Long-term creatine supplementation is safe in aged patients with Parkinson disease.
Level 2 - randomized trial
Individual randomized controlled trial with 2-year follow-up
PubMed 19083405 · doi:10.1016/j.nutres.2008.01.001
What was done
Sixty older patients with Parkinson disease were enrolled in a randomized controlled trial receiving either oral creatine at 4 g/day (n = 40) or placebo (n = 20) for 2 years. Participants were evaluated across 6 follow-up study visits with blood and urine laboratory tests assessing overall side effects and tubular and glomerular renal markers, including cystatin C.
What was found
Creatine was generally well tolerated, with gastrointestinal complaints being the main side effect. Serum creatinine levels increased in the creatine group due to the degradation of creatine, but all other tubular and glomerular markers—especially cystatin C—remained normal, indicating unaltered kidney function. The abstract does not provide exact numerical values, event rates, or statistical test results.
Why it matters
This trial provides long-term safety data in an older clinical population, showing that multi-year creatine use does not harm renal function and confirming that serum creatinine rises represent benign metabolite clearance rather than renal impairment.
Limits
The sample size is modest (60 patients total) and the abstract lacks exact numerical data, baseline characteristics, dropout rates, and statistical significance metrics. Findings at 4 g/day in Parkinson disease may not generalize to higher loading doses or patients with baseline renal impairment.
Cited by
- supports Creatine supplementation converts to creatinine and can falsely suggest kidney failure on standard blood tests, whereas cystatin C testing avoids this artifact.