The evaluating self-management and educational support in severely obese patients awaiting multidisciplinary bariatric care (EVOLUTION) trial: rationale and design

In Canada, demand for multidisciplinary bariatric (obesity) care far outstrips capacity. Consequently, prolonged wait times exist and contribute to substantial health impairments.

A supportive, educational intervention (with in-person and web-based versions) designed to enhance the self-management skills of patients wait-listed for multidisciplinary bariatric medical and surgical care has been variably implemented across Alberta, Canada. However, its effectiveness has not been evaluated. Our objectives were: 1. To determine if this program improves clinical and humanistic outcomes and is cost-effective compared to a control intervention; and 2. To compare the effectiveness and cost-effectiveness of in-person group-based versus web-based care. We hypothesize that both the web-based and in-person programs will reduce body weight and improve outcomes compared to the control group. Furthermore, we hypothesize that the in-person version will be more effective but more costly than the web-based version.

This pragmatic, prospective controlled trial will enrol 660 wait-listed subjects (220 per study arm) from regional bariatric programs in Alberta and randomly assign them to: 1. an in-person, group-based intervention (9 modules delivered over 10 sessions); 2. a web-based intervention (13 modules); and 3. controls who will receive mailed literature. Subjects will have three months to review the content assigned to them (the intervention period) after which they will immediately enter the weight management clinic. Data will be collected at baseline and every 3 months for 9 months (study end), including: 1. Clinical [5% weight loss responders (primary outcome), absolute and % weight losses, changes in obesity-related comorbidities]; 2. Humanistic (health related quality of life, patient satisfaction, depression, and self-efficacy); and 3. Economic (incremental costs and utilities and cost per change in BMI assessed from the third party health care payor perspective) outcomes. Covariate-adjusted baseline-to-nine-month change-scores will be compared between groups for each outcome using linear regression for continuous outcomes and logistic regression for dichotomous ones.

Our findings will determine whether this intervention is effective and cost-effective compared to controls and if online or in-person care delivery is preferred. This information will be useful for clinicians, health-service providers and policy makers and should be generalizable to similar publically-funded bariatric care programs.

Trial Identifier: NCT01860131