Risk of incident dementia and cognitive impairment in patients with chronic obstructive pulmonary disease (COPD): A large UK population-based study.

ABSTRACT

BACKGROUND: Although cognitive impairment and dementia are common comorbidities in patients with chronic obstructive pulmonary disease (COPD), estimates of incidence following a diagnosis of COPD are inconclusive. OBJECTIVE: To determine the incidence of cognitive impairment and dementia in people with and without a COPD diagnosis. METHODS: A population-based study using UK General Practice (GP) health records from The Health Improvement Network database was conducted. Patients with confirmed COPD diagnosis, ≥40 years old, were matched to up to four subjects without a COPD diagnosis by age, sex and GP practice. Cox proportional hazards models were used to assess the incidence rates of cognitive impairment and dementia. RESULTS: Of patients with COPD (n = 62,148), 9% developed cognitive impairment, compared with 7% of subjects without COPD (n = 230,076), p < 0.001. The incidence of cognitive impairment following COPD diagnosis was greater than in subjects without COPD following index date (adjusted Hazard Ratio (aHR), 1.21; 95% CI 1.16 ─ 1.26, p < 0.001). The coded incidence of either cognitive impairment or dementia was also greater in patients with COPD following adjustment for confounders (aHR 1.13, 95% CI 1.09 ─ 1.18, p < 0.001). Coded incident dementia alone was not different between patients with COPD and subjects without COPD (aHR, 0.91, 95% CI 0.83 ─ 1.01, p = 0.053). CONCLUSION: Despite the increased incidence of cognitive impairment in patients with COPD, incidence of dementia was not as frequently recorded in patients with COPD. This raises the concern of undiagnosed dementia and emphasises the need for a systematic assessment in this population.