Observed Cost and Variations in Short Term Cost-Effectiveness of Therapy for Ischemic Stroke in Interventional Management of Stroke (IMS) III

Abstract

Background: Examination of linked data on patient outcomes and cost of care may help identify areas where stroke care can be improved. We report on the association between variations in stroke severity, patient outcomes, cost, and treatment patterns observed over the acute hospital stay and through the 12-month follow-up for subjects receiving endovascular therapy compared to intravenous tissue plasminogen activator alone in the IMS (Interventional Management of Stroke) III Trial.

Methods and results: Prospective data collected for a prespecified economic analysis of the trial were used. Data included hospital billing records for the initial stroke admission and subsequent detailed resource use after the acute hospitalization collected at 3, 6, 9, and 12 months. Cost of follow-up care varied 6-fold for patients in the lowest (0-1) and highest (20+) National Institutes of Health Stroke Scale category at 5 days, and by modified Rankin Scale at 3 months. The kind of resources used postdischarge also varied between treatment groups. Incremental short-term cost-effectiveness ratios varied greatly when treatments were compared for patient subgroups. Patient subgroups predefined by stroke severity had incremental cost-effectiveness ratios of $97 303/quality-adjusted life year (severe stroke) and $3 187 805/quality-adjusted life year (moderately severe stroke).

Conclusions: Detailed economic and resource utilization data from IMS III provide powerful evidence for the large effect that patient outcome has on the economic value of medical and endovascular reperfusion therapies. These data can be used to inform process improvements for stroke care and to estimate the cost-effectiveness of endovascular therapy in the US health system for stroke intervention trials.

Clinical trial registration: URL: http://www.clinicaltrials.gov. Registration number: NCT00359424.

Keywords: cost; cost‐effectiveness; ischemic; stroke; stroke care; tissue‐type plasminogen activator.

Figure 1

Details of the populations included in the economic analyses. *US subjects; ^#non‐US subjects. Note: The index hospital admission is the initial admission for stroke. FU costs are calculated from resource use data collected at the 3‐, 6‐, 9‐, and 12‐month follow‐up visit or call. FU indicates follow‐up; QALY, quality‐adjusted life year.

Figure 2

Distribution of costs after initial acute stroke hospitalization by type of resources used over the 12 months by treatment group. EVT indicates subjects randomized to endovascular therapy; IV Only are subjects who are randomized to receive only intravenous tissue plasminogen activator; Q1 through Q4 indicate first through fourth quarter year in the study; Rahab, cost for rehabilitation care; Hospital, cost of hospital admissions; ER, cost of emergency visits; Office, cost of medical office visits; HomeHlt, cost of home health care; HomeAid, cost of care delivered by home health aids; NsgHome, cost of days in a skilled nursing facility.

Figure 3

Severe stroke only: distribution of costs after initial acute stroke hospitalization by type of resources used over the 12 months by treatment group. EVT indicates subjects randomized to endovascular therapy; IV Only are subjects who are randomized to receive only intravenous tissue plasminogen activator; Q1 through Q4 indicate first through fourth quarter year in the study; Rahab, cost for rehabilitation care; Hospital, cost of hospital admissions; ER, cost of emergency visits; Office, cost of medical office visits; HomeHlt, Cost of home health care; HomeAid, cost of care delivered by home health aids; NsgHome, cost of days in a skilled nursing facility.

Figure 4

Variations in differences in cost and QALYs for patients with severe stroke based on 1000 bootstrap replications. Note: The panel on the left shows the distribution of cost and QALYs from 1000 bootstrap estimates for patients with severe stroke. The right‐hand panel shows the cost‐effectiveness acceptability curve for the ICERs produced by 1000 bootstrap replications for subjects with severe stroke based on observed QALYs and observed or estimated costs for all subjects with severe stroke at baseline. ICERs indicates incremental cost‐effectiveness ratios; QALYs, quality‐adjusted life years.

Figure 5

Effect of uncertainty on ICERs presented in Table 4. Note: The panels show the distribution of cost and QALYs from 1000 bootstrap estimates for the respective patient groups. ICERs indicates incremental cost‐effectiveness ratios; MD, physician costs included; QALYs, quality‐adjusted life years.