Based on a cohort of 2821 patients hospitalized for COVID-19, we found a simple COVID-19 severity scale using admission oxygen requirements and intensive care unit designation correlates well with inpatient mortality and is highly predictive of administration of COVID-19-specific medications (3.5-fold more likely to receive a drug therapy for COVID-19 in patients of highest vs lowest severity level).

Additional predictors of treatment were calendar time, fever, low oxygen saturation, presence of co-morbidities, and elevated inflammatory biomarkers.

Pharmacological treatment for patients hospitalized for COVID-19 is highly correlated with disease severity and oxygen requirement is a key driver.

Non-randomized studies evaluating treatment effectiveness for COVID-19 must consider these important determinants of treatment decisions for COVID-19.