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Ibuprofen versus placebo effect on acute kidney injury in ultramarathons: a randomised controlled trial
  1. Grant S Lipman1,
  2. Kate Shea1,
  3. Mark Christensen1,
  4. Caleb Phillips2,
  5. Patrick Burns3,
  6. Rebecca Higbee4,
  7. Viktoria Koskenoja5,
  8. Kurt Eifling6,
  9. Brian J Krabak7
  1. 1 Department of Emergency Medicine, Stanford University School of Medicine, Stanford, California, USA
  2. 2 Department of Computational Sciences, University of Colorado at Boulder, Boulder, Colorado, USA
  3. 3 Emergency Medicine Residency, University of Washington, Seattle, USA
  4. 4 Stanford-Kaiser Emergency Medicine Residency, Stanford, USA
  5. 5 Harvard Affiliated Emergency Medicine Residency, Harvard Medical School, Boston, USA
  6. 6 Washington University in St. Louis Emergency Medicine Residency, St. Louis, USA
  7. 7 Department of Orthopedics and Sports Medicine, University of Washington, Seattle, USA
  1. Correspondence to Dr Grant S Lipman, Department of Emergency Medicine, Stanford University School of Medicine, 900 Welch Road, Stanford; grantlip{at}


Background Despite concerns that non-steroidal anti-inflammatory drugs (NSAIDs) contribute to acute kidney injury (AKI), up to 75% of ultramarathon runners ingest these during competition. The effect of NSAID on AKI incidence in ultramarathon runners is unclear.

Methods Multisite randomised double-blind placebo-controlled trial in the Gobi, Atacama, Ecuador and Sri Lankan deserts to determine whether ibuprofen (400 mg every 4 hours) would be non-inferior to placebo during a 50-mile (80 km) foot race. The primary outcome was incidence of AKI defined as severity categories of ‘risk’ of injury of 1.5× baseline creatinine (Cr) or ‘injury’ as 2× Cr, combined to calculate total incidence at the finish line. Non-inferiority margin for difference in AKI rates was defined as 15%.

Results Eighty-nine participants (47% ibuprofen and 53% placebo) were enrolled with similar demographics between groups. The overall incidence of AKI was 44%. Intent-to-treat analysis found 22 (52%) ibuprofen versus 16 (34%) placebo users developed AKI (18% difference, 95% CI –4% to 41%; OR 2.1, 95% CI 0.9 to 5.1) with a number needed to harm of 5.5. Greater severity of AKI was seen with ibuprofen compared with placebo (risk=38% vs 26%; 95% CI –9% to 34%; injury=14% vs 9%; 95% CI –10% to 21%). Slower finishers were less likely to encounter AKI (OR 0.67, 95% CI 0.47 to 0.98) and greater weight loss (−1.3%) increased AKI (OR 1.24, 95% CI 1.00 to 1.63).

Conclusion There were increased rates of AKI in those who took ibuprofen, and although not statistically inferior to placebo by a small margin, there was a number needed to harm of 5.5 people to cause 1 case of AKI. Consideration should therefore be taken before ingesting NSAID during endurance running as it could exacerbate renal injury.

Trial registration number NCT02272725.

  • wilderness medicine
  • renal
  • environmental medicine, wilderness medicine
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  • Contributors GSL had full access to all the data in the study and takes full responsibility for the integrity of the data and the accuracy of the data analysis. GSL and CP were responsible for data management, analysis and interpretation of the data, and statistical analysis. Study concept and design: GSL, BJK, KS. Acquisition, analysis or interpretation of data, and drafting of the manuscript: all authors. Obtained funding: GSL. Study supervision: GSL, KS.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Ethics approval Stanford University School of Medicine.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement There is no additional unpublished data from this study that has been made available.

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