Total plasma homocysteine in hospitalized elderly: Associations with vitamin status and renal function

Aims: To describe the prevalence of hyperhomocystein- emia (>15 μmol/l) in hospitalized elderly and to investigate whether nutrition status and other factors are related to total plasma homocysteine (tHcy). Methods: Sixty hospitalized elderly patients (age 83.0 ± 7.9 years) participated in this cross-sectional study. Blood was drawn in fasting state and analyzed for albumin, prealbumin, lymphocytes, tHcy, cystatin C, folic acid, and vitamin B₁₂. The nutritional status was assessed. Statistical analyses included multivariate regression. Results: The prevalence of hyperhomocysteinemia was 31.7%, increased cystatin C was observed in 38.3% of the subjects. tHcy correlated positively with cystatin C, but negatively with vitamin B₁₂ and folic acid. Neither age nor nutritional status were related to tHcy. In multivariate analysis, folic acid and cystatin C remained significant predictors of tHcy (adjusted R² = 60.6%). According to the regression model, serum folic acid concentrations >30.3 nmol/l are required to achieve a mean tHcy <15.0 μmol/l in patients with reduced renal function. Conclusions: Hyperhomocysteinemia is frequent in hospitalized elderly. Cystatin C and folic acid explain most of the tHcy variance. Higher folic acid levels within the normal range might further decrease tHcy. The current lower folic acid cutoff value (7 nmol/l) might not be sufficient in preventing homocysteinemia in hospitalized elderly with reduced renal function.