Fasting and postprandial plasma glucose contributions to hemoglobin A1c and time in range in people with diabetes on multiple daily injection insulin therapy: Results from the PRONTO-T1D and PRONTO-T2D clinical trials

Abstract

AimsTo investigate contributions of changes in fasting plasma glucose (FPG) and postprandial glucose (PPG) to changes in hemoglobin A1c (HbA1c) and time-in-range (TIR, 70–180 mg/dL) in people with type 1 diabetes (T1D) and type 2 diabetes (T2D) treated with multiple daily injections (MDI) of insulin lispro (rapid/ultra-rapid formulations). MethodsMultivariate regression models were used to quantify the contributions of FPG and PPG reductions to change in HbA1c and TIR using data from the PRONTO-T1D (N = 1222) and PRONTO-T2D (N = 673) clinical trials. TIR was derived from 10-point self-monitored blood glucose (SMBG) profiles overall, as well as from continuous glucose monitoring (CGM) in the PRONTO-T1D CGM substudy (n = 269/1222). ResultsA 1 mmol/L FPG reduction corresponded with a 0.09–0.12 % (95 % confidence interval [CI] 0.06–0.15 %) HbA1c reduction in PRONTO-T1D and 0.17–0.26 % (95 % CI 0.13–0.30 %) in PRONTO-T2D (both p < 0.0001). A 1 mmol/L PPG reduction corresponded with a 0.05–0.09 % (95 % CI 0.01–0.12 %) HbA1c reduction in PRONTO-T1D (p < 0.001) and 0.10–0.15 % (95 % CI 0.05–0.19 %) in PRONTO-T2D (p < 0.0001). Reductions in FPG and PPG were significantly associated with increased TIR whether derived from SMBG (7.87–12.95 % [95 % CI 6.81–14.23 %]; all p < 0.0001) or CGM (3.35–4.18 % [95 % CI 2.11–5.39 %]; all p < 0.05). ConclusionsFPG and PPG significantly impact HbA1c and TIR. Balanced management of both FPG and PPG is important to achieve glycemic goals for people with diabetes on MDI insulin therapy. Clinical trials registrationPRONTO-T1D ClinicalTrials.gov identifier: NCT03214367; PRONTO-T2D ClinicalTrials.gov Identifier: NCT03214380