Detection of acute deterioration in health status visit among COPD patients by monitoring COPD assessment test score

Background: The Chronic Obstructive Pulmonary Disease Assessment Test (CAT) could play a role in detecting acute deterioration in health status during monitoring visits in routine clinical practice. Objective: To evaluate the discriminative property of a change in CAT score from a stable baseline visit for detecting acute deterioration in health status visits of chronic obstructive pulmonary disease (COPD) patients. Methods: The CAT questionnaire was administered to stable COPD patients routinely attending the chest clinic of Chiang Mai University Hospital who were monitored using the CAT score every 1-3 months for 15 months. Acute deterioration in health status was defined as worsening or exacerbation. CAT scores at baseline, and subsequent visits with acute deterioration in health status were analyzed using the t-test. The receiver operating characteristic curve was performed to evaluate the discriminative property of change in CAT score for detecting acute deterioration during a health status visit. Results: A total of 354 follow-up visits were made by 140 patients, aged 71.1 +/- 8.4 years, with a forced expiratory volume in 1 second of 47.49% +/- 18.2% predicted, who were monitored for 15 months. The mean CAT score change between stable baseline visits, by patients' and physicians' global assessments, were 0.05 (95% confidence interval [CI], -0.37-0.46) and 0.18 (95% CI, -0.23-0.60), respectively. At worsening visits, as assessed by patients, there was significant increase in CAT score (6.07; 95% CI, 4.95-7.19). There were also significant increases in CAT scores at visits with mild and moderate exacerbation (5.51 [95% CI, 4.39-6.63] and 8.84 [95% CI, 6.29-11.39], respectively), as assessed by physicians. The area under the receiver operating characteristic curve of CAT score change for the detection of acute deterioration in health status was 0.89 (95% CI, 0.84-0.94), and the optimum cut-off point score was at 4, with a sensitivity, specificity, and accuracy of 76.8%, 83.6%, and 82.4%, respectively. Conclusions: Change in CAT score during monitoring visits is useful for detecting acute deterioration in health status, and a change of 4 units could make a moderate prediction of acute deterioration in health status.