Economic Benefit of Increasing Utilization of Intravenous Tissue Plasminogen Activator for Acute Ischemic Stroke in the United States
Background and Purpose— Health economic analyses of intravenous tissue plasminogen activator (tPA) in acute ischemic stroke reveal a substantial cost savings. Unfortunately, tPA is vastly underused. The purpose of this study was to determine the economic impact of increasing tPA utilization in the United States.
Methods— Annual incidence estimates of ischemic stroke in the United States and individual states were obtained. The proportion of all ischemic stroke patients who receive tPA was derived from published data. Economic analyses that report the expected annual cost savings of tPA were consulted. The analysis was conducted from the perspective of the healthcare system over a time period of 1 year. With incremental increases in the proportion of all ischemic stroke patients treated with tPA, potential cost savings were recalculated. The outcomes are expressed in dollars saved annually.
Results— There are 616 000 new ischemic stroke patients annually. A $600 net cost savings is associated with each tPA-treated patient. Currently, an estimated 2% of all ischemic stroke patients receive tPA. If the proportion was increased to 4, 6, 8, 10, 15, or 20%, the realized cost savings would be approximately $15, 22, 30, 37, 55, and 74 million, respectively.
Conclusions— If even small manageable increases in the proportion of all ischemic stroke patients who received tPA were achieved, it would result in an enormous realized savings for America’s healthcare system.
The US Food and Drug Administration approved tissue plasminogen activator (tPA) as a therapy for acute ischemic stroke on June 18, 1996. Shortly thereafter, there was early speculation that the acute costs of thrombolysis could be offset by a greater likelihood of favorable recovery.1 This estimation was subsequently confirmed when Markov modeling was used to demonstrate that the increased hospitalization costs were offset by a decrease in rehabilitation costs for a net cost savings to the healthcare system.2 It was readily observed that integrated healthcare systems (acute care, rehabilitation, and nursing home facilities) have an economic incentive for using tPA in stroke patients.3 Other authors have supported use of tPA as a strategy for reducing stroke costs, recognizing it as a treatment associated with important health gains (4 to 6 quality-adjusted life-years gained per 100 patients over a lifetime) and cost savings.4–6 Unfortunately, the enthusiasm of the late 1990s was dampened in the early 2000s with the recognition that only a very small proportion, 2%, of stroke patients were actually being treated with tPA.4,7 Over the past 9 years, the overall proportion of ischemic stroke patients in the United States treated with tPA has slowly crept up and several urban and nonurban primary stroke centers report impressive proportions (10% to 20%) of stroke patients receiving tPA.8–11 It appears to be time to revisit the potential for economic benefit of increasing utilization of tPA for acute ischemic stroke.
Our purpose is to estimate the national and state cost savings in the first year poststroke generated from modest incremental increases in tPA use for acute ischemic stroke, over a range of 2% to 20%.
The annual incidence estimate of ischemic stroke in the United States was derived from the American Stroke Association and for each individual state based on stroke mortality data from National Center for Health Statistics.12 The net cost after the first year after tPA treatment was estimated, with 90% certainty, to be (a savings of) −$600 (95% confidence interval [CI] −$3481 to $2004) per treated patient (1996 reference year values) based on a US cost-effectiveness analysis of tPA in stroke.2 National and state cost savings in the first year were calculated as such:
We then used the fifth and ninety-fifth percentiles of cost at 1 year poststroke provided by Fagan et al and performed a basic sensitivity analyses on the best estimates of US cost savings in the first year postischemic stroke by varying proportions of patients that receive intravenous tPA.
In 2003, there were an estimated 616 000 ischemic stroke cases in the United States. Over $7 million would be saved in the United States for every 2% increase in tPA-treated stroke patients. Almost $37 million and $74 million would be saved by treating 10 and 20% of ischemic stroke patients, respectively (see Table 1⇓). Individual state cost saving estimates are also listed in Table 1⇓.
