Interventions targeted at primary care practitioners to improve the identification and referral of adults with co-morbid obesity: a realist review
Obesity is one of the biggest public health problems in the UK today. Policy suggests more can be done in primary care to support adults with obesity, particularly identifying and referring individuals with “high risk” obesity (obesity with co-morbidities) to weight management services. The purpose of this study is to inform the development of a theory-driven, evidence-based intervention targeted at primary care practitioners to improve the management of co-morbid obesity, in line with the MRC Framework for design and evaluation of complex interventions.
Realist synthesis is a theory-driven approach to literature synthesis aimed at discerning what works, for whom, in what circumstances, and why. It is particularly suited to understanding complex interventions. A search strategy informed by a previous Cochrane systematic review was developed, including: Medline, EMBASE, CINAHL, PsycINFO, Web of Science and Science Direct, for years 2004-2014. Titles and abstracts of retrieved studies were screened independently by two reviewers. Full texts of potentially eligible studies were independently assessed, with disagreements resolved by a third reviewer. Quality appraisal used recognised checklists. A pre-piloted data extraction form was used to extract information on context (C), mechanisms (M) and outcomes (O) – the core building blocks of realist synthesis. CMO configurations were then used to test and refine the initial “programme theories” of the interventions in the review. Qualitative interviews with nine key stakeholders involved in adult weight management services informed the review process.
The search strategy yielded 4,233 records; 27 studies were finally included. 19 were from the USA, with the remainder being from Europe (7) and Australia (1). Most of the studies used multiple intervention strategies (e.g. educational, behavioural and organisational, according to the EPOC classification); operating at different levels (e.g. individual, interpersonal, and institutional). Reported outcomes included discussion of weight with patients, recording of BMI, referral to weight management services, and weight loss. A number of important mechanisms (e.g. trust, confidence, feedback, incentives, normalisation) were identified for each of the outcomes of interest. Several contextual factors supported these mechanisms, for example: at the patient level, being female, older, and having co-morbidities; at the interpersonal level, having continuity of care; and at the institutional level, having good pre-existing engagement between primary care and the weight management service.
This is the first realist review in this healthcare field where complexity and variability are the norm. Despite the heterogeneity of the included studies, there are a number of recommendations – at the individual, interpersonal, and institutional levels – that can be made about what works, for whom, and in what circumstances. Parallels can be drawn between brief interventions in primary care for weight management and those for smoking cessation. However, there remain significant barriers that are unique to weight management.