Risk factors for sepsis mortality: A national Swedish cohort study (1998–2018)

Objective Large population-based studies that could identify risk factors associated with sepsis mortality are scarce, but could be helpful in clinical risk assessments. With this study, the authors aimed to examine possible risk factors for sepsis mortality. Methods The authors conducted an open nationwide cohort study, including 157,143 individuals aged ≥ 18-years diagnosed with (first event) sepsis (1998–2018). The outcome was 30-day all-cause mortality following sepsis. The predictors were sociodemographic factors, the Charlson Comorbidity Index, severe mental disorders, pyelonephritis and influenza/pneumonia diagnosis within 30-days before sepsis. Logistic regression models were used to calculate Odds Ratios (OR) and 95% Confidence Intervals (95% CI). Results The overall 30-day mortality proportion was 17.9%, and 30.5% among those aged ≥ 85-years. In the full model, several sociodemographic factors were associated with mortality. For example, individuals aged ≥ 85-years had higher mortality (OR = 13.02, 95% CI 11.50–14.74) compared to those aged 18–44 years. Mortality was also higher among individuals with low educational level (1.09, 1.05–1.13), with low family income (1.17, 1.14–1.21), living outside large cities (1.09, 1.06–1.12), and not being married/cohabiting (1.17, 1.14–1.21), whereas individuals not born in Sweden (0.93, 0.89–0.98) had slightly lower mortality, compared to their respective reference category. Pyelonephritis was associated with lower mortality (0.25, 0.22–0.28) compared with no preceding diagnosis, whereas influenza/pneumonia had no significant association with mortality (1.06, 0.99–1.13). Conclusion These findings can be used to increase the awareness of potential risk factors for sepsis mortality in all settings where patients with sepsis are treated and subsequently followed.