The prevalence of anxiety is 55% in patients with COPD,1 and it is associated with
worse disease control. Therefore, early recognition and institution of treatment of
this comorbidity significantly improve patient’s quality of life. Recently, a questionnaire
called the COPD assessment test (CAT) has been incorporated into the Global Initiative
for Chronic Obstructive Lung Disease (GOLD) guidelines for the management of COPD,
and a higher score is associated with increased COPD symptoms.2 Considering the regular
use of CAT, it was evaluated whether this tool can also be used to identify anxiety.
The CAT score was correlated with the Hospital Anxiety and Depression Scale (HADS)
to determine the level at which CAT may predict anxiety.
Materials and methods
The study was approved by the Human Research Ethics Committee of the Royal Perth Hospital
(HREC study 2012/055), with a waiver given for patient consent. All patient data remained
confidential. Clinical data were collected from 100 patients with confirmed COPD,
who attended the COPD outreach clinic, of whom 78 patients completed spirometry. COPD
severity was graded according to the GOLD criteria, and the CAT and HADS scores were
collected on 2 consecutive consultations separated by 6 months with a 100% completion
rate. The severity of the cohort was classified as GOLD 1 (2 patients), GOLD 2 (29
patients), GOLD 3 (39 patients) and GOLD 4 (8 patients). A total of 45 patients had
clinically significant anxiety on the first visit and 38 patients on the second visit
as per HADS. The prevalence of anxiety in COPD GOLD 1 is 0%, GOLD 2 is 45% (13), GOLD
3 is 56% (22) and GOLD 4 is 38% (3) in visit 1. Data from the second visit were similar,
apart from the decreased prevalence in GOLD 3 (13, 43%) and the increased prevalence
in GOLD 4 (6, 67%).
A CAT score was found to have significant correlation with anxiety with an OR of 1.25
(95% CI 1.13–1.4). At each visit, the CAT score could discriminate between those with
anxiety and those without. In visit 1, area under receiver operating characteristic
curve was 0.74 (95% CI 0.64–0.84), and in visit 2, area under the receiver operating
characteristic curve was 0.76 (95% CI 0.66–0.85). A CAT cutoff score of ≥20 gives
a sensitivity of 80% and 84% and an acceptable specificity of 52% and 47% in visit
1 and visit 2, respectively (Table 1). The change in FEV1 from visit 1 to visit 2
did not correlate with the change in CAT (R
2=0.03), which is an interesting observation requiring further investigation. These
pilot data suggest that CAT may identify patients with anxiety and form the basis
for future studies with a larger sample size.
This study suggests that anxiety must be specifically investigated in COPD patients,
especially with a CAT score of ≥20. Further analysis with a larger sample size should
further evaluate the value of CAT score correlation with anxiety in COPD patients.