Temporal Trends in Mortality of Critically Ill Patients with Sepsis in the United Kingdom, 1988-2019.

RATIONALE: Sepsis is a frequent cause of intensive care unit (ICU) admission and mortality.

OBJECTIVES: To evaluate temporal trends in presentation and outcomes of patients admitted to the ICU with sepsis and assess the contribution of changing case mix on outcomes.

METHODS: Retrospective cohort study of patients admitted to 261 ICUs in the United Kingdom during 1988-1990 and 1996-2019 with non-surgical sepsis.

MEASUREMENTS AND MAIN RESULTS: 426,812 patients met study inclusion. Patients were a median (IQR) 66 (53-75) years and 55.6% male. The most common sites of infection were respiratory (60.9%), genitourinary (11.5%), and gastrointestinal (10.3%). Compared to patients in 1988-1990, patients in 2017-2019 were older (median 66 versus 63 years), less acutely ill (median APACHE II acute physiology score 14 versus 20), and more often had genitourinary sepsis (13.4% versus 2.0%). Hospital mortality decreased from 54.6% (95%CI:51.0-58.1%) in 1988-1990 to 32.4% (95%CI:32.1-32.7%) in 2017-2019, adjusted odds ratio 0.64 (95%CI:0.54-0.75). The adjusted absolute hospital mortality reduction from 1988-1990 to 2017-2019 was 8.8% (95%CI:5.6-12.1). Thus, of the observed 22.2 percentage point reduction in hospital mortality, 13.4 percentage points (60% of total reduction) were explained by case mix changes, while 8.8 percentage points (40% of total reduction) were not explained by measured factors and may be due to improvements in ICU management.

CONCLUSIONS: Over a thirty-year period, mortality for ICU admissions with sepsis decreased substantially. While changes in case mix accounted for the majority of observed mortality reduction, there was an 8.8 percentage point reduction in mortality not explained by case mix.