Estimation of the disposition index based on components of metabolic syndrome

Decreased insulin sensitivity (IS) and impaired insulin secretion are major pathological features of type 2 diabetes (T2DM). The product of these factors is the disposition index (DI). We aimed to develop an equation for predicting DI. We enrolled 167 participants in our study. We randomly assigned 126 (75%) of the participants to the study group, whose data would be used to build the equation for estimating the DI. The remaining 41 participants comprised the external validation group. A frequently sampled intravenous glucose-tolerance test was performed for all participants, and the IS, the glucose sensitivity, the acute insulin response to the glucose load, and the DI were determined. Three factors were selected from multiple linear regression analysis, and we constructed the equation log (DI) = 2.449 - 0.113 × fasting plasma glucose + 0.046 × body mass index - 0.612 × high-density lipoprotein cholesterol. Using this equation, the calculated log (DI) significantly correlated with the measured log (DI) in the external validation group (r = 0.428, p = 0.007). By using the equation based on the demographic data and measurements of metabolic syndrome components, the DI could be predicted with acceptable accuracy (r = 0.428). Because of the relationships between the MetS and demographic parameters, this method of predicting DI may help further clinicians' understanding of the underlying pathological mechanisms in T2DM.