I started taking creatine 10 months ago. I had my annual physical recently and my creatinine levels came back high at 1.4. My glomerular filtration rate came in low at 59.3. My doctor was concerned that I may have kidney problems. Is this all explained by me taking creatine and its not a symptom of a kidney problem?

I was surprised at my doctors response when I told him I take creatine. He said it doesn't help at all and the so called gains in weight lifting are from other things included in the creatine supplement. I showed him the exact brand I take (https://www.amazon.com/Muscle-Feast-Monohydrate-Gluten-Free-Unflavored/dp/B008S0I1Q4/ref=sr_1_1_sspa) and he said it was bogus because there's no way it doesn't have other stuff in there like something to stop it from clumping.

What's the consensus here? Is my doctor uninformed about creatine? Am I way off base?