Impact of an addiction medicine consult service on patients admitted to the hospital with injection drug use-associated infective endocarditis

Background: The addition of an addiction medicine consult service has been shown to improve mortality and decrease hospital costs but its impact on the proportion of patients discharged against medical advice (DAMA) and in-hospital initiation of medication for opioid use disorder (MOUD) has not been examined. Methods: A retrospective before-after cohort study was performed at an urban, academic medical center between January 1, 2015 and November 1, 2019. We included adult patients with infective endocarditis and injection drug use determined by admitting diagnosis ICD-9 or ICD-10 codes or documentation within the history section of electronic health recordEHR. Our institution implemented a formal addiction medicine consult service on July 1, 2018. We determined the proportion of patients DAMA and the proportion of patients started on MOUD among patients in the pre-intervention (i.e. hospitalized before July 1, 2018) and intervention (i.e. hospitalized July 1, 2018 or after) groups. Results: A total of 171 patients among hospitalized patients with injection drug use-associated infective endocarditis were included with 119 patients in the pre-intervention group and 52 patients in the intervention group. There was no statistically significant difference in patients DAMA [19% vs 15%, absolute risk difference 4.6% (95% confidence interval -8.6% to 17.7%)] between the intervention and pre-intervention groups. However, there was an increase in the proportion of inpatient MOUD initiation in the intervention group compared to the pre-intervention group [56% vs 21%, absolute risk difference 35% (95% confidence interval 19% to 50%)]. Conclusions: The initiation of an addiction medicine consult service was associated with a higher proportion of MOUD initiation but there was no statistically significant association with the proportion of patients DAMA