Increased Rates of Supplement-Associated Oxalate Nephropathy During COVID-19 Pandemic

Peter Fong, Raghav Wusirika, Jose Rueda, Kalani L. Raphael, Shehzad Rehman, Megan Stack, Angelo de Mattos, Renu Gupta, Kendall Michels, Firas G. Khoury, Vanderlene Kung, Nicole K. Andeen

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Introduction: Causes of secondary oxalate nephropathy include enteric dysfunction and excessive intake of oxalate or oxalate precursors. During the COVID-19 pandemic, there has been a dramatic rise in sales of supplements and vitamin C, during which time we observed an apparent increase in the proportion of ingestion-associated oxalate nephropathy. Methods: We retrospectively reviewed secondary oxalate nephropathy and compared pre-pandemic (2018–2019) and pandemic (2020–early 2022) time periods. Results: We identified 35 patients with kidney biopsy proven (30 native, 5 allograft) oxalate nephropathy at a single academic institution. Supplement-associated oxalate nephropathy comprised a significantly higher proportion of cases during COVID-19 pandemic compared with the preceding 2 years (44% vs. 0%, P = 0.002), and was associated with use of vitamin C, dietary changes, and supplements. Oxalate nephropathy in the kidney allograft, in contrast, remained associated with enteric hyperoxaluria, antibiotic use, and dehydration. Many patients had diabetes mellitus (57%), hypertension (40%) and/or pre-existing chronic kidney disease (CKD, 49%). Of 9 patients in which the potentially causative ingestion was identified and removed, 8 experienced improvement in kidney function. Conclusion: There was a shift toward supplements rather than enteric hyperoxaluria as a leading cause of secondary oxalate nephropathy during the COVID-19 pandemic. Kidney outcomes are better than those observed for enteric hyperoxaluria, if the offending agent is identified and removed.

Original languageEnglish (US)
Pages (from-to)2608-2616
Number of pages9
JournalKidney International Reports
Issue number12
StatePublished - Dec 2022


  • COVID-19
  • SARS-CoV-2
  • gastric bypass
  • kidney biopsy
  • oxalate
  • vitamin C

ASJC Scopus subject areas

  • Nephrology


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