title: Incentives in Diabetic Eye Assessment by Screening (IDEAS): study protocol of a three-arm randomized controlled trial using financial incentives to increase screening uptake in London.
abstract: BACKGROUND
  Diabetes is an increasing public health problem in the UK and globally. Diabetic retinopathy is a microvascular complication of diabetes, and is one of the leading causes of blindness in the UK working age population. The diabetic eye screening programme in England aims to invite all people with diabetes aged 12 or over for retinal photography to screen for the presence of diabetic retinopathy. However, attendance rates are only 81 %, leaving many people at risk of preventable sight loss.
  
  
  METHODS
  This is a three arm randomized controlled trial to investigate the impact of different types of financial incentives (based on principles from behavioral economics) on increasing attendance at diabetic eye screening appointments in London. Eligible participants will be aged 16 or over, and are those who have been invited to screening appointments annually, but who have not attended, or telephoned to rearrange an appointment, within the last 24 months. Eligible participants will be randomized to one of three conditions: 1. Control condition (usual invitation letter) 2. Fixed incentive condition (usual invitation letter, including a voucher for £10 if they attend their appointment) 3. Probabilistic incentive condition (invitation letter, including a voucher for a 1 in 100 chance of winning £1000 if they attend their appointment). Participants will be sent invitation letters, and the primary outcome will be whether or not they attend their appointment. One thousand participants will be included in total, randomized with a ratio of 1.4:1:1. In order to test whether the incentive scheme has a differential impact on patients from different demographic or socio-economic groups, information will be recorded on age, gender, distance from screening center, socio-economic status and length of time since they were last screened. A cost-effectiveness analysis will also be performed.
  
  
  CONCLUSIONS
  This study will be the first trial of financial incentives for improving uptake of diabetic eye screening. If effective, the intervention may suggest a cost-effective way to increase screening rates, thus reducing unnecessary blindness.
  
  
  BACKGROUND
  ISRCTN14896403, 25 February 2016.
authors.affiliation: Department of Surgery and Cancer, Imperial College London, St. Mary's Campus, Praed Street, London, W2 1NY, UK. G.Judah@imperial.ac.uk.
authors.forename: Gaby
authors.identifier: http://orcid.org/0000-0003-3322-9760
authors.initials: G
authors.lastname: Judah
authors.affiliation: Warwick Business School, University of Warwick, Scarman Road, Coventry, CV4 7AL, Coventry, UK.
authors.forename: Ivo
authors.initials: I
authors.lastname: Vlaev
authors.affiliation: Department of Integrative Health Science, Stetson University, 421 North Woodland Blvd., DeLand, Florida, 32723, USA.
authors.forename: Laura
authors.initials: L
authors.lastname: Gunn
authors.affiliation: Department of Surgery and Cancer, Imperial College London, St. Mary's Campus, Praed Street, London, W2 1NY, UK.
authors.forename: Dominic
authors.initials: D
authors.lastname: King
authors.affiliation: Personal Social Services Research Unit, London School of Economics & Political Science, Houghton Street, London, WC2A 2AE, UK.
authors.forename: Derek
authors.initials: D
authors.lastname: King
authors.affiliation: Imperial College Healthcare NHS Trust, St. Mary's Hospital, Praed Street, London, W2 1NY, UK.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Valabhji
authors.affiliation: Department of Surgery and Cancer, Imperial College London, St. Mary's Campus, Praed Street, London, W2 1NY, UK.
authors.forename: Ara
authors.initials: A
authors.lastname: Darzi
authors.affiliation: Department of Surgery and Cancer, Imperial College London, St. Mary's Campus, Praed Street, London, W2 1NY, UK.
authors.forename: Colin
authors.initials: C
authors.lastname: Bicknell
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D003930:Diabetic Retinopathy / Q000175:diagnosis*; D060909:Economics, Behavioral; D006801:Humans; D008131:London; D008875:Middle Aged; D009042:Motivation; D010349:Patient Compliance / Q000523:psychology; D010358:Patient Participation / Q000191:economics*; D010781:Photography; D011320:Primary Health Care / Q000191:economics; D012052:Reimbursement, Incentive; D012107:Research Design; D012201:Reward; D011795:Surveys and Questionnaires; D015351:Vision Screening / Q000191:economics*
keywords: Behavior change; Behavioral economics; Diabetes; Diabetic retinopathy; Financial incentives; Screening