Where in England would Mobile Stroke Units be Cost-Effective and what are the Implications for Equity of Access: A model based Distributional Cost-Effectiveness Analysis

Background Mobile Stroke Units (MSUs) have been shown to be an effective means to improve outcomes following stroke by increasing the rate and speed of thrombolysis. The consequences of MSU implementation in the UK’s National Health Service have not been examined but is important because contextual geographical and organisational dependencies may influence effectiveness, cost-effectiveness, and equality of access. We aimed to develop a model to explore these issues across the ten English NHS Ambulance Services. Methods A previously developed model estimated the improvement to stroke outcomes through deployment of MSUs around the existing stroke service infrastructure. We estimated the net cost-effectiveness of MSUs by combining this with a model that estimates the lifetime health benefits and cost saving associated with these improvements in stroke outcomes. Inequality of health benefits was estimated in terms of absolute gains of the most and least deprived quintiles of populations. Possible MSU locations (either at a comprehensive stroke centre or an acute stroke unit) were compared in terms of cost-effectiveness and equity, both independently and combined in Distributional Cost Effectiveness Analysis. Results No locations were financially sustainable without the addition of the financial benefits derived from willingness-to-pay for health benefits. Over a patient’s lifetime and from a secondary care perspective, more than one third of locations were cost-effective at a £20,000 willingness-to-pay threshold per Quality Adjusted Life Year, with each regional Ambulance Service having at least one cost-effective location for an MSU However, choice of location of MSUs will also be influenced by a willingness to pay for heath gains in the most deprived quintile compared to the general population, with all Ambulance Services having additional locations that could reduce inequity, at the cost of overall benefits. Conclusions MSUs have a heterogenous impact on cost-effectiveness and equity of access of stroke care in the English NHS, with benefits mainly confined to localities with specific geographical and organisational characteristics. Commissioners can consider them as an option in the context of local service provision and resource availability along with other advances in prehospital care, but it cannot be assumed that they would be beneficial in all locations.