MON-LB116 FGF-21 Is A Reliable Marker Of Insulin Resistance Before The Occurrence Of Glucose Intolerance

Background and aims: Fibroblast growth factor (FGF)-21 is a polypeptide that results in metabolic rearrangement mostly related to glucose and lipid metabolism. Serum FGF-21 level is elevated in obesity and in type 2 diabetes. The goal of this study is to evaluate the relationship between FGF-21 and peripheral insulin resistance in a wide range of baseline BMI and glucose metabolism status. Materials and methods: seventy one participants reported to the clinical research center in a fasting state twice. BMI and fat mass were calculated. Glucose metabolism was determined by fasting glucose, hemoglobin A1c and OGTT. Serum lipids panel was measured. Peripheral insulin resistance was determined using the hyperinsulinemic euglycemic clamp study. FGF-21 level was measured using enzyme-linked immunosorbent assay before and after clamp study. Study was approved by university institutional review board. Results: Of 71 participants, 48 were obese and 23 were lean. Normal glucose metabolism was documented in 43 individuals. Serum FGF-21 was significantly elevated in insulin resistant compared to insulin sensitive subgroups (0.28 ng/ml ± 0.136 vs. 0.14 ng/ml ± 0.112. p < 0.001). Despite the fact that FGF-21 is elevated in all obese population, the level was significantly higher in the insulin resistant obese subgroup compared to the insulin sensitive obese one (0.30 ng/ml ± 0.167 vs. 0.17 ng/ml ± 0.126. P =0.003). Furthermore, significantly higher FGF-21 level was also found in lean insulin resistant compared to lean insulin sensitive subgroups (0.18 ng/ml ± 0.106 vs. 0.09 ng/ml ± 0.061, p = 0.04]. Adjustment to preexisting impaired glucose tolerance did not affect the correlation between FGF-21 level and insulin resistance which remained statically significant in the seemingly healthy obese and lean subgroups. Conclusion: Serum FGF-21 level strongly correlates to peripheral insulin resistance in both obese and lean population. Nonetheless, FGF-21 level rises way before glucose metabolism abnormality can be detected. Our study suggests a cutoff level for each subgroup which may enable clinicians to risk-stratify patients and allow for early intervention.