Design of a randomized cross-over study evaluating effects of carbohydrate intake on glycemic control in persons with type 1 diabetes

Abstract

IntroductionDiet is an important factor in managing glycemic control in type 1 diabetes (T1D). Reducing carbohydrate intake may be important for stabilizing blood glucose levels in certain groups of patients with T1D. There are few studies examining the effects of a low carbohydrate diet in patients with T1D. The aim of this study is to investigate the effects of carbohydrate intake on glucose control in adults with T1D.Materials and methodsAdults with T1D (N = 54) and inadequate glycemic control (HbA1c ≥ 7.5%; 58 mmol/mol) were randomized in a cross-over design to a moderate carbohydrate diet (30 percent of total energy from carbohydrates) versus a traditional diabetes diet (50 percent of total energy from carbohydrates) for 4 weeks with a between wash-out period of 4 weeks. Masked continuous glucose monitoring was used throughout the study to evaluate effects on mean blood glucose levels, time-in-range, hypoglycemia, hyperglycemia, and glycemic variability. Diabetes treatment satisfaction, hypoglycemic confidence, and physical activity were measured using questionnaires during different phases of the trial. HbA1c, blood lipids, blood pressure, and ketone levels were also measured. The primary endpoint is the difference in mean blood glucose level between the diet periods. Study completion is anticipated during winter 2022.DiscussionThe study seeks to increase knowledge about the effects of dietary carbohydrate intake on glycemic control and other health parameters in patients with T1D. If beneficial effects on mean blood glucose level without elevated risk of hypoglycemia or ketoacidosis are shown, a moderate carbohydrate diet may be a treatment option for people with T1D that have unsatisfactory blood glucose levels.Clinical Trials Registration:www.clinicaltrials.gov, ID: NCT03400618.

The effect of carbohydrate intake on glycaemic control in individuals with type 1 diabetes: a randomised, open-label, crossover trial

“…Study design and methods have previously been described in detail. 24 The study protocol and CONSORT checklist is in eMethods1 and eMethods2 , respectively. The study was approved by the regional ethics committee of Gothenburg, Sweden (No.…”

“…During the first 2 weeks diabetes nurses and dietitians assisted with insulin and diet adjustments, respectively. 24 Evaluations were completed during the last 2 weeks of each treatment phase when participants did not receive any clinical support.…”

“…Traditional diet included approximately 50 percent of total energy from carbohydrates, 20 from proteins, and 30 from fat, and included foods according to guidelines. 1 , 2 , 3 Both diets have been described in detail 24 and were individualised by a dietitian to fit in terms of energy and macronutrient intake and in line with current nutrition guidelines. All participants were encouraged to consume carbohydrates evenly throughout the day, and diets were calculated to maintain energy balance and avoid weight changes.…”