COPD characteristics and progression of patients with high vs. low health status: an analysis of the observational DACCORD study

Introduction: The COPD assessment test (CAT) total score is frequently used to quantify the symptom load of COPD patients. In the German non-interventional, prospective DACCORD study, COPD patients were followed over 2 years. Here, we compare the subgroups with a low (CAT < 10) vs. a high (CAT > 30) symptom burden at baseline.

Methods: DACCORD recruited COPD patients who either initiated or changed COPD maintenance medication prior to study entry. During the follow-up period, CAT score and spirometry were evaluated annually with exacerbations and COPD medication captured every 3 months.

Results: Out of 6611 patients with valid follow-up documentation, 735 patients had a CAT < 10 and 496 patients a CAT > 30 at baseline. Patients in the CAT > 30 group were more likely to be female (49.8% vs. 38.8%) and to have comorbidities (74.6% vs. 61.2% with at least one comorbidity). Patients with CAT > 30 had worse lung function at inclusion (FEV₁% predicted: 53.8% vs. 66.0%) and had exacerbated more frequently in the 6 months before study entry (46.4% vs. 12.4%). During follow-up, exacerbation frequency remained low in the CAT < 10 group and decreased in the CAT > 30 group to 30.8% exacerbating patients in year 2. This is in accordance with changes in CAT score, which remained rather stable in patients with low CAT score while 80% of patients with CAT > 30 experienced a clinically meaningful improvement.

Conclusion: In DACCORD, patients with a low CAT score remained relatively stable over a course of 2 years. Patients with a CAT > 30, however, showed an improvement in CAT total score and a reduction in the exacerbation rate during follow up, suggesting that this improvement is driven by the optimization of therapy going along with the initiation or change of medication at baseline.