Increased incidence of VTE in sickle cell disease patients: risk factors, recurrence and impact on mortality.

Previous reports show increased incidence of venous thromboembolism [VTE, deep-vein thrombosis (DVT) and pulmonary embolus (PE)] in sickle cell disease (SCD) patients but did not account for frequency of hospitalization. We determined the incidence of VTE in a SCD cohort versus matched controls. For SCD patients, risk factors for incident VTE, recurrence and the impact on mortality were also determined. Among 6237 patients with SCD, 696 patients (11·2%) developed incident-VTE: 358 (51·6%) had PE (±DVT); 179 (25·7%) had lower-extremity DVT only and 158 (22·7%) had upper-extremity DVT. By 40 years of age, the cumulative incidence of VTE was 17·1% for severe SCD patients (hospitalized ≥3 times a year) versus 8·0% for the matched asthma controls. Amongst SCD patients, women (Hazard ratio [HR] = 1·22; 95% confidence interval [CI]: 1·05-1·43) and those with severe disease (HR = 2·86; 95% CI: 2·42-3·37) had an increased risk of VTE. Five-year recurrence was 36·8% in patients with severe SCD. VTE was associated with increased risk of death (HR = 2·88, 95% CI: 2·35-3·52). In this population-based study, the incidence of VTE was higher in SCD patients than matched controls and was associated with increased mortality. The high incidence of recurrent VTE in patients with severe SCD suggests that extended anticoagulation may be indicated.