Chronic Obstructive Pulmonary Disease as a Risk Factor of Alzheimer's Disease among Elderly Population in Taiwan: A Population-Based Retrospective Cohort Study

Purpose: To evaluate the association between chronic obstructive pulmonary disease (COPD) and Alzheimer's disease (AD) among the elderly and to use those findings to guide the formulation of suggestions aimed at improving clinical and health policies. Methods: This nationwide population-based cohort study used data from the National Health Insurance Research Database for the period 2000-2013 to identify patients aged 65 years or older who were diagnosed with COPD (i.e., the case group). The control group was formed by performing 1:1 matching for age, sex, insurance premiums (as a proxy for salary), and the Charlson Comorbidity Index. Kaplan Meier's Survival Curves and the time-dependent Cox proportional-hazards regression model were used to assessing the association between COPD and AD. Results: After matching related covariates, 13,438 subjects were respectively assigned to the case and control groups. The cumulative incidence of AD was higher in the COPD group than in the non-COPD group (p-value for log-rank test < 0.001). The hazard ratio of AD in the case group was 1.04 times (95% confidence interval: 1.02-1.06, p = 0.002) that in the control group, based on the competing risk model. Conclusions: This study observed a positive correlation between COPD and AD; therefore, health policy related to the prevention of AD should treat COPD as a risk factor rather than a co-morbidity of AD. Copyright (C) 2020, Taiwan Society of Geriatric Emergency & Critical Care Medicine.