Ascertainment of VTE, AF, ischemic stroke and ECATE
The validation of AF has been assessed and presented in our previous reports, with a high positive predictive value (PPV) of 89%.20 The accuracy of VTE was reliable in the Taiwan insurance claim system and some published studies also used the same diagnosis method.10,21 Ischemic stroke was also validated with high PPVs.22In terms of ECATE, a validation study was conducted at our medical center, randomly sampling 100 hospitalizations for systemic thromboembolism who were selected using the same criteria as mentioned in this study. After experienced physicians (YSL and VCCW) reviewed the medical records and all imaging results, including vascular duplex, computed tomography angiography and intervention reports, the PPV of systemic thromboembolism was 88% (data not shown).