Rural-urban differences in hospitalizations for opioid use-associated infective endocarditis in Kentucky, 2016-2019

Purpose: In 2016, the US rate of opioid use-associated infective endocarditis (OUA IE) hospitalizations was 3.86/100,000 for rural and 3.49/100,000 for urban residents. This study estimates the Kentucky OUA IE hospitalization rates, 2016-2019, describing differences in rural-urban residency trends, demographics, relevant comorbidities, and discharge disposition. OUA IE hospitalization rates between counties with and without syringe services programs (SSPs) are also compared. Methods: We used Kentucky statewide inpatient discharge records from 2016 to 2019. An OUA IE hospitalization was identified by an infective endocarditis discharge diagnosis in any diagnosis field and a concurrent diagnosis indicating opioid use. Rurality was determined based on the 2013 Rural-Urban Continuum Codes (RUCC). Findings: Kentucky's rate of OUA IE hospitalizations in 2016 was 8.9/100,000, with no significant variation between rural and urban residents. By 2019, the average rate for urban residents doubled to 17.9/100,000, significantly higher than the rural resident rate, 13.2/100,000. There were no significant rural-urban differences in percentages of those with concurrent diagnoses of HIV (<1%) or HCV (>60%). Counties that established SSPs in 2017-2018 had a 39.4% increase in OUA IE rates from 2016 to 2019, while counties without SSPs had a 79.5% increase. Conclusion: The estimated 2016 Kentucky rates of OUA IE hospitalizations are 2 times higher than reported national rates, highlighting Kentucky as one of the areas most affected by this particular opioid use disorder complication. Despite challenges and barriers to the effectiveness of SSPs as a harm reduction measure, our study suggests a positive effect that should be further investigated.