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

To describe the prevalence of hyperhomocystein- emia (>15 micromol/l) in hospitalized elderly and to investigate whether nutrition status and other factors are related to total plasma homocysteine (tHcy).

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 B(12). The nutritional status was assessed. Statistical analyses included multivariate regression.

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 B(12) 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 R(2) = 60.6%). According to the regression model, serum folic acid concentrations >30.3 nmol/l are required to achieve a mean tHcy <15.0 micromol/l in patients with reduced renal function.

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.