Higher plasma homocysteine is associated with lower vitamin B6 status in critically ill surgical patients.

Background: Hyperhomocysteinemia might be at least partially due to compromised B vitamin status in critically ill patients and has been linked with critical illness. This study was conducted to examine the association between plasma homocysteine with B vitamins and clinical outcomes in critically ill surgical patients.
Methods: Thirty-two patients in the surgical intensive care unit (SICU) were enrolled. Disease severity (Acute Physiology and Chronic Health Evaluation II score), hematological values, serum and erythrocyte folate, serum vitamin B₁₂, plasma, and erythrocyte pyridoxal 5'-phosphate (PLP) were determined within 24 hours of admission and again after 7 days.
Results: The prevalence of hyperhomocysteinemia in the patients was either 46.9% (plasma homocysteine ≥12 µmol/L) or 31.3% (plasma homocysteine ≥15 µmol/L) on day 1 in the SICU and increased to 62.5% (plasma homocysteine ≥12 µmol/L) and 37.5% (plasma homocysteine ≥15 µmol/L) on day 7 after admission to the SICU. Plasma homocysteine, serum folate, and vitamin B₁₂ significantly increased by day 7, whereas plasma and erythrocyte PLP remained constant throughout the study. Plasma homocysteine was not correlated with serum folate and vitamin B₁₂. However, plasma and erythrocyte PLP on day 1 were adversely associated with day 1 levels of plasma homocysteine after adjusting for potential confounders. Plasma homocysteine on day 1 or changes (Δ day 7-day 1) did not show any association with clinical outcomes.
Conclusions: Lower plasma PLP might be a significant factor for increased plasma homocysteine in critically ill surgical patients. The association between plasma homocysteine and clinical outcomes was not found.