Short-term reproducibility of total homocysteine determinations in stable renal transplant recipients

Abstract

BETWEEN 1972 and 1996, at least 17 independent investigative groups documented the presence of significantly increased plasma or serum levels of the putatively arteriosclerotic sulfur amino acid homocysteine in endstage renal disease (ESRD) patients. Despite the chronic, modest reduction in fasting total homocysteine (tHcy) levels afforded by successful renal transplantation relative to ongoing maintenance dialysis in ESRD patients, we recently demonstrated that an excess prevalence of both fasting and postmethionine loading hyperhomocysteinemia persists in stable renal transplant recipients versus matched, population-based controls free of renal disease. Hyperhomocysteinemia may contribute to the disproportionately high rate of arteriosclerotic outcomes experienced by renal transplant recipients, which remains unexplained by the traditional vascular disease risk factors. The reproducibility of any putative risk factor measurement (eg, tHcy), determines, to an important extent, the ability to ascertain its potential association with a disease (eg, arteriosclerotic vascular disease) in a given population. Although data are available on the reliability of fasting or postmethionine loading tHcy determinations in general populations, no comparable analyses have been performed in clinically stable renal transplant recipients. The purpose of our study was to evaluate the short-term reproducibility of fasting and postmethionine loading tHcy level measurements in this specific patient population. For comparison, we simultaneously evaluated the short-term reproducibility of fasting total cholesterol, an established arteriosclerotic risk factor in general populations, and a likely arteriosclerotic risk factor in renal transplant recipients.