Evolution of characteristics and outcomes for patients hospitalized for COVID-19 during successive waves of the epidemic in France.

PURPOSE: To explore changes in in-hospital mortality, admission to critical care unit (CCU) and clinical characteristics of patients hospitalized for COVID-19 in France.

METHODS

Hospital discharge data were used to analyse outcomes during epidemic waves: W1 (January-July 2020), W2 (August 2020-June 2021), W3 (July-October 2021),W4 (November 2021-May 2022), W5 (June-September 2022). Join-point, logistic and survival regressions were used for the analyses.

RESULTS

Overall, 502,532 patients were included. W3 patients were younger (median age: 61 years; interquartile-range: 44-76) and fewer than 10 % had a Charlson Comorbidity Index ≥ 3. The proportion of patients aged ≥ 75 years old was higher (59 %) during W5. Compared to W1, W3 patients had a higher risk of admission to CCU, adjusted odds ratios ranged from 1.18 (CI: 1.09-1.28) for < 45 years old to 1.30 (1.17-1.34) for ≥ 75 years old. In CCU the risk of death decreased by 47 % during W2 in < 45 years old, increased by 11 % during W4 for 45-74 years old, and increased by 13 % and 10 % during W2 and W3 respectively, for ≥ 75 years old.

CONCLUSION

This analysis confirms the age as a major risk factor for adverse outcomes of COVID-19, and highlights the importance of hospital discharge data for future pandemics.