Cost effectiveness of streptokinase therapy was similar for patients of 70, 75, or 80 years of age
ACP J Club. 1993 Jan-Feb;118:30. doi:10.7326/ACPJC-1993-118-1-030
Krumholz HM, Pasternak RC, Weinstein MC, et al. Cost effectiveness of thrombolytic therapy with streptokinase in elderly patients with suspected acute myocardial infarction. N Engl J Med. 1992 Jul 2;327:7-13.
To compare the cost effectiveness of streptokinase (SK) therapy for suspected acute myocardial infarction among persons at various ages over 65 years.
An economic model was applied to data from an observational study of patients presenting to the hospital with acute chest pain, from 2 randomized controlled trials of SK compared with placebo, and from hospital cost estimates.
Chest pain study. N Engl J Med. 1988;318:797-803; GISSI. Lancet. 1986;1:397-402; ISIS-2. Lancet. 1988;2:349-60; Boston hospitals.
Main comparisons and assumptions
Standard treatment without SK for patients with suspected myocardial infarction entering the hospital within 6 hours of onset of chest pain was compared with treatment plus SK. Benefits were expected reductions of in-hospital mortality from SK among patients with confirmed acute myocardial infarction. The pooled mortality from the 2 trials of SK therapy for patients > 75 years who did not receive SK was 29% compared with 25% among those who received SK; the corresponding figures for patients 65 to 74 years were 18% and 15%, and for patients < 65 years, 8% and 6%. Risks from SK therapy were applied to all patients who received SK, regardless of whether myocardial infarction was confirmed. Discounted cost estimates included costs of administering SK and treating its major complications, including hemorrhage, hemorrhagic stroke, and myocardial reinfarction, plus the costs of medical care for years of life gained from receiving SK.
For patients > 75 years with suspected myocardial infarction, for every 33 patients treated with SK, 1 additional life would be saved. By comparison, 1 life would be saved for every 56 patients < 65 years and 1 for every 54 patients aged 65 to 74 years. In univariate sensitivity analyses, a treatment benefit persisted for a patient > 75 years if the probability of myocardial infarction on admission was > 9%, if the relative reduction in mortality was > 1%, if the risk for in-hospital death without SK treatment was > 3%, or if the risk for major complications of SK was ≤ 4%. The cost-effectiveness ratio was $21 200 per year of life saved for an 80-year-old patient, $22 400 for a 75-year-old patient, and $21 600 for a 70-year-old patient. Despite widely varied assumptions about cost and other factors, SK therapy remained < $55 000 per year of life saved.
Within a wide range of assumptions, streptokinase therapy was beneficial for elderly patients, and its cost effectiveness was similar for patients of 70, 75, or 80 years of age.
Sources of funding: Agency for Health Care Policy and Research and the National Heart, Lung, and Blood Institute.
For article reprint: Dr. H.M. Krumholz, Section of Cardiovascular Medicine, Yale School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA. FAX 203-785-7144.
The study by Krumholz and colleagues raises 2 important issues. The first is the reluctance of clinicians to deliver therapies such as thrombolytic agents, aspirin, and warfarin to elderly patients. Although the therapies are effective in reducing the risk for fatal or nonfatal myocardial infarction and other disorders, physicians perceive an increased risk for adverse effects such as intracranial bleeding. Unfortunately, clinicians also fail to consider that the benefits may be greater for elderly patients. The authors combine results from trials of thrombolytic therapy in suspected myocardial infarction that included elderly persons in order to quantify the increased benefits and risks for bleeding in elderly patients compared with other adult patients. The decision analytic model is useful in further helping the clinician to understand the extent of the risk/benefit trade-off. The second issue raised concerns the role of cost-effectiveness analysis to help set policies and make decisions for emergency departments and coronary care units (1). The estimated cost-effectiveness ratios compare favorably with those associated with other commonly used effective health care interventions such as treatment of hypertension and hypercholesterolemia for patients with established coronary artery disease (secondary prevention).
A convincing argument is made for both individual clinicians (SK therapy helps more than hurts) (2) and policy makers (the cost-effectiveness ratios were relatively attractive) that thrombolytic therapy with SK for elderly patients with suspected myocardial infarction, presenting with ST-segment elevation within 6 hours of the onset of symptoms, is an effective and cost-effective approach.
Allan S. Detsky, MD, PhD
University of TorontoToronto, Ontario, Canada
2. Laupacis A, Feeny D, Detsky AS, Tugwell P. How attractive does a new technology have to be to warrant adoption and utilization? Tentative guidelines for using clinical and economic evaluations. Can Med Assoc J. 1992;146: 472-81.