Clinical Usefulness of the Two-Question Assessment Tool for Depressive Symptoms in Japanese Patients with Chronic Obstructive Pulmonary Disease

Abstract

Depressive symptoms are highly prevalent in patients with chronic obstructive pulmonary disease (COPD) and have been associated with poor outcomes. Developing a concise questionnaire to measure depressive symptoms in COPD patients is needed in outpatient settings. We evaluated the clinical usefulness of a concise two-question instrument to assess depressive symptoms in patients with COPD. The study was conducted as a cross-sectional analysis in patients with COPD. All patients completed a self-reported questionnaire consisting of the two-question instrument, as well as a shortened version of the Center for Epidemiologic Studies Depression Scale (CESD-10) to measure depressive symptoms. Performance of the two-question instrument was evaluated using the results for CESD-10 as standard. We also measured patients' health-related quality of life using the Medical Outcomes Study 8-Item Short-Form Health Survey (SF-8) to determine whether the instrument was related to SF-8. Sensitivity of the two-question instrument in the detection of depressive symptoms was 73.3 % (95 % confidence interval [CI] 51-95.7), specificity was 73 % (95 % CI 58.7-87.3), and area under the receiver operating characteristics curve was 0.73 (95 % CI 0.59-0.87). When study patients were divided into two groups with a cutoff of 1 point on the two-question instrument, scores for all subscales of the SF-8 except "bodily pain" were significantly lower in patients with than without depressive symptoms. This concise two-question instrument is useful as assessment of depressive symptom in patients with COPD in busy outpatient settings.