p value RR (95% CI) Age ns   Sex ns   Preoperative Hb (Hb<13.15 gr/dl) 0.0002 2.763 (1.67-4.57) Antiagregants (yes vs no) 0.034 2.137 (1.125-4.066) Anticoagulants (yes vs no) ns   TXA (yes vs no) 0.0024 0.5608 (0.3539-0.8886)

Table 2: Univariate analysis of risk factor for allogeneic blood transfusion in total knee replacement surgery.