Photo Credit: Feodora Chiosea

To test the viability of a COPD assessment test, researchers developed a study drawing from the COMFORT Study, a multicenter prospective observational study.

It has been well-documented that anxiety and depression are common comorbidities of chronic obstructive pulmonary disease (COPD). However, diagnosing these comorbidities during examinations to address COPD remains challenging. Although several questionnaires ascertain an anxiety and/or depression diagnosis in patients with COPD, these tools are time-consuming and benefit from a level of psychiatric knowledge that may not be available to the physician in attendance.

CAT Correlation

A questionnaire widely used to gauge COPD progression in a patient, known as the COPD assessment test (CAT), extracts information from the patient on respiratory symptoms, systemic symptoms, obstruction of daily activity, personal life issues, and emotional well-being. Emotional health is addressed in this standard test, so providers could potentially identify anxiety and depression through this tool, thereby saving time while still providing psychological insights.

To test the viability of this application of CAT, Kewu Huang, MD, and colleagues developed a study drawing from an ongoing multicenter prospective observational study known as the Cohort Study for COPD in China (COMFORT Study) to investigate the clinical characteristics of COPD. Dr. Huang and colleagues applied logistic regression analysis and receiver operating characteristic (ROC) curve analysis to determine the predictive value of CAT to identify anxiety and depression in patients with COPD.

Anxiety and Depression

To test the hypothesis of the study, the researchers used the Generalized Anxiety Disorder questionnaire (GAD-7) and the Patient Health Questionnaire (PHQ-9) to confirm the applicability of CAT as a diagnostic tool for anxiety and depression in patients with COPD.

The study enrolled 530 patients with stable COPD. The participants had a median age of 64.9±7.8 years. Applying GAD-7 and PHQ-9, it was determined that 17% of the participants had a diagnosis of anxiety, and 21.5% had a diagnosis of depression.

A greater risk of both anxiety and depression was found to correlate with a higher CAT score (OR=1.089, 95% CI: 1.059–1.121, P< 0.001; OR=1.148, 95% CI: 1.113–1.183, P<0.001; respectively). After adjusting for potential confounders, these associations were still found to be significant when multivariate analysis was applied (OR=1.094, 95% CI: 1.057–1.131, P< 0.001; OR=1.143, 95% CI: 1.104–1.183, P< 0.001; respectively). The CAT score was also found to have a significant predictive value for anxiety (Area under the ROC curve [AUC]=0.709, 95% CI: 0.668–0.747, P< 0.001) as well as depression (AUC=0.791, 95% CI: 0.754–0.825, P< 0.001) according to the ROC curve analysis. (Table)

Researchers noted that certain items in the CAT questionnaire had better predictive value than others. Sleep, for example, displayed the most significant predictive value for anxiety (AUC=0.708, 95% CI: 0.667–0.746), and energy levels displayed the most significant predictive value for depression (AUC=0.765, 95% CI: 0.727–0.801).

As Dr. Huang and colleagues wrote in COPD: Journal of Chronic Obstructive Pulmonary Disease, which published the findings of the study, “Our results showed that CAT has limited value in screening concomitant anxiety or depression in stable COPD patients; however, a lower CAT score is a good indicator for excluding anxiety and depression. In addition, non-respiratory components among CAT items can better identify anxiety and depression than respiratory-related components.”