Recurrence rates were again low (4.4% for recurrent CVT and 6.5% with a recurrent venous thromboembolism [VTE] in a different site), which led to an overall incidence of recurrence of 23.6 events per 1000 patient-years (95% CI, 17.8 28.7). Most events occurred after anticoagulation discontinuation. Somewhat surprisingly, the recurrence rate was similar in patients with unprovoked CVT and in patients with CVT secondary to known risk fac- years [95% CI, 15.9 32.6] ver- previous VTE was the only significant predictor of recurrence with multivariate analysis (hazard ratio [HR], 2.70; 95% CI, Many of the recurrent VTEs occurred in women when the first CVT occurred during pregnancy/ puerperium or was secondary to OC or HT use; however, nei- ther female sex (HR, 1.37; 95% CI, 0.83 2.25), pregnancy/ puerperium (HR, 1.05; 95% CI, 0.48 2.28), or use of OC/HT (HR, 0.72; 95% CI, 0.45 1.14) was an independent risk factor for VTE recurrence.199 This was in contrast to the results from a study by Martinelli et al,197 which found that male sex was a risk factor for recurrence (HR, 9.66; 95% CI, 2.86 32.7). The higher risk in men could potentially be attributable to more correctable or transient risk factors in women (use of OCs, pregnancy, etc) or may simply reflect the fact that this study enrolled fewer patients (n=145) and may have been under- powered for sex-specific analysis.197 Recurrence tends to occur within the first year of the index CVT. 