title: Effects of evidence-based strategies to reduce the socioeconomic gradient of uptake in the English NHS Bowel Cancer Screening Programme (ASCEND): four cluster-randomised controlled trials.
abstract: BACKGROUND
  Uptake in the national colorectal cancer screening programme in England varies by socioeconomic status. We assessed four interventions aimed at reducing this gradient, with the intention of improving the health benefits of screening.
  
  
  METHODS
  All people eligible for screening (men and women aged 60-74 years) across England were included in four cluster-randomised trials. Randomisation was based on day of invitation. Each trial compared the standard information with the standard information plus the following supplementary interventions: trial 1 (November, 2012), a supplementary leaflet summarising the gist of the key information; trial 2 (March, 2012), a supplementary narrative leaflet describing people's stories; trial 3 (June, 2013), general practice endorsement of the programme on the invitation letter; and trial 4 (July-August, 2013) an enhanced reminder letter with a banner that reiterated the screening offer. Socioeconomic status was defined by the Index of Multiple Deprivation score for each home address. The primary outcome was the socioeconomic status gradient in uptake across deprivation quintiles. This study is registered, number ISRCTN74121020.
  
  
  RESULTS
  As all four trials were embedded in the screening programme, loss to follow-up was minimal (less than 0·5%). Trials 1 (n=163,525) and 2 (n=150,417) showed no effects on the socioeconomic gradient of uptake or overall uptake. Trial 3 (n=265 434) showed no effect on the socioeconomic gradient but was associated with increased overall uptake (adjusted odds ratio [OR] 1·07, 95% CI 1·04-1·10, p<0·0001). In trial 4 (n=168 480) a significant interaction was seen with socioeconomic status gradient (p=0·005), with a stronger effect in the most deprived quintile (adjusted OR 1·11, 95% CI 1·04-1·20, p=0·003) than in the least deprived (1·00, 0·94-1·06, p=0·98). Overall uptake was also increased (1·07, 1·03-1·11, p=0·001).
  
  
  CONCLUSIONS
  Of four evidence-based interventions, the enhanced reminder letter reduced the socioeconomic gradient in screening uptake, but further reducing inequalities in screening uptake through written materials alone will be challenging.
  
  
  BACKGROUND
  National Institute for Health Research.
authors.affiliation: Department of Epidemiology and Public Health, University College London, London, UK.
authors.forename: Jane
authors.initials: J
authors.lastname: Wardle
authors.affiliation: Department of Epidemiology and Public Health, University College London, London, UK. Electronic address: c.wagner@ucl.ac.uk.
authors.forename: Christian
authors.initials: C
authors.lastname: von Wagner
authors.affiliation: Department of Biostatistics, King's Clinical Trials Unit, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.
authors.forename: Ines
authors.initials: I
authors.lastname: Kralj-Hans
authors.affiliation: NHS Bowel Cancer Screening Programme Southern Hub, Royal Surrey County Hospital NHS Foundation Trust, Guildford, Surrey, UK; Royal Surrey County Hospital NHS Foundation Trust, Guildford, and University of Surrey, Guildford, UK.
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Halloran
authors.affiliation: Department of Epidemiology and Public Health, University College London, London, UK; Wolfson Institute of Preventive Medicine, Queen Mary University of London, London, UK.
authors.forename: Samuel G
authors.initials: SG
authors.lastname: Smith
authors.affiliation: Department of Epidemiology and Public Health, University College London, London, UK.
authors.forename: Lesley M
authors.initials: LM
authors.lastname: McGregor
authors.affiliation: Department of Epidemiology and Public Health, University College London, London, UK.
authors.forename: Gemma
authors.initials: G
authors.lastname: Vart
authors.affiliation: Department of Surgery and Cancer, Imperial College London, London, UK.
authors.forename: Rosemary
authors.initials: R
authors.lastname: Howe
authors.affiliation: NHS Bowel Cancer Screening Programme Southern Hub, Royal Surrey County Hospital NHS Foundation Trust, Guildford, Surrey, UK.
authors.forename: Julia
authors.initials: J
authors.lastname: Snowball
authors.affiliation: NHS Bowel Cancer Screening Programme North East Hub, Gateshead Health NHS Foundation Trust, Queen Elizabeth Hospital, Gateshead, UK.
authors.forename: Graham
authors.initials: G
authors.lastname: Handley
authors.affiliation: NHS Bowel Cancer Screening Programme Eastern Hub, Nottingham University Hospitals, Nottingham, UK.
authors.forename: Richard F
authors.initials: RF
authors.lastname: Logan
authors.affiliation: NHS Bowel Cancer Screening Hub, London Hub, Northwick Park and St Mark's Hospital, Harrow, Middlesex, UK.
authors.forename: Sandra
authors.initials: S
authors.lastname: Rainbow
authors.affiliation: NHS Bowel Cancer Screening Programme Midlands and North West Hub, University Hospitals Coventry and Warwickshire NHS Trust, Hospital of St Cross, Rugby, UK.
authors.forename: Steve
authors.initials: S
authors.lastname: Smith
authors.affiliation: Department of Applied Health Research, University College London, London, UK.
authors.forename: Mary C
authors.initials: MC
authors.lastname: Thomas
authors.affiliation: Cancer Research Centre UK and University College London Cancer Trials Centre, University College London, London, UK.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Counsell
authors.affiliation: Department of Applied Health Research, University College London, London, UK.
authors.forename: Steve
authors.initials: S
authors.lastname: Morris
authors.affiliation: Wolfson Institute of Preventive Medicine, Queen Mary University of London, London, UK.
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Duffy
authors.affiliation: Cancer Research Centre UK and University College London Cancer Trials Centre, University College London, London, UK.
authors.forename: Allan
authors.initials: A
authors.lastname: Hackshaw
authors.affiliation: Wolfson Institute of Preventive Medicine, Queen Mary University of London, London, UK.
authors.forename: Sue
authors.initials: S
authors.lastname: Moss
authors.affiliation: Department of Surgery and Cancer, Imperial College London, London, UK.
authors.forename: Wendy
authors.initials: W
authors.lastname: Atkin
authors.affiliation: Department of Applied Health Research, University College London, London, UK.
authors.forename: Rosalind
authors.initials: R
authors.lastname: Raine
mesh_terms: D000368:Aged; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D015709:Correspondence as Topic; D055088:Early Detection of Cancer / Q000706:statistics & numerical data*; D004739:England; D019317:Evidence-Based Medicine / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000706:statistics & numerical data; D008875:Middle Aged; D009780:Occult Blood; D010342:Patient Acceptance of Health Care / Q000706:statistics & numerical data*; D017010:Reminder Systems; D012923:Social Class; D013222:State Medicine / Q000458:organization & administration