A toxicity index for comparison of side effects among different drugs.

This report describes the development of a morbidity toxicity index and a mortality toxicity index for comparing the overall toxicity of different drugs. The task required the step-by-step procedure of 1) development of techniques for valid estimation of the numerator, i.e., the number of particular toxic events with a specific drug, 2) development of a denominator, i.e., a valid estimate of the years of exposure to a specific drug, 3) establishment of appropriate weights for different side effects, 4) deciding upon a particular index structure using weights and severity, 5) elaborating on and refining the final index, and 6) use of statistical techniques for adjustment and for comparison among drugs. In addition to describing the proposed structure and design of the morbidity and mortality toxicity indexes, we outline our preliminary results in comparing morbidity from major classes of antirheumatic drugs with the use of these indexes, and we discuss the potential use of the indexes by others who are studying drug toxicities