First, this study used whopper doses of creatine that "supposedly" impaired kidney function. Although there is no evidence this occurs in humans, I found the protective effective of artichoke extract impressive.
https://cat.inist.fr/?aModele=afficheN&cpsidt=19989620
The kidneys function to filter out much of the metabolic waste your workouts, etc create. While they usually function fine, things like Rx drugs (more than you'd imagine) and age knock down kidney function, so it pays to have things like this in your back pocket!