Background Patients with Idiopathic Inflammatory Myopathies (IIM) have an increased risk of thrombotic event (TE) compared with the general population (1). The role of traditional thrombotic risk factors, IIM disease activity, presence of antiphospholipid antibodies (aPL) and adhesion molecules, in the pathogenesis of TE is unknown.
Objectives We aimed to investigate the prevalence of TE (pulmonary embolism (PE), deep venous thrombosis (DVT), myocardial infarction (MI), stroke, transitory ischemic attack (TIA) or peripheral arterial thrombosis (PAT)) in IIM patients. We also compared clinical and serological characteristics of IIM patients with and without TE.
Methods 286 IIM patients followed between 1993–2014, with and without TE, were identified. Information on traditional risk factors for TE, autoantibody profiles, disease activity and medical treatment was retrieved from registries and medical records. Serum levels of anti-β2-glycoprotein I (anti-β2-GPI) and anticardiolipin antibodies (aCL) as well as serum levels of adhesion molecules i.e. vascular cell adhesion molecule 1 (VCAM), intercellular adhesion molecule 1 (ICAM) and e-selectin were analysed on stored sera. Sera of patients with TE were screened for levels of adhesion molecules at the time of IIM diagnosis and at the time of TE. Levels of adhesion molecules were also analysed in 40 healthy individuals.
Results Sixty-seven (23.4%) of the 286 IIM patients suffered from at least one TE, 33 presented with arterial thrombosis (MI, Stroke, TIA, PAT), 31 with venous thrombosis (DVT, PE), 3 with both. Among traditional risk factors for TE, higher age at diagnosis (p<0.001), male gender (p<0.05) and hypertension (p<0.05) occurred more frequently in patients with TE than in those without. No other significant differences in terms of prevalence of risk factors, disease activity, medical treatment or autoimmune profile were found. Significantly higher levels of VCAM, ICAM and E-selectin (p<0.001, p<0.001 and p<0.05, respectively) were found in patients with IIM compared to controls. However, there was no significant difference in the levels of any of the investigated adhesion molecules between IIM patients with TE and those without. Moreover, no significant difference in the levels of adhesion molecules at the time of IIM diagnosis and at the time of TE was observed.
Conclusions The main finding of this study is the striking prevalence of thrombotic events in patients with IIM. The fact that 1 out of 5 patients suffered from a TE should alert the clinician to screen for TE when clinically indicated as well as to consider prophylactic treatment in risky situations, including surgery, immobilisation or pregnancy. Male gender, higher age at IIM diagnosis and hypertension should be taken into account when estimating TE risk. High disease activity or aPL positivity were not specific features of IIM patients with TE, nor were elevated serum levels of adhesion molecules. The mechanisms leading to increased risk of TE in patients with IIM need further investigations.
Danko K, Ponyi A, Constantin T, Borgulya G, Szegedi G. Long-term survival of patients with idiopathic inflammatory myopathies according to clinical features: a longitudinal study of 162 cases. Medicine (Baltimore). 2004;83(1):35–42.
Disclosure of Interest None declared