Patel’s retrospective cohort study (25) of 5153 participants aged 40 to 74 with a fasting glucose ≥70 mg/dL and without diabetes by history or laboratory testing showed that serum C-peptide levels could serve as a marker of insulin resistance and to predict cardiovascular and overall death better than other known insulin resistance measures such as fasting plasma glucose, fasting serum insulin, and HOMA-IR. This evidence concerns the gene INS and diabetes mellitus.