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Abstract: TH-OR09

Properties of Proenkephalin (penKid) in Septic AKI

Session Information

Category: Acute Kidney Injury

  • 102 AKI: Clinical, Outcomes, and Trials

Authors

  • Nusshag, Christian, Heidelberg University Hospital Department of Nephrology, Heidelberg, Germany
  • Szudarek, Roman, Heidelberg University Hospital Department of Anesthesiology, Heidelberg, Germany
  • Rupp, Christoph, Heidelberg University Hospital Department of Anesthesiology, Heidelberg, Germany
  • Speer, Claudius, Heidelberg University Hospital Department of Nephrology, Heidelberg, Germany
  • Kälble, Florian, Heidelberg University Hospital Department of Nephrology, Heidelberg, Germany
  • Zeier, Martin G., Heidelberg University Hospital Department of Nephrology, Heidelberg, Germany
  • Uhle, Florian, Heidelberg University Hospital Department of Anesthesiology, Heidelberg, Germany
  • Merle, Uta, Heidelberg University Hospital Department of Gastroenterology, Heidelberg, Germany
  • Morath, Christian, Heidelberg University Hospital Department of Nephrology, Heidelberg, Germany
  • Weigand, Markus A., Heidelberg University Hospital Department of Anesthesiology, Heidelberg, Germany
  • Brenner, Thorsten, Heidelberg University Hospital Department of Anesthesiology, Heidelberg, Germany
Background

Acute kidney injury (AKI) remains a serious complication in critically ill patients. The current definition of AKI continues to be based on changes in serum creatinine (SCr) and diuresis. However, neither SCr nor changes in diuresis provide an accurate estimate of true renal function. Proenkephalin (penKid) is a small and stable peptide derived from the same precursor molecule as encephalins. Recent evidence suggests that plasma PenKid concentrations more accurately reflect the true glomerular filtration rate than SCr. We therefore investigated the kinetic and diagnostic properties of penKid in critically ill patients with septic AKI.

Methods

In a secondary analysis of a prospective observational study, penKid levels were measured longitudinally in 200 patients with positive Sepsis-3 criteria. Plasma penKid levels were analyzed in relation to the severity and course of AKI and under renal replacement therapy. Area under the receiver-operating characteristic curve (AUC-ROC) analyses were performed.

Results

Sixty-two patients had no or mild AKI, 96 patients developed moderate or severe AKI without requiring RRT, and 42 patients developed RRT criteria or died within seven days after inclusion. Thirty-nine patients had transient AKI and 92 patients experienced persistent AKI or required RRT. Overall, penKid kinetics were more dynamic than SCr, and penKid courses preceded corresponding SCr courses by 48 h to 72 h. In patients without AKI, penKid levels generally remained below 50 pmol/L. Moreover, penKid levels discriminated well between transient and persistent AKI or the need for RRT. After 24 hours of sepsis therapy, the combination of SCr and penKid showed an improved AUC of 0.82 (95% CI 0.76-0.88) for predicting RRT or death compared with SCr or penKid alone (SCr: AUC 0.78, 95% CI 0.70-0.86; penKid: AUC 0.80, 95% CI 0.73-0.87). Interestingly, penKid courses were hardly affected by RRT and in some cases even increased under RRT.

Conclusion

Plasma penKid appears to indicate changes in renal function more dynamically than SCr and seems to provide additional diagnostic information on renal function. Remarkably, RRT appears to have little effect on plasma concentrations of penKid. Thus, penKid could allow assessment of renal function under RRT. Further research is needed to verify these results.