Evolution of baseline characteristics and severe outcomes in COVID-19 inpatients during the first and second waves in Northeastern France

•Patients hospitalized with COVID-19 during the second wave of the epidemics were associated with a shorter time between symptom onset and hospitalization, milder symptoms at admission, and higher steroid prescriptions compared with patients of the first epidemic wave.•Patients of the second epidemic wave had a lower death rate and fewer ICU hospitalizations than patients of the first epidemic wave.•Except for cardiovascular events, which were more frequently observed during the second epidemic wave, there was no change in other extrapulmonary complications during the two epidemic waves. Two COVID-19 epidemic waves occurred in France in 2020. This single-center retrospective study compared patients’ characteristics and outcomes. We included all patients with confirmed COVID-19 admitted to Colmar Hospital in March (n=600) and October/November (n=205) 2020. Median ages, sex ratio, body mass index, and number of comorbidities were similar in wave 1 and 2 patients. Significant differences were found for temperature (38°C vs. 37.2), need for oxygen (38.6% vs. 26.8%), high-flow cannula (0% vs. 8.3%), and steroid use (6.3% vs. 54.1%). Intensive care unit (ICU) hospitalizations (25.5% vs. 15.1%, OR: 0.44, 95% CI [0.28; 0.68], P=0.002) and deaths (19.2% vs. 12.7%, OR: 0.61, 95% CI [0.37; 0.98], P=0.04) decreased during the second wave. Except for cardiovascular events (5.5% vs. 10.2%), no change was observed in extrapulmonary events. Deaths and ICU hospitalizations were significantly reduced during the second epidemic wave.