Hematocrit and the Risk of Recurrent Venous Thrombosis: A Prospective Cohort Study

BACKGROUND: Venous thromboembolism (VTE) is a multicausal disease which recurs. Hematocrit is associated with a thrombotic risk. We aimed to investigate if hematocrit is associated with the recurrence risk. METHODS: Patients with a first VTE were followed after anticoagulation. Patients with VTE provoked by a transient risk factor, natural inhibitor deficiency, lupus anticoagulant, homozygous or double heterozygous defects, cancer, or long-term antithrombotic treatment were excluded. The study endpoint was recurrent VTE. RESULTS: 150 (23%) of 653 patients had recurrence. Only high hematocrit was significantly associated with recurrence risk [hazard ratio (HR) for 1% hematocrit increase with the third tertile 1.08; 95% CI 1.01-1.15]. No or only a weak association for hematocrits within the first and second tertile was seen (HR 1.03; 95% CI 0.97-1.09, and 1.07; 95% CI 1.00-1.13). Hematocrit was associated with recurrence risk only among women. After five years, the probability of recurrence was 9.9% (95% CI 3.7%-15.7%), 15.6% (95% CI 9.7%-21.2%) and 25.5% (95% CI 15.1%-34.6%) in women, and was 29.2% (95% CI 21.1%-36.5%), 30.1% (95% CI 24.1%-35.7%) and 30.8% (95% CI 22.0%-38.7%) in men for hematocrits in the first, second and third tertile, respectively. Men had a higher recurrence risk (1.9; 95% CI 1.1-2.7; p = 0.03), which dropped by 23.5% after adjustment for hematocrit. Hematocrit was not a significant mediator of the sex-difference in recurrence risk (p = 0.223). CONCLUSIONS: High hematocrit is associated with the recurrence only in women. The different recurrence risk between men and women is possibly partly explained by hematocrit

Long-term follow-up of patients with portal vein thrombosis and myeloproliferative neoplasms

Background: Myeloproliferative neoplasms (MPNs) are frequently identified as an underlying cause in patients with non-cirrhotic portal vein thrombosis (PVT). The aim of this study was to describe the long-term outcome of patients with PVT and MPN. Methods: A cohort study was performed including all adult patients referred to our hospital between 1980 and 2008 with non-cirrhotic, non-malignant PVT and confirmed MPN. Results: A total of 44 patients (70% female) were included, with a median age at PVT-diagnosis of 48 years (range 18-79). In 31 patients (70%) PVT was the first manifestation of an MPN. Additional risk factors for thrombosis were present in 20 patients (45%). Median follow-up was 5.8 years (range 0.4-21). Twenty-three patients (52%) were treated with oral anticoagulants after diagnosis of PVT, of whom 15 (34%) received long-term therapy. During follow-up, 17 patients (39%) experienced at least one episode of gastrointestinal bleeding. Additional thrombotic events occurred in 12 patients (27%). Twelve patients (27%) had progression of the underlying MPN. Seventeen patients (39%) died at a median age of 64 years (range 30-88). Death was directly related to end-stage MPN in eight patients (47%) and to a new thrombotic event in three patients (18%). No patients died from gastrointestinal bleeding. Conclusions: PVT is often the presenting symptom of an underlying MPN, highlighting the need for thorough screening for this disease. Recurrent thrombosis is a common and severe complication in patients with PVT and MPN. Mortality is primarily related to the underlying MPN and not to complications of portal hypertension