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NIHR publishes new framework on complex interventions to improve health

Published: 01 October 2021

The NIHR and The Medical Research Council (MRC) has launched a new complex intervention research framework.

The new framework provides an updated definition of complex interventions, highlighting the dynamic relationship between the intervention and its context.

Complex interventions are widely used in the health service, in public health practice, and in areas of social policy that have important health consequences, such as education, transport, and housing. 

Interest in complex interventions has increased rapidly in recent years. Given the pace and extent of methodological development, there was a need to update the core guidance and address some of the remaining weaknesses and gaps. 

Using the framework’s core elements

There are four main phases of research: intervention development or identification, e.g. from policy or practice, feasibility, evaluation, and implementation.

At each phase, the guidance suggests that six core elements should be considered: 

  1. how does the intervention interact with its context?
  2. what is the underpinning programme theory?
  3. how can diverse stakeholder perspectives be included in the research? 
  4. what are the key uncertainties?
  5. how can the intervention be refined?
  6. do the effects of the intervention justify its cost?  

These core elements can be used to decide whether the research should proceed to the next phase, return to a previous phase, repeat a phase, or stop.

The journey of a research project through the phases of complex intervention research is illustrated in the below NIHR-funded study: Football Fans In Training (FFIT)

A randomised controlled trial set in professional football clubs established the effectiveness and cost-effectiveness of the Football Fans in Training (FFIT) programme. FFIT aimed to help men lose at least 5-10% of their weight and keep it off over the long term. The programme was developed to appeal to Scottish football fans and to help them improve their eating and activity habits.

Researchers found that participation in FFIT leads to significant sustained weight loss and improvements in diet and physical activity. As well as losing weight, participants benefited from reduced waist size, less body fat and lower blood pressure, which can all be associated with a lower risk of heart disease, diabetes and stroke. The study team considered all of the 6 core elements of complex intervention research, during each of the four phases of the research. 

Implementation was considered from the outset, the study team engaged with key stakeholders in the development phase to explore how the intervention could be implemented in practice, if proven to be effective. 

A cost effectiveness analysis demonstrated that FFIT was inexpensive to deliver, making it appeal to decision makers for local and national health provision.  The positive and sustainable results have made the programme appealing for nations with similar public health priorities such as the reduction of obesity, heart disease and improvement of mental health.

Professor Hywel Williams, NIHR Scientific and Coordinating Centre Programmes Contracts Advisor, said: “This updated framework is a landmark piece of guidance for researchers working on such interventions. The updated guidance will help researchers to develop testable and reproducible interventions that will ultimately benefit NHS patients. The guidance also represents a terrific collaborative effort between the NIHR and MRC that I would like to see more of.”

Professor Nick Wareham, Professor Nick Wareham, Chair of MRC’s Population Health Sciences Group, said: “Previous versions of the guidance on the development and evaluation of complex interventions have been extremely influential and are widely used in the field. We are delighted that the successful partnership between MRC and NIHR has enabled the guidance to be updated and extended. It is particularly important to see how the new framework brings in thinking about the interplay between an intervention and the context in which it is applied.”

Dr Kathryn Skivington, Research Fellow, MRC/CSO Social and Public Health Sciences Unit and lead author of the framework, said: “The new and exciting developments for complex intervention research are of practical relevance and I feel sure they will stimulate constructive debate, leading to further progress in this area.”

Read the full paper, published in the British Medical Journal

Find out more in the NIHR Journals Library

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