Depression in Japanese patients with chronic obstructive pulmonary disease: a cross-sectional study.

BACKGROUND Some investigations have revealed an association between depression and physical measurements of COPD patients in North America and Europe, but few related studies have been performed in Asia. METHODS In this cross-sectional study, 84 consecutive, stable out-patients with COPD (mean ± SD age 72.0 ± 9.0 y, percent-of-predicted FEV1 46 ± 15%, 15 [17.9%] female) in a Japanese community hospital were recruited. "Probable depression" was defined as a score of ≥ 6 on the short-form Geriatric Depression Scale (SF-GDS). Relationships among commonly used physical measurements, SF-GDS raw score, and probable depression were evaluated with the Spearman rank correlation test, multiple linear regression analysis, logistic regression analysis, and receiver operating characteristic curves. RESULTS Thirty-two subjects (38.1%) had probable depression. Body mass index, obstruction, dyspnea, exercise capacity index, percent-of-predicted FEV1, Modified Medical Research Council dyspnea score, 6-min walk distance, and SpO2 had: simple correlations (r 0.42-0.60, P < .001 for all) with the SF-GDS raw score; partial correlations (r 0.25-0.51, P < .05 for all) with the SF-GDS raw score after adjusting for demographic and social factors; association with probable depression in the logistic regression analysis after adjusting for demographic and social factors (P < .05 for all); and areas under the receiver operating characteristic curve of 0.72-0.84 (P < .001 for any) for probable depression. CONCLUSIONS Physical parameters were associated with depression in our Japanese COPD out-patients.