Hi Dr. Spry — 39/yo amateur bodybuilder here. I learned a couple years ago that I have kidney dysplasia, one side completely polycystic kidney and the other mildly hypertrophied. I am used to my creatinine running high (over 1.3) and GFR just shy of 60. However some recent labs have disturbed me! Serum Creatinine 2.0 — note that I weigh ~100kg/225lbs largely muscle, this has crept up over time correlated with my weight gain (1.3, 1.5, 1.7, 1.8…) 24 hr urine contained 2.3g protein! — note that I didn’t know not to train, and trained legs (intensely) the day of sample collection eGFR 35-40 — could this be related to creatinine? BUN 44 — Note that I have been on very high protein diet, upwards of 4g/kg (400-450g total) I have been on Losartan for hypertension for about a year and a half. My BP is usually well controlled. Due to some other chronic illness (HIV, well controlled CD4 healthy normal range) I track my lab values in a spreadsheet. I can see a correlation between my weight/muscle gains from 200-220lbs and the increased serum creatinine and reduced eGFR. When I learned that I had the kidney dysplasia I had a proper radioactive measurement, and all I have in my notes is that GFR was fine and healthy for one kidney. Questions: 1. Is it possible/believable that this is all caused by my atypical muscle mass and intense training? (High creatinine, thus low GFR, exercise induced proteinuria) 2. With the kidney dysplasia, do I technically have CKD with basically 50% of a normal person’s kidney function? I am freaked out thinking that I’ve suddenly in the last 9-12 months had some sudden kidney injury!

By definition, you have chronic kidney disease (CKD) because the dysplastic polycystic kidney has been present for at least three months.  Hence, you do have reduced kidney function.  The body building that you are doing will increase the serum creatinine but it should not change your glomerular filtration rate (GFR).  The estimating equations that we use could be inaccurate with your large muscle mass and a 24 hour urine collection may be more accurate for measuring your GFR (measuring your creatinine clearance by 24 hour urine collection).

Finally, the muscle mass would not increase the amount of protein that you are spilling in your urine, hence, this is quite concerning for kidney damage that is occurring for some reason.  I recommend that you consult with your primary care physician (PCP) and discuss whether you need to be seen by a nephrologist.


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