Woo Ho Ban, Hyonsoo Joo, Jeong Uk Lim, Hyeon Hui Kang, Hwa Sik Moon, Sang Haak Lee

The detection of insomnia in patients with COPD is assumed to be significantly lower than the actual prevalence. In this study, we investigated the prevalence of insomnia and the relationship between insomnia and health status in patients with COPD using two fairly simple and straightforward questionnaires: COPD assessment test (CAT) and insomnia severity index (ISI). A cross-sectional study was conducted using data from patients undergoing treatment for COPD at St Paul's Hospital, The Catholic University of Korea, between December 2015 and August 2016. Patients were classified into three groups according to the ISI score: a "clinical insomnia" group (ISI≥15), a "subthreshold insomnia" group (ISI 8-15), and a "non-insomnia" group (ISI<8). Clinical parameters including past medical history, pulmonary function tests, and questionnaire data were collected and analyzed. A total of 192 patients were recruited, of which 25.0% were found to have clinical insomnia (ISI≥8). Insomnia severity was related to all CAT component items except for cough, and patients with higher CAT scores generally had more severe insomnia. Logistic regression analysis revealed that CAT score was significantly associated with insomnia in these patients (odds ratio, 1.23; 95% CI, 1.13-1.34; p<0.0001). CAT score was also a significant predictor of insomnia (area under receiver operating characteristic curve, 0.779; p<0.001). The optimal predictive cutoff value was a CAT score >14, giving a sensitivity and specificity of 66.7% and 71.5%, respectively. CAT score was closely related to insomnia severity in patients with COPD. The use of CAT scores to assess for the presence and severity of insomnia in these patients may allow for better detection and management and improve clinical practice.