Cost-effectiveness of streptokinase for acute myocardial infarction: A combined meta-analysis 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 likelihood of infarction on the cost-effectiveness of intravenous streptokinase (IVSK) for suspected acute myocardial infarction (AMI).

DESIGN

A meta-analysis of short-term survival was combined with a simple decision tree to determine marginal cost-effectiveness ratios for different infarct locations and different likelihoods of AMI (pMI).

SETTING

Six randomized trials comparing IVSK with conservative treatment.

PATIENTS

31,940 patients with onset of symptoms of AMI from four to 24 hours earlier and, with the exception of one trial, electrocardiographic abnormalities. Patients with contraindications to thrombolytic treatment such as uncontrolled hypertension were excluded.

MAIN RESULTS

If AMI is certain, treatment with IVSK has marginal cost-effectiveness ratios for each additional life saved of $9,900, $56,600, and $28,400, respectively, for patients with anterior, inferior, and other locations of AMI. If pMI is 50% treatment with IVSK has marginal cost-effectiveness 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 certain. Assuming society is willing to pay $250,000 per life saved, IVSK therapy should be given if the chance of acute anterior infarction exceeds 7%, if the chance of inferior infarction exceeds 32%, or if the chance of infarction in other locations exceeds 17%. In patients with suspected acute myocardial infarction, IVSK saves lives and is a reasonable use of societal resources.