This single-center, prospective cohort study comprised 485 consecutive carotid surgery patients. B-vitamin baseline concentrations of B12 and FA were used to compute a PI for postoperative overall survival from January 2003 to January 2012 (mean observation period 102.3 months).
Increasing B12 serum concentrations showed a nonlinear association with overall survival (P = .033). A B vitamin-based PI significantly predicted overall (hazard ratio [HR] per standard deviation = 1.97, confidence interval [CI] 1.37-2.82; P < .001), cardiovascular (HR = 3.03, CI 1.78-5.14; P < .001), and stroke-free survival (HR = 2.20, CI 1.22-3.98; P = .009), and revealed that the highest adverse event-free survival was predicted by high FA (16.3 ± 12.9 ng/mL) but only moderate B12 (360.3 ± 156.0 pmol/L) baseline concentrations.
Prediction of increased long-term overall, cardiovascular, and stroke-free survival is based on high FA but only moderate B12 serum concentrations. Excessive B12 concentrations might harbor a potential harm and are no requisite for low homocysteine concentrations. The association between B vitamins and survival might serve either as a tool for risk stratification or, if causative, as effective therapy, if optimal dosing of B vitamins is provided and on-treatment concentrations, including homocysteine and renal functions, are closely monitored.