https://immattersacp.org/weekly/archives/2011/12/06/6.htm

Two-thirds of adverse drug event hospitalizations in elderly linked to four drugs

Just four drugs were involved in more than two-thirds of the hospitalizations of older patients for adverse drug events from 2007 through 2009, a new analysis found.


Just four drugs were involved in more than two-thirds of the hospitalizations of older patients for adverse drug events from 2007 through 2009, a new analysis found.

Researchers used 2007-2009 data from the 58 hospitals that participate in the National Electronic Injury Surveillance System-Cooperative Adverse Drug Event Surveillance (NEISS-CADES) project to estimate the frequency and rate of emergency hospitalizations of adults aged 65 years and older. They also looked at the roles of specific medications in the hospitalizations, such as drugs designated as high-risk in the elderly by the 2011 Healthcare Effectiveness Data and Information Set (HEDIS) or as “potentially inappropriate” for use in older adults by the updated Beers criteria. Included cases involved hospitalizations for conditions that a clinician expressly attributed to use of a drug, or to a drug-specific adverse effect. Prescription and over-the-counter drugs, vaccines and dietary supplements were included in the analysis. Results were published in the Nov. 24 New England Journal of Medicine.

On the basis of 5,077 cases in the researchers' sample, they estimated that 99,628 elderly patients had emergency hospitalizations for adverse drug events. Four medications, taken alone or in combination, were linked to 67% of the cases: warfarin (33.3%), insulin (13.9%), oral antiplatelets (13.3%) and oral hypoglycemics (10.7%). Most hospitalizations involving warfarin (95.1%), insulin (99.4%) or oral hypoglycemics (99.1%) came from unintentional overdoses. Of hospitalizations attributed to warfarin, a second medication was implicated in 12.5% of visits, most commonly an antiplatelet (6.7%); of hospitalizations attributed to insulin, another medication was implicated in 15.4% of visits, most commonly an oral hypoglycemic (10.1%).

Medications dubbed high-risk by HEDIS were involved in just 1.2% of hospitalizations, while those dubbed potentially inappropriate by Beers criteria were involved in 6.6%. Forty-eight percent of adverse events involved patients aged 80 years or older, and the hospitalization rate was 3.5 times higher for adults 85 years or older versus those 65 to 69 years. Sixty-six percent of the hospitalizations were due to unintentional overdoses.

The analysis probably underestimated the number of emergency hospitalizations, the authors said, because NEISS-CADES data rely on emergency doctors' identification and documentation of adverse drug events, thus events confirmed during hospitalization or by patient interviews aren't likely to be captured. Overall, efforts to improve medication safety in older adults should focus on areas likely to yield the largest, and most measurable and clinically significant effects, such as management of antithrombotics and diabetes drugs, they said.