Treatment and outcome of COVID-19 patients in a specialized hospital during the third wave: advance of age and increased mortality compared with the first/second waves

PURPOSE: To elucidate the clinical course of patients with coronavirus disease 2019 (COVID-19) treated at a specialized hospital mainly for those with mild and moderate severity during the third wave, and to compare that with the first and second (1st/2nd) waves. METHODS: We retrospectively reviewed the severity on admission, treatment, and outcome of a total of 581 patients from September, 2020, to March, 2021, and examined the risk factors for deterioration of respiratory condition, defined as requiring oxygen ≥ 7 L/min for 12 h. RESULTS: The median age was 78 (interquartile range 62−83) years, older than in the 1st/2nd waves (53 years), and 50% of the patients was male. The number of patients classified as mild (peripheral oxygen saturation (SpO(2)) ≥ 96%), moderate I, II, and severe (requiring admission to the ICU or mechanical ventilation) was 121, 324, 132, and 4, respectively. Favipiravir, ciclesonide, dexamethasone, and/or heparin were administered for treatment. Respiratory condition recovered in 496 (85%) patients. It worsened in 81 patients (14%); 51 (9%) of whom were transferred to tertiary hospitals and 30 (5%) died. Mortality rate increased by fivefold compared during the 1st/2nd waves. Age, male sex, increased body mass index, and C-reactive protein (CRP) on admission were responsible for worsening of the respiratory condition. CONCLUSION: Patients were older in the third wave compared with the 1st/2nd waves. Respiratory condition recovered in 85%; whereas 5% of the patients died. Old age, male sex, increased body mass index, and CRP would be responsible for worsening of the respiratory condition.