The results of the sensitivity analysis are portrayed in Table 2. Although the best estimate (with 90% certainty) is for a net cost savings of $7.4 million for every 2% increase in tPA-treated patients, the sensitivity analysis displays that the range includes a maximal potential cost savings of $43 million and the possibility of a loss of $25 million.
Although national estimates of tPA use for acute ischemic stroke continue to be low and disappointing (1% to 2%), there are a number of communities with stroke centers that have demonstrated striking improvements in proportions of tPA-treated stroke patients (&20%). This information confirms that under ideal circumstances a higher proportion of patients can have access to this acute therapy. Barriers to more uniform and timely access to stroke center care and tPA continue to exist, but they are being identified and addressed. We carefully selected the lower (2%) proportion to reflect the current estimated national average proportion of stroke patients receiving tPA and the upper (20%) proportion to reflect what might currently be achievable in a North American community or setting. There may be a relative ceiling or maximum achievable proportion in the current era of acute stroke care. Even if 100% of eligible acute ischemic stroke patients received tPA in a given stroke center, the overall proportion of ischemic stroke patients who receive tPA would be far less, perhaps approximately 20% maximum. This ceiling figure, representing the maximal achievable proportion, is influenced largely by prehospital components (recognition of stroke symptoms, timeliness of 911 call, emergency medical services evaluation and transport), and exclusion criteria for tPA administration (clinical, radiologic, and laboratory). Estimates of the proportion of stroke patients who present to hospital within the first 3 hours vary by stroke center and community, but this figure can be as high as 50% to 62%.9,13,14,15 Estimates of the proportion of acute ischemic stroke patients (who present under 3 hours) who are eligible and receive tPA are as high as 35%.14,15 Therefore, we propose an estimated ceiling figure of 22% (0.35%×62%). We have used this line of reasoning to justify the upper limit of &20% in our analysis. This ceiling is not static. It may continue to rise and settle in the 25% to 35% range optimally, in the future, as public education and prehospital acute stroke transport improve.
This analysis is simply an illustrative estimate of the anticipated savings that would result from even modest, feasible increases in use of tPA in the United States, assuming an integrated healthcare system existed. It should be noted that the available American cost-effectiveness study for tPA was conducted from the perspective of an integrated healthcare system, although even the authors acknowledge that such a system is rare in the United States.2 A perceived limitation of this analysis is that it failed to include costs associated with interventions aimed at increasing the number of patients eligible for acute stroke therapy. There are certainly costs associated with public education, prehospital emergency medical services care, and the establishment of new primary and comprehensive stroke centers (PSC and CSC). Fagan et al2 elected not to include these costs because they do not, strictly speaking, belong to tPA, but rather to all acute therapies for both ischemic and hemorrhagic stroke. Even before completion of the NINDS rtPA Stroke Trial, the National Stroke Association and American Stroke Association promoted the concept of early evaluation and treatment of acute stroke and enhanced public awareness of stroke symptoms and signs. Brain Attack Coalition (BAC) authors of recommendations for the establishment of primary stroke centers and comprehensive stroke centers emphasize that it is difficult to determine accurate and meaningful costs for a PSC or CSC because of the paucity of published data.16,17 This is also a limitation in determining the costs of public education and prehospital emergency medical services stroke care systems. Estimates of the cost associated with building and staffing a new stroke unit range from $50 000 to $500 000 and the annual operating cost estimates range from $8000 to $200 000. The BAC authors point out that, at the present time, data simply do not exist to project an accurate or meaningful cost analysis or cost–benefit analysis for PSC/CSC and similar efforts.
This simple model emphasizes what is already known about tPA for stroke; the therapy is efficacious in clinical trials, effective in the real world, and results in a net cost savings. Given such a favorable economic profile, it behooves us to continue to determine safe, effective means for more widespread use of this therapy.
This research was presented in poster form at the International Stroke Conference February 5–7, 2004 in San Diego, and the abstract was published in Stroke 2004.
- Received May 12, 2005.
- Revision received July 7, 2005.
- Accepted July 27, 2005.
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