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

BACKGROUND: In Canada, demand for multidisciplinary bariatric (obesity) care far outstrips capacity. Consequently, prolonged wait times exist that contribute to substantial health impairments. A supportive, educational, self-management intervention (with in-person and web-based versions) for patients wait-listed for bariatric care has already been implemented in Northern and Central Alberta, Canada, but its effectiveness is unknown. The objective of this trial is to evaluate the clinical and economic outcomes of two self-management programs of varying intensity that are currently in use. METHODS: We conducted a pragmatic, prospective, parallel-arm, randomized controlled trial of 651 wait-listed patients from two regional bariatric programs. Patients were randomized to (1) an in-person, group-based intervention (13 sessions; n = 215) or (2) a web-based intervention (13 modules; n = 225) or (3) control group (printed educational materials; n = 211). After randomization, subjects had 3 months to review the content assigned to them (the intervention period) prior to bariatric clinic entry. The primary outcome was the proportion of patients achieving 5% weight loss at 9 months. Intention-to-treat two-way comparisons were performed and adjusted for baseline age, sex, site and body mass index. RESULTS: At baseline, mean age was 40.4 ± 9.8 years, mean weight was 134.7 ± 25.2 kg, mean body mass index was 47.7 ± 7.0 kg/m(2) and 83% of participants were female. A total of 463 patients (71%) completed 9 months follow-up. At least 5% weight loss was achieved by 24.2% of those in the in-person strategy, 24.9% for the web-based strategy and 21.3% for controls (adjusted p value = 0.26 for in-person vs. controls, 0.28 for web-based vs. controls, 0.96 for in-person vs. web-based). Absolute and relative (% of baseline) mean weight reductions were 3.7 ± 7.1 kg (2.7 ± 5.4%) for in-person strategy, 2.8 ± 6.7 kg (2.0 ± 4.8%) for web-based and 2.9 ± 8.8 kg (1.9 ± 5.9%) for controls (p > 0.05 for all comparisons). No between-group differences were apparent for any clinical or humanistic secondary outcomes. Total annual costs in Canadian dollars were estimated at $477,000.00 for the in-person strategy, $9456.78 for the web-based strategy and $2270.31 for provision of printed materials. DISCUSSION: Two different self-management interventions were no more effective and were more costly than providing printed education materials to severely obese patients. Our findings underscore the need to develop more potent interventions and the importance of comprehensively evaluating self-management strategies before widespread implementation. TRIAL REGISTRATION: ClinicalTrials.gov, NCT01860131. Registered 17 May 2013. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12916-017-0808-6) contains supplementary material, which is available to authorized users.