Who stays, who drops out? Biosocial predictors of longer-term adherence in participants attending an exercise referral scheme in the UK

Background: Exercise referral schemes are one of the most popular forms of physical activity intervention in primary care in the UK and present an opportunity to better understand the factors related to exercise adherence. But standard schemes tend to be delivered over a short period and so provide information about the factors associated with short-term adherence. This retrospective register-based study of a longer-duration scheme allowed investigation of longer-term adherence. Methods: Social, physiological and anthropometric data were extracted from records of a cohort of ERS participants who had enrolled between 01 January and 31 December 2007 (n = 701). Characteristics of adherers and non-adherers were compared and potential predictors of longer-term adherence examined using binomial logistic regression. Results: Significant adjusted odds ratios predicting longer-term adherence were found for age and medical condition. For every 10 year increase in age, the odds of people continuing exercise increased by 21.8% (OR = 1.02; CI = 1.00 to 1.04; p = 0.03). Participants referred with orthopaedic (OR = 0.25; CI = 0.07-0.94; p = 0.04), cardiovascular (OR = 0.18; CI = 0.05-0.70; p = 0.01) and other (OR = 0.20; CI = 0.04-0.93; p = 0.04) problems had significantly lower odds of adhering than those with metabolic conditions. Conclusion: Improved understanding of the factors that influence adherence to exercise referral schemes will enable providers develop better referral guidance and tailor schemes to better meet participants' needs. Longer-term schemes offer the opportunity to understand participants' likelihood of maintaining adherence to exercise.