US Hospitalizations and 60-Day Readmission Rates Associated with Herpes simplex virus Encephalitis: Analysis of All Cause Readmissions and Encephalopathy Associated Readmissions.

BACKGROUND Herpes simplex encephalitis (HSE) is the most common cause of encephalitis hospitalizations. We sought to describe and analyze features associated with all cause readmissions and encephalopathy associated readmissions amongst HSE cases. METHODS HSE hospitalizations and 60-day rehospitalizations were assessed in a retrospective cohort using linked hospitalizations from the Healthcare Utilization Project (HCUP) National Readmission Database (NRD) from 2010 through 2017. Risk factors for all-cause readmissions and encephalopathy associated readmissions were assessed with a weighted logistic regression model. RESULTS There were 10,272 HSE cases in the US between 2010 and 2017, resulting in a national rate of 4.95 per 100,000 hospitalizations. A total of 23.7% were readmitted at least once within 60-days. Patients that were readmitted were older (mean age 62.4 vs. 57.9, p<0.001), had a greater number of procedures at the index hospitalization (aOR 1.03, p<0.001) and have a higher Charlson comorbidity score (aOR 1.11, p<0.001). Amongst those readmitted, 465 (16.5%) had an encephalopathy related diagnosis. Over eight years, the rate of encephalopathy associated readmissions increased from 0.12 to 0.20. Encephalopathy specific readmissions were found to be associated with greater age (mean age 65.9 vs. 61.7, p = 0.004) and findings of cerebral edema at index hospitalization (aOR 2.16, p <0.001). CONCLUSIONS HSE readmissions are relatively common, particularly among older and sicker individuals. However, early signs and symptoms of neurological disease at index were correlated with encephalopathic specific readmissions.