Importance: Sepsis is one of the leading causes of morbidity and mortality. The majority of sepsis cases is attributed to bacterial infections, but virus infections can also induce sepsis. Conflicting results in incidence rates and case fatality trends of sepsis is reported, and how the COVID-19 pandemic influenced these trends are unknown. Objective: To estimate temporal trends in incidence rate and case fatality during a 14-year period from 2008 through 2021, and to assess possible shifts in these trends during the COVID-19 pandemic. Design: A nationwide longitudinal registry study using ICD-10 discharge codes to identify sepsis. Setting: All Norwegian hospitals from 2008 through 2021. Participants: All sepsis cases included 317.705 patients and of these, 222.832 had a first sepsis episode. Main outcomes and measures: Annual age-standardized incidence rates with 95% confidence intervals (CI). Poisson regression was used to estimate changes in incidence rates across time, and logistic regression was used to estimate odds ratios for in-hospital death. Results: Among 12.619.803 adult hospitalizations, 317.705 (2.5%) patients met the sepsis criteria and 222.832 (70.0%) had a first sepsis episode. In the period 2009-2019, the annual incidence rate for a first sepsis episode was stable (incidence rate ratio per year, 0.999; 95% CI, 0.994-1.004), whereas for all sepsis the incidence rate increased by 15.5% during the period (annual incidence rate ratio, 1.013; 95% CI 1.007-1.019). During the COVID-19 pandemic, the incidence rate ratio for a first sepsis was 0.877 (95% CI, 0.829-0.927) in 2020 and 0.929 (95% CI, 0.870-0.992) in 2021, and for all sepsis it was 0.870 (95% CI, 0.810-0.935) in 2020 and 0.908 (95% CI, 0.840-0.980) in 2021, compared to the previous 11-year period. In-hospital deaths declined in the period 2009-2019 (odds ratio per year, 0.954 [95% CI,0.950-0.958]), whereas deaths increased during the COVID-19 pandemic in 2020 (odds ratios, 1.061 [95% CI 1.001-1.124] and in 2021 odds ratio (1.164 [95% CI, 1.098-1.233]). Conclusion and relevance: We found a stable incidence rate of a first sepsis episode during the years 2009-2019. However, the increasing burden of all sepsis admissions indicates that sepsis awareness with updated guidelines and education must continue.

The authors have declared no competing interest.

This study did not receive any funding

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

the Regional Committee for Medical and Health Research Ethics (REK) in Eastern Norway (2019/42772) and the Data Access Committee in Nord-Trondelag Hospital Trust (2021/184) gave ethical approval for this work.

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All data produced in the present study are available upon reasonable request to the authors