The mortality of untreated pulmonary embolism in emergency department patients

Much of the literature on pulmonary embolism that is commonly referenced by emergency physicians begins with statistics concerning how often the diagnosis is missed and the lethality of pulmonary embolism if undiagnosed and untreated. It is likely that many emergency physicians continue to pursue an aggressive diagnostic strategy even in low-risk patients because of concerns about the potential for poor patient outcome and the medicolegal consequences of a missed diagnosis. The believed and often-quoted mortality and recurrence rates for untreated or missed pulmonary embolism are 26% to 30%. However, these figures originate from investigations that have little relevance to modern emergency medicine, which include studies dating to the 1940s, many of which have significant methodologic pitfalls. These data are also based primarily on either inpatient or autopsy populations, neither of which is representative of patients treated in the emergency department (ED). Analysis of untreated or missed pulmonary embolism in ambulatory patients reveals mortality and recurrence rates of less than 5%. This article discusses the background of commonly quoted pulmonary embolism statistics and highlights the need for future investigations enrolling ED patients that focus on disease outcome in this population.