Risk Factors Associated with the Mortality of COVID-19 Patients Aged ≥60 Years Neither Intubated nor Treated with Mechanical Ventilation: A Multicentre Retrospective Cohort Study during the First Wave in Spain

Background: To determine risk factors of death in diagnosed patients with COVID-19 who were aged ≥60 years and could not benefit from intubation and mechanical ventilation. Methods: Retrospective multicentre study including all patients with COVID-19 admitted to four medium-stay centres in Catalonia (March-June 2020). At the multivariate level, we calculated hazard ratios (HR) with 95% confidence intervals (CI) to determine risk factors associated with mortality. Results: 683 patients were included, of whom 227 died (case fatality rate of 33%, reaching 42% in patients of more than 90 years). Mean survival was 21.92 (20.98–22.86) days. Factors associated with death were fever (HR:1.5 (1.06–2.13)), malaise (HR:1.4 (1.04–1.99)), dyspnoea (HR:1.98 (1.41–2.79)) and atrial fibrillation (HR:1.45 (1.03–2.05)), while coughing (HR: 0.66 (0.46–0.94)), diarrhoea (HR:0.46 (0.23–0.92)), dyslipidaemia (HR:0.47 (0.28–0.82)), and receiving antithrombotic treatment (HR:0.56 (0.40–0.78)) had a protective effect. The analysis by age group showed that other factors were uniquely associated with each age group, such as chronic obstructive pulmonary disease at 60–74 years and polypharmacy at 75–90 years, among other factors. Conclusions: Case fatality in COVID-19 patients who could not benefit from intubation and mechanical ventilation was exceptional. Clinical manifestations such as fever, malaise, dyspnoea and atrial fibrillation helped to identify patients at higher risk of mortality, while antithrombotic treatment had a protective effect. Although some symptoms are very general regarding COVID-19, in the context of the first wave without vaccination, when not much was known about the disease, such symptoms could be useful.