Hospital factor and prognosis of COVID-19 in New York City, the United States of America: insights from a retrospective cohort study

Background: April 22nd, 2020, New York City (NYC) was the epicenter of the pandemic of Coronavirus disease 2019 (COVID-19) in the US with differences of death rates among its 5 boroughs. We aimed to investigate the difference in mortality associated with hospital factors (teaching versus community hospital) in NYC. Design: Retrospective cohort study. Methods: We obtained medical records of 6509 hospitalized patients with laboratory confirmed COVID-19 from the Mount Sinai Health System including 4 teaching hospitals in Manhattan and 2 community hospitals located outside of Manhattan (Queens and Brooklyn) retrospectively. Propensity score analysis using inverse probability of treatment weighting (IPTW) with stabilized weights was performed to adjust for differences in the baseline characteristics of patients initially presenting to teaching or community hospitals, and those who were transferred from community hospitals to teaching hospitals. Results: Among 6509 patients, 4653 (72.6%) were admitted in teaching hospitals, 1462 (22.8%) were admitted in community hospitals, and 293 (4.6%) were originally admitted in community and then transferred into teaching hospitals. Patients in community hospitals had higher mortality (42.5%) than those in teaching hospitals (17.6%) or those transferred from community to teaching hospitals (23.5%, P < 0.001). After IPTW-adjustment, when compared to patients cared for at teaching hospitals, the hazard ratio (HR) and 95% confidence interval (CI) of mortality were as follows: community hospitals 2.47 (2.03-2.99); transfers 0.80 (0.58-1.09)). Conclusions: Patients admitted to community hospitals had higher mortality than those admitted to teaching hospitals.