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We would like to thank Dr Moiseev1 for his interest in our recent paper on the risk of venous thromboembolism (VTE) in patients with giant cell arteritis (GCA).2 We agree that all systemic autoimmune rheumatic diseases (SARDs) are associated with an increased risk of VTE, as we and others have reported.3–6 Additionally, we have confirmed the increased risk of VTE in patients with GCA in another sample, and those results will be published soon.
We also agree with Dr Moiseev that the risk of VTE varies among SARDs. We have reported that patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis have a higher risk of VTE than those with GCA.7 It is likely that the interaction between the procoagulant state and each SARD may be different depending on the intrinsic pathogenesis of each disease.
It seems that Dr Moiseev is surprised that he did not see an increased risk of VTE in his small cohort of GCA cases; without knowing the characteristics of his cohort, we are unable to comment further on his findings. Dr Moiseev also inquired about cost-effective strategies to prevent VTE and raised concern about which patients should use preventive anticoagulation. In our paper, we proposed that preventative anticoagulation may be indicated only for those at high risk. Dr Moiseev asked who those patients that are at high risk are. This is a research question with no answer yet. We believe such investigation should be conducted urgently as it could result in the prevention of VTE.
In our study, we observed only one fatal event in the GCA cohort and nine in the non-GCA cohort. However, the low fatality rate observed does not contradict the use of preventative anticoagulation, given that VTE is associated with significant morbidity. Once we know who is at high risk, a randomised clinical trial should be implemented to test the hypothesis that preventable anticoagulation is cost effective. Until then, we agree that further research needs to be done to confirm our results, and to develop and test screening strategies to identify patients who may benefit from preventative anticoagulation.
Competing interests None.
Provenance and peer review Commissioned; internally peer reviewed.