key: cord-0764166-ot03e7un
authors: Patel, Niralee; Rein, Joshua L.; Sanchez-Russo, Luis; Winston, Jonathan; Uribarri, Jaime
title: In Reply to ‘COVID-19–Associated Kidney Injury’
date: 2020-11-22
journal: Kidney Med
DOI: 10.1016/j.xkme.2020.10.003
sha: f94a45d56b9b2457f716354411090cd2fa6734fd
doc_id: 764166
cord_uid: ot03e7un

nan

that the serum urea nitrogen (SUN) to creatinine ratio, as cited in reference #2 should become the standard definition of a hypercatabolic state (3) . In that reference, the ratio was a pre-specified outcome, their patients had a different phenotype compared to ours, the great majority did not have acute kidney injury (AKI), and their work did not account for the influence of total parenteral nutrition on urea levels. It is widely known that parenteral nutrition is extensively and intensively used in intensive care units and may contribute significantly to increased SUN out of proportion to serum creatinine (4).

Moreover, we have other data quantifying in a more precise way, the inordinate levels of urea generation in COVID-19-associated AKI among patients similar to our cohort (5), strongly supporting a hypercatabolic state. We also disagree with Dr. Parmar's interpretation of the meaning of near normal creatinine kinase (CK) in our patients; indeed, we believe these CK values support our hypothesis that there was no actual loss of muscle cell integrity (rhabdomyolysis), but only increased muscle protein breakdown induced by the cytokine storm. We agree there is much more to learn about the pathophysiology of this condition, both in COVID-19 and other critical illness.

COVID-19-Associated Acute Kidney Injury

COVID-19-Associated Acute Kidney Injury: A Case Series

Elevated urea-to-creatinine ratio provides a biochemical signature of muscle catabolism and persistent critical illness after major trauma

Impact of early parenteral nutrition on metabolism and kidney injury