Exploring the impact of comorbid dementia on exacerbation occurrence in general practice patients with chronic obstructive pulmonary disease.

OBJECTIVE Previous studies have shown an increased risk of dementia in patient with COPD, but whether comorbid dementia modifies the risk of exacerbations in patients with COPD is unknown. We explored exacerbation occurrence in patients with COPD with comorbid dementia and compared this to patients with COPD without comorbid dementia. METHODS We performed a retrospective cohort study based on medical record data from 88 Dutch general practices. Patients diagnosed with COPD and comorbid dementia (n = 244, index group) were matched 1:1 to patients with COPD without comorbid dementia (n = 244, controls). Exacerbations were assessed 1 year before and 1 year after the dementia diagnosis (or corresponding date in controls) and compared between index and control groups by calculating Rate Ratios (RRs). RESULTS Average number of COPD exacerbations after dementia diagnosis increased from 5 to 14 per 100 patient years in the index group (RR = 2.70, 95%CI 1.42-5.09; p = 0.02) and from 17 to 30 per 100 patient years in the control group (RR = 1.74, 1.19-2.54; p = 0.04). These RRs did not significantly differ between the index and control groups (RR ratio = 1.55, 0.74-3.25; p = 0.25). DISCUSSION We conclude that although the risk of exacerbation increased after patients with COPD were diagnosed with dementia, their change in exacerbation risk did not seem to differ from the change observed in patients with COPD without comorbid dementia. However, as our study was hypothesis-generating in nature, further investigations on the subject matter are needed.