Disability Retirement After First Admission with Acute Exacerbation of Chronic Obstructive Pulmonary Disease: A Danish Nationwide Registry Cohort Study Using a Retrospective Follow-Up Design

Introduction: Many chronic obstructive pulmonary disease (COPD) patients below retirement age are outside the workforce. The existing knowledge about association between acute exacerbation of COPD (AECOPD) and disability retirement is limited.

Aim: The aim of this study is to explore disability retirement in COPD patients 3 years following first-ever AECOPD.

Methods: This retrospective registry-based follow-up cohort study design is based on nationwide Danish registry data. Patients admitted to the hospital for the first time between 1999 and 2017 with AECOPD and age between 35 and 59 years, active in the workforce, were included in the study. Socio-demographics, comorbidities and inhaled medication use were explored. COPD patients' hazard ratio of disability retirement during 3-year follow-up was calculated. Cox regression was used to examine the effects of covariates on disability retirement.

Results: A total of 4032 patients were included in the study. During follow-up, 17.2% (692/4032) experienced disability retirement from the workforce. Factors associated with disability retirement were expressed as hazard ratio (95% confidence intervals): Higher age (ref. age 46-50: Age 51-55, 1.42, (1.12-1.81); age 56-59, 1.37 (1.08-1.74)); living alone (1.34 (1.14-1.56)); number of comorbidities for 1, 2, and 3 comorbidities (1.36 (1.14-1.62), 1.57 (1.19-2.07), 1.77 (1.20-2.60)); emphysema (2.01 (1.44-2.79)); depression (1.60 (1.12-2.28)); cardiac comorbidity (1.38 (1.07-1.78)); triple inhalation therapy (2.76 (2.20-3.47)); ICS + LAMA or ICS + LABA treatment (1.82 (1.48-2.23)); and ICS treatment (1.49 (1.17-1.90)). Higher educational level was associated with a significantly reduced risk of disability retirement, medium, short higher and long higher educational level, relative to low education level (0.78 (0.67-0.91), 0.63 (0.48-0.83) and 0.27 (0.12-0.60)).

Conclusion: Patients vulnerable to disability retirement are patients with markers of severe COPD, comorbidities, and social vulnerability.