Outcomes of Infective Endocarditis Cases Among People Who Inject Drugs: Assessing the effects of an inpatient addiction medicine consult service

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Publication Date



Maine Medical Center, Medical Education, Maine Medical Center Research Institute, Infectious Disease, Internal Medicine, Center for Outcomes Research & Evaluation

MeSH Headings

Addiction Medicine, Inpatients, Endocarditis, Endocarditis, Bacterial, Referral and Consultation


Purpose/Background: Infective endocarditis (IE), an infection of the cardiac endothelium, is a significant complication of injection drug use (IDU) that is increasing among people who inject drugs. Once considered to be rare, the incidence of IE has increased twelve-fold in the past ten years. To treat and prevent complications from IDU, hospitals have begun to provide inpatient addiction consults, including Maine Medical Center (MMC), which developed an integrated medication for addiction treatment (IMAT) team in 2016. Our objectives are to 1) describe demographics, clinical characteristics among patients who presented to MMC with IE by IDU from 2016-2019 and 2) using a previous study by Dr. Thakarar et al involving 107 patients admitted with IE at MMC from 2013-2016, compare health service utilization and health outcomes in individuals admitted for IE before and after the implementation of MMC’s addiction medicine consult service. Based on local and national IDU-IE trends, we expect there to be an increased number of IDU-IE cases from 2016-2019. We also hypothesize that the implementation of an IMAT team will be associated with reduced health service utilization and reduced 90-day mortality among patients with IDU-IE.

Methods/Approach: This study will be a retrospective analysis of patients who presented for care to MMC with definite or probable IE from January 1, 2013 to January 1, 2019. Data will be collected from MMCs electronic medical record. We will describe various demographic variables, health characteristics, hospitalization data, IE characteristics, IMAT service utilization data, and health care utilization data among people with IDU versus non-IDU IE. In a subgroup analysis among patients with IDU-IE, we will also stratify data pre- and post-IMAT implementation. In this subgroup analysis, we will assess for the following primary outcomes: 1) 90-day post-discharge ED utilization, 2) 30-day readmission rates, and 3) 90-day mortality rates, with IMAT consultation as the main exposure of interest. Secondary outcomes assessed include percentage of patient discharged against medical advice and number of overdoses after hospital discharge.

Results: Data collection is in progress and has already been collected for 2013-2016. We will examine the incidence of IE cases from MMC between 2016 and 2019, as well as overall trends from 2013-2019. We will assess the demographics, clinical characteristics, and healthcare utilization of patients with IDU versus non-IDU-IE. Among people with IDU-IE, we will stratify by IMAT service and examine any differences in 90-day post-discharge ED visits, 30-day readmission rates, and 90-day mortality rates.

Conclusions: We will review our major findings here and make assessments of how IMAT services have been utilized among the vulnerable IDU population as well as suggest areas for future study.


2020 Costas T. Lambrew Research Retreat, abstract only.

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