Patients with COPD at Increased Risk of Cognitive Impairment

Previous studies suggest that COPD is associated with hypoxemia and cognitive impairment. Cross-sectional studies have also reported a higher frequency of mild cognitive impairment (MCI) in individuals with compared with those without a diagnosis of COPD. In the absence of curative therapy for dementia, the early identification of modifiable risk factors for MCI, the earliest symptomatic phase of dementia, is important for preventing or delaying the onset of cognitive impairment. Researchers of the University of Nottingham, United Kingdom conducted a study to determine the incidence of cognitive impairment and dementia in people with and without a COPD diagnosis.

It was a population-based study using the UK General Practice (GP) health records from The Health Improvement Network database. Researchers identified a total of 2,92,224 patients among which 62,148 were diagnosed with COPD and 230,076 were without COPD. 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. Researchers used Cox proportional hazards models to assess the incidence rates of cognitive impairment and dementia.

Key findings of the study were:

♦ Among patients with COPD (n=62,148) researchers observed, 9% developed cognitive impairment, compared with 7% of subjects without COPD (n=230,076).

♦ They also observed that the incidence of cognitive impairment was greater in subjects with COPD than in subjects without COPD following index date (adjusted Hazard Ratio (aHR), 1.21)

♦ After adjusting the confounders, they found a coded incidence of either cognitive impairment or dementia was also greater in patients with COPD (aHR: 1.13).

♦ They reported that coded incident dementia alone was not different between patients with COPD and subjects without COPD (aHR, 0.91)

The authors concluded, "Despite the increased incidence of cognitive impairment in patients with COPD, the incident 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".

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DOI: https://doi.org/10.1016/j.rmed.2020.106288