Introduction Venous thromboembolism (VTE) is a major health problem, especially in the elderly. A variety of intrinsic factors, acute medical illnesses and surgery have been shown to increase VTE risk. Despite this, VTE has not been adequately described in terms of clinical history, clinical risk factors and VTE prophylaxis. The objective of the Prospective Registry On Venous thromboembolic Events (PROVE) is to characterize the profile of patients with ultrasound-confirmed deep-vein thrombosis (DVT), the prior use and type of VTE prophylaxis and its relationship to demographic and comorbid factors.
Methods PROVE is a multinational, multi-center, observational study. Patients were recruited during a 3 month period, beginning in February 2003, in centers possessing an ultrasound laboratory. Patients with ultrasound-confirmed DVT were consecutively enrolled. There were no exclusion criteria once DVT was diagnosed.
Results Of 3527 enrolled patients in 254 centers in 19 countries (48% Asian and 52% non-Asian), data from 3508 (99%) were analyzable. Patients were: 51% male, mean age 53±18 years, mean BMI 26.0±5.1 kg/m2, 46.7% Caucasian, 47.1% Asian, 1.6% African and 4.4% other ethnicity. Patient status when DVT was diagnosed was: 59.7% home, 35.7% acute care hospital, 3.3% chronic care facility, 1.3% other. Locations of DVT were 25.0% calf only, 20.8% proximal without calf, and 58.9% proximal and calf. The incidences of idiopathic DVT, DVT following a precipitating factor, and recurrent DVT according to patient status at the time of diagnosis are shown in Table 1. Of patients who had a precipitating factor for DVT (see Table 2), 16% had received prior VTE prophylaxis. Types of VTE prophylaxis were: 53% low-molecular-weight heparin, 10% unfractionated heparin, 17% vitamin K antagonist, 29% elastic stockings, 2% venal caval filter, and 17% other.
Conclusion Overall, the incidence of idiopathic DVT was similar to the incidence of DVT occurring after a precipitating event, as observed in other published studies. However, the incidence of idiopathic DVT was higher in patients at home at the time of diagnosis, while the incidence of DVT in patients with a precipitating factor was higher in acute care hospitals and chronic care facilities. The occurrence of DVT in patients who had received VTE prophylaxis may be due, at least in part, to the use of inadequate prophylaxis regimens.
Table 1 Type of DVT according to patient status when DVT was diagnosed
Patient status Idiopathic DVT,* n (%) DVT after a precipitating event,* n (%) Recurrent DVT,* n (%) * DVT was recorded as more than one type in some patients Home (N=2091) 1092 (52) 818 (39) 221 (11) Acute care hospital (N=1250) 396 (32) 807 (65) 74 (6) Chronic care facility (N=115) 35 (30) 64 (56) 16 (14) Other (N=45) 19 (42) 24 (53) 3 (7) Total 1542 (44) 1713 (49) 314 (9)
Table 2 VTE prophylaxis received by patients with a precipitating factor for DVT (N=1715)
Precipitating factor for DVT Patients with precipitating factor, n (%) Patients who had received VTE prophylaxis, n (%) Acute medical condition 775 (45) 92 (12) Surgery 498 (29) 124 (25) Trauma without surgery 239 (14) 44 (18) Pregnancy/postpartum 158 (5) 10 (6) Long airplane travel 56 (2) 3 (5)