Venous thromboembolism in emergency department patients with rigid immobilization for lower leg injury: Incidence and risk factors

Objectives: To determine the incidence and risk factors for symptomatic venous thromboembolism (VTE) in adults who are discharged from the ED with rigid immobilization for lower limb injury.

Methods: Eligible patients presenting between 1 December 2008 and 31 December 2010 were identified retrospectively from the Southern Health ED (Monash Medical Centre, Dandenong Hospital, Casey Hospital, all located in Melbourne, Australia) information system. Age, sex, diagnosis, type of splint and other defined potential VTE risk factors were recorded. VTE was confirmed from archived diagnostic imaging or hospital re-attendance records. Patients presenting between 1 October 2010 and 31 December 2010 were contacted to detect VTE diagnosed and treated outside of Southern Health. VTE incidence is reported, and comparison of risk factors performed.

Results: VTE was initially confirmed in 33 of 1231 patients (2.7%, 95% confidence interval 1.9-3.7). VTE was reported by 3 of 174 in the contacted subgroup (1.7%, 0.4-4.6). Applying this 'missed rate' to the whole sample, the estimated VTE incidence is between 3.1% and 7.1%. Multivariate risk factor analysis found VTE risk to increase with age and a diagnosis of Achilles tendon rupture.

Conclusion: The estimated VTE incidence was between 3% and 7% in this ED population with age and diagnosis of Achilles tendon rupture increasing risk. Prospective research to more accurately determine incidence, severity and risk stratification is required before firm recommendations on the likely risk versus benefit profile of thromboprophylaxis can be made for this population.