Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry, UK.
EPPI-Centre, Social Science Research Unit, UCL Institute of Education, University College London, London, UK.
Health Expect. 2018 Jun;21(3):574-584. doi: 10.1111/hex.12667. Epub 2018 Mar 5.
Previous systematic reviews of weight management programmes (WMPs) have not been able to account for heterogeneity of effectiveness within programmes using top-down behavioural change taxonomies. This could be due to overlapping causal pathways to effectiveness (or lack of effectiveness) in these complex interventions. Qualitative comparative analysis (QCA) can help identify these overlapping pathways.
Using trials of adult WMPs with dietary and physical activity components identified from a previous systematic review, we selected the 10 most and 10 least effective interventions by amount of weight loss at 12 months compared to minimal treatment. Using intervention components suggested by synthesis of studies of programme user views, we labelled interventions as to the presence of these components and, using qualitative comparative analysis, developed pathways of component combinations that created the conditions sufficient for interventions to be most effective and least effective.
Informed by the synthesis of views studies, we constructed 3 truth tables relating to quality of the user-provider relationship; perceived high need for guidance from providers; and quality of the relationship between peers in weight management programmes. We found effective interventions were characterized by opportunities to develop supportive relationships with providers or peers, directive provider-led goal setting and components perceived to foster self-regulation.
Although QCA is an inductive method, this innovative approach has enabled the identification of potentially critical aspects of WMPs, such as the nature of relationships within them, which were previously not considered to be as important as more concrete content such as dietary focus.
之前的体重管理项目（WMP）系统评价无法使用自上而下的行为改变分类法来解释项目内效果的异质性。这可能是由于这些复杂干预措施中存在重叠的因果途径（或缺乏有效性）。定性比较分析（QCA）可以帮助识别这些重叠途径。
使用之前系统评价中确定的包含饮食和身体活动成分的成人 WMP 试验，我们选择了 10 个减肥效果最好和 10 个最差的干预措施，与最低治疗相比，在 12 个月时的减肥效果。根据对项目用户观点研究的综合分析，我们用干预组件来标记干预措施，使用定性比较分析，开发出了产生干预措施最有效和最无效的条件的组件组合途径。
根据观点研究的综合分析，我们构建了 3 个与用户与提供者关系质量、提供者提供指导的感知高需求、体重管理项目中同行之间关系质量相关的真实表。我们发现有效的干预措施的特点是有机会与提供者或同行建立支持性关系，提供者主导的目标设定以及促进自我调节的组件。
尽管 QCA 是一种归纳方法，但这种创新方法使我们能够识别 WMP 的潜在关键方面，例如其中的关系性质，这些方面以前被认为不如饮食重点等更具体的内容重要。
