Endocarditis as a Marker for New Epidemics of Injection Drug Use

We examined discharges for infective endocarditis (IE) at an academic teaching hospital for over 10 years to evaluate if an increase in hospitalizations for IE and increase in hepatitis C virus (HCV) in patients with IE could predict a new epidemic of injection drug use (IDU).

Retrospective medical record review of discharged patients with the diagnosis of IE as defined by the modified Duke criteria. Student's t test, chi-squared test and Fisher's exact test were used to calculate P values.

There were 542 discharges among 392 unique patients with IE and 104 patients were readmitted 2-7 times. Of the total discharges, 367 (67.7%) were not screened for HCV, and of those tested, 86 (49.1%) were HCV+; 404 (74.5%) were not screened for HIV and of those tested, 28 (20.3%) were HIV+. Patients who self-identify as a person who injects drugs were more likely to be tested for HCV, 75 (69.4%) versus 12 (31.5%, P < 0.0001), and for HIV, 72 (66.6%) versus 13 (34.2%, P < 0.0001) compared with those who self-report no IDU. Those with a positive result for opiate or heroin toxicology test were more likely to be screened for HCV, 70 (66%) versus 22 (44.8%, P < 0.0001), and for HIV, 66 (62.2%) versus 25 (51%, P < 0.0001) than those with negative result for toxicology test. Over this period, there was a 2-fold increase in IE cases, a 3-fold increase in HCV antibody prevalence and a 6-fold increase in opiate toxicology screens showing positive result, but no increase in HIV.

Although IDU is a known risk factor for IE, the observation of a sharp increase in IE cases may signal a new epidemic of IDU and HCV.