title: Statistical analysis plan for the Laser-1st versus Drops-1st for Glaucoma and Ocular Hypertension Trial (LiGHT): a multi-centre randomised controlled trial.
abstract: BACKGROUND
  The LiGHT trial (Laser-1st versus Drops-1st for Glaucoma and Ocular Hypertension Trial) is a multicentre randomised controlled trial of two treatment pathways for patients who are newly diagnosed with open-angle glaucoma (OAG) and ocular hypertension (OHT). The main hypothesis for the trial is that lowering intraocular pressure (IOP) with selective laser trabeculoplasty (SLT) as the primary treatment ('Laser-1st') leads to a better health-related quality of life than for those started on IOP-lowering drops as their primary treatment ('Medicine-1st') and that this is associated with reduced costs and improved tolerability of treatment. This paper describes the statistical analysis plan for the study.
  
  
  METHODS
  The LiGHT trial is an unmasked, multi-centre randomised controlled trial. A total of 718 patients (359 per arm) are being randomised to two groups: medicine-first or laser-first treatment. Outcomes are recorded at baseline and at 6-month intervals up to 36 months. The primary outcome measure is health-related quality of life (HRQL) at 36 months measured using the EQ-5D-5L. The main secondary outcome is the Glaucoma Utility Index. We plan to analyse the patient outcome data according to the group to which the patient was originally assigned. Methods of statistical analysis are described, including the handling of missing data, the covariates used in the adjusted analyses and the planned sensitivity analyses.
  
  
  BACKGROUND
  The trial was registered with the ISRCTN register on 23/07/2012, number ISRCTN32038223 .
authors.affiliation: Marie Curie Palliative Care Research Department, UCL Division of Psychiatry, University College London, 6th Floor, Maple House, 149 Tottenham Court Road, London, W1T 7NF, UK. v.vickerstaff@ucl.ac.uk.|The Research Department of Primary Care and Population Health, University College London, Rowland Hill Street, London, NW3 2PF, UK. v.vickerstaff@ucl.ac.uk.
authors.forename: Victoria
authors.initials: V
authors.lastname: Vickerstaff
authors.affiliation: Department of Statistical Science, University College London, Gower Street, London, WC1E 6BT, UK.
authors.forename: Gareth
authors.initials: G
authors.lastname: Ambler
authors.affiliation: NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital and UCL Institute of Ophthalmology, City Road, London, UK.
authors.forename: Catey
authors.initials: C
authors.lastname: Bunce
authors.affiliation: NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital and UCL Institute of Ophthalmology, City Road, London, UK.
authors.forename: Wen
authors.initials: W
authors.lastname: Xing
authors.affiliation: NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital and UCL Institute of Ophthalmology, City Road, London, UK.
authors.forename: Gus
authors.initials: G
authors.lastname: Gazzard
mesh_terms: D060433:Administration, Ophthalmic; D000959:Antihypertensive Agents / Q000008:administration & dosage* / Q000009:adverse effects; D002985:Clinical Protocols; D003131:Combined Modality Therapy; D003627:Data Interpretation, Statistical; D004334:Drug Administration Schedule; D005902:Glaucoma, Open-Angle / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D053685:Laser Therapy / Q000009:adverse effects / Q000379:methods / Q000706:statistics & numerical data; D015233:Models, Statistical; D009798:Ocular Hypertension / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D009883:Ophthalmic Solutions; D011788:Quality of Life; D012107:Research Design; D013997:Time Factors; D014130:Trabeculectomy / Q000009:adverse effects / Q000379:methods / Q000706:statistics & numerical data; D016896:Treatment Outcome; D006113:United Kingdom
chemical_list: D000959:Antihypertensive Agents; D009883:Ophthalmic Solutions