As Drs Moll and Ortel are certainly aware, the exact worldwide incidence is not known for most diseases, including those causing hypercoagulability. The incidence reported in the literature is obviously subject to the bias of where the study is performed. For example, in Spain,1 the incidence of APLA syndrome is much lower than that found in Canada2 or Texas.3 In my own patient population, APLA syndrome is far more common in thrombophilic patients than even factor V Leiden mutation, probably because of a lower northern European influence in the south Florida area. As such, the incidence stated is an estimate derived from the available evidence.
Thomas RH. Hypercoagulable Disorders—Reply. Arch Intern Med. 2002;162(15):1785-1787. doi: