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The dietary education trial in carbohydrate counting (DIET-CARB Study): study protocol for a randomised, parallel, open-label, intervention study comparing different approaches to dietary self-management in patients with type 1 diabetes
  1. Bettina Ewers1,
  2. Tina Vilsbøll1,2,
  3. Henrik Ullits Andersen1,
  4. Jens Meldgaard Bruun3,4
  1. 1 Steno Diabetes Center Copenhagen, Gentofte, Denmark
  2. 2 Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
  3. 3 Steno Diabetes Center Aarhus, Aarhus, Denmark
  4. 4 Department of Clinical Medicine, University of Aarhus, Aarhus, Denmark
  1. Correspondence to Bettina Ewers; bettina.ewers{at}


Introduction Clinical guidelines recommend that patients with type 1 diabetes (T1D) learn carbohydrate counting or similar methods to improve glycaemic control. Although systematic educating in carbohydrate counting is still not offered as standard-of-care for all patients on multiple daily injections (MDI) insulin therapy in outpatient diabetes clinics in Denmark. This may be due to the lack of evidence as to which educational methods are the most effective for training patients in carbohydrate counting. The objective of this study is to compare the effect of two different educational programmes in carbohydrate counting with the usual dietary care on glycaemic control in patients with T1D.

Methods and analysis The study is designed as a randomised controlled trial with a parallel-group design. The total study duration is 12 months with data collection at baseline, 6 and 12 months. We plan to include 231 Danish adult patients with T1D. Participants will be randomised to one of three dietician-led interventions: (1) a programme in basic carbohydrate counting, (2) a programme in advanced carbohydrate counting including an automated bolus calculator or (3) usual dietary care. The primary outcome is changes in glycated haemoglobin A1c or mean amplitude of glycaemic excursions from baseline to end of the intervention period (week 24) between and within each of the three study groups. Other outcome measures include changes in other parameters of plasma glucose variability (eg, time in range), body weight and composition, lipid profile, blood pressure, mathematical literacy skills, carbohydrate estimation accuracy, dietary intake, diet-related quality of life, perceived competencies in dietary management of diabetes and perceptions of an autonomy supportive dietician-led climate, physical activity and urinary biomarkers.

Ethics and dissemination The protocol has been approved by the Ethics Committee of the Capital Region, Copenhagen, Denmark. Study findings will be disseminated widely through peer-reviewed publications and conference presentations.

Trial registration number Registry (NCT03623113).

  • randomised controlled trial
  • type 1 diabetes
  • carbohydrate counting
  • basic carbohydrate counting
  • advanced carbohydrate counting
  • nutritional education

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  • Contributors BE conceived the original idea for this trial, planned the study design, performed the sample size calculations and wrote the first draft of the protocol manuscript. TV and JMB provided valuable input regarding trial design, planning and analytical considerations, and edited the first draft of the protocol manuscript. HUA has contributed intellectually to the protocol. All authors approved the final version of the clinical trial protocol. BE is the principle investigator and is responsible for correspondence with all authorities regarding the study and is responsible for the data collection (recruitment, screening and clinical study examinations), overall monitoring the trial and for conducting the statistical analyses. TV, JMB and HUA are supervisors and coinvestigators of this trial. Should any safety concerns arise during the conduct of the study these will be brought to the attention of HUA, TV and JMB by BE and will be carefully reviewed.

  • Funding This work was supported by The Beckett Foundation (grant number 17-2-0957), the Axel Muusfeldts Foundation (grant no 2017-856) and the Novo Nordisk Foundation (no assigned grant number) as part of a supplementary treatment initiative at SDCC in 2018-2020. Roche has provided voucher codes for free use of the bolus calculator ‘MySugr Pro’ in the 12-month trial period for patients randomized to the ACC group in the study.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval The study has been approved by the Ethics Committee of the Capital Region, Copenhagen (#H-18014897) and has been approved for data storage by the Danish Data Protection Agency (journal no VD-2018–124, I-suite no 6367).

  • Provenance and peer review Not commissioned; externally peer reviewed.

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