Growing proportion of cardiac arrests in U.S. considered opioid related

Observational data indicate that the number of hospitalizations for cardiac arrests linked to opioid use roughly doubled from 2012 to 2018.

“This was an observational study, so we cannot conclude that all of the arrests were caused by opioids, but the findings do suggest the opioid epidemic is a contributor to increasing rates,” Senada S. Malik, of the University of New England, Portland, Maine, reported at the virtual annual congress of the European Society of Cardiology.

The data were drawn from the Nationwide Inpatient Sample (NIS) from 2012 to 2018, the most recent period available. Cardiac arrests were considered opioid related if there was a secondary diagnosis of opioid disease. The rates of opioid-associated hospitalizations for these types of cardiac arrests climbed from about 800 per year in 2012 to 1,500 per year in 2018, a trend that was statistically significant (P < .05).

The profile of patients with an opioid-associated cardiac arrest was different from those without secondary diagnosis of opioid disease. This included a younger age and lower rates of comorbidities: heart failure (21.2% vs. 40.6%; P < .05), renal failure (14.3% vs. 30.2%; P < .05), diabetes (19.5% vs. 35.4%; P < .05), and hypertension (43.4% vs. 64.9%; P < .05).

Mortality from opioid-associated cardiac arrest is lower

These features might explain the lower rate of in-hospital mortality for opioid-associated cardiac arrests (56.7% vs. 61.2%), according to Ms. Malik, who performed this research in collaboration with Wilbert S. Aronow, MD, director of cardiology research, Westchester Medical Center, Valhalla, N.Y.

When compared to those without a history of opioid use on admission, those with opioid-associated cardiac arrest were more likely to be depressed (18.8% vs. 9.0%), to smoke (37.0% vs. 21.8%) and to abuse alcohol (16.9% vs. 7.1%), according to the NIS data.

While these findings are based on cardiac arrests brought to a hospital, some opioid-induced cardiac arrests never result in hospital admission, according to data included in a recently issued scientific statement from the American Heart Association.

Rate of opioid-associated cardiac arrests underestimated

In that statement, which was focused on opioid-associated out-of-hospital cardiac arrests (OA-OHCA), numerous studies were cited to support the conclusion that these events are common and underestimated. One problem is that opioid-induced cardiac arrests are not always accurately differentiated from cardiac arrests induced by use of other substances, such as barbiturates, cocaine, or alcohol.

For this and other reasons, the data are inconsistent. One study based on emergency medical service (EMS) response data concluded that 9% of all out-of-hospital cardiac arrests are opioid associated.

In another study using potentially more accurate autopsy data, 60% of the non–cardiac-associated cardiac arrests were found to occur in individuals with potentially lethal serum concentrations of opioids. As 40% of out-of-hospital cardiac arrests were considered non–cardiac related, this suggested that 15% of all out-of-hospital cardiac arrests are opioid related.

In the NIS data, the incident curves of opioid-related cardiac arrests appeared to be flattening in 2018, the last year of data collection, but there was no indication they were declining.