Serum cystatin C is an independent predictor of total homocysteine levels in stable Korean renal transplant recipients with normal serum creatinine.

Objective: To examine the determinants of fasting plasma total homocysteine (tHcy) levels such as cystatin C, serum creatinine (SCr), estimated glomerular filtration rate (GFR) from Cockroft-Gault equation, albumin, plasma folate, vitamin B12, and pyridoxal-5'-phosphate (PLP) among Korean renal transplant recipients (RTR) with normal SCr levels (< or =1.4 mg/dL).

Methods: Cross-sectional study. Methods: Nephrology and Transplant Service, Catholic University Kangnam St. Mary's Hospital, Seoul, Korea. Methods: Fifty-one chronic stable Korean RTR with normal SCr levels (< or =1.4 mg/dL) 6 months or more following transplantation. Methods: Medical record review, anthropometric measurements, and overnight (10 to 14 hours) fasting blood samples for measurement of plasma tHcy, folate, vitamin B12, PLP, SCr, albumin, and cystatin C.

Results: General linear regression model including age, gender, vitamin status, and measurements of renal function showed that cystatin C and folate were independent predictors of tHcy levels. The partial regression coefficient for folate was -0.444 (P <.01) and for cystatin C, it was +0.334 (P <.05). SCr, estimated GFR, vitamin B12, PLP, age, and gender were not independent predictors of tHcy levels in this model.

Conclusions: Both cystatin C and folate status were major independent determinants of fasting tHcy levels in the subgroup of Korean RTR with normal SCr.