Proenkephalin A 119-159 (Penkid) Is an Early Biomarker of Septic Acute Kidney Injury: The Kidney in Sepsis and Septic Shock (Kid-SSS) Study

Introduction: Sepsis is the leading cause of acute kidney injury (AKI) in critically ill patients. The Kidney in Sepsis and Septic Shock (Kid-SSS) study evaluated the value of proenkephalin A 119-159 (penkid)-a sensitive biomarker of glomerular function, drawn within 24 hours upon intensive care unit (ICU) admission and analyzed using a chemiluminescence immunoassay-for kidney events in sepsis and septic shock. Methods: The Kid-SSS study was a substudy of Adrenomedullin and Outcome in Severe Sepsis and Septic Shock (AdrenOSS) (NCT02393781), a prospective, observational, multinational study including 583 patients admitted to the intensive care unit with sepsis or septic shock and a validation cohort of 525 patients from the French and euRopean Outcome reGistry in Intensive Care Units (FROG-ICU) study. The primary endpoint was major adverse kidney events (MAKEs) at day 7, composite of death, renal replacement therapy, and persistent renal dysfunction. The secondary endpoints included AKI, transient AKI, worsening renal function (WRF), and 28-day mortality. Results: Median age was 66 years (interquartile range 55-75), and 28-day mortality was 22% (95% confidence interval [CI] 19%-25%). Of the patients, 293 (50.3%) were in shock upon ICU admission. Penkid was significantly elevated in patients with MAKEs, persistent AKI, and WRF (median = 65 [IQR = 45-106] vs. 179 [114-242]; 53 [3970] vs. 133 [79-196] pmol/l; and 70 [47-121] vs. 174 [93-242] pmol/l, all P < 0.0001), also after adjustment for confounding factors (adjusted odds ratio = 3.3 [95% CI = 1.8-6.0], 3.9 [95% CI = 2.1-7.2], and 3.4 [95% CI = 1.9-6.2], all P < 0.0001). Penkid increase preceded elevation of serum creatinine with WRF and was low in renal recovery. Conclusion: Admission penkid concentration was associated with MAKEs, AKI, and WRF in a timely manner in septic patients.