Life-Course accumulation of morbidity in COPD patients: A register-based cohort study in Sweden

Background: Patients with a diagnosis of chronic obstructive pulmonary disease (COPD) often have other chronic disorders, both prior to and after their COPD diagnosis. However, the extent to which this increased risk of morbidity is evident before COPD onset, and its long-term development after a COPD diagnosis, remains unclear. Methods: Among all residents aged 50-90 years in Sweden in 1997, people with a hospital COPD diagnosis were identified using Swedish national registers (1997-2018). Each patient with COPD (=case) was matched by sex, birthyear and county of residency with up to five COPD-free individuals (=controls). Other chronic disease diagnoses were identified during 1987-2018. Conditional logistic regression calculated risk of diseases diagnosed prior to first COPD diagnosis, producing odds ratios (OR) and 95% confidence intervals (95% CI). Cox regression estimated risk of diagnoses after first COPD diagnosis, producing hazard ratios (HR) and 95% CI. Results: Among 2,706,814 individuals, 225,159 (8.3%) had COPD. The nested case-control sample included 223,945 COPD-cases with 1,062,731 controls. Prior to first COPD diagnosis, future COPD patients had higher risks than controls for most examined conditions. Highest risks were seen for chronic heart failure (OR=3.25, 3.20-3.30), peripheral arterial disease (OR=3.12, 3.06-3.18) and lung cancer (OR=12.73, 12.12-13.37). Following the COPD diagnosis, individuals with COPD had higher risks of most conditions than individuals without COPD. Chronic heart failure (HR=3.50, 3.46-3.53), osteoporosis (HR=3.35, 3.30-3.42), depression (HR=2.58, 2.53-2.64) and lung cancer (HR=6.04, 5.90-6.18) predominated. The risk of vascular dementia was increased after COPD diagnosis (HR= 1.53, 1.48-1.58), but not Alzheimer’s disease. Conclusion: Accumulation of chronic morbidity may precede COPD. Following the diagnosis, an increased burden of cardiovascular disease and cancer is to be expected, but subsequent depression, osteoporosis, and vascular dementia should also be noted. Management strategies for patients with COPD should consider the higher-than-average risk of multimorbidity.