title: Detailed statistical analysis plan for a cluster randomised controlled trial of the Healthy Lifestyles Programme (HeLP), a novel school-based intervention to prevent obesity in school children.
abstract: The Healthy Lifestyles Programme (HeLP) trial is being conducted to determine whether a novel school-based intervention is effective and cost-effective in preventing obesity in 9-10 year-old children. This article describes the detailed statistical analysis plan for the HeLP trial, including an amendment (and rationale for amendment) made to originally planned sensitivity analyses.
  
  
  
  The HeLP trial is a definitive, pragmatic, superiority, cluster randomised controlled trial with two parallel groups and blinded outcome assessment. This update article describes in detail (1) the primary and secondary outcomes, (2) the statistical analysis principles (including which children will be included in each analysis, how the clustered nature of the study design will be accounted for, which covariates will be included in each analysis, how the results will be presented), (3) planned sensitivity analyses, planned subgroup analyses and planned adherence-adjusted analyses for the primary outcome, (4) planned analyses for the secondary outcomes and (e) planned longitudinal analyses.
  
  
  
  International Standard Randomised Controlled Trial Number (ISRCTN) register: ISRCTN15811706 . Registered on 1 May 2012.
authors.affiliation: Peninsula Clinical Trials Unit and Medical Statistics Group, Plymouth University Peninsula Schools of Medicine and Dentistry (formerly Peninsula College of Medicine and Dentistry), ITTC Building, Plymouth Science Park, Plymouth, Devon, PL6 8BX, UK. siobhan.creanor@plymouth.ac.uk.
authors.forename: Siobhan
authors.identifier: 0000-0002-7373-8263
authors.initials: S
authors.lastname: Creanor
authors.affiliation: Institute of Health Services Research, University of Exeter Medical School (formerly Peninsula College of Medicine and Dentistry), South Cloisters, St. Luke's Campus, Exeter, Devon, EX1 2LU, UK.
authors.forename: Jenny
authors.initials: J
authors.lastname: Lloyd
authors.affiliation: Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter St. Luke's Campus, Heavitree Road, Exeter, Devon, EX1 2LU, UK.
authors.forename: Melvyn
authors.initials: M
authors.lastname: Hillsdon
authors.affiliation: Institute of Health Services Research, University of Exeter Medical School (formerly Peninsula College of Medicine and Dentistry), South Cloisters, St. Luke's Campus, Exeter, Devon, EX1 2LU, UK.
authors.forename: Sarah
authors.initials: S
authors.lastname: Dean
authors.affiliation: Institute of Health Services Research, University of Exeter Medical School (formerly Peninsula College of Medicine and Dentistry), South Cloisters, St. Luke's Campus, Exeter, Devon, EX1 2LU, UK.
authors.forename: Colin
authors.initials: C
authors.lastname: Green
authors.affiliation: Institute of Health Services Research, University of Exeter Medical School (formerly Peninsula College of Medicine and Dentistry), South Cloisters, St. Luke's Campus, Exeter, Devon, EX1 2LU, UK.
authors.forename: Rod S
authors.initials: RS
authors.lastname: Taylor
authors.affiliation: Isca Academy, Earl Richards Road, Exeter, Devon, EX2 6AP, UK.
authors.forename: Emma
authors.initials: E
authors.lastname: Ryan
authors.affiliation: Institute of Health Services Research, University of Exeter Medical School (formerly Peninsula College of Medicine and Dentistry), South Cloisters, St. Luke's Campus, Exeter, Devon, EX1 2LU, UK.
authors.forename: Katrina
authors.initials: K
authors.lastname: Wyatt
mesh_terms: D000367:Age Factors; D002648:Child; D002652:Child Behavior; D016000:Cluster Analysis; D003627:Data Interpretation, Statistical; D004739:England; D005260:Female; D015438:Health Behavior; D007722:Health Knowledge, Attitudes, Practice; D006293:Health Promotion / Q000379:methods / Q000706:statistics & numerical data*; D000070497:Healthy Lifestyle; D006801:Humans; D008297:Male; D063766:Pediatric Obesity / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control* / Q000523:psychology; D011314:Preventive Health Services / Q000379:methods / Q000706:statistics & numerical data*; D012107:Research Design / Q000706:statistics & numerical data*; D012307:Risk Factors; D040242:Risk Reduction Behavior; D012572:School Health Services / Q000706:statistics & numerical data*; D013997:Time Factors
keywords: Childhood obesity; Cluster randomised controlled trial; School-based; Statistical analysis plan