Behavioural intervention for weight loss maintenance versus standard weight advice in adults with obesity: A randomised controlled trial in the UK (NULevel Trial)

BackgroundScalable weight loss maintenance (WLM) interventions for adults with obesity are lacking but vital for the health and economic benefits of weight loss to be fully realised. We examined the effectiveness and cost-effectiveness of a low-intensity technology-mediated behavioural intervention to support WLM in adults with obesity after clinically significant weight loss (≥5%) compared to standard lifestyle advice.Methods and findingsThe NULevel trial was an open-label randomised controlled superiority trial in 288 adults recruited April 2014 to May 2015 with weight loss of ≥5% within the previous 12 months, from a pre-weight loss BMI of ≥30 kg/m2. Participants were self-selected, and the majority self-certified previous weight loss. We used a web-based randomisation system to assign participants to either standard lifestyle advice via newsletter (control arm) or a technology-mediated low-intensity behavioural WLM programme (intervention arm). The intervention comprised a single face-to-face goal-setting meeting, self-monitoring, and remote feedback on weight, diet, and physical activity via links embedded in short message service (SMS). All participants were provided with wirelessly connected weighing scales, but only participants in the intervention arm were instructed to weigh themselves daily and told that they would receive feedback on their weight. After 12 months, we measured the primary outcome, weight (kilograms), as well as frequency of self-weighing, objective physical activity (via accelerometry), psychological variables, and cost-effectiveness. The study was powered to detect a between-group weight difference of ±2.5 kg at follow-up. Overall, 264 participants (92%) completed the trial. Mean weight gain from baseline to 12 months was 1.8 kg (95% CI 0.5–3.1) in the intervention group (n = 131) and 1.8 kg (95% CI 0.6–3.0) in the control group (n = 133). There was no evidence of an effect on weight at 12 months (difference in adjusted mean weight change from baseline: −0.07 [95% CI 1.7 to −1.9], p = 0.9). Intervention participants weighed themselves more frequently than control participants and were more physically active. Intervention participants reported greater satisfaction with weight outcomes, more planning for dietary and physical activity goals and for managing lapses, and greater confidence for healthy eating, weight loss, and WLM. Potential limitations, such as the use of connected weighing study in both trial arms, the absence of a measurement of energy intake, and the recruitment from one region of the United Kingdom, are discussed.ConclusionsThere was no difference in the WLM of participants who received the NULevel intervention compared to participants who received standard lifestyle advice via newsletter. The intervention affected some, but not all, process-related secondary outcomes of the trial.Trial registrationThis trial is registered with the ISRCTN registry (ISRCTN 14657176; registration date 20 March 2014).背景 针对肥胖成人的可推广体重维持（weight loss maintenance, WLM）干预方案目前仍较为匮乏，但此类方案对于充分发挥减重带来的健康与经济效益至关重要。本研究针对临床显著减重（≥5%）后的肥胖成人，对比了低强度技术介导行为干预用于体重维持，与标准生活方式建议的有效性及成本效益。 研究方法与结果 NULevel试验为开放标签随机对照优效性试验，于2014年4月至2015年5月间招募288名成人受试者。受试者需满足在过去12个月内减重≥5%，且减重前体重指数（body mass index, BMI）≥30 kg/m²。受试者均为自愿报名，多数自行申报既往减重史。本研究采用基于网页的随机分配系统，将受试者分为两组：对照组接受通过通讯简报推送的标准生活方式建议，干预组则接受技术介导的低强度行为体重维持干预方案。干预方案包含单次面对面目标设定会议、自我监测，以及通过短信息服务（short message service, SMS）内嵌链接获取体重、饮食与体力活动的远程反馈。所有受试者均被提供无线连接体重秤，但仅干预组受试者被要求每日称重，并被告知将收到体重相关反馈。随访12个月后，本研究评估了主要结局指标——体重（千克），同时测量了自我称重频率、客观体力活动水平（经加速度计法测定）、心理变量及成本效益。本研究的检验效能可检测随访时组间体重差异±2.5 kg。最终，264名受试者（92%）完成试验。干预组（n=131）从基线至12个月的平均体重增幅为1.8 kg（95%置信区间0.5–3.1），对照组（n=133）为1.8 kg（95%置信区间0.6–3.0）。未观察到12个月时体重变化存在组间差异（校正后的基线体重变化组间差异：−0.07 [95%置信区间1.7至−1.9]，p=0.9）。干预组受试者的自我称重频率高于对照组，体力活动水平也更优。干预组受试者对体重管理结局的满意度更高，在饮食与体力活动目标设定、失误应对规划方面表现更出色，且在健康饮食、减重及体重维持方面的自信心更强。本研究还讨论了潜在局限性，例如两组均采用了联网体重秤研究方案、未测量能量摄入，以及受试者仅招募自英国单一地区。 结论 与通过通讯简报获取标准生活方式建议的受试者相比，接受NULevel干预的受试者在体重维持方面无显著差异。该干预仅对部分而非全部与流程相关的次要结局指标产生了影响。 试验注册 本试验已在ISRCTN注册中心注册（ISRCTN 14657176；注册日期2014年3月20日）。