Trends in Sepsis Mortality and Use of Invasive Interventions
Objective: To investigate trends in hospital mortality for critically ill septic patients over a recent ten-year timeframe subdivided by illness severity. In addition, identify trends in use of invasive interventions over time across different illness severity.
Design & Setting: Retrospective cohort study of patients admitted to critical care units from 2008-2019 as accessed from MIMIC-IV, a publicly accessible database of patients admitted to Boston's Beth Israel Deaconess Medical Center (BIDMC). Among the 76540 ICU stays in MIMIC-IV, we selected the 35010 ICU stays with sepsis diagnosis (69211 non-sepsis ICU stay excluded). We then selected 31983 first-time ICU stays with sepsis diagnosis (3027 recurrent ICU stays excluded). Data were collected on demographics, illness severity, mechanical ventilation, vasopressor, and renal replacement therapy (RRT) use. Patients were categorized into severity level groups based on their ICU admission Sequential Organ Failure Assessment (SOFA) scores. Primary outcome was hospital mortality over time and across illness severity. Secondary outcomes were use of mechanical ventilation, vasopressors, and RRT. Data were adjusted to account for age, gender, comorbidities, and SOFA score.
Results: The likelihood of in-hospital mortality per year increased for septic patients with SOFA 0-5 (odds ratio [OR] 1.19; 95%; confidence interval [CI] 1.13-1.25), SOFA 6-10 (OR, 1.06; CI, 1.01-1.10), and SOFA 16+ (OR, 1.16; CI, 1.01-1.33) , but not for SOFA 11-15, adjusting for gender, age, Charlson Comorbidity Index (CCI), exact SOFA score, vasopressor use, RRT, and mechanical ventilation. After adjusting for age, gender, CCI and exact SOFA score, vasopressor use similarly increased per year in these same groups [SOFA 0-5 (OR, 1.12; CI, 1.08-1.16), SOFA 6-10 (OR, 1.15; CI, 1.11-1.19), and SOFA 16+ (OR, 1.98; CI, 1.10-3.56)]. Mechanical ventilation use increased in patients with SOFA 0-5 (OR, 1.12; CI, 1.09-1.16) and 6-10 (OR, 1.08; CI, 1.04-1.12) but not in SOFA 11-15 and 16+; RRT use decreased in SOFA 0-5 (OR, 0.78; CI, 0.70-0.86) and 6-10 (OR, 0.78; CI, 0.74-0.83) but not in SOFA 11-15 and 16+.
Conclusions: We discovered significantly increasing mortality among the lowest and highest severity groups over time from 2008 to 2019, but not in the moderate severity group. We also observe significant changes over time in the use of invasive interventions in these same groups. Further studies are needed to investigate whether these findings are mere associations and whether causality can be inferred.
document link: https://docs.google.com/document/d/1D8h_DyFGFDN00u74yXa-vJSbGZyLGahJQxyIFADzFzw/edit?pli=1