Cystatin C and derived measures of renal function as risk factors for mortality and acute kidney injury in sepsis – A post-hoc analysis of the FINNAKI cohort
Erik Linné, Alma Elfström, Anna Åkesson, Jane Fisher, Anders Grubb, Ville Pettilä, Suvi T. Vaara, Adam Linder, Peter Bentzer
Abstract
To assess the association between cystatin C-derived estimates of kidney function and mortality and acute kidney injury (AKI) in sepsis. Post-hoc analysis of sepsis patients in the FINNAKI-cohort (n = 802). Primary outcome was 90-day mortality. We measured plasma cystatin C and creatinine at intensive care unit (ICU) admission and estimated glomerular filtration rates (eGFRcys, eGFRcrea) and shrunken pore syndrome (SPS; defined as eGFRcys/eGFRcrea ratio < 0.7). Associations were assessed using Cox- or logistic regression. Increased cystatin C and decreased eGFRcys were associated with mortality in unadjusted analyses and in analyses adjusted for illness severity and creatinine. Hazard ratios (HRs) in unadjusted analyses were 3.30 (95% CI; 2.12–5.13, p < 0.001) and 3.26 (95% CI; 2.12–5.02, p < 0.001) respectively. SPS was associated with mortality in an unadjusted- (HR 1.78, 95% CI; 1.33–2.37, p < 0.001) and in an adjusted analysis (HR 1.54, 95% CI; 1.07–2.22, p = 0.021). All cystatin C-derived measures were associated with mortality also after adjustment for AKI development. Cystatin C was associated with AKI in unadjusted analyses but not in analyses adjusted for creatinine. Cystatin C and derived measures of kidney function at ICU admission are associated with an increased 90-day mortality. Increased AKI incidence does not fully explain this association.