Investigating the effectiveness of pre-surgical ‘health optimisation’ public health interventions for obesity and smoking in elective hip and knee replacement surgery from health service and patient perspectives

Research question What impact do pre-surgical health optimisation interventions (for obesity and smoking) in hip and knee replacement patients have on patient outcomes, are they cost effective and do they risk causing health inequalities?

Background Clinical Commissioning Groups (CCGs) have introduced 'health optimisation' interventions (HOIs) that require or support National Health Service (NHS) patients to lose weight and/or stop smoking ahead of surgical referral.

The interventions are intended to: Improve clinical outcomes from surgery Reduce the need for surgery Trigger long-term lifestyle changes in patients at a key moment in their lives when they are motivated to improve their health There is significant geographical variation in intervention content, reflecting the current inadequate evidence-base for their effects on patients, public health and cost-effectiveness.

They also have potential unintended consequences of increasing health inequalities through differential impact on vulnerable sociodemographic groups' access to surgery. Evaluations of existing interventions have not been published.

Aims and objectives Investigate the effectiveness, cost-effectiveness and impact on health inequalities of HOIs for body mass index (BMI) and smoking in elective hip and knee replacement surgery from NHS and patient perspectives, using a mixed methodology approach.

Methods Complete four Work Packages and a training and development programme through collaboration with clinical, commissioning and research settings and with integral patient and public involvement (PPI): Natural experimental study using existing data centred on the National Joint Registry for England to determine the impact of HOIs on surgery rates, patient clinical and public health outcomes and association with sociodemographic inequality.

Data will be analysed using interrupted time series and difference-in-differences analyses to assess the effect of HOI introduction on trends in outcomes before and after the date a HOI was introduced in each CCG area. Extended natural experimental study with an embedded case study of a CCG's new HOI in one of its sub-regions.

This will address deficits in existing datasets and evaluations by measuring patient engagement and changes in BMI and smoking status, and the associated costs, alongside the outcomes addressed above.

Health economic modelling with use of data from Work Packages 1 and 2 and published literature to estimate the long-term cost-effectiveness of HOIs relating to hip and knee replacement surgery.

Qualitative study using interviews with 30 key stakeholders and six citizen focus groups in two contrasting English regions to investigate their views on HOIs and the motivations and barriers to their introduction.

Timelines Three-year full-time doctoral fellowship where the Work Packages are completed in parallel including time for reporting and dissemination.

Anticipated impact and dissemination I will work with PPI groups and collaborators to use the findings to form and disseminate meaningful recommendations to policy decision-makers and wider stakeholders to enable their evidence-based decisions on the ongoing use or expansion of HOIs. This will have an immediate impact on many thousands of patients.

There may be the result of a recommendation of a standard HOI for all CCGs where this would improve outcomes, public health and use of health and care resources.