Effects Of Bromocriptine Quick-Release (Bcqr) Therapy On Glycemic Control, Insulin Sensitivity, And Vascular Function In Type 1 Diabetes (T1d)

BCQR is approved for adjunct therapy in type 2 diabetes (T2D). BCQR improves glycemic control and appears to reduce cardiovascular events in T2D. People with T1D have decreased insulin sensitivity (IS), correlating with vascular dysfunction. We evaluated the effects of BCQR on glycemic control, estimated IS, and vascular function in a random order, placebo-controlled crossover study of a 4-week intervention with BCQR in adolescents (12-21 yrs) and adults (22-60 yrs) with T1D. Outcomes included: insulin total daily dose (TDD), urine albumin to creatinine ratio (UACR), vascular markers using Dynapulse and EndoPAT, CGM, estimated IS scores (from CACTI and RESISTANT study models), and a mixed meal tolerance test (MMTT). Treatment effect was examined in mixed models and reported as LS mean ± SE adjusted for age, sex, phase, and treatment order. Interactions were examined by age and diabetes duration (DD). Participants‡ (n=84) were 50% adult, age 28.6 ± 14.5 yrs, 44% male, and 49% lean, with HbA1c 7.8% [7, 8.5] and DD 14.2 ± 11.7 yrs. Insulin TDD, log UACR, and CGM outcomes (average glucose, SD, % time BG\u003e180 or 5 yrs (68 ± 1.2 vs. 72 ± 1.2, p=0.0038). Reactive hyperemia index (endothelial function estimate) was lower on BCQR in adolescents (2.03 ± 0.12 vs. 2.32 ± 0.12, p=0.0039), and systemic vascular resistance (SVR) was lower on BCQR in adults (1408 ± 62 vs. 1479 ± 63, p=0.006). Dynapulse cardiac output and brachial artery distensibility did not differ by treatment. MMTT triglyceride (TG) peak minus baseline was lower on BCQR (22 ± 3.0 vs. 27 ± 2.9, p=0.0360). IS measured by MMTT fasting and AUC glucose/insulin, and by CACTI and RESISTANT scores, did not differ by treatment. In sum, BCQR did not affect CGM glycemia or estimated IS, but it improved cardiovascular measures such as SBP, DBP, SVR, and TG. ‡Mean ± SD or Median [Interquartile Range]. Disclosure S. Tell: None. J.K. Snell-Bergeon: Stock/Shareholder; Self; GlaxoSmithKline plc. T.B. Vigers: None. A. Baumgartner: None. E. Lyon: None. S. Gross: None. M. Schafer: None. S. Polsky: None. K.J. Nadeau: None. I.E. Schauer: None. Funding JDRF (3-SRA-2015-125-M-R)