A Catch in `a Catch in the Reye'

Abstract

To the Editor.— The "Catch in the Reye"1 is not in the data but rather in the authors' interpretation. They incorrectly surmise that finding that only one in 20 patients with Reye syndrome had taken aspirin makes it unlikely that aspirin is a risk factor for Reye syndrome. This conclusion ignores the relationship between the prevalence of a risk factor (such as aspirin), the relative risk (RR), and the population attributable risk (PAR). In a population in which aspirin use is uncommon, such as Australia, only a small proportion of all patients with Reye syndrome will have a history of aspirin use.