• gastrointestinal events;
  • gastrointestinal hospitalization;
  • Alzheimer's disease


To estimate and compare the incidence of serious upper and lower gastrointestinal (GI) events in individuals aged 65 and older with and without Alzheimer's disease (AD).


Retrospective cohort study.


PharMetrics, a large population-based health insurance claims database was used for the study.


Individuals aged 65 and older with a diagnosis of AD (International Classification of Diseases, Ninth Revision, Clinical Modification Code 331.0) were identified between January 1, 2003, and December 31, 2006, using the PharMetrics database. The control cohort consisted of a random sample of health plan enrollees matched to the AD cohort according to age, sex, location, and index year in a 1:1 ratio.


The outcomes of interest were serious GI events, including ulceration, perforation, and bleeding in the upper or lower GI tract.


Twenty-seven thousand seventy-six individuals with AD were identified. Approximately 66% of them were age 80 and older, and 65% were female. Participants with AD had higher incidence of serious GI events (upper GI: AD vs non-AD: 27.4 vs 17.1/1000 person-years, HR = 1.49, 95%CI = 1.34–1.65; lower GI: AD vs non-AD: 9.4 vs 6.9/1000 person-years, HR = 1.26, 95%CI = 1.06–1.48). The association was also present in participants without a history of GI bleeding (upper GI: HR = 1.54, 95%CI = 1.37–1.73; lower GI: HR = 1.37, 95%CI = 1.14–1.64).


Participants with AD had higher incidence of serious upper and lower GI events, compared to those without AD. Physicians should recognize the high risk of serious GI events that exists in individuals with AD.