The association between adherence and dementia in chronic obstructive pulmonary disease

Our previous studies have shown that patients with chronic obstructive pulmonary disease (COPD) have an increased risk of dementia and that COPD combined with dementia confers an increased risk of acute respiratory dysfunction, severe sepsis, and hospital mortality. The aim of this study was to investigate whether medication adherence can decrease the risk of dementia in COPD. This retrospective study enrolled COPD patients from 1 million beneficiaries randomly sampled from all beneficiaries in Taiwan. We excluded COPD patients not prescribed a bronchodilator or those using theophylline or short-acting β2-agonists for <1 year. To ensure a sufficient observation period, we excluded patients diagnosed with dementia within 1 year after the diagnosis of COPD or those prescribed bronchodilators after the diagnosis of dementia. Patients with COPD and a history of severe mental disorders were also excluded. There was a total of 13,015 first diagnoses of COPD from 1998 to 2012, of whom 9,489 had a proportion of days covered (PDC) <80% and 1,206 had a PDC ≥80% before matching. In the high PDC group, 226 (18.74%) patients had acute exacerbations of COPD and were hospitalized within 1 year after diagnosis. Compared with the PDC <80% group, the PDC ≥80% group had a risk of dementia with an adjusted hazard ration of 0.88, but there were no statistically significant differences (95% confidence interval, 0.57–1.35). Medication adherence to bronchodilators may not modify the risk of dementia in patients with COPD.