EPO and acute kidney injury: Two of the non-comparative studies found varying ratesof AKI among Witnesses, with one study reporting it in 2.5% of patients,4 whereas Duce et al.,8 which compared outcomes for Witnesses given EPO pre operatively tothose not given EPO, found AKI rates to be 47.17% and 41.51%, respectively.The wide difference in rates reported may be accounted for by the varyingdefinition of AKI used and the vast array in type of surgeries carried outin different studies, which makes it problematic to form any definitiveconclusion concerning the risk of AKI in Witnesses following cardiacsurgery.