I don't mean to question the reality of your recent scare, but can't some supplementation skew results? Was your doctor well versed in your particular supplements?
Memory could be way off here, but I recall something like
creatine supplementation increases your urinary creatinine levels, the latter of which is used as a marker for kidney stress. So just taking creatine makes it
look like your kidneys are in worse shape than they are (I think the excess creatinine was shown to be due to excess intake, not intake-induced stress).