134-OR: Associations of Growth Hormone (GH) Mediators with Loss of Glycemic Control in Youth with Type 2 Diabetes (T2D)

Abstract

T2D in youth has a more severe phenotype than in adults, with puberty as a potential contributor to this difference. Pubertal changes in GH mediators (e.g., insulin-like growth factor 1 (IGF-1), growth hormone receptor (GHR), insulin-like growth factor binding protein 1 (IGFBP-1)) may impact insulin sensitivity and beta cell function. We examined associations of GH mediators with loss of glycemic control in youth with T2D using the Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY) cohort (N= 310). We performed paired comparison of plasma concentrations of IGF-1, GHR, and IGFBP-1 (ELISA), between 0mo and 36mo based on TODAY primary outcome of loss of glycemic control vs. maintained glycemic control (LGC vs MGC), with LGC defined as HbA1c ≥ 8% for 6 months and/or insulin dependence. We studied associations of GH mediators with HbA1c, insulinogenic index, oral disposition index, and 1/fasting insulin. Models were adjusted for age, sex, race, treatment arm, and baseline HbA1c (linear regression). Mean plasma IGF-1 (ng/mL) was lower in LGC group at 0mo (LGC: 451 ± 141, MGC: 485 ± 155, p = 0.04), and at 36mo (LGC: 340 ± 117, MGC: 400 ± 136, p< 0.0001). Increase in IGF-1 between 0-36mo predicted lower HbA1c at 36mo (B = -3.2E-3, SE = 9.0E-4, p < 0.001). Higher GHR was associated with higher HbA1c (B = 1.2E-2, SE = 3.0E-3, p < 0.001) and lower 1/fasting insulin (B = -6.6E-4, SE = 2.1E-4, P < 0.01) at 0mo. Increase in GHR between 0-36mo predicted higher 36mo HbA1c (B = 3.0E-2, SE = 9.4E-3, p < 0.01). IGFBP-1 was positively associated with 1/fasting insulin at 0m (B = 1.1E-3, SE = 4.9E-4, p = 0.03). In exploratory analyses stratified by Tanner stage (TS) at study entry, GH mediators changed differentially between TS 1-3 (n = 31) vs TS 4-5 (n = 274). In conclusion, GH mediators differed based on primary outcome in TODAY, and were associated with HbA1c and insulin sensitivity. Whether changes in GH mediators contribute to, or are the result of, changes in glucose metabolism is a key area for future studies. Disclosure C.Lu: None. D.Wolfs: None. L.El ghormli: None. L.M.Laffel: Advisory Panel; Medtronic, Lilly Diabetes, Novo Nordisk, Vertex Pharmaceuticals Incorporated, Roche Diagnostics, Provention Bio, Inc., Consultant; Dexcom, Inc., Janssen Pharmaceuticals, Inc., Medscape. M.Patti: Consultant; MBX Biosciences, AstraZeneca, Hanmi Pharm. Co., Ltd., Other Relationship; Fractyl Health, Inc. E.M.Isganaitis: None. Funding National Institutes of Health (2T32DK007260-46); National Institute of Diabetes and Digestive and Kidney Diseases (5U01DK061230-16)