Unique Metabolic Features of Adults Discordant for Indices of Insulin Resistance

Purpose: Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) and Adipose Insulin Resistance index (ADIPO-IR) values are often concordant. In this study we evaluated whether there are groups discordant for HOMA-IR and ADIPO(palmitate)-IR and, if so, what are their defining characteristics. Methods: The body composition, basal metabolic rate (BMR), fasting plasma lipids, insulin, glucose, and free fatty acid (FFA) palmitate concentrations data of 466 volunteers from previous research studies were abstracted and analyzed. The middle 2 population quartiles for HOMA-IR and Adipose Insulin Resistance index palmitate concentration (ADIPO(paimitate)-IR) defined medium HOMA-IR and ADIPO(paimitate)-IR (MH and MA), the top and bottom quartiles were defined as high/low HOMA (HH/LH), and high/low ADIPO(paimitate) as HA/LA. Because ADIPO(paimrtate)-IR was significantly greater in women than in men, we established sex-specific quartiles for each index. We identified groups discordant for HOMA-IR and ADIPO-IR (HHMA, LHMA, MHHA, and MHLA). Results: Body fat and fasting triglycerides (TGs) were significantly greater with higher indices in the concordant groups (HHHA > MHMA > LHLA). MHHA differed from MHLA by visceral fat (P< .01) and fasting TGs (P < .05), whereas HHMA differed (P < .01) from LHMA by BMR. By multivariate regression, the group factor contributed to BMR (P < .01) and visceral fat (P < .05). Conclusions: Adults discordant for HOMA-IR and ADIPO-IR have unique features including differences in visceral fat, TGs, and BMR. This suggests different forms of insulin resistance are present, which should be considered when studying insulin resistance in the future.