 cases (42%); of GMS/AGECAT sub-threshold depression (1-2) 34 (25%); and GMS/AGECAT non-depression (0) 46 (33%). Comparison of MRADL score in the three groups (mean, 95% confidence intervals) revealed [GMS >or= 3 = 9.9 (8.4 to 11.3) vs GMS = 1-2, 12.9 (11.2 to 14.4) vs GMS = 0, 15.6 (14 to 16.6) p < 0.0001]. BPQ scores (mean, 95% confidence intervals) showed [GMS >or= 3 = 54 (50 to 57) vs GMS = 1-2, 40 (36.3 to 44) GMS = 0, 33 (30.6 to 36.7) p < 0.0001]. There was no significant difference in FEV(1) between the three groups.

Conclusion: Sub-threshold depression accounted for 25% of the sample. In this study disability associated with sub-threshold depression in patients with COPD was intermediate to that associated with case-level depression and no with depression and significantly worse than in the latter group. Sub-threshold depression is associated with substantial morbidity in COPD.