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“One question is, how were these patients selected.”
LisaRose,
A set of inclusion criteria was constructed and all patients who refused blood transfusion were identified for inclusion in the study. The JWs who met the criteria but were in palliative care were excluded. For years 1998-2007 there were 10,786 hospital admissions of 3,529 JW patients admitted to 4 hospitals. After reviewing these records it was found that 103 patients met the criterion.
The same criterion was applied to all patients who accepted blood transfusion over the same period admitted to the same 4 hospitals. Patients in this group were selected based on a random drawing at a 1-to-1 ratio with the model group (above) from the same diagnose related sub-category as the model group. This resulted in a randomly selected group that was very well matched across a spectrum of variances to narrow the distinction down to one thing: accept blood or refuse blood.
“Was it all severe anemia cases in those four hospitals, or were there cases of severe anemia in those hospitals that were not selected for some reason?”
All cases of severe anemia were evaluated for inclusion. The only instances of exclusion were patients whose presentation met inclusion criterion but were in palliative care.
“Were patients from other areas moved to these hospitals because of the study, or for some other reason?”
We must assume patients are transferred to hospitals better equipped for critical conditions. For this reason my review ignored any possibility of mortality at a hospital without trauma service because all of the hospitals in this study had facilities and staff to offer trauma services. Because my values are achieved against a hard number of mortalities then, if anything, this method has the effect of understating the actual mortality of JWs in New Zealand with severe anemia refusing blood.
“What has changed due to the increased use of blood substitutes and fractions since the study ended?”
The change you mention occurred in year 2000. Most of the years included in the Beliaev study fall after the change. Hence retrospectively any values achieved would be conservative by comparison.
“What is the death rate in New Zealand for severe anemia overall? That would be a great sanity check to see if we are in the ballpark.”
Based values expressed in the Beliaev study, and after prorating based on assigning mortality values to 57% of the population of the 2 regions his data came from, I get an annual mortality of 0.0000086% of the population. This does no adjust upward for the increased rate of mortality among JWs in New Zealand but because JWs are such a small minority an adjusted value would not add much.
“Why do four hospitals out of eighty treat 57% of the population?”
The 57% figure does not represent 4 out of 80 hospitals.
The 57% figure represents the population of New Zealand serviced by the 4 hospitals whose patient data was included in Beliaev’s study.
Marvin Shilmer