To the Editor:
In their case series of acute kidney injury (AKI) associated with coronavirus disease 2019 (COVID-19), Patel et al1 proposed that a hypercatabolic state with muscle breakdown was the cause of AKI as they presented 3 cases that typify hypercatabolic state, with rapid increase in serum urea nitrogen levels, hyperuricemia, and hyperphosphatemia. However, in all 3 cases, the urea-creatinine ratio (UCR) was unchanged and was not elevated, as is observed in a hypercatabolic state.2 Serum urea nitrogen and creatinine levels (UCR initial/peak: case 1, 17.5/16.2; case 2, 12/13; case 3, 9.7/13) in all 3 cases were essentially unchanged and were not in keeping with a true hypercatabolic state.2 In addition, the near-normal creatine kinase levels do not support significant muscle breakdown unless these patients had pre-existing cachexia. The hyperuricemia and hyperphosphatemia could very well be the effects of AKI rather than initiating factors; however, their role in perpetuation of AKI can not be excluded. The rapid decrease in serum albumin level is more consistent with a capillary leak syndrome, as seen in severe sepsis-systemic inflammatory response syndrome that I agree results from the various inflammatory cytokines (interleukin 6, tumor necrosis factor, etc). I agree with the authors that better understanding of the factors associated with COVID-19–associated AKI and the role of cytokines is important.
Article Information
Financial Disclosure
The author declares that he has no relevant financial interests.
Peer Review
Received August 29, 2020. Accepted September 10, 2020, after editorial review by the Editor-in-Chief.
References
- 1.Patel N., Rein J.L., Sanchez-Russo L., Winston J., Uribarri J. COVID-19-associated acute kidney injury: a case series. Kidney Med. 2020;2(5):668–669. doi: 10.1016/j.xkme.2020.06.004. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Haines R.W., Zolfaghari P., Wan Y., Pearse R.M., Puthucheary Z., Prowle J.R. Elevated urea-to-creatinine ratio provides a biochemical signature of muscle catabolism and persistent critical illness after major trauma. Intensive Care Med. 2019;45(12):1718–1731. doi: 10.1007/s00134-019-05760-5. [DOI] [PubMed] [Google Scholar]