Venous thrombotic events in patients admitted to a tuberculosis centre

Background: Considering the relationship between inflammation and thrombosis, patients with tuberculosis (TB) patients might be at high risk of venous thrombosis. Aim: To evaluate the risk of venous thromboembolism in patients admitted to the Beatrixoord Tuberculosis Centre (BTBC), a tertiary centre for TB. We specifically explored which cofactors elevate the risk of venous thrombosis (VTE), and whether the timing of venous thrombotic events would justify extended primary prophylaxis. Design: retrospective cohort study. Methods: We performed a retrospective chart review of all patients with TB discharged from BTBC between 2000 and 2010. We excluded patients who were already on therapeutic anticoagulation before their TB episode, below the age of 18 years and patients in which TB diagnosis was withdrawn. For evaluating the timing of venous thrombosis, we calculated the time between commencement of anti TB therapy and the VTE. Results: Of 750 included in the final analysis, 18 (2.4%) suffered a venous thrombotic event. 3 of these events were not related to classic risk factors or hospitalization. Most (13/18) VTE's occurred in the time window of two weeks before starting TB medication. In the multivariate analysis, only Human Immunodeficiency Virus (HIV) infection was strongly associated with risk of VTE (adjusted Odds ratio 8.2 (95% confidence interval: 2.9-22.7)). Conclusions: This high risk in HIV co-infected TB patients suggests that standard thrombo-prophylaxis should be routinely considered in this group. However, our findings might not be generalizable due to referral bias. Further prospective studies in unselected HIV co-infected TB patients are needed to corroborate our findings.