Thanks for bumping this thread, Reazon.
Shander's study that is discussed in this thread has been on my mind lately because I wanted to expand on the flaws that have been pointed out already.
Where this study's flaws become apparent is in the selection of groups. Shander et al was comparing a group of non-transfused surgical patients (all JWs) to a group of patients who received transfusions and made the conclusion that
Overall risk of mortality in severely anemic critically
ill bloodless patients appeared to be comparable with transfused
patients, albeit the latter group had older age and higher Acute
Physiology and Chronic Health Evaluation II score.
What Shander is referring to in his conclusion is that the "bloodless" group - the JWs - were generally in better health and younger than the group that was transfused. The reason for this is simple - bloodless methods cannot be done on severely ill patients or those who are too elderly.
Shander has pointed out that difference in groups but he fails to take into account a couple of other factors that would have skewed the results in favor of the non-transfused group.
This is how the groups were selected:
The main eligibility criterion was severe anemia at ICU
admission defined as at least one hemoglobin level less
than or equal to 8 g/dL from a blood sample taken within
24 hours of ICU admission. Exclusion criteria were age less
than 18 years old; death within 24 hours of admission; treatment
with artificial hemoglobin-based oxygen carriers;
admission with diagnosis of traumatic brain injury or acute
myocardial infarction; and status postcardiac surgery and
pregnancy. For patients with multiple hospital admissions,
only the first admission leading to ICU admission was considered.
Patients were grouped into two cohorts: bloodless
patients who did not receive any allogeneic blood transfusions;
and transfused patients, who received allogeneic RBC
transfusions during ICU stay.
So, Shander excluded those patients who died during the first 24 hours, and we know that the bloodless group would have more deaths than the transfused group - that 24 hour window is when emergency transfusions would be required and that is something that none of the bloodless group would have received.
Shander's solution to that data problem is to just exclude it. Don't include it in the study at all.
And he also left out another high risk group within the bloodless group. And that is the bloodless patients who required a second surgery. Note that only the first admission was considered and this criteria would pertain primarily to the "bloodless" group. One of the ways that "bloodless" surgery deals with a non-transfused person who requires a complicated or lengthy surgical procedure is to do it in two steps rather than one. This is either scheduled in advance for surgeries that anticipate a large blood loss or, sometimes a surgery is cut short when unexpected complications arise. In a conventional surgery, the patient would be given blood and the surgery completed. But, in a non-transfused JW patient, the patient is closed, taken to recovery, and the surgery completed later once the patient is stable enough.
So what ends up happening through this selection process, is that the JWs most likely to die from bloodless surgery have been excluded from the study's data. And the ones who don't make it as far as the operating theater are excluded.
This is a common feature of many of the studies that the bloodless industry has promoted. When you hear this: "Jehovah's Witnesses do better than those who use blood", be very suspicious. Shander has just illustrated quite simply how the data can be manipulated before the study even starts. Just leave out the high risk ends of the time line. The ones who have the most risk of dying.