In a national study of hospital emergency department visits for opioid overdoses, 67.8 percent of the overdoses involved prescription opioids (including methadone), followed by heroin, other unspecified opioids and multiple opioids, according to a research letter published online by JAMA Internal Medicine.

Opioid overdoses are a leading cause of death in the United States but little is known nationally about how opioid overdoses present in emergency departments (EDs).

Michael A. Yokell, Sc.B., of the Stanford University School of Medicine, Stanford, Calif., and colleagues analyzed the 2010 Nationwide Emergency Department Sample using diagnostic codes to define opioid overdoses. They identified 135,971 weighted ED visits that were coded for opioid overdose.

In addition to 67.8 percent of overdoses involving prescription opioids, researchers found heroin accounted for 16.1 percent of overdoses, unspecified opioids for 13.4 percent and multiple opioid types in 2.7 percent of overdoses. The greatest proportion of prescription opioid overdoses happened in urban areas (84.1 percent), in the South (40.2 percent) and among women (53 percent). The overall death rate was low (1.4 percent) once patients arrived in the ED, which the authors suggest supports increased use of emergency services for overdoses.

Many patients who overdosed shared common coexisting illnesses, including chronic mental health, circulatory and respiratory diseases, so health care providers who prescribe opioids to patients with these preexisting conditions should do so with care and counsel the patients, according to the authors. About half of the patients in the study sample who went to the ED for opioid overdoses were admitted to the hospital and costs for both inpatient and ED care totaled nearly $2.3 billion.

"Opioid overdose exacts a significant financial and health care utilization burden on the U.S. health care system. Most patients in our sample overdosed on prescription opioids, suggesting that further efforts to stem the prescription opioid overdose epidemic are urgently needed," the study concludes.