An interesting study in AJKD published revealed a possible risk of AKI with marathon runners. This is the first study to evaluate urine microscopy in parallel with conventional and novel biomarkers of injury and repair in marathon runners. The authors prospectively showed that the AKI in runners is secondary to structural injury, mainly acute tubular injury, as evidenced by serum creatinine levels, urine microscopy analysis, and levels of novel biomarkers of injury and repair.
One would expect these changes likely were related to elevated CPK levels and rhabdomyolysis. Interesting, while the subjects had high CPK levels, they did not correlate with AKI episodes. The authors hypothesize that heat stress and increase in core body temperature along with systemic inflammation are likely associated with AKI in marathon runners. They said that this might be similar to the CKD that is prevalent in Central American in sugarcane workers. Agricultural workers have been shown to have acute decreases in kidney function and progression to CKD associated with dehydration, systemic inflammation, and oxidative stress. It is also possible that compared with agricultural workers, marathon runners have controlled ischemic preconditioning throughout their training, which may improve the kidney’s ability to better tolerate repeated injury. That is an interesting analogy.
82% developed AKIN defined stage 1 and 2 AKI. A total of 16 (73%) runners were scored as having positive microscopy findings on day 1 or day 2. Some ( minor amount ) were taking NSAIDS but 50% were on some form of herbal medications. Regardless, this is an interesting study and perhaps should be repeated in a larger marathon population such as the NYC marathon. In addition, curious what the hyponatremia incidence was?