Inequalities in the uptake of weight management interventions in a pragmatic trial: an observational study in primary care

BACKGROUND: Primary care referral to a commercial open-group behavioural weight-loss programme is a cost-effective intervention, but only 10% of patients receiving this intervention are male. AIM: To explore whether observed biases in participation in these interventions reflect biases in the uptake of the invitation to participate. DESIGN AND SETTING: Comparison of invited population and recruited participants in a multicentre randomised controlled trial of primary care referral to a commercial open-group behavioural weight-loss programme in England (WRAP [Weight loss Referrals for Adults in Primary care]). METHOD: Between October 2012 and February 2014, participants were recruited through 23 primary care practices in England; 17 practices provided data on the characteristics of invited participants. RESULTS: Females were twice as likely as males to enrol in the trial (odds ratio [OR] 2.01, 95% confidence interval [CI] = 1.75 to 2.32). However, the proportion of males was threefold higher than seen in routine primary care referrals or similar trials that invited patients opportunistically. People from less deprived areas were more likely to enrol than those in more deprived areas (OR 1.77, 95% CI = 1.55 to 2.03). Older patients (≥40 years) were more likely to enrol than younger patients (OR 1.60, 95% CI = 1.34 to 1.91). CONCLUSION: Males, younger people, and those from more deprived areas were less likely to take up the invitation to participate in this trial. The gender bias was smaller than observed in routine practice, suggesting that a substantial proportion of the inequity observed previously is a consequence of bias with regard to the offer of intervention. This study suggests that a simple way to overcome much of the gender bias is to write to patients who are overweight and offer referral. Uptake of the invitation to participate was lower in groups of lower socioeconomic status suggesting the need to preferentially offer referrals to this group to reduce health inequalities and for research to explore barriers to uptake.