Drug-Linked Heart Infections Drop 18% as Stimulants Take Larger Share

Hospitalizations for drug use-associated infective endocarditis fell 18 percent nationally between 2020 and 2022, ending years of increase, but the cases that remain involve stimulants far more often than they did a decade ago, according to a study published Tuesday in Clinical Infectious Diseases. Researchers counted more than 118,000 such hospitalizations across the seven years from 2016 through 2022.

The infection peaked at roughly 18,700 hospitalizations in 2020, the first pandemic year, then dropped to about 15,300 in 2022. The decline was driven largely by fewer opioid-associated cases. Over the same period, the share of these hospitalizations involving methamphetamine or cocaine — alone or alongside opioids — climbed from about 37 percent in 2016 to nearly 47 percent in 2022.

"Our goal was to provide an updated national picture of these serious infections, which often affect younger adults in their 30s," said Paul Christine, MD, PhD, an assistant professor of medicine at the University of Colorado Anschutz and the paper's first author. "With opioid injection historically accounting for a large share of these infections, we wanted to understand whether greater availability to addiction treatments and harm reduction services, along with changes in how people use drugs, may have influenced hospitalization trends nationwide."

What the infection does to a patient

Infective endocarditis begins when bacteria enter the bloodstream and colonize the lining of the heart or its valves. In people who inject drugs, the injection itself is the route. The result can be destroyed valves, surgery, weeks of intravenous antibiotics in a hospital bed and, in some cases, death. Treatment is expensive and slow, and it is one of the most visible ways the opioid crisis presents in hospital medicine — the reason hospitals have spent the past several years building addiction consult services for exactly this population.

The study drew on national hospitalization data covering a period that includes both the tail of the prescription-opioid era and the fentanyl-dominated years, which is why its central finding is a reversal rather than a level.

Three possible explanations, none confirmed

The researchers offer two candidates for the decline and present them as hypotheses rather than conclusions. The first is expanded access to addiction treatment and harm reduction: sterile syringe programs, education on safer injection practices, and stronger efforts to link people with opioid use disorder to medication. The second is a change in route of administration — a shift from injecting to smoking — which the authors say would reduce the chance of bacteria entering the bloodstream without any change in how much a person uses.

Neither explanation can be tested with discharge data alone, and the paper does not claim otherwise. The study also cannot separate a true decline in disease from a decline in the subset of patients who reach a hospital with a diagnosis coded clearly enough to be counted.

Where stimulants now dominate

The regional split is steep. The researchers estimated a 59 percent probability that a drug use-associated endocarditis hospitalization in the Pacific region involved stimulants, compared with 34 percent in New England — a gap the authors highlight as evidence that the stimulant share of this disease is not distributed evenly across the country.

"I believe the problem isn't simply that stimulants are becoming more prominent," Christine said. "It's that the healthcare system currently has fewer effective tools to treat stimulant use disorder than opioid use disorder."

That gap is structural. Opioid use disorder has three FDA-approved medications — buprenorphine, methadone and naltrexone — and a treatment system organized around them. Stimulant use disorder has no FDA-approved medication. What exists is behavioral treatment, contingency management where it is available, and stimulant-specific rehab programs that are far scarcer than opioid treatment capacity.

The hospital as the intervention point

Christine and his colleagues say their next step is studying hospital-based interventions for patients who use stimulants, with an emphasis on connecting them to addiction care and keeping them in it after discharge. A hospital stay for endocarditis is, in practical terms, a stretch of forced contact with the health system — often several weeks — and addiction medicine has increasingly treated that window as the moment to start treatment rather than the moment to discharge.

They also plan to look at whether the same declines are showing up in other drug use-associated infections, including skin, soft tissue and bone infections.

For now the paper's contribution is a national baseline that runs through 2022 and a warning embedded in its own regional numbers: the opioid-driven wave of this disease appears to be receding, and the stimulant-driven one is arriving in the same hospital beds. Hospitals that built inpatient addiction services around opioid withdrawal management are now being asked to treat patients for whom there is no equivalent medication to offer.