Comorbidities increase likelihood of ADRs in elderly

Comorbidity from chronic diseases and severity of illness increased the likelihood of adverse drug reactions (ADRs) in senior patients, according to a new study published online June 26 in the Annals of Pharmacotherapy. 

In the study, led by Khokan C. Sikdar, PhD, adjunct professor at the Memorial University of Newfoundland, St. John's, Newfoundland, Canada, researchers reviewed the hospitalization records of more than 64,000 patients who were aged 65 years or older with at least one hospital admission from April 1, 1995, to March 31, 2007. The retrospective cohort study used a database of hospital separations from all acute care hospitals in the Canadian province of Newfoundland and Labrador.

The researchers found an ADR incidence rate of 15.2 per 1,000 person years, and 15.4% of patients had recurrent ADRs. Comorbid conditions, including congestive heart failure, diabetes, and cancer, were strong predictors of ADRs. Seniors living in rural areas also had an increased risk of ADRs, but the researchers found that age and sex did not impact ADRs.

The researchers also found that the most common drug category implicated in ADRs was cardiovascular drugs.

“Comorbidity from chronic diseases and severity of illness, rather than individual characteristics (advancing age and sex), increased the likelihood of ADRs. Changes in the delivery of care, focusing on the monitoring of prescribed drugs in elderly patients with comorbidities, could mitigate ADRs,” the researchers wrote.