Association between Neuroleptics and Venous Thromboembolism: A Case-Control Study.

Background:

Preliminary reports suggest that use of antipsychotic drugs is associated with an increased risk of venous thromboembolism (VTE), but others did not confirm these results.

Objective:

To evaluate the relationship between antipsychotic drugs and VTE.

Design:

Case-control study (EDITH) designed to investigate genetic and environmental risk factors of VTE.

Setting:

Brest University Hospital.

Participants:

857 patients consecutively hospitalized for a documented venous thromboembolic event were included between May 2000 and May 2004. Controls were matched on age, sex and the main risk factors of venous thromboembolism (cancer, surgery, pregnancy…).

Results:

The mean age of patients was 67.7 year. No significant difference was found between cases and controls concerning the main characteristics, except for smocking and body mass index. Among cases, 89 (10.4%) were current users of neuroleptics compared to 35 (4.8%) among controls. Current use of neuroleptics was associated with a significant increased risk of venous thromboembolism (OR = 2.32, 95% CI: 1.55–3.48). Excluding neuroleptics used for non psychiatric disorders, and after adjustment on the main confounding factors, this association remained significant (OR = 3.48, 95% CI: 2.00–6.04). No difference was found between the different chemical categories of neuroleptics, but the number of patients in some groups had limited statistical power to demonstrate significant differences. Biological mechanisms of action have been proposed to explain this relation. Analyses are ongoing for anti-phospholipid antibodies and homocysteine.

Conclusion:

In this case-control study of hospitalized patients, neuroleptics use was associated with a significant increased risk of venous thromboembolism. These results are concordant with previous reports. Nevertheless, further investigations are needed to explain wich mechanisms may be involved in such association and before use of neuroleptics can be definitely considered as risk factor for venous thromboembolism.