Cost-Effectiveness of Mobile Stroke Unit Care in Norway

Abstract

Background: Acute ischemic stroke treatment in mobile stroke units (MSUs) reduces time-to-treatment and increases thrombolytic rates, but implementation requires substantial investments. We wanted to explore the cost-effectiveness of MSU care incorporating novel efficacy data from the Norwegian MSU study, Treat-NASPP (the Norwegian Acute Stroke Prehospital Project).

Methods: We developed a Markov model linking improvements in time-to-treatment and thrombolytic rates delivered by treatment in an MSU to functional outcomes for the patients in a lifetime perspective. We estimated incremental costs, health benefits, and cost-effectiveness of MSU care as compared with conventional care. In addition, we estimated a minimal MSU utilization level for the intervention to be cost-effective in the publicly funded health care system in Norway.

Results: MSU care was associated with an expected quality-adjusted life-year-gain of 0.065 per patient, compared with standard care. Our analysis suggests that about 260 patients with ischemic stroke need to be treated with MSU annually to result in an incremental cost-effectiveness ratio of about NOK385 000 (US$43 780) per quality-adjusted life-year for MSU compared with standard care. The incremental cost-effectiveness ratio varies between some NOK1 000 000 (US$113 700) per quality-adjusted life-year if an MSU treats 100 patients per year and to about NOK340 000 (US$38 660) per quality-adjusted life-year if 300 patients with acute ischemic stroke are treated.

Conclusions: MSU care in Norwegian settings is potentially cost-effective compared with conventional care, but this depends on a relatively high annual number of treated patients with acute ischemic stroke per vehicle. These results provide important information for MSU implementation in government-funded health care systems.

Keywords: ischemic stroke; repefusion; thrombectomy; time-to-treatment; triage.

Figure 1.

One-way cost-effectiveness sensitivity analysis showing how the incremental cost-effectiveness ratio (ICER) for mobile stroke unit (MSU) compared with standard ambulance depend on the annual number of patients served by 1 MSU. The lower dotted line represents the assumed willingness to pay (WTP) per quality-adjusted life-year (QALY) in Norway when the severity of acute ischemic stroke (AIS) is taken into account. The upper dotted line represents the assumed maximum WTP in Norway for conditions assumed to be most severe.

Figure 2.

Results of probabilistic cost-effectiveness analysis comparing mobile stroke unit (MSU) with standard care, based on an assumption of 180 patients with acute ischemic stroke (AIS) treated annually. A, Scatter plot with incremental cost-effectiveness following a simulation with 10 000 iterations. The diagonal line illustrates a willingness to pay (WTP) of NOK385 000 (US$43 780) per quality-adjusted life-year (QALY). Green color indicates observations that were cost-effective at this WTP (15.5%), and red color indicates observations that were not. B, Cost-effectiveness acceptability curve for a range of WTP per QALY.