Incidence of pulmonary embolism: is it declining?

Several factors make analysis of time trends in the incidence of pulmonary embolism difficult. Apart from the methodologic problems, a number of factors could explain an increasing as well as a decreasing incidence. The few studies on pulmonary embolism discovered after death are discussed, and the evidence shows a decrease in incidence, especially after the mid 1970s. This can be explained by many factors, of which the 2 most important are the increased use of thromboprophylaxis and better treatment of established deep vein thrombosis.