Impact on Clinical and Cost Outcomes of a Centralized Approach to Acute Stroke Care in London: A Comparative Effectiveness Before and After Model

Background: In July 2010 a new multiple hub-and-spoke model for acute stroke care was implemented across the whole of London, UK, with continuous specialist care during the first 72 hours provided at 8 hyper-acute stroke units (HASUs) compared to the previous model of 30 local hospitals receiving acute stroke patients. We investigated differences in clinical outcomes and costs between the new and old models. Methods: We compared outcomes and costs 'before' (July 2007-July 2008) vs. 'after' (July 2010-June 2011) the introduction of the new model, adjusted for patient characteristics and national time trends in mortality and length of stay. We constructed 90-day and 10-year decision analytic models using data from population based stroke registers, audits and published sources. Mortality and length of stay were modelled using survival analysis. Findings: In a pooled sample of 307 patients 'before' and 3156 patients 'after', survival improved in the 'after' period (age adjusted hazard ratio 0.54; 95% CI 0.41-0.72). The predicted survival rates at 90 days in the deterministic model adjusted for national trends were 87.2% 'before' % (95% CI 86.7%-87.7%) and 88.7% 'after' (95% CI 88.6%-88.8%); a relative reduction in deaths of 12% (95% CI 8%-16%). Based on a cohort of 6,438 stroke patients, the model produces a total cost saving of 5.2 pound million per year at 90 days (95% CI 4.9- pound 5.5 pound million; 811 pound per patient). Conclusion: A centralized model for acute stroke care across an entire metropolitan city appears to have reduced mortality for a reduced cost per patient, predominately as a result of reduced hospital length of stay.