A number of studies have found that programs such as the Diabetes Prevention Program (DPP) delay or prevent the progression from prediabetes to type 2 diabetes mellitus. However, a substantial proportion of the participants in these programs eventually develop type 2 diabetes. To explore possible reasons for this persistent progression, we previously developed an Insulin Resistance Risk Score (IRRS) to assess insulin resistance (IR) using insulin and C-peptide levels measured by mass spectrometry. This method correlates well with formal assessment of whole-body insulin resistance (IR) as measured by the steady-state plasma glucose (SSPG) during the insulin suppression test. We used this relationship to create a risk score called the Insulin Resistance Risk Score (IRRS) that assesses the risk of top tertile insulin resistance as measured by SSPG and used it to examine the association of changes in IR during the course of DPPs. We found that although the IRRS declines in some individuals (4/15) with high baseline IRRS in parallel with observed weight loss and normalization of glycemic indices, this did not occur in most participants (11/15) with a high baseline IRRS. Furthermore, a substantial number of individuals who did achieve DPP targets for weight loss and normalization of fasting glucose and HbA1c, had a high IRRS at baseline and throughout the DPP. This suggests that persistence of insulin resistance at the conclusion of a DPP may contribute to the future development of diabetes and that the assessment the IRRS of participants at the conclusion of a DPP might assist in the identification of those at risk of progression to type 2 diabetes and who may benefit from additional weight loss.
M.J. McPhaul: Consultant; Quest Diagnostics.
