Researchers identified more than 118,000 hospitalizations for drug use-associated infective endocarditis nationwide during the seven-year period. Hospitalizations peaked at approximately 18,700 in 2020, during the COVID-19 pandemic, before declining by 18% to about 15,300 in 2022. The decline was driven largely by a decrease in opioid-associated cases, the study found, even as the overall burden of these infections remained substantial.

“Our goal was to provide an updated national picture of these serious infections, which often affect younger adults in their 30s,” said the paper’s first author, Paul Christine, MD, PhD, assistant professor of medicine at the University of Colorado Anschutz. “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.”

The researchers hypothesized several possible factors contributing to the decline. One possible explanation is expanded access to addiction treatment and harm reduction services for opioid use, such as access to sterile syringes and education about safer drug use practices, as well as greater efforts to connect people with opioid use disorder to medications that can help them enter recovery. The researchers emphasized that these are hypothesized explanations rather than causes demonstrated by the study itself.

Another possible explanation is a shift from injecting drugs to smoking them. Because injecting drugs can introduce bacteria into the bloodstream, fewer people injecting may be helping reduce the risk of developing these serious infections. The study’s design, based on hospitalization records, cannot directly confirm which of these mechanisms contributed most to the observed decline, and the researchers presented them as candidate explanations for future investigation.

Alongside the overall decline, the study documented a striking shift in the substances involved. While opioid-associated hospitalizations are declining, stimulants such as methamphetamine and cocaine are accounting for a growing share of these serious infections, particularly in the Western part of the United States. Nationwide, in 2016, approximately 37% of drug use-associated endocarditis hospitalizations involved stimulants, either alone or in combination with opioids. By 2022, that proportion had increased to nearly 47%.

Regional variation was pronounced. The researchers estimated a 59% probability of stimulant-involved infective endocarditis in the Pacific region, compared to 34% in New England, underscoring how differently the drug supply and patterns of use vary across the country. These figures are model-based estimates of the share of cases involving stimulants, not counts of hospitalizations, and they highlight a geographic divide in which substances are driving the most severe injection-related infections.

Christine argued that the growing stimulant share reflects a gap in the treatment landscape rather than simply a change in drug use patterns. “I believe the problem isn’t simply that stimulants are becoming more prominent. It’s that the healthcare system currently has fewer effective tools to treat stimulant use disorder than opioid use disorder,” he said. He explained that while significant attention and resources have been rightly devoted to treating opioid use disorder, comparatively fewer efforts have focused on engaging and treating people who use stimulants. Additionally, unlike opioid use disorder, which has several effective medication options, there are currently no FDA-approved medications specifically for stimulant use disorder.

Looking ahead, Christine and his colleagues plan to explore more effective hospital-based interventions for patients who use stimulants, with a focus on helping them access addiction treatment and connect with ongoing care after discharge. They also want to investigate whether similar declines are occurring in other serious infections associated with drug use, including skin, soft tissue and bone infections. The findings come at a time when the national picture of drug use-associated infective endocarditis appears to be changing: fewer total hospitalizations than at the pandemic peak, but a rising proportion of cases tied to stimulants, especially in the western United States, where the healthcare system has fewer pharmacological tools to offer the affected patients.

Subject of Research: National trends in drug use-associated infective endocarditis hospitalizations in the United States from 2016 to 2022

Article Title: National study finds decline in drug use-associated heart infections but growing share involve stimulants

Article References: National study finds decline in drug use-associated heart infections but growing share involve stimulants. Original publication (Bibliographic details unavailable.)

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DOI: Not provided

Keywords: infective endocarditis, drug use, opioids, stimulants, methamphetamine, cocaine, hospitalizations, harm reduction, opioid use disorder, stimulant use disorder, University of Colorado Anschutz, Clinical Infectious Diseases