While Ikizler and coworkers [31] define metabolic acidosis as a dichotomous variable (i.e., serum bicarbonate level <22 mEq/l), we prospectively explored the association of serum bicarbonate as a continuous variable and insulin resistance over a broad range of values of serum bicarbonate (i.e., from 18 to 31 mEq/l). This evidence concerns the gene INS and metabolic acidosis.