ABSTRACT
COVID-19 vaccination impact on hospital outcome metrics among patients hospitalized with COVID-19 is not well known. We evaluated if covid-19 vaccination was associated with better hospital outcomes such as in-hospital mortality, overall length of stay, and home discharge. This retrospective study analyzed data from the electronic health records of 29,732 patients admitted with COVID-19 with or without vaccination (21,525 unvaccinated and 8207 vaccinated) from January to December 2021. The association of COVID-19 vaccination status with overall length of hospitalization, in-hospital mortality rate, home discharge after hospitalization was investigated using a multivariate logistic regression and a generalized linear model. The mean age of all groups was 58.16 ± 17.39 years. The unvaccinated group was younger (54.95 ± 16.75) and had less comorbidities compared to the vaccinated group. Patients that had received COVID-19 vaccination exhibited decreased in-hospital mortality (OR 0.666, 95 % CI 0.580-0.764), decreased length of stay (-2.13 days, CI 2.73-1.55 days), and increased rate of home discharge (OR 1.168, CI 1.037-1.315). Older age and cerebrovascular accident diagnosis at admission demonstrated a negative effect on hospital outcomes with decreased home discharge (OR 0.950 per 1 year, CI 0.946-0.953 and OR 0.415, CI 0.202-0.854) and increased inhospital mortality (OR 1.04 per 1 year, CI 1.036-1.045 and OR 3.005, CI 1.961-4.604). This study shows the additional positive impact of COVID-19 vaccination has not just on in-hospital mortality but also in reducing overall length of stay and improved hospital outcome metrics including increasing likelihood of home discharge after hospitalization.