Testing innovative strategies to reduce the social gradient in the uptake of bowel cancer screening: a programme of four qualitatively enhanced randomised controlled trials

Abstract

BackgroundBowel cancer screening reduces cancer-specific mortality. There is a socioeconomic gradient in the uptake of the English NHS Bowel Cancer Screening Programme (BCSP), which may lead to inequalities in cancer outcomes.ObjectiveTo reduce socioeconomic inequalities in uptake of the NHS BCSP’s guaiac faecal occult blood test (gFOBt) without compromising uptake in any socioeconomic group.DesignWorkstream 1 explored psychosocial determinants of non-uptake of gFOBt in focus groups and interviews. Workstream 2 developed and tested four theoretically based interventions: (1) ‘gist’ information, (2) a ‘narrative’ leaflet, (3) ‘general practice endorsement’ (GPE) and (4) an ‘enhanced reminder’ (ER). Workstream 3 comprised four national cluster randomised controlled trials (RCTs) of the cost-effectiveness of each intervention.MethodsInterventions were co-designed with user panels, user tested using interviews and focus groups, and piloted with postal questionnaires. RCTs compared ‘usual care’ (existing NHS BCSP invitations) with usual care plus each intervention. The four trials tested: (1) ‘gist’ leaflet (n = 163,525), (2) ‘narrative’ leaflet (n = 150,417), (3) GPE on the invitation letter (n = 265,434) and (4) ER (n = 168,480). Randomisation was based on day of mailing of the screening invitation. The Index of Multiple Deprivation (IMD) score associated with each individual’s home address was used as the marker of socioeconomic circumstances (SECs). Change in the socioeconomic gradient in uptake (interaction between treatment group and IMD quintile) was the primary outcome. Screening uptake was defined as the return of a gFOBt kit within 18 weeks of the invitation that led to a ‘definitive’ test result of either ‘normal’ (i.e. no further investigation required) or ‘abnormal’ (i.e. requiring referral for further testing). Difference in overall uptake was the secondary outcome.ResultsThe gist and narrative trials showed no effect on the SECs gradient or overall uptake (57.6% and 56.7%, respectively, compared with 57.3% and 58.5%, respectively, for usual care; allp-values > 0.05). GPE showed no effect on the gradient (p = 0.5) but increased overall uptake [58.2% vs. 57.5% in usual care, odds ratio (OR) = 1.07, 95% confidence interval (CI) 1.04 to 1.10;p < 0.0001]. ER showed a significant interaction with SECs (p = 0.005), with a stronger effect in the most deprived IMD quintile (14.1% vs. 13.3% in usual care, OR = 1.11, 95% CI 1.04 to 1.20;p = 0.003) than the least deprived (34.7% vs. 34.9% in usual care OR = 1.00, 95% CI 0.94 to 1.06;p = 0.98), and higher overall uptake (25.8% vs. 25.1% in usual care, OR = 1.07, 95% CI 1.03 to 1.11;p = 0.001). All interventions were inexpensive to provide.LimitationsIn line with NHS policy, the gist and narrative leaflets supplemented rather than replaced existing NHS BCSP information. This may have undermined their effect.ConclusionsEnhanced reminder reduced the gradient and modestly increased overall uptake, whereas GPE increased overall uptake but did not reduce the gradient. Therefore, given their effectiveness and very low cost, the findings suggest that implementation of both by the NHS BCSP would be beneficial. The gist and narrative results highlight the challenge of achieving equitable delivery of the screening offer when all communication is written; the format is universal and informed decision-making mandates extensive medical information.Future workSocioculturally tailored research to promote communication about screening with family and friends should be developed and evaluated.Trial registrationCurrent Controlled Trials ISRCTN74121020.FundingThis project was funded by the National Institute for Health Research (NIHR) Programme Grants for Applied Research programme and will be published in full inProgramme Grants for Applied Research; Vol. 5, No. 8. See the NIHR Journals Library website for further project information.