In conclusion, among several proinsulin measures tested in our prospective METSIM study, fasting proinsulin, proinsulin levels at 30 min and 120 min, and proinsulin AUC 0–30 min were significant predictors for the worsening of hyperglycemia or type 2 diabetes, with fasting proinsulin being the most consistent predictor. Here, INS is linked to type 2 diabetes mellitus.