Objectives: The cost-effectiveness of computed tomographic (CT) scanning after acute stroke was investigated to assess the contribution of brain imaging to the diagnosis and management of stroke and to estimate the costs, benefits, and risks of different imaging strategies to provide data to inform national and local policy on the use of brain imaging in stroke.
Methods: A decision-analysis model was developed to represent the pathway of care in acute stroke, using “scan all patients within 48 hours” as the comparator against twelve alternative scan strategies. Hospitals in Scotland were the setting. The participants were patients admitted to the hospital with a first stroke and those managed as outpatients. The interventions included the effect on functional outcome after ischemic or hemorrhagic stroke, tumors, or infections of correctly administered antithrombotic or other treatment; of time to scan and stroke severity on diagnosis by CT or magnetic resonance imaging (MRI); on management, including length of stay, functional outcome, and quality-adjusted life years (QALYs) of the diagnostic information provided by CT scanning; and the cost-effectiveness (cost versus QALYs) of different strategies for use of CT after acute stroke. The main outcome measures were death and functional outcome at long-term follow-up; accuracy of CT and MRI; cost of CT scanning by time of day and week; effect of CT diagnosis on change in health outcome, length of stay in hospital, and QALYs; and cost-effectiveness of various scanning strategies.
Results: CT is very sensitive and specific for hemorrhage within the first 8 days of stroke only. Suboptimal scanning used in epidemiology studies suggests that the frequency of primary intracerebral hemorrhage (PICH) has been underestimated. Aspirin increases the risk of PICH. There were no reliable data on functional outcome or on the effect of antithrombotic treatment given long-term after PICH. In 60 percent of patients with recurrent stroke after PICH, the cause is another PICH and mortality is high among PICH patients. A specific MR sequence (gradient echo) is required to identify prior PICH reliably. CT scanners were distributed unevenly in Scotland, 65 percent provided CT scanning within 48 hours of stroke, and 100 percent within 7 days for hospital-admitted patients, but access after hours was very variable and for outpatients was poor. The average cost of a CT brain scan for stroke was £30.23 to £89.56 in normal working hours and £55.05 to £173.46 after hours. Average length of stay was greatest for severe strokes and those who survived in a dependent state. For a cohort of 1,000 patients 70–74 years of age, the policy “scan all strokes within 48 hours,” cost £10,279,728 and achieved 1982.3 QALYS. The most cost-effective strategy was “scan all immediately” (£9,993,676 and 1982.4 QALYS). The least cost-effective was to “scan patients on anticoagulants, in a life-threatening condition immediately and the rest within 14 days.”
Conclusions: In general, strategies in which most patients were scanned immediately cost least and achieved the most QALYs, as the cost of providing CT (even after hours) was less than the cost of inpatient care. Increasing independent survival by even a small proportion through early use of aspirin in the majority with ischemic stroke, avoiding aspirin in those with hemorrhagic stroke, and appropriate early management of those who have not had a stroke, reduced costs and increased QALYs.
