Enhancing adherence in trials promoting change in diet and physical activity in individuals with a diagnosis of colorectal adenoma; a systematic review of behavioural intervention approaches.

Background: Little is known about colorectal adenoma patients' ability to adhere to behavioural interventions promoting a change in diet and physical activity. This review aimed to examine health behaviour intervention programmes promoting change in diet and/or physical activity in adenoma patients and characterise interventions to which this patient group are most likely to adhere.

Methods: Searches of eight databases were restricted to English language publications 2000-2014. Reference lists of relevant articles were also reviewed. All randomised controlled trials (RCTs) of diet and physical activity interventions in colorectal adenoma patients were included. Eligibility and quality were assessed and data were extracted by two reviewers. Data extraction comprised type, intensity, provider, mode and location of delivery of the intervention and data to enable calculation of four adherence outcomes. Data were subject to narrative analysis.

Results: Five RCTs with a total of 1932 participants met the inclusion criteria. Adherence to the goals of the intervention ranged from 18 to 86 % for diet and 13 to 47 % for physical activity. Diet interventions achieving ≥ 50 % adherence to the goals of the intervention were clinic based, grounded in cognitive theory, delivered one to one and encouraged social support.

Conclusions: The findings of this review indicate that behavioural interventions can encourage colorectal adenoma patients to improve their diet. This review was not however able to clearly characterise effective interventions promoting increased physical activity in this patient group. Further research is required to establish effective interventions to promote adherence to physical activity in this population.