Bart M. Demaerschalk, MD, MSc; Jeffrey A. Switzer, DO; Jipan Xie, MD, PhD; Liangyi Fan, BA; Kathleen F. Villa, MS; and Eric Q. Wu, PhD
Stroke is a leading cause of severe disability, and the fourthleading cause of death in the adult population in the United States.1,2
Acute ischemic stroke (AIS) accounts for more than 80% of all strokes.3
Administration of intravenous (IV) thrombolysis within a 3-hour window of the onset of AIS reduces disability.4
A recent clinical trial has demonstrated that IV thrombolysis administered between 3 and 4.5 hours after the onset of AIS could also significantly improve clinical outcome.5
Extending the 3-hour traditional time window by 1.5 hours is likely to increase the demand for IV thrombolysis because more AIS patients would present to the hospitals in time for treatment.
Despite the effectiveness of IV thrombolysis, fewer than 5% of patients who suffer AIS in the United States receive IV thrombolysis.6
One of the major barriers to IV thrombolysis administration is that most hospitals do not have the resources required to enable timely diagnosis and treatment of AIS patients. Hospitals with access to qualified personnel (eg, 24/7 on-call vascular neurologists) are most likely to provide care due to the time limitation. However, it is not feasible for every hospital to meet such resource and personnel requirements, especially those in remote rural areas. To serve communities without a stroke center, telestroke referral networks have been set up to connect a stroke center (the hub hospital) with local hospitals (spoke hospitals) and thus extend the reach of the acute stroke care team of the hub hospital to spoke hospitals. Through this establishment, AIS patients can receive more accurate diagnoses, more correct thrombolysis eligibility determination, and more appropriate emergency treatment, all resulting in potentially better prognoses. For instance, research studies revealed that telestroke results in correct diagnosis and thrombolysis decision making in 96% of instances.7
A hub-and-spoke telestroke network is an effective way to extend quality emergency stroke care to remote hospitals and improve patient outcomes. The costs associated with these networks, as well as the health-related outcomes, must be considered. We previously conducted a cost-effectiveness analysis (CEA) from the hospitals’ perspective.8
Building on that model,8
the current study aimed to assess the cost utility of a hub-and-spoke telestroke network compared with no network (absence of regional stroke system of care and telemedicine) in the management of AIS from the societal perspective. Two such studies were published and subsequently independently appraised and scored by the Tufts Medical Center Cost Effectiveness Analysis Registry.9,10 However, our study was the first to develop a cost decision model that included the possibility of endovascular therapy in addition to IV thrombolysis and the first to include an expanded array of cost inputs associated with dedicated network program managers and personnel, higher estimates of inpatient care, inter-hospital transfer, rehabilitation, long-term care, and caregiver costs, as well as a wider range of spoke-to-hub transfer rates, using 2 independent telestroke network data input sets.METHODS
A Markov model was developed to estimate the incremental costs and effectiveness with and without a telestroke network for the management of AIS over a lifetime. The model had 3 health states defined by the modified Rankin scale (mRS)11
: (1) minimal-to-no disability (mRS 0-2); (2) moderate-to-severe disability (mRS 3-5); and (3) death (mRS 6). A hypothetical cohort of AIS patients with a mean age of 68 years were assumed to receive acute care in a telestroke network versus a no-network setting and to transition between these health states at the beginning of each cycle (1 year). The mean age of 68 years was obtained from a US epidemiology study of patients with first-time stroke.12 Figure 1
illustrates the decision and treatment process for AIS and subsequent transitions. Building on the previous model,8
the base case of this study modeled a network with 1 hub and 7 spokes, with a total of 1112 unique AIS patients presenting to emergency departments in the network hospitals per year. The number of spoke hospitals in the network was based on a recent survey of active telestroke networks by Silva and colleagues,13
and the average number of AIS patients for spoke hospitals was obtained from the Georgia Health Sciences University and the Mayo Clinic telestroke networks. The number of AIS patients for the hub hospital was assumed to be 400 , based on the typical size of a hub hospital. Data on network characteristics were obtained from the Georgia Health Sciences University and the Mayo Clinic telestroke networks (see eAppendix
available at www.ajmc.com); these data were described in a study based on the same network.8
The following assumptions were made in the model estimation:
Acute ischemic stroke patients could only transition from a less severe to a more severe health state or remain in the same health state at each cycle.
Stroke treatments between a telestroke network and no network differed only during the initial hospitalization for AIS, not after discharge from acute care.
Incremental effectiveness associated with treatments in a telestroke network only resulted from IV thrombolysis or endovascular stroke therapy during the initial hospitalization for the first-time AIS.
There was no difference in stroke-related mortality between patients with and without IV thrombolysis,and between patients with and without endovascular stroke therapy during hospitalization. We made these assumptions because clinical trials on IV thrombolysis did not show a significant difference in mortality between patients who received IV thrombolysis and patients who did not, though the former group had a numerically lower rate.4,14 In addition, there was also a lack of randomized controlled trial data comparing the efficacy of endovascular stroke therapy with no such therapy.15,16 Therefore, we assumed no mortality difference in mortality in the base case, which could be a conservative assumption.
Rate of recurrent stroke was the same regardless of the treatment received during the initial hospitalization for AIS.
Model inputs included 3 major groups: health state distributions, costs, and utilities.Health State Distributions
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