Long-term temporal trends in incidence rate and case fatality of sepsis and COVID-19-related sepsis: nationwide registry study
Authors: Skei Nina Vibeche , Lund Nilsen Tom Ivar , Knoop Siri Tandberg , Prescott Hallie C. , Lydersen Stian , Mohus Randi Marie , Brkic Alen , Liyanarachi Kristin Vardheim , Solligård Erik , Damås Jan Kristian , Gustad Lise Tuset 
Published: November 2022

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.

Key Points

Question

Has there been a change in incidence rate and case fatality of sepsis over the past decade, and how did the COVID-19 pandemic influence sepsis incidence rates and in-hospital mortality?

Findings

In this nationwide longitudinal registry study the incidence rate of all sepsis episodes increased and the incidence rate of a first sepsis episode was stable during the period 2009-2019, whereas in 2020 and 2021, the incidence rate of a first and all sepsis episodes was lower than in the preceding 11-year period. Case fatality risk declined from 2009 to 2019, but increased somewhat in 2020 and 2021, when 9.7% of first sepsis cases were identified as COVID-19 related sepsis.

Meaning

Despite a stable incidence rate of first-time sepsis admissions over time, the burden of sepsis is rising due to an increased rate of patients admitted multiple times with sepsis. The COVID-19 pandemic have had an impact on sepsis incidence rate and hospital mortality and needs further evaluation.