Risk factors of mortality among patients hospitalised with COVID-19 in a critical care or hospital care unit: analysis of the French national medicoadministrative database

OBJECTIVE: To explore mortality risk factors for patients hospitalised with COVID-19 in a critical care unit (CCU) or a hospital care unit (HCU). DESIGN: Retrospective cohort analysis using the French national (Programme de médicalisation des systèmes d’information) database. SETTING: Any public or private hospital in France. PARTICIPANTS: 98 366 patients admitted with COVID-19 for more than 1 day during the first semester of 2020 were included. The underlying conditions were retrieved for all contiguous stays. MAIN OUTCOME MEASURES: In-hospital mortality and associated risk factors were assessed using frailty Cox models. RESULTS: Among the 98 366 patients included, 25 765 (26%) were admitted to a CCU. The median age was 66 (IQR: 55–76) years in CCUs and 74 (IQR: 57–85) years in HCUs. Age was the main risk factor of death in both CCUs and HCUs, with adjusted HRs (aHRs) in CCUs increasing from 1.60 (95% CI 1.35 to 1.88) for 46 to 65 years to 8.17 (95% CI 6.86 to 9.72) for ≥85 years. In HCUs, the aHR associated with age was more than two times higher. The gender was not significantly associated with death, aHR 1.03 (95% CI 0.98 to 1.09, p=0.2693) in CCUs. Most of the underlying chronic conditions were risk factors for death, including malignant neoplasm (CCU: 1.34 (95% CI 1.25 to 1.43); HCU: 1.41 (95% CI 1.35 to 1.47)), cirrhosis without transplant (1.41 (95% CI 1.22 to 1.64); 1.27 (95% CI 1.12 to 1.45)) and dementia (1.30 (95% CI 1.16 to 1.46); 1.07 (95% CI 1.03 to 1.12)). CONCLUSION: This analysis confirms the role of age as the major risk factor of death in patients with COVID-19 irrespective to admission to critical care and therefore supports the current vaccination policies targeting older individuals.