Patients with a high plasma level of factor VIII have an increased risk of recurrent venous thromboembolism.

The risk of recurrent venous thromboembolism is higher among men than women.

Objectives: To establish risk factors of PTS and its impact on venous thrombotic disease. Patients: We prospectively followed 406 patients after a first symptomatic DVT for a median of 60 months. Patients with recurrent DVT, a natural inhibitor deficiency, the lupus anticoagulant, cancer, long-term anticoagulation, an observation time < 18 months and DVTrecurrence prior PTS-assessment were excluded. Study outcomes were occurrence of PTS and recurrent symptomatic DVT. Results: PTS was assessed after 44 ± 23 months (mean ± SD) using a clinical classification score. PTS developed in 176 of 406 patients (43.3%). Severe PTS was rare (1.4%). Proximal DVT was the strongest risk factor of PTS [odds ratio (OR) 2.1, 95% confidence interval (CI) 1. 3-3.7]. Male gender (OR 1.6, 95% CI 1.0-2.8) and elevated D-dimer levels (OR 1.9, 95% CI 1.0-3.9) were weaker risk factors. Factor V Leiden, factor II G20210A or high factor VIII did not confer an increased risk of PTS. At 4 years, the cumulative probability of recurrence was 7.4% (95% CI 3.2-11.7) among patients with PTS when compared with 1.6% (95% CI 0-3.5; P < 0.02) among patients without PTS. The risk of recurrence was 2.6-fold (95% CI 1.2-5.9) increased when PTS was present. Conclusions: Proximal DVT, male gender, and high D-dimer levels are independently associated with the development of PTS in patients with a first DVT. Patients with PTS have an increased risk of recurrent venous thromboembolism.

Context Widespread screening of patients with venous thromboembolism (VTE) for thrombophilic risk factors has become common clinical practice. Because of the increasing number of risk factors, assessing the risk of recurrence in an individual patient is intricate; therefore, a laboratory method that measures multifactorial thrombophilia is required.Objective To prospectively study the relationship between the risk of recurrent VTE and D-dimer, a global marker of coagulation activation and fibrinolysis.Design, Setting, and Participants Prospective cohort study of 610 patients older than 18 years who were treated with oral anticoagulants for at least 3 months with a first spontaneous VTE, in whom D-dimer levels were measured shortly after discontinuation of oral anticoagulation. The study was conducted at Main Outcome Measure Objectively documented symptomatic recurrent VTE.Results A total of 79 (13%) of 610 patients had recurrent VTE with a mean observation time of 38 months. Patients with recurrence had significantly higher D-dimer levels compared with those without recurrence (553 ng/mL vs 427 ng/mL, P=.01). Compared with patients with D-dimer levels of 750 ng/mL or higher, the relative risk (RR) of recurrence was 0.6 (95% confidence interval [CI], 0.3-1.4), 0.6 (95% CI, 0.3-1.2), and 0.3 (95% CI, 0.1-0.6) in patients with D-dimer levels of 500 to 749 ng/mL, 250 to 499 ng/mL, and less than 250 ng/mL, respectively. The cumulative probability of recurrent VTE at 2 years was 3.7% (95% CI, 0.9%-6.5%) among patients with Ddimer levels of less than 250 ng/mL compared with 11.5% (95% CI, 8.0%-15.0%) among patients with higher levels (P=.001). Patients with D-dimer levels of less than 250 ng/mL had a 60% lower RR of recurrence compared with patients with higher levels (RR, 0.4; 95% CI, 0.2-0.8). ConclusionPatients with a first spontaneous VTE and a D-dimer level of less than 250 ng/mL after withdrawal of oral anticoagulation have a low risk of VTE recurrence.

Background: Excess body weight is a risk factor for a first venousthromboembolism.Theimpactofexcessbodyweight on risk of recurrent venous thrombosis is uncertain. Methods: We studied 1107 patients for an average of 46 months after a first unprovoked venous thromboembolism and withdrawal of anticoagulant therapy. Excluded were pregnant patients, those requiring longterm antithrombotic treatment, and those who had a previous or secondary thrombosis, natural coagulation inhibitor deficiency, lupus anticoagulant, or cancer. Our study end point was symptomatic recurrent venous thromboembolism. Results: A total of 168 patients had recurrent venous thromboembolism. Mean (SD) body mass index (BMI) (calculated as weight in kilograms divided by height in meters squared) was significantly higher among patients with recurrence than among those without recurrence: 28.5 (6.0) vs 26.9 (5.0) (P = .01). The relationship between excess body weight and recurrence was linear; the adjusted hazard ratio for each 1-point increase in BMI was 1.044 (95% confidence interval [CI], 1.013-1.076) (P Ͻ .001). Four years after discontinuation of anticoagulant therapy, the probability of recurrence was 9.3% (95% CI, 6.0%-12.7%) among patients of normal weight and 16.7% (95% CI, 11.0%-22.3%) and 17.5% (95% CI, 13.0%-22.0%) among overweight and obese patients, respectively. Compared with patients of normal weight, the hazard ratio of recurrence adjusted for age, sex, factor V Leiden, prothrombin G20210A mutation, high factor VIII levels, and type of initial venous thromboembolic event was 1.3 (95% CI, 0.9-1.9) (P=.20) among overweight patients and 1.6 (95% CI, 1.1-2.4) (P = .02) among obese individuals. The population attributable risk corresponding to excess body weight was 26.8% (95% CI, 5.3%-48.2%). Conclusion: Excess body weight is a risk factor of recurrent venous thromboembolism.