SUMMARY: Background The aim of this cross-sectional study was to assess risk factors for
bleeding in
immune thrombocytopenia (
ITP) adults, including the determination of platelet count thresholds. Methods We selected all newly diagnosed
ITP adults included in the Cytopénies Auto-immunes Registre Midi-PyrénéEN (CARMEN) register and at the French referral center for autoimmune
cytopenias. The frequencies of any
bleeding, mucosal
bleeding and severe
bleeding (gastrointestinal, intracranial, or macroscopic
hematuria) at
ITP onset were assessed. Platelet count thresholds were assessed by the use of receiver operating characteristic curves. All potential risk factors were included in logistic regression models. Results Among the 302 patients, the frequencies of any, mucosal and severe
bleeding were 57.9%, 30.1%, and 6.6%, respectively. The best discriminant threshold of platelet count for any
bleeding was 20 × 109 L-1 . In multivariate analysis, factors associated with any
bleeding were platelet count (< 10 × 109 L-1 versus ≥ 20 × 109 L-1 , odds ratio [OR] 48.2, 95% confidence interval [CI] 20.0-116.3; between 10 × 109 L-1 and 19 × 109 L-1 versus ≥ 20 × 109 L-1 , OR 5.2, 95% CI 2.3-11.6), female sex (OR 2.6, 95% CI 1.3-5.0), and exposure to non-steroidal anti-inflammatory drugs (
NSAIDs) (OR 4.8, 95% CI 1.1-20.7). A low platelet count was also the main risk factor for mucosal
bleeding. Exposure to
anticoagulant drugs was associated with severe
bleeding (OR 4.3, 95% CI 1.3-14.1). Conclusions Platelet counts of < 20 × 109 L-1 and < 10 × 109 L-1 were thresholds for major increased risks of any and mucosal
bleeding. Platelet count, female sex and exposure to
NSAIDs should be considered for assessment of the risk of any
bleeding. Exposure to
anticoagulant drugs was a major risk factor for severe
bleeding.