Assessment of methods and indexes of insulin sensitivity

Abstract

Insulin resistance contributes to the pathophysiology of diabetes and is a hallmark of obesity, metabolic syndrome, and many cardiovascular diseases. Therefore, quantifying insulin sensitivity/resistance in humans and animal models is of great importance.Various methods are used to assess insulin sensitivity both in individuals and in study populations. Validity, reproducibility, cost, and degree of subject burden are important factors for both clinicians and researchers to consider when weighing the merits of a particular method. Some methods rely on steady-state analysis of glucose and insulin, whereas others rely on dynamic testing. Each of these methods has distinct advantages and limitations. Thus, optimal choice and employment of a specific method depend on the nature of the studies being performed. Established direct methods for measuring insulin sensitivity in vivo are relatively complex. Finally, simple surrogate indexes for insulin sensitivity/resistance are available that are derived from blood insulin and glucose concentrations under fasting conditions (steady state) or in the postprandial state (dynamic). This article highlight merits, limitations, and appropriate use of current in vivo measures of insulin sensitivity/resistance and presents the advantages and disadvantages of each.