COST-EFFECTIVENESS OF STREPTOKINASE FOR ACUTE MYOCARDIAL-INFARCTION -A COMBINED METAANALYSIS AND DECISION-ANALYSIS OF THE EFFECTS OF INFARCT LOCATION AND OF LIKELIHOOD OF INFARCTION

Objective: To determine the effects of infarct location and of the lik elihood of infarction on the cost-effectiveness of intravenous strepto kinase (IVSK) for suspected acute myocardial infarction (AMI). Design: A meta-analysis of short-term survival was combined with a simple dec ision tree to determine marginal cost-effectiveness ratios for differe nt infarct locations and different likelihoods of AMI (pMI). Setting: Six randomized trials comparing IVSK with conservative treatment. Pati ents: 31,940 patients with onset of symptoms of AMI from four to 24 ho urs earlier and, with the exception of one trial, electrocardiographic abnormalities. Patients with contraindications to thrombolytic treatm ent such as uncontrolled hypertension were excluded. Main results: If AMI is certain, treatment with IVSK has marginal cost-effectiveness ra tios for each additional life saved of $9,900, $56,600, and $28,400, r espectively, for patients with anterior, inferior, and other locations of AMI. If pMI is 50%, treatment with IVSK has marginal cost-effectiv eness ratios for each additional life saved of $22,700, $131,800, and $63,100, respectively, for patients with anterior, inferior, and other locations of AMI. Conclusions: The marginal cost-effectiveness ratio for IVSK therapy of inferior infarction is six times that for anterior infarction and rises steeply as the presence of AMI becomes less cert ain. Assuming society is willing to pay $250,000 per life saved, IVSK therapy should be given if the chance of acute anterior infarction exc eeds 7%, if the chance of inferior infarction exceeds 32%, or if the c hance of infarction in other locations exceeds 17%. In patients with s uspected acute myocardial infarction, IVSK saves lives and is a reason able use of societal resources.