title: Efficacy of carbohydrate counting in type 1 diabetes: a systematic review and meta-analysis.
abstract: BACKGROUND
  Although carbohydrate counting is the recommended dietary strategy for achieving glycaemic control in people with type 1 diabetes, the advice is based on narrative review and grading of the available evidence. We aimed to assess by systematic review and meta-analysis the efficacy of carbohydrate counting on glycaemic control in adults and children with type 1 diabetes.
  
  
  METHODS
  We screened and assessed randomised controlled trials of interventions longer than 3 months that compared carbohydrate counting with general or alternate dietary advice in adults and children with type 1 diabetes. Change in glycated haemoglobin (HbA1c) concentration was the primary outcome. The results of clinically and statistically homogenous studies were pooled and meta-analysed using the random-effects model to provide estimates of the efficacy of carbohydrate counting.
  
  
  RESULTS
  We identified seven eligible trials, of 311 potentially relevant studies, comprising 599 adults and 104 children with type 1 diabetes. Study quality score averaged 7·6 out of 13. Overall there was no significant improvement in HbA1c concentration with carbohydrate counting versus the control or usual care (-0·35% [-3·9 mmol/mol], 95% CI -0·75 to 0·06; p=0·096). We identified significant heterogeneity between studies, which was potentially related to differences in study design. In the five studies in adults with a parallel design, there was a 0·64% point (7·0 mmol/mol) reduction in HbA1c with carbohydrate counting versus control (95% CI -0·91 to -0·37; p<0·0001).
  
  
  CONCLUSIONS
  There is some evidence to support the recommendation of carbohydrate counting over alternate advice or usual care in adults with type 1 diabetes. Additional studies are needed to support promotion of carbohydrate counting over other methods of matching insulin dose to food intake.
  
  
  BACKGROUND
  None.
authors.affiliation: Boden Institute of Obesity, Nutrition, Exercise and Eating Disorders, and the School of Molecular Bioscience, University of Sydney, Sydney, NSW, Australia.
authors.forename: Kirstine J
authors.initials: KJ
authors.lastname: Bell
authors.affiliation: Boden Institute of Obesity, Nutrition, Exercise and Eating Disorders, and the School of Molecular Bioscience, University of Sydney, Sydney, NSW, Australia; Australian Diabetes Council, Sydney, NSW, Australia.
authors.forename: Alan W
authors.initials: AW
authors.lastname: Barclay
authors.affiliation: Department of Statistics, Macquarie University, Sydney, NSW, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Petocz
authors.affiliation: Boden Institute of Obesity, Nutrition, Exercise and Eating Disorders, and the School of Molecular Bioscience, University of Sydney, Sydney, NSW, Australia.
authors.forename: Stephen
authors.initials: S
authors.lastname: Colagiuri
authors.affiliation: Boden Institute of Obesity, Nutrition, Exercise and Eating Disorders, and the School of Molecular Bioscience, University of Sydney, Sydney, NSW, Australia. Electronic address: jennie.brandmiller@sydney.edu.au.
authors.forename: Jennie C
authors.initials: JC
authors.lastname: Brand-Miller
mesh_terms: D000328:Adult; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000178:diet therapy*; D050528:Diet, Carbohydrate-Restricted; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D008297:Male; D016032:Randomized Controlled Trials as Topic
chemical_list: D006442:Glycated Hemoglobin