Impact of major stroke service centralisation on mortality and care: analysis of admissions, interventions and outcomes in South Australia.

Background: Major system reform is complex but can yield improved outcomes at multiple levels. We aimed to evaluate the impact of implementing a hub and spoke model of stroke care across metropolitan Adelaide (population 1.2 million), South Australia on mortality, morbidity, service and quality stroke indicators.

Methods: Analysis of 24 months of prospectively collected, patient-level data covering all metropolitan stroke admissions during the contiguous pre-, during- and post-implementation time periods, linked to mortality data from the National Death Index. The three metropolitan tertiary hospital-based stroke units undertook the implementation of a centralised 'hub and spoke' model: one central comprehensive stroke centre offering 24 h stroke reperfusion therapies, and two primary stroke centres providing 12 h thrombolysis. The main outcome measures were mortality (any cause) up to 180 days post-admission; reperfusion treatment proportions and timings; stroke care quality composite metric; length of stay.

Results: There were 3917 confirmed stroke admissions over the 24-month period (3325 (84.9%) ischaemic) and 650 deaths (19.6%) within 180 days. Compared to the baseline period, post-intervention mortality and discharge disability did not differ, although a possible temporary increase in ischaemic stroke mortality during implementation was seen. Rates of endovascular thrombectomy (EVT) (5.7% vs. 12.5%, adjusted Rate Ratio (aRR) = 1.94, 95%CI 1.21,3.10) and timeliness of EVT (median 126 min (IQR 83, 154) vs. 95 min (53, 132), p < 0.001) improved as did the composite stroke quality metric indicator (0.60, 95% CI 0.50, 0.70 vs. 0.64, 95% CI 0.50, 0.75; adjusted difference 0.041, 95% CI 0.015, 0.066). Length of stay decreased for ischaemic stroke (8.2 (SD 12.4) vs. 7.9 (SD 8.9) days, adjusted geometric mean ratio = 0.83, 95% CI 0.73. 0.94) but not for intracerebral haemorrhage.

Conclusion: The major implementation of a metropolitan centralised 'hub and spoke' model of acute stroke care was associated with overall significant improvements in process indicators but a possible temporary increase in ischaemic stroke mortality during implementation.