Refining prediction of major bleeding on antiplatelet treatment after transient ischaemic attack or ischaemic stroke

Introduction Bleeding is the main safety concern of treatment with antiplatelet drugs. We aimed to refine prediction of major bleeding on antiplatelet treatment after a transient ischaemic attack (TIA) or stroke by assessing the added value of new predictors to the existing S2TOP-BLEED score. Patients and methods We used Cox regression analysis to study the association between candidate predictors and major bleeding among 2072 patients with a transient ischaemic attack or ischaemic stroke included in a population-based study (Oxford Vascular Study - OXVASC). An updated model was proposed and validated in 1094 patients with a myocardial infarction included in OXVASC. Models were compared with c-statistics, calibration plots, and net reclassification improvement. Results Independent predictors for major bleeding on top of S2TOP-BLEED variables were peptic ulcer (hazard ratio (HR): 1.72; 1.04-2.86), cancer (HR: 2.40; 1.57-3.68), anaemia (HR: 1.55; 0.99-2.44) and renal failure (HR: 2.20; 1.57-4.28). Addition of those variables improved discrimination from 0.69 (0.64-0.73) to 0.73 (0.69-0.78) in the TIA/stroke cohort (p = 0.01). Performance improved particularly for upper gastro-intestinal bleeds (0.70; 0.64-0.75 to 0.77; 0.72-0.82). Net reclassification improved over the entire range of the score (net reclassification improvement: 0.56; 0.36-0.76). In the validation cohort, discriminatory performance improved from 0.68 (0.62-0.74) to 0.70 (0.64-0.76). Discussion and Conclusion Peptic ulcer, cancer, anaemia and renal failure improve predictive performance of the S2TOP-BLEED score for major bleeding after stroke. Future external validation studies will be required to confirm the value of the STOP-BLEED+ score in transient ischaemic attack/stroke patients.