21 Jul UCSF Study Finds Acute Kidney Injury Does Not Worsen Course of CKD

MedicalResearch.com Interview with:

Dr. Chi-yuan Hsu

Chi-yuan Hsu, MD, MSc (he/him/his)
Professor and Division Chief
Robert W. Schrier Distinguished Professor
Division of Nephrology
University of California, San Francisco

MedicalResearch.com: What is the background for this study?

Response: Acute kidney injury (AKI) had previously been considered a reversible short-term medical problem among hospitalized patients without long-term sequalae in that there is recovery of kidney function back to baseline should the patient survive the hospitalization.

Then about 15 years ago, the concept began to shift as research by us and others showed that for patients with severe AKI (e.g. AKI severe enough to require acute dialysis in the hospital), there was more rapid subsequent loss of renal function. 

Now based largely on additional observational studies in humans (and animal models), many nephrologists and opinion leaders think that even mild to moderate cases of AKI have long-term sequelae.  We are concerned that the paradigm has swung too much in the opposite direction and we questioned the results of many published studies which did not fully account for differences in background kidney function among those who did and did not experience AKI.

MedicalResearch.com: What are the main findings?

Response:  We found that after more rigorously accounting for differences in background kidney function (and other clinical conditions) among those who did and did not experience AKI, it appears that mild to moderate AKI did not was not associated with worsening kidney function.

Our results suggested that any true causal effect is a small/weak one (with the caveat that one cannot really draw conclusions about causality from observational studies such as ours).

Rather, the worse kidney function observed after mild to moderate AKI reflect worse kidney function that was already present prior to the development of AKI.

MedicalResearch.com: Did the etiology of either the AKI or CKD make a difference in the CKD progression?

Response:  We were limited in our ability to dissect out differences related to etiology of AKI or CKD.  For example, our patients did not undergo kidney biopsies, which is considered the gold standard way to determine etiology of AKI or CKD. (Kidney biopsies are frequently not available in regular clinical practice).

MedicalResearch.com: What should readers take away from your report?

Response: Much of the kidney disease observe after mild to moderate AKI was already present before AKI. The independent contribution of AKI appears small. Nevertheless, AKI episodes can be thought of as “failed kidney stress tests” and they identify high risk patients who would benefit from more intensive follow-up and treatment.

MedicalResearch.com: What recommendations do you have for future research as a results of this study?

Response: Do not conduct interventional studies with the notion that preventing mild to moderate AKI will reduce subsequent burden of CKD.  (This has been the basis of a number of high profile studies e.g. PMID: 24886787 and 2913081.)

MedicalResearch.com:  Is there anything else you would like to add?

Response: We have a video on the Annals website.
https://www.acpjournals.org/doi/10.7326/M22-3617

No financial COI to disclose.

Citation: Muiru AN, Hsu JY, Zhang X, Appel LJ, Chen J, Cohen DL, Drawz PE, Freedman BI, Go AS, He J, Horwitz EJ, Hsu RK, Lash JP, Liu KD, McCoy IE, Porter A, Rao P, Ricardo AC, Rincon-Choles H, Sondheimer J, Taliercio J, Unruh M, Hsu CY; CRIC Study Investigators. Risk for Chronic Kidney Disease Progression After Acute Kidney Injury: Findings From the Chronic Renal Insufficiency Cohort Study. Ann Intern Med. 2023 Jul;176(7):961-968. doi: 10.7326/M22-3617. Epub 2023 Jul 11. PMID: 37429030.

https://pubmed.ncbi.nlm.nih.gov/37429030/

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Last Updated on July 21, 2023 by Marie Benz MD FAAD