Venous thrombosis in an ALS population over four years.

We conducted a retrospective chart review of all ALS patients seen at our institution over four years to determine the incidence of venous thromboembolism and to identify risk factors in this population. Events occurred in 13 of 438 patients (2.97%), yielding an annual incidence rate of 33.1 events per 1,000 patients (95% CI 17.5-55.3). ALS patients have a risk of venous thromboembolism that is higher than the general population but lower than the population of patients with acute stroke or spinal cord injury. Immobility was significantly associated with increased risk of venous thrombosis (RR = 4.96; 95% CI 1.39-17.78).