Comparison of characteristics, predictors and outcomes between the first and second COVID-19 waves in a tertiary care centre in Switzerland: an observational analysis

AIM OF THE STUDY To compare admission characteristics, predictors and outcomes of patients with confirmed coronavirus disease 2019 (COVID-19) hospitalised in a tertiary care hospital in Switzerland during the first and second waves of the pandemic. METHODS This retrospective observational analysis included adult patients with severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) infection confirmed by a real-time reverse transcriptase polymerase chain reaction (RT-PCR) or rapid antigen test and hospitalised at the Cantonal Hospital Aarau from 26 February to 30 April 2020 (first wave) and from 1 October to 31 December 2020 (second wave). The primary endpoint was all-cause in-hospital mortality. The secondary endpoints were transfer to the intensive care unit (ICU) and length of hospital stay (LOS). RESULTS Overall, 486 patients (mean age 65.9 years ± 14.7 SD, 65% male) were included. Ninety-two patients (19%) died during the hospital stay and 92 patients (19%) were transferred to the ICU. Admission characteristics, including comorbidities and frailty, were similar for patients of the first (n = 100) and second wave (n = 386). However, during the second wave the median time from symptom onset to presentation to the emergency department (ED) was shorter (7 days, interquartile range [IQR] 4–9 vs 8 days, IQR 4–11; p = 0.02). In the second wave, most patients received high-dose glucocorticoid treatment (0% vs 76%, p