Treating patients with acute ischemic stroke (AIS) at a primary stroke center (PSC) compared with a non-PSC setting is cost effective, researchers reported in a study published online April 25 in Stroke. Based on their analyses, increasing the number of patients annually admitted to a PSC improved cost effectiveness.
In 2011, Xian et al found that patients with AIS who were admitted to a designated stroke center had modestly lower mortality rates and greater use of thrombolytic therapy than patients admitted to nondesignated hospitals (JAMA 2011;305:373-380). While that large, observational study demonstrated the clinical effectiveness of PSCs, David L. Veenstra, PharmD, PhD, of the pharmacy department at the University of Washington in Seattle, and colleagues wanted to examine the cost effectiveness as well.
Using data from Xian et al’s study, they created a hypothetical cohort for their patient population. From that, Veenstra and colleagues developed a decision analytic model that allowed them to project the lifetime outcomes and costs of two groups of AIS patients: one treated at a PSC and one treated at a non-PSC hospital. They conducted their analyses from the payor perspective, calculating life years, quality-adjusted life years (QALYs), lifetime direct medical costs and the incremental cost-effectiveness ratio (ICER).
They found that admission to a PSC compared with a non-PSC hospital resulted in a gain of 0.22 years of life and 0.15 QALYs per patient, plus an increased cost of $3,621. The ICER per QALY for care in a PSC was $23,990.
“Our analysis supports PSCs increasing average life expectancy and QALYs in a cost-effective manner,” the authors wrote. “On average, AIS patients treated at a PSC live approximately 82 days longer than do patients treated at a non-PSC, at an additional cost of approximately $3,600 per patient.”
Based on scenario analyses, they determined that the more patients who were entered into the model, the lower ICERs became. Treating seven and fewer AIS patients per year resulted in an ICER that exceeded the $100,000 willingness to pay threshold while treating 500 AIS patients per year had an ICER of $16,589. Ninety-nine percent of their simulations resulted in ICERs of less than $50,000/QALY.
“For a PSC that treats 75 AIS patients per year, approximately 16.8 life years or 11.3 QALYs may be gained per annual cohort,” Veenstra and colleagues continued. “A PSC that treats 500 AIS patients per year could gain as much as 112 life years and 75 QALYs per cohort. Because the cost per patient of a PSC decreases as the number of patients increases, higher volume centers appear to provide greater economic value.”
They noted that the mortality reduction associated with PSCs also meant survival benefits and consequently higher lifetime costs, but that the incremental cost per QALY decreases as survival increases. They argued that result adds the weight of cost effectiveness to efforts to reduce mortality with PSCs.
Among limitations, they listed their use of data from the Xian et al study and the possibility of potential confounding. In their cost model, they assumed the PSC had a 24-hour call team available for all admissions and neuroimaging capabilities. They acknowledged that their results don’t apply to programs that lack those resources.
“Our findings support existing recommendations for establishing PSCs in more locations throughout the country,” the authors concluded. They added that the use of a telemedicine hub and spoke model to transfer AIS patients to a PSC may be appropriate in settings where there likely are fewer than 10 AIS patients per year.
The study was funded by Genentech and a grant from the National Institutes for Health.