A handful of commonly prescribed drugs are responsible for two-thirds of emergency hospitalizations among older adults, according to a study in the New England Journal of Medicine.

Using three years of data from 58 hospitals participating in an adverse drug-event surveillance project, researchers from the Centers for Disease Control and Prevention identified four high-risk blood thinners and diabetes medications that account for a disproportionate share of serious events such as overdoses.

Thirty-three percent of emergency hospitalizations, for instance, involved the blood thinner warfarin. An additional 14% involved insulin, according to the study.

“These data suggest that focusing safety initiatives on a few medicines that commonly cause serious, measurable harms can improve care for many older Americans,” Dr. Dan Budnitz, director of the CDC's Medication Safety Program, and lead author of the study, said in a news release. “Blood thinners and diabetes medicines often require blood testing and dosing changes, but these are critical medicines for older adults with certain medical conditions.”