Clinical Application of Reduced-Carbohydrate Diets for Type 1 Diabetes Management: A Retrospective Case Series

Abstract

Background: The aim of this study was to explore the clinical application of reduced-carbohydrate (RC) diets for type 1 diabetes (T1D) management at a community-based diabetes centre. Methods: To be included in this retrospective case series, adults with T1D must have attended at least two appointments with a Credentialled Diabetes Educator and Accredited Practising Dietitian (CDE/APD) for advice regarding: (a) advanced carbohydrate counting, (b) carbohydrate reduction, and/or (b) low-carbohydrate diet support. Data regarding specific dietary recommendations and clinical outcomes was extracted from patient records stored at the center. A semi-structured interview with the CDE/APD was conducted to collect additional information about the design and delivery of the RC diets. Thematic analysis was used to identify core components of the RC diets, and descriptive statistics were used to assess pre-post changes in clinical T1D outcomes. Results: 26 adults with T1D were eligible and included (77% female). The RC diets represented a patient-led approach involving adjustments to energy and macronutrient intakes, glucose self-monitoring, and insulin management. 22/26 participants attended the center seeking low-carbohydrate diet support, and the average carbohydrate prescription was 63g/day (22-253g/day) which translated to a 37% reduction from baseline. HbA1c reduced from 9.0% (75mmol/mol) to 7.0% (53mmol/mol) (-5.7 to -0.1%), with an average follow-up of 55weeks (n=8). Estimated A1c reduced from 7.1% (54mmol/mol) to 6.3% (45mmol/mol) (-2.9 to+0.6%) over 21 weeks (n=19). Mean total daily insulin reduced from 44 to 31 U/day (-46 to+6 U/day), with an average follow-up of 17 weeks (n=15). Conclusions: This study provides real-world insights into the clinical application of RC diets in the management of adults with T1D at a community-based diabetes centre. Prospective clinical trials are needed to conclusively determine the effects of RC diets on clinical T1D outcomes.