Endocarditis as a Marker for New Epidemics of Injection Drug Use

Background: 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). Materials and Methods: 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. Results: 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. Conclusions: 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.