OBJECTIVES : A detailed understanding around the risk factors associated with COVID-19 infection will help in understanding the disease prognosis, resource utilization, and treatment. This study evaluated the risk factors associated with hospitalization in patients with COVID-19 infection.

METHODS : This retrospective observational study included patients diagnosed with COVID-19 infection between 1^st April to 30^th September 2020 with ICD-10 CM diagnosis recorded in a large deidentified database of US health insurance claims. Patients having continuous enrollment between 1 year before (baseline period) to 3 months post (follow-up period) first diagnosis of COVID-19 (index date) were included in study. Comorbid conditions were identified using ICD-10 CM codes during the 1-year baseline period. The primary outcome variable was the hospitalizations due to COVID-19. Multivariate regression model was used to assess the association between sociodemographic characteristics, baseline comorbid conditions and hospitalization related to COVID-19.

RESULTS : The study included 176,284 patients with diverse race/ethnicity (83,863 [47.6%] White, 18,708 [10.6%] African-American, and 27,211 [15.4%] Hispanic), a mean (SD) age of 55.5 (21.9) years and 44% males. Regression adjusted clinical predictors for hospitalization included asthma (OR: 1.27 CI: 1.21-1.32), chronic kidney disease (OR: 1.38 CI: 1.34-1.43), chronic obstructive pulmonary disease (OR: 1.20 CI: 1.16-1.25), diabetes (OR: 1.30 CI: 1.26-1.34), hyperlipidemia (OR: 1.12 CI: 1.09-1.16), hypertension (OR: 1.54 CI: 1.49-1.60), ischemic heart disease (OR: 1.15 CI: 1.11-1.19), rheumatoid arthritis / osteo arthritis (OR: 1.09 CI: 1.06-1.13), prostate cancer (OR: 1.11 CI: 1.03-1.20), endometrial cancer (OR: 1.29 CI: 1.05-1.57) and lung cancer (OR: 1.35 CI: 1.18-1.54). Demographics related risk factors included male sex (OR: 1.29 CI: 1.25-1.33) older age->=55 years (OR: 1.77 CI: 1.70-1.85) and African-American race (OR: 1.58 CI: 1.51-1.65) and Hispanic race (OR: 1.25 CI: 1.20-1.30).

CONCLUSIONS : In this study COVID-19 hospitalizations were significantly associated with older age, male sex, and comorbidity burden. Prospective studies are needed to understand mechanism and causality.