Supplementary Material for: Greater Attendance at a Community Weight Loss Programme over the First 12 Weeks Predicts Weight Loss at 2 Years

Background: There is considerable heterogeneity in long-term weight loss among people referred to obesity treatment programmes. It is unclear whether attendance at face-to-face sessions in the early weeks of the programme is an independent predictor of long-term success. Objective: To investigate whether frequency of attendance at a community weight loss programme over the first 12 weeks is associated with long-term weight change. Methods: Participants were randomised to receive brief support only (control, n = 211), or a weight loss programme for 12 weeks (n = 530) or 52 weeks (n = 528). This study included participants with data on session attendance over the first 12 weeks (n = 889) compared to the control group. The association between attendance (continuously) and weight loss was explored using a linear model. A multi-level mixed-effects linear model was used to investigate whether attendance (categorised as 0, 1, 2–5, 6—9, and 10–12 sessions) was associated with weight loss at 3, 12, and 24 months compared to the control. Results: For every session attended in the first 12 weeks, the average weight loss was –0.259 kg/session at 24 months (p = 0.005). Analysis by attendance group found only those attending 10–12 sessions had significantly greater weight loss (–7.5 kg [95% CI –8.1 to –6.9] at 12 months; –4.7 kg [95% CI –5.3 to –4.1] at 24 months) compared to the control group (–3.4 [95% CI –4.5 to –2.4] at 12 months, –2.5 [95% CI –3.5 to –1.5] at 24 months). Early attendance was higher for people ≥70 years, but there was no evidence of a difference by gender, ethnicity, education, or income. Conclusions: Greater attendance at a community weight loss programme in the first 12 weeks is associated with enhanced weight loss up to 24 months. Regular attendance at a programme could be used as a criterion for continued provision of weight loss services to maximise the cost-effectiveness of interventions.

研究背景：参与肥胖治疗项目的人群在长期体重减轻方面存在显著异质性。目前尚不明确，项目初期几周的线下课程出勤情况是否为长期减重成功的独立预测因素。
研究目的：探讨社区减重项目前12周的出勤频率是否与长期体重变化存在关联。
研究方法：本研究受试者被随机分为三组，分别接受仅简短支持干预（对照组，n=211）、12周减重项目干预（n=530）或52周减重项目干预（n=528）。本研究纳入前12周拥有课程出勤数据的受试者（n=889），并与对照组进行比较。首先采用线性模型探究出勤次数（连续变量）与体重减轻的关联；随后采用多水平混合效应线性模型，分析将出勤次数划分为0次、1次、2~5次、6~9次及10~12次五个组别后，与对照组相比，在3个月、12个月及24个月时的体重变化差异。
研究结果：随访至24个月时，前12周每多参加1次课程，平均体重可多减轻0.259 kg/次（P=0.005）。按出勤组进行的分析显示，仅出勤10~12次的受试者体重减轻程度显著高于对照组：对照组在12个月时平均体重减轻3.4 kg（95%置信区间：-4.5~-2.4），24个月时为2.5 kg（95%置信区间：-3.5~-1.5）；而出勤10~12次的受试者12个月时平均体重减轻7.5 kg（95%置信区间：-8.1~-6.9），24个月时为4.7 kg（95%置信区间：-5.3~-4.1）。年龄≥70岁的受试者初期出勤次数更多，但未发现性别、种族、教育程度或收入水平对出勤情况存在显著影响。
研究结论：社区减重项目前12周的出勤次数越多，至24个月时的体重减轻效果越显著。可将规律出勤作为持续提供减重服务的评判标准，以最大化干预措施的成本效益。