PENK and acute kidney injury: In the third study, which had a larger cohort of 978 patients, PENK was identified as a reliable indicator of AKI, the necessity for renal replacement therapy (RRT), and mortality, with odds ratios of 4.0 (95% CI 3.0–5.4) and 1.5 (95% CI 1.2–1.8), respectively [101].