tHcy levels are highly elevated in renal failure patients. Impaired renal excretion and/or tubular metabolism of Hcy, and extra renal factors, like secondary vitamin deficiencies (e.g., in connection with hemodialysis), genetic causes and altered Hcy metabolism are among the reasons.
In a cross-sectional study, Muntner, et al., measured plasma tHcy levels in 16,000 patients in comparison with their glomerular filtration rate (GFR). After standardization for age, race or ethnicity, and sex, the estimated GFR was found to be strongly associated with higher levels of tHcy. When the patient group's average tHcy levels were higher than 32.5 μmol/L, their GFR rates were more than 5 times lower than patient groups with lower average tHcy levels (Figure 12).