high creatinine and abnormal ultrasound: should I be concerned?

For the past few years, I have had elevated serum creatinine levels (around 1.3 - 1.5 mg/dL). Until recently, I assumed this wasn’t a problem, as I supplement with creatine monohydrate, eat a very high protein diet***, and have more muscle mass than the average individual. However, a recent kidney ultrasound has me a bit worried. The ultrasound report states: “bilateral kidneys are slightly enlarged with echogenic cortices consistent with medical renal disease.” I plan to follow up with a nephrologist. However, in the meantime, I would like to know if any of the abnormalities seen in the ultrasound are in some sense “normal” for people that lift weights and/or eat a high protein diet (e.g., much like a high creatinine level is “normal” for muscular individuals that consume creatine monohydrate). As I am 100% certain the nephrologist will tell me to lower my protein consumption, I would also like to know if there is evidence that a high protein diet causes or accelerates the progression of CKD. I suspect, though I do not know, any damage to my kidneys was caused by a 6-month period of very heavy NSAID use that I went through in 2019.

***I would estimate I eat at least 350g of protein per day – mostly from animal sources.

Unfortunately that ultrasound finding does not tell me much here in isolation, but I would not expect it to be a “normal” finding just from a high protein diet.

We discuss this topic further here: Abnormal Labs in Exercise Part I: Kidney Function | Barbell Medicine

You will need additional evaluation to determine the significant of this creatinine measurement.