Table 4.

Summary Information About Some of the Large VTE Registries and their Key Features

	Setting	Enrollment Timeline	Study Population (DVT, PE, VTE)	Sample Size	Follow-up Period	Main Objectives
MASTER(36)	25 centers from Italy	January 2002 to October 2004	Adults with objectively-confirmed VTE	2,111	All patients were followed up to 24 months. Patient management was at the discretion of the attending physicians.	To describe the demographics, risk factors, clinical features, and outcomes of patients with VTE during short-term and long-term follow-up.
EMPEROR(37)	Emergency departments from 22 academic and community hospitals in the United States	January 2005 to December 2008	Adults with objectively-confirmed PE	1,880	Main follow-up was up to 30 days.	To define the presenting symptoms, signs, risk factor profile, treatments (including use of anticoagulants), and short-term outcomes of patients with PE presenting to emergency departments.
IPER(38)	47 hospitals from Italy	September 2006 to 2010	Adults with objectively-confirmed PE	1,716	NA, follow-up ended in August 2014	Similar to MASTER (see above).
SWIVTER(39)	18 hospitals in Switzerland	January 2009 to May 2010	Adults with objectively-confirmed VTE	1,247	No systematic follow-up beyond hospital discharge	A study to determine characteristics of patients with VTE, and key subgroups, including the elderly, and those with cancer.
VTEval(40)	Started as a single center study in Germany with plan to involve more centers	April 2013 –ongoing	Adults with objectively-confirmed VTE	2,000 planned, unclear details.	Active follow-up is planned for 36 months.	To determine the symptoms, risk factors, as well as psychosocial, environmental and lifestyle factors associated with VTE. The study is also collecting blood samples for future “omics” studies, on genome, transcriptome, proteome, metabolome and phenome.
PREFER in VTE(41)	381 centers from 7 European countries	January 2013 –July 2014	Adults with objectively-confirmed VTE	3,545	Up to 12 months (by phone calls)	To determine the clinical characteristics, management, and outcomes, but also healthcare resource utilization and costs of care for 12 months of treatment.
GARFIELD-VTE(42)	500 sites from 28 countries	July 2014 –ongoing	Adults with objectively-confirmed acute VTE.	10,000 planned, recruitment recently completed.	Minimum follow-up for 36 months.	To describe the global treatment patterns and outcomes for VTE. Utilization and outcomes of patients receiving non-vitamin K antagonist oral anticoagulants, descriptions about regional variations in care, and description of long-term outcomes such as post-thrombotic syndrome and chronic thromboembolic pulmonary hypertension could be named.
RIETE	179 centers from 24 countries	2001 –ongoing	Adults with objectively-confirmed VTE. In recent years, also enrolling patients with thrombosis at unusual sites.	72,107 patients as of June 2017. Still recruiting.	Minimum follow-up for 3 months, but many have longer follow-up (see Figure1B).	Detailed in the current manuscript. In brief, to describe the epidemiology, treatment patterns and outcomes of a large group of patients with VTE, including many of the understudied subgroups. Also to provide a platform for several additional investigations, including pragmatic trials.

Only dedicated VTE registries with >1,000 patients discussed. The list is not meant to be exhaustive and did not include several of the registries from the prior years. EMPEROR: Emergency Medicine Pulmonary Embolism in the Real World Registry; GARFIELD: Global Anticoagulant Registry in the FIELD; IPER: Italian Pulmonary Embolism Registry; NA: not available. MASTER: Multicenter Advanced Study for a ThromboEmbolism Registry; PE: pulmonary embolism; SWIVTER: SWIss Venous ThromboEmbolism Registry ; VTE: venous thromboembolism.