A Retrospective Study of Clinical Characteristics and Proportionate Morbidity of Injection Drug Use-Related Infective Endocarditis: Impact of the Opioid Epidemic

Abstract

Background. The national dialog surrounding the opioid epidemic has focused on the mortality of overdose while other medical consequences of this epidemic remain poorly characterized. This 11 year retrospective chart review seeks to better describe the epidemiology and clinical features of native valve infectious endocarditis (IE) stratified by drug use. Methods. IE cases were identified using ICD-9 codes from patients discharged from WFUBMC between January 2004 and September 2015. Cases with cardiac devices, previous endocarditis, and prosthetic valves were excluded. Self-reported drug use with drug name and route of abuse explicitly stated were required for classification as injection drug users (IDU). Data were analyzed with t tests, chi-square tests, and Fisher's exact tests. Results. Two hundred seventy-seven IE cases were identified: 188 in non-injectors (non-IDU) and 89 in IDU with an increasing proportion of cases attributable to IDU over time. Oxymorphone became the most frequently reported drug of abuse (figure). The IDU group was younger than the non-IDU group (average age of 31.8 ± 9.3 versus 54.2 ± 15.4, respectively, p < 0.001), more likely to be Caucasian (95.5% versus 76.1%, p < 0.001) and to be female (51.7% versus 36.2%, p < 0.05). The IDU group was less likely to have mitral (20.2% IDU versus 43.6% non-IDU, p < 0.01) or aortic valve disease (12.4% IDU versus 34.6% non-IDU, p < 0.01), have cerebral emboli (7.9% versus 27.1%, p < 0.001) and to die (5.6% versus 23.4%, p < 0.001). There was no difference in length of stay (20.8 ± 14.8 IDU versus 17.6 ± 13.2 non-IDU, p = 0.09), need for intensive care (61.8% IDU versus 66.8% non-IDU, p = 0.41) or dialysis initiation (11.2% IDU versus 14.9% non-IDU, p = 0.57). While the non-IDU group trended towards more frequent valve replacement (p = 0.055), there was no difference in the number of cardiac surgeries when valve replacement and repair were taken together (23.6% for IDU versus 29.3% for non-IDU, p = 0.32). Staphylococcus aureus was the most common cause in both groups (76.4% IDU and 40.5% non-IDU). Conclusion. WFUBMC is experiencing a rise in the proportion of IE cases associated with IDU. The demographics of IDU-associated cases differ substantially from non-IDU cases but clinical morbidity of IDU-associated IE is surprisingly severe and equivalent to non-IDU IE by many clinical parameters. (Figure Presented) .