Kidney Week

Abstract: PUB002

Eureka! The Kidney Biopsy That Never Happened: It Ain't AKI; It's Pseudohypercreatininemia from Daily Creatine Monohydrate Supplementation

Session Information

• Publication Only

Category: Acute Kidney Injury

• 102 AKI: Clinical, Outcomes, and Trials

Authors

• Onuigbo, Macaulay A., University of Vermont The Robert Larner MD College of Medicine, Burlington, Vermont, United States

Macaulay A. Onuigbo, MD, MS, MBA, FASN

• Do, Lynn, University of Vermont The Robert Larner MD College of Medicine, Burlington, Vermont, United States

Lynn Do, MA

• McCarthy-Sioss, Jean, University of Vermont The Robert Larner MD College of Medicine, Burlington, Vermont, United States

Jean McCarthy-Sioss, RN

• Irving, Crystal, University of Vermont The Robert Larner MD College of Medicine, Burlington, Vermont, United States

Crystal Irving, RN

• Andreozzi, Samantha, University of Vermont The Robert Larner MD College of Medicine, Burlington, Vermont, United States

Samantha Andreozzi, RN

Introduction

Creatine monohydrate (CM) is a widely used dietary supplement with reported benefits in athletic performance and recent claims for improved "brain health". There is controversy about its renal safety. We report asymptomatic rising creatinine with daily CM.

Case Description

A 67-yo female, BMI 27.1 kg/m², with gastric bypass in June 2021 (biliopancreatic diversion with duodenal switch), hypertension, diabetes mellitus and cirrhosis with alcoholism in remission, on weekly Tirzepatide, was evaluated in January 2026 for progressively rising serum creatinine up to 1.8 mg/dL (Fig 1). She was otherwise asymptomatic, and not on NSAIDs. Physical examination was unremarkable. A comprehensive acute kidney injury work-up was non-diagnostic. A kidney biopsy was scheduled. Just before the biopsy, she revealed being on daily CM for about 6 months. CM was stopped. Kidney biopsy was canceled. Repeat labs showed promptly improved creatinine down to 0.84 mg/dL (Fig 2).

Discussion

We dubbed the rising creatinine pseudo-hypercreatininemia, to distinguish this from true acute kidney injury. We avoided a kidney biopsy. The role of previous gastric bypass to pseudo-hypercreatininemia remains speculative. Serum Cystatin C analysis would have been helpful. Noteworthily, BUN, available only in 2026, decreased from 15 mg/dL to 10 mg/dL after CM was stopped.

Rising serum creatinine with creatine supplement

Promptly normalized serum creatinine with creatine discontinuaton