Response to: ‘Venous thromboembolic events in systemic vasculitis’ by Novikov et al
=======================================================================================

* J Antonio Aviña-Zubieta
* V M Bhole
* N Amiri
* E C Sayre
* H K Choi

*   Systemic vasculitis
*   Treatment
*   Rehabilitation

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.

## Footnotes

*   Competing interests None.

*   Provenance and peer review Commissioned; internally peer reviewed.

## References

1.  Novikov P, Makarov E, Moiseev S, et al. Venous thromboembolic events in systemic vasculitis. Ann Rheum Dis 2015;74:e27.
    
    

2.  Aviña-Zubieta JA, Bhole VM, Amiri N, et al. The risk of deep venous thrombosis and pulmonary embolism in giant cell arteritis: a general population-based study. Ann Rheum Dis 2014. Published Online First: 29 Sep 2014. doi:[10.1136/annrheumdis-2014-205665](http://dx.doi.org/10.1136/annrheumdis-2014-205665)
    
    

3.  Carruthers EC, Choi HK, Sayre EC, et al. Risk of deep venous thrombosis and pulmonary embolism in individuals with polymyositis and dermatomyositis: a general population-based study. Ann Rheum Dis 2014.
    
    

4.  Choi H, Rho Y, Zhu Y, et al. The risk of pulmonary embolism and deep vein thrombosis in rheumatoid arthritis: a UK population-based outpatient cohort study. Ann Rheum Dis 2013;72:1182–7.
    
    [Abstract/FREE Full Text](http://ard.bmj.com/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6MTE6ImFubnJoZXVtZGlzIjtzOjU6InJlc2lkIjtzOjk6IjcyLzcvMTE4MiI7czo0OiJhdG9tIjtzOjI2OiIvYW5ucmhldW1kaXMvNzQvMy9lMjguYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

5.  Lee J, Pope J. A meta-analysis of the risk of venous thromboembolism in inflammatory rheumatic diseases. Arthritis Research & Therapy 2014;16:435.
    
    [CrossRef](http://ard.bmj.com/lookup/external-ref?access_num=10.1186/s13075-014-0435-y&link_type=DOI) 
    
    [PubMed](http://ard.bmj.com/lookup/external-ref?access_num=25253302&link_type=MED&atom=%2Fannrheumdis%2F74%2F3%2Fe28.atom) 

6.  Zoller B, Li X, Sundquist J, et al. Risk of pulmonary embolism in patients with autoimmune disorders: a nationwide follow-up study from Sweden. Lancet 2012;379:244–9.
    
    [CrossRef](http://ard.bmj.com/lookup/external-ref?access_num=10.1016/S0140-6736(11)61306-8&link_type=DOI) 
    
    [PubMed](http://ard.bmj.com/lookup/external-ref?access_num=22119579&link_type=MED&atom=%2Fannrheumdis%2F74%2F3%2Fe28.atom) 
    
    [Web of Science](http://ard.bmj.com/lookup/external-ref?access_num=000299316100039&link_type=ISI) 

7.  Canadian Rheumatology Association Meeting Whistler, British Columbia, Canada 24 February to 1 March 2014. *J Rheumatol* 2014;41:1546 (Abstract).