Bulger, Jane

OBJECTIVE The Centers for Medicare & Medicaid Services (CMS) requires a low C-peptide level for insulin pump coverage unless the individual is β-cell autoantibody positive, which precludes coverage of automated insulin delivery (AID) systems for many people with type 2 diabetes. RESEARCH DESIGN AND METHODS In the Randomized Trial Evaluating the Efficacy and Safety of Control-IQ+ Technology in Adults With Type 2 Diabetes Using Basal-Bolus Insulin Therapy study evaluating the t:slim X2 insulin pump with Control-IQ+ technology, adults with insulin-treated type 2 diabetes were categorized into high C-peptide (n = 195) and low C-peptide (n = 59) groups based on CMS criteria. RESULTS In the AID group, mean HbA1c decreased from baseline by 0.8%, which was significantly greater than in the control group with both high (P < 0.001) and low (P = 0.02) C-peptide levels. Results were similar in participants ≥65 years old. CONCLUSIONS The benefit of AID is present with high and low C-peptide levels. Thus, requiring a low C-peptide level as a prerequisite for AID therapy is not warranted.

Abstract INTRODUCTION Cognition is reduced at low and high glucose, reflecting cognitive vulnerability to glucose (CVG) fluctuations. The impact of glucose fluctuations on the aging brain remains unclear. We examined whether CVG is associated with plasma biomarkers of Alzheimer's disease (AD) pathology and neurodegeneration. METHODS Participants included N = 114 adults with type 1 diabetes assessed for processing speed and sustained attention using ecological momentary assessment (EMA) combined with continuous glucose monitoring (CGM). We characterized associations between CVG and amyloid beta (Aβ) 42/40, phosphorylated tau (p‐tau) 181 and 217, neurofilament light chain, and glial fibrillary acidic protein. RESULTS CVG was associated with all plasma biomarkers, except Aβ 42/40. CVG for sustained attention exhibited strong associations with p‐tau biomarkers that persisted across covariate specifications. DISCUSSION CVG may be a useful digital phenotype of AD. It remains unclear whether CVG contributes to versus arises from neurodegeneration. We consider possible mechanisms linking cognitive vulnerability and long‐term glucose variability to the development of neuropathology. Highlights Cognitive vulnerability to glucose (CVG) may be a useful digital phenotype of neurodegeneration. We used cognitive ecological momentary assessment and continuous glucose monitoring to investigate CVG's associations with plasma biomarkers. Associations of CVG for sustained attention and phosphorylated tau 181 remained significant across covariates. We discuss possible mechanisms relating glucose variability, cognition, and neurodegeneration.