Long-Term Infective Endocarditis Mortality Risk Among Injection Drug Users

The expected burden of infective endocarditis (IE) is considerable among injection drug users in the United States, according to data published in Clinical Infectious Diseases. Investigators recommended adopting a harm reduction approach that addresses injection behaviors since they could play a major role in decreasing mortality associated with the opioid epidemic.

Infections such as IE are tied to injection behaviors and have increased significantly with the expansion of the opioid epidemic in the United States. Investigators developed a microsimulation model of the natural history of injection opioid use to estimate the population-level IE mortality among injection opioid users. This was compared with risk of IE death against risk of death from other causes.

The model was developed using primary and published data for competing risks of death. Investigators modeled cohorts of 1 million individuals with different injection behavior profiles until 60 years of age. The model-generated estimates were then combined with published data in order to project the total expected IE deaths by 2030.

Higher infection risk technique is defined as the combination of sharing drug paraphernalia and not using sterile technique; lower infection risk technique is defined as the combination of not sharing equipment and using sterile technique. For men aged 20, 30, or 40 years with high frequencies of use, the probability of IE death with higher infection risk techniques compared to lower risk techniques for IE was 53.8% vs 3.7%, 51.4% vs 3.1%, and 44.5% vs 2.2%, respectively. Among all risk groups, the predicted population-level attributable fraction of 10-year mortality of IE was 20%. Investigators estimated that by 2030, approximately 257,800 people are expected to die from IE.

Investigators acknowledge several study limitations. This model represents a simplification of complex biological, clinical, and social processes that require many assumptions and potential confounders. The use of primarily cohort studies and large national databases as data sources means the conclusions may not be representative of the overall US population. “In particular, this is relevant with regard to the population-level impact in which older estimates of the prevalence of people who inject drugs were used,” noted investigators.

Estimates from this model “should serve as a road map, rather than dogma, to guide policy decisions and future research aimed at reducing the burden of disease from these infections,” according to investigators. They recommend that future models incorporate the effect of hospital-based interventions such as addiction consult services.

They were able to conclude that a large expected burden of IE is anticipated among injection drug users, adding that the data demonstrates the importance of adopting harm reduction approaches with this population. “The highest priority intervention is to address their injection technique to include skin cleaning and use of sterile equipment, even before addressing drug use itself.” In doing so, researchers predict reductions in risk of drug use mortality greater than 90% could be achieved even while drug use itself is increasing.

Reference

Barocas JA, Yazdi GE, Savinkina, A, et al. Long-term infective endocarditis mortality associated with injection opioid use in the United States: a modeling study. Published online September 9, 2020. Clin Infect Dis. doi:10.1093/cid/ciaa1346.