BACKGROUND: Case studies and reviews have shown that creatine supplementation can affect kidney function.
OBJECTIVE: The objective of this study was to verify the effects of eight weeks of creatine supplementation on renal function (creatinine clearance - primary outcome) in patients with symptomatic peripheral arterial disease.
METHODS: Twenty-nine patients, of both genders, were randomized (1:1) in a double-blind manner for administration of Placebo (PLA, n=15) or creatine monohydrate (Cr, n = 14). The supplementation protocol consisted of 20g/day for one week divided into four equal doses (loading phase), followed by single daily doses of 5g in the subsequent seven weeks (maintenance phase). Before and after the supplementation period, markers of renal function, serum creatinine, creatinine excretion rate, and creatinine clearance were evaluated. The Generalized Estimation Equation Model was used for comparison between groups. The level of significance was P <0.05.
RESULTS: No significant differences were found between groups before and after the intervention for serum creatinine (Cr - pre 1.00 ± 0.15 ml/dl vs. post 1.07 ± 0.16 ml/dl; PLA pre 1.30 ± 0.53 ml/dl vs. post 1.36 ± 0.47 ml/dl, p = 0.590), creatinine excretion rate (Cr - pre 81.73 ± 43.80 mg/dl vs. post 102.92 ± 59.57 mg/dl; PLA pre 74.37 ± 38.90 mg/dl vs. post 86.22 ± 39.94 mg/dl, p = 0.560), or creatinine clearance (Cr pre 108 ± 59 ml.min-1.1.73 m-2 vs. post 117 ± 52 ml.min-1.1.73 m-2; PLA pre 88 ± 49 ml.min-1.1.73 m-2 vs. post 82 ± 47 ml.min-1.1.73 m-2, p = 0.366).
CONCLUSIONS: Eight weeks of creatine supplementation is safe and does not compromise the renal function of patients with peripheral arterial disease.