INS and diabetes mellitus: Several lines of evidence strongly suggest that preserving beta-cell function is critical to prevent loss of glucose control and progression from prediabetes to overt diabetes [20], [21], [22] or from use of OHAs to insulin therapy in subjects with long-standing disease [3], [23], [24], [25].Nonetheless, insulin therapy is not an inexorable end, and the rate of progression in T2DM appears to differ individually.