THROMBOTIC THROMBOCYTOPENIC PURPURA - EVOLUTION ACROSS 15 YEARS

Thrombotic thrombocytopenic purpura (TTP) was originally described 70 years ago. It is considered an uncommon disorder with a reported occur rence rate of one case per 1 million patients. Mortality has decreased from almost 100% early on to 30-50% with the advent of newer treatmen t methods. We reviewed 41 patients with a diagnosis of TTP spanning th e years 1980 to mid 1994. We found a much higher case rate, one per 60 00 hospital admissions, and an overall death rate of 40%. However, iso lating 5 year periods we noted a marked fall in mortality from 54% (19 80-1984), 44% (1985-1989), to 18% (1990-1994). Previous reports descri be relapsing TTP and report an incidence of 7-15% although very recent data suggests a higher incidence. In our study, we found an overall r elapse rate of 25% and by 5 year periods 23% (1980-1984), 13% (1985-19 89), and 46% (1990-1994). We suggest that the improvement in survival and the increase in relapse rate are related and reflect more effectiv e therapy for this once almost always fatal disease. Patients now surv ive their initial episode and thus are at risk for recurrence. Identif ication of risk factors for relapse will require further study. (C) 19 96 Wiley-Liss, Inc.