Researchers published  a study in the July 5, 2017 issue in Emergency Medicine Journal  found that long distance runners doubled their risk of acute kidney/renal injury or renal problems.

This was troubling as studies have shown that nearly 75 percent of ultramarathoners use ibuprofen while running to relieve pain.

The study examined the use of ibuprofen in ultramarathoners, following 89 participants who took either ibuprofen or a placebo during a 50-mile stretch of one of four different seven-day, 155-mile ultramarathons.

Participants were prevented from taking ibuprofen at least 12 hours before the 50-mile stretch of several ultramarathons.

Researchers then tested their weight, electrolyte levels and renal function 12 to 36 hours later depending on the speed of the runners.

Results showed that 39 of the 89 participants had acute kidney injury at the end of the 50-mile stretch, an 18 percent higher rate of acute kidney injury among those who took ibuprofen compared to those who took the placebo.

“Basically, for every five runners who took ibuprofen, there was one additional case of acute kidney injury. That’s a pretty high rate,” Lipman said.

Acute kidney injury is common in marathon runners due to the high rate of dehydration causing reduced blood flow and rhabdomyolsis, which is a breakdown of muscle tissue leading to the release of muscle fiber contents into the blood.

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.

Although this study looked at ultradistance and ultramarthoners, the authors warn that any distance athlete should exercise caution before ingesting NSAID’s as endurance running and other endurance sports could cause or exacerbate kidney injury.

Source: Ibuprofen versus placebo effect on acute kidney injury in ultramarathons: a randomised controlled trial | Emergency Medicine Journal