BENEFIT-RISK RATIOS IN THE ASSESSMENT OF THE CLINICAL-EVIDENCE OF A NEW THERAPY

All therapeutic decisions involve some trade-off between therapeutic b enefits and risks; a new therapy may be associated with greater effica cy but also a greater risk of adverse effects. In making treatment dec isions clinicians must examine the clinical evidence regarding the mag nitudes of benefit and risk and the precision with which they have bee n estimated. Ideally this requires a systemic assessment of the qualit y of the research and the strength of the evidence. We examine how the concept of number needed to treat can be used to improve the current presentation of clinical trials data of efficacy and side-effects to g ive clinicians a more clinically meaningful and quantitative measure o f benefit-risk trade-offs. We propose a benefit-risk ratio that quanti fies for a new therapy how many therapeutic (efficacy) events will be achieved for each adverse event incurred. We show how data from a clin ical trial with a single binary measure of efficacy and a single adver se event of concern can be used to provide point estimates and confide nce intervals for the benefit-risk ratio. The approach is illustrated using data from the GUSTO trial comparing tissue plasminogen activator and streptokinase in the management of patients with acute myocardial infarction. (C) Elsevier Science Inc. 1997.