Opiate Injection-associated Infective Endocarditis in the Southeastern United States

Abstract

Background: Opiate pain reliever (OPR) misuse by injection is increasing in the United States. Infective endocarditis (IE), a devastating complication of injection OPR use, has been understudied.

Methods: We conducted a retrospective chart review of IE cases at an academic tertiary care hospital in North Carolina. Hospital admissions from 2009-2014 were screened for cases of definite IE. Subjects reporting injection drug use (IDU) were classified as IDU-IE, and compared to those without reported IDU, classified as No IDU-IE. Rates of IDU-IE and No IDU-IE, patient demographics, microbiologic data and outcomes were compared between the groups.

Results: A total of 127 incident admissions for IE were identified, 48 (37.8%) were classified as IDU-IE and 79 (62.2%) as No IDU-IE. IDU-IE cases increased from 14% of hospitalizations for IE in 2009 to 56% in 2014; reporting of OPR injection increased in 2012 and continued through the study period. IDU-IE subjects were younger (32.6 ± 11.7 versus 54.4 ± 13.1, P < 0.0001), more likely to be single (n = 33 [68.8%] versus n = 23 [29.1%], P < 0.0001) and to reside in rural communities (n = 36 [75.0%] versus n = 25 [31.6%], P < 0.0001) than No IDU-IE subjects. Hospital length of stay (26 days versus 12 days, P < 0.0001) and intensive care unit length of stay (2 days versus 1 day, P = 0.04) were longer for IDU-IE patients and hospital mortality did not differ (10.4% IDU-IE versus 8.9% No IDU-IE, P = 0.77).

Conclusions: IDU-IE rates increased over time, and OPR injection use in rural communities appears to be a major contributor. Interventions to reduce IDU-IE and OPR misuse are needed to halt this growing epidemic in at-risk rural communities.

Keywords: Critical care; Infection; Injection drug use; Opana; Oxymorphone.

FIGURE

Trends in infective endocarditis and injection drug use. (A) Rates of injection drug use infective endocarditis (IDU-IE) and noninjection drug use infective endocarditis (No IDU-IE) were calculated per 1000 hospital admissions over each quarter year (left y axis). Yearly percentages of IDU-IE to No IDU-IE cases over the study period were calculated (right y axis). The line represents a 4-quarter moving average of IDU-IE to No IDU-IE. (B) Type of drugs that patients reported injecting in the IDU-IE cohort over the study period. The “Other” category included 1 case each of morphine extended release, methadone and cocaine. Some patients reported injecting more than one drug. In 13 subjects with IDU-IE, a specific injection drug was not identified.