Proteinuria in a high-altitude 161-km (100-mile) ultramarathon

Urine dipstick analysis (UDA) is a useful tool in clinical practices. Abnormalities in UDA parameters have been observed as a result of extreme exercise. The exact incidence of UDA abnormalities, particularly proteinuria, as the result of running ultramarathons is unknown. The purpose of this study was to estimate the incidence of proteinuria and to identify the characteristics of those with proteinuria.

We conducted a prospective observational study using urine samples from volunteer athletes before and immediately after the Leadville Trail 100 Run in August 2014. There were 33 runners with both pre-race and post-race samples and a total of 70 provided post-race samples. Demographic information was collected as a part of a larger study.

At least one abnormality was demonstrated in 89% of post-race urine samples. Twenty-one (30%) runners had post-race proteinuria (≥1+). Serum creatine kinase concentration (CK) was the only variable that was significantly correlated with the incidence of proteinuria in a multiple logistic regression model.

A majority of runners developed abnormalities in their UDA. Proteinuria was common and found to be associated with serum CK concentration.