Background: Both sepsis and AKI are diseases of major concern in intensive care unit (ICU). This study aimed to evaluate the excess mortality attributable to sepsis for acute kidney injury (AKI).
Methods: A propensity score-matched analysis of a prospective cohort study about sepsis epidemiology in 18 Chinese ICUs (January 2014-August 2015) was performed (registration number: ChiCTR-ECH-13003934). Propensity score model was sequentially conducted to match AKI patients with and without sepsis on day 1, day 2, and day 3-5. The primary outcome was hospital death of AKI patients. Propensity score-matched analyses were conducted to estimate the excess mortality attributable to sepsis for AKI.
Results: A total of 2008 AKI patients (40.9%) were eligible for the study. Of the 1010 AKI patients with sepsis, 619 (61.3%) were matched to 619 AKI patients in whom sepsis did not develop during the screening period of the study. The hospital mortality rate of matched AKI patients with sepsis was 205 of 619 (33.1%) compared with 150 of 619 (24.0%) for their matched AKI controls without sepsis (p = 0.001). The attributable mortality of total sepsis for AKI patients was 9.1% (95% CI 4.8-13.3%). Matched AKI patients with and without sepsis were subgrouped according to the severity of sepsis (sepsis, septic shock). Of the matched patients with sepsis, 328 (53.0%) diagnosed septic shock. The mortality rate showed remarkably higher in matched AKI patients with septic shock (43.9%) than their controls of patients without sepsis (27.7%). The attributable mortality of septic shock for AKI was 16.2% (95% CI 11.3-20.8%, p < 0.001). Further, the attributable mortality of sepsis for AKI was 1.4% (95% CI 4.1-5.9%, p = 0.825), although there was no significant difference of mortality rate observed between matched AKI patients with and without sepsis (21.0% vs. 19.6%).
Conclusions: The attributable hospital mortality of total sepsis for AKI were 9.1%. Septic shock contributes to major excess mortality rate for AKI than sepsis.