Patient-related factors influence venous thromboembolism risk

Pedersen AB. J Bone Joint Surg. 2010;92:2156-2164. doi:10.2106/JBJS.I.00882.

Danish investigators have identified patient-related risk factors for venous thromboembolism in those undergoing total hip replacement and pharmacological thromboprophylaxis.

“This information on the associated risk factors could be used to better anticipate the risk of venous thromboembolism for an individual patient,” wrote Alma B. Pedersen, MD, PhD, and colleagues at Aarhus University Hospital and Odense University Hospital, Denmark.

The investigators used medical databases to identify all Danish patients who underwent primary total hip replacement and received pharmacological thromboprophylaxis from 1995 to 2006. The investigators chose hospitalization with venous thromboembolism within 90 days of surgery as their outcome measure. Potential risk factors were: age, sex, indication for primary THR, calendar year of surgery and comorbidity history.

Overall, the hospitalization rate within 90 days of primary THR was 1.02% (686 hospitalizations after 67,469 surgeries); median was 22 days. The incidence of symptomatic deep venous thrombosis was 0.7%. The rate of nonfatal pulmonary embolism was 0.3%. The prevalence of death caused by venous thromboembolism was 0.05% (38 patients); the incidence of the death from all causes was 1.0% (678 patients).

The relative risk for venous thromboembolism was reduced in patients with rheumatoid arthritis compared with patients with osteoarthritis (adjusted relative risk=0.47%). Patients with a high Charlson comorbidity index score had an increased relative risk of venous thromboembolism vs. patients with a low score (adjusted relative risk=1.45). Patients with a history of cardiovascular disease or prior venous thromboembolism had an increased risk for venous thromboembolism.