Blood Transfusions bad?

Stephen Cauchi comments on blood transfusions in his article "Are transfusions the holy grail? Don't take it as read" in The Age newspaper (Australia):

"Professor Spiess cited a Swedish study involving Jehovah's Witnesses, whose religion forbids them to accept transfusions. It showed that 499 Witnesses who
had open-heart surgery had better survival rates than other open-heart patients."