Figure 1.

Associations of plasma vitamin C with risk of graft failure in kidney transplant recipients, within the (A) whole study population and (B) after exclusion of outliers of the distribution of plasma vitamin C (n = 10). To create graph B, the same analysis was performed as for graph A, but after exclusion of outliers. X-axis represents plasma vitamin C concentration, and y-axis represents the estimated hazard ratios using median plasma vitamin C (44 µmol/L) as reference value. Data were fitted by Cox proportional-hazards regression. The black line represents the hazard ratio and the gray area represents the 95% confidence interval. The histogram of plasma vitamin C is provided in the background. Patients with plasma vitamin C lower and higher than the median were, respectively, at lower and higher risk of graft failure.