Continuous glucose monitoring with low-carbohydrate nutritional coaching improves type diabetes control: A randomized quality improvement program evaluation (Preprint)

BACKGROUND Type 2 Diabetes Mellitus is a leading cause of morbidity and mortality worldwide with adverse health consequences largely related to hyperglycemia. Despite clinical practice guideline recommendations, effective pharmacotherapy and interventions to support patients and providers, up to 60% of patients with diagnosed are estimated to have hemoglobin A1c levels above recommended targets due to these multilevel barriers hindering optimal glycemic control. OBJECTIVE To compare change in hemoglobin A1c (HbA1c) among patients with poorly controlled Type 2 Diabetes Mellitus (T2DM) who were offered the opportunity to use a continuous glucose monitor (CGM) and receive personalized low-carbohydrate nutrition counseling (<100 gm/day) versus usual care. METHODS A 12-month, pragmatic, randomized, quality improvement program. All adult patients with T2DM who received primary care at one university-affiliated primary care clinic (n=1,584) were randomized to either Usual Care (UC) or Enhanced Care (EC). Within each program arm we identified individuals with HbA1c >7.5% who were medically eligible for tighter glycemic control, and we defined these subgroups as Usual Care-High Risk (UC-HR) or Enhanced Care-High Risk (EC-HR). UC-HR participants (n=197) received routine primary care. EC-HR participants (n=185) were invited to use a CGM and to receive low-carbohydrate nutrition counseling. The primary outcome was mean change in HbA1c from baseline to 12-months using an intention-to-treat difference-in-differences analysis comparing EC-HR to UC-HR groups. We conducted follow-up semi-structured interviews to understand EC-HR participant experiences with the intervention. RESULTS HbA1c decreased by 0.41% (p=0.036) more from baseline to 12-months among EC-HR versus UC-HR participants, although only 61/185 EC-HR participants (33%) engaged in the program. Among the EC-HR participants who wore CGMs (n=61), HbA1c was 1.10% lower at 12-months compared to baseline (p<0.001). Interviews revealed themes related to EC-HR participants’ program engagement and CGM use. CONCLUSIONS A combined approach that includes use of CGM technology and low-carbohydrate nutrition counseling is effective in patients with sub-optimally controlled T2DM compared to standard of care. CLINICALTRIAL University of Michigan Institutional Review Board [HUM00147295] and [HUM00148100].