Critical appraisal of

1. The importance of early treatment with tranexamic acid in bleeding trauma patients: an exploratory analysis of the CRASH-2 randomised controlled trial CRASH-2 trial collaborators Lancet 2011; 377: 1096–101

2. Background CRASH-2 trial collaborators Lancet 2010; 376: 23–32 Effects of tranexamic acid on death, vascular occlusive events, and blood transfusion in trauma patients with significant haemorrhage (CRASH-2): a randomised, placebo-controlled trial

5. Were all patients who entered the trial accounted for?

10. Aside from the allocated treatment, were groups treated equally?

13. Absolute Risk Reduction (ARR)

14. Absolute Risk Reduction (ARR) ARR AC = 0.16 – 0.145 = 0.015 or 1.5% ARR B = 0.057 – 0.049 = 0.008 or 0.8%

15. Relative Risk Reduction (RRR)

16. Relative Risk Reduction (RRR) RRR AC = 1 – 0.91 = 0.09 or 9% RRR B = 1 – 0.85 = 0.15 or 15%

17. Number Needed to Treat (NNT)

18. Number Needed to Treat (NNT) NNT AC = 1 / (0.16 – 0.145) = 67(40- 198 ) NNT B = 1 / (0.057 – 0.049) = 125(69- 450)

21. Initial analysis

22. Initial analysis Post hoc change from <1

24. Results

25. Patient characteristics by time to treatment

26. Patient characteristics by time to treatment

27. Patient characteristics by time to treatment

28. Patient characteristics by time to treatment

30. Death due to bleeding by subgroup

31. Death due to all cause by subgroup