Increases in Infective Endocarditis Admissions Caused By Injection Drug Use

Infectious complications of opioid use disorder and injection drug use are major downstream consequences of the opioid crisis.¹ The United States Centers for Disease Control and Prevention reported a 9.6% increase in deaths related to opioid overuse across the US; the cities of Pittsburg and Philadelphia in Pennsylvania have had some of the highest rates of overdose-related deaths. The number of opioid-related hospitalizations increased 103.6% between 2008 and 2015 in Pennsylvania,² and injection drug use-related infective endocarditis (IE) hospitalizations increased in a similarly significant percentage between 2013 and 2017, according to research results recently published in Clinical Infectious Diseases.³

To examine IE trends in Pennsylvania, researchers conducted a retrospective cohort study to examine the length of stay and characteristics between individuals with and without opioid use disorder, using data from the Pennsylvania Health Care Cost Containment Council.

Between January 1, 2013, and March 31, 2017, there were 17,224 acute care hospitalizations for IE, of which 11.1% were for drug use-related IE. Total quarterly IE admissions increased from 923 during the first quarter of 2013 to 1112 during the first quarter of 2017, representing a 20% increase. There was also a 6.5% increase in non-drug use-related IE admissions (867 to 923) and a 238% increase in drug use-related IE admissions (56 to 189) during that period.

Patients with drug use-related IE had a longer length of stay than those with non-drug use-related IE (10 vs 7 days; P <.001). However, in the multivariable adjusted models, history of opioid use disorder or injection drug use was no longer statistically significant with length of stay (incidence rate ratio, 1.02; 95% CI, 0.98-1.07; P =.363).

Compared with patients admitted with non-drug use-related IE, patients admitted with drug use-related IE were younger (median age: 33 years vs 69 years), were predominantly insured by Medicaid (68.3% vs 13.4%), had higher hospital charges ($86,622 vs $66,802), were more likely to leave against medical advice (15.7% vs 1.1%), were more likely to have tricuspid valve replacements (30.4% vs 5.2%), and were more likely to have infectious comorbidities such as HIV and hepatitis C virus (P <.001 for all). In-hospital mortality, however, was lower in the drug use-related IE group (4.5% vs 8.5%; P <.001).

A secondary analysis evaluating those admitted in either Philadelphia or Allegheny counties, 2 high opioid use disorder prevalence urban areas in Pennsylvania, showed a larger increase in the percentage of IE admissions associated with drug use during the study period: a 112% increase in Philadelphia County and a 443% increase in Allegheny County. Other parameters, including length of hospital stay, incurred hospital costs, and rates of patients who left the hospital against medical advice, were comparable between Philadelphia and Allegheny counties.

“The higher hospital charges, higher proportion of patients on Medicaid, and high rates of patients leaving [against medical advice] among those with [drug use-related] IE demonstrate the notable burden that the opioid epidemic is having on the healthcare system,” noted the researchers. “There is an urgent need to develop innovative and integrative models to improve the treatment for patients with substance use and its many downstream consequences,” they concluded.

References

1. Rapoport AB, Beekmann SE, Polgreen PM, Rowley CF. Injection drug use and infectious disease practice: a national provider survey. Open Forum Infect Dis. 2017;4(Suppl 1):S340.

2. Pennsylvania Health Care Cost Containment Council. Hospital admissions for opioid overdose and opioid use disorder. Published October 2018. Accessed October 30, 2019.

3. Meisner JA, Anesi J, Chen X, Grande D. Changes in infective endocarditis admissions in Pennsylvania during the opioid epidemic [published online October 20, 2019]. Clin Infect Dis. doi:10.1093/cid/ciz1038