INTRODUCTION: In response to the evolution of the coronavirus disease 2019 (COVID-19) pandemic, the admission protocol for the temporary COVID-19 hospital in Mexico City has been updated to hospitalize patients preemptively with an oxygen saturation (SpO2) of >90%. METHODS: This prospective, observational, single-center study compared the progression and outcomes of patients who were preemptively hospitalized versus those who were hospitalized based on an SpO2 ⩽90%. We recorded patient demographics, clinical characteristics, COVID-19 symptoms, and oxygen requirement at admission. We calculated the risk of disease progression and the benefit of preemptive hospitalization, stratified by CALL Score: age, lymphocyte count, and lactate dehydrogenase (<8 and ⩾8) at admission. RESULTS: Preemptive hospitalization significantly reduced the requirement for oxygen therapy (odds ratio 0.45, 95% confidence interval 0.31-0.66), admission to the intensive care unit (ICU) (0.37, 0.23-0.60), requirement for invasive mechanical ventilation (IMV) (0.40, 0.25-0.64), and mortality (0.22, 0.10-0.50). Stratification by CALL score at admission showed that the benefit of preemptive hospitalization remained significant for patients requiring oxygen therapy (0.51, 0.31-0.83), admission to the ICU (0.48, 0.27-0.86), and IMV (0.51, 0.28-0.92). Mortality risk remained significantly reduced (0.19, 0.07-0.48). CONCLUSION: Preemptive hospitalization reduced the rate of disease progression and may be beneficial for improving COVID-19 patient outcomes.