Lisette van Dam

Chapter 4 64 RESULTS Study population The Wells rule was calculated in all 305 Theia study patients, of whom 163 (53%) had an unlikely CDR. In 10 patients who had an unlikely CDR according the original Wells rule, D-dimer results were unavailable for unknown reasons. These 10 patients were excluded in this analysis, leaving 295 patients of whom 64 patients (22%) were on anticoagulant treatment ≥ 48 hours at study inclusion. The baseline characteristics of the included patients in this analysis are shown in Table 2 . The recurrent DVT prevalence was 45% (103/231; 95%CI 36-54%) in patients without anticoagulant treatment and 22% (14/64; 95%CI 12-37%) in patients with anticoagulant treatment. Table 2. Baseline characteristics of 295 patients with suspected recurrent ipsilateral DVT of the leg and with results of clinical probability assessment and D-dimer testing available Patients without anticoagulant treatment at baseline (n = 231) Patients treated with anticoagulant treatment at baseline (n = 64) Mean age (+/- SD) – years 56 (16) 56 (17) Male – no (%) 109 (53) 38 (59) Median duration of complaints (IQR) – days 4 (2-7) 4 (2-7) More than 1 prior VTE episode – no (%) 50 (22) 44 (69) Mean time since the last DVT episode (+/- SD) – years 6.9 (9.2) 4.6 (7.5) Active malignancy – no (%) 10 (4.3) 8 (13) Immobility for > 3 days or recent long travel > 6 hours in the past 4 weeks – no (%) 15 (6.5) 6 (9.4) Trauma/surgery during the past 4 weeks – no (%) 9 (3.9) 2 (3.1) Hormone (replacement) therapy – no (%) 5 (2.2) 1 (1.6) Known genetic thrombophilia – no (%) 18 (7.8) 21 (33) DVT, deep vein thrombosis; IQR, interquartile range; no, number of patients; SD, standard deviation; VTE venous thromboembolism.