Post-Nephrectomy Transfusion Rate is Underestimated
ATLANTA—The rate of perioperative blood transfusion after nephrectomy appears to be higher in general practice than the rates commonly cited in published urologic reports, researchers reported at the American Urological Association 2012 Annual Scientific Meeting.
The results are drawn from a large population-based, retrospective study of patients who underwent nephrectomy for a renal mass. Overall, 18.2% of patients required a transfusion perioperatively, which is about three times the rate reported thus far in the literature.
Gino Vricella, MD, chief resident in urology at Case Western Reserve University in Cleveland, and colleagues determined the rates of blood transfusion as well as patient, surgeon, and hospital risk factors for transfusion in 10,902 patients who underwent a laparoscopic or open partial or radical nephrectomy for a renal mass over a recent five-year period. The procedures were performed at facilities in seven Canadian provinces, and information on patient demographics and treatment approach were obtained from a nationwide database.
“There are reports in the contemporary medical literature stating that patients who receive transfusions for whatever reasons have worse outcomes,” Dr. Vricella said. “However, most outcomes data in urologic oncology are reported by higher volume surgeons and institutions, and the paucity of population-based analyses means that our current understanding of expected outcomes after surgery for kidney cancer is susceptible to publication and reporting bias. This is especially true for highly technical procedures such as laparoscopic partial nephrectomy.”
He said that the study was undertaken to determine the transfusion rate for all “comers” and to identify specific factors that predict which patients will require a transfusion.
Overall, 28.2% of patients undergoing open radical nephrectomy required at least one transfusion postoperatively.
The transfusion rate decreased steadily, with 12.7%, 9.2% and 8.6% of patients requiring transfusion after open partial nephrectomy, laparoscopic radical nephrectomy, and laparoscopic partial nephrectomy, respectively.
The transfusion rate was strongly associated with patient factors such as age and comorbidity such that transfusion rates were 11.2% and 14.5%, respectively, in patients under 50 years of age and patients with a Charlson co-morbidity score of 0 compared with 28.2% and 40.7% in patients 80 years of age or older and patients with a Charlson score of 3 or higher.
Other factors shown on multivariable analysis to be strongly associated with the need for transfusion were provider variables such as procedure type, surgeon and hospital volume. Year of surgery, gender, and income quintile had no impact on the transfusion rate.
“Our findings allow us to better counsel patients preoperatively, which, in turn, makes them more knowledgeable when providing informed consent,” Dr. Vricella said. “Before our study, we might have told patients that it was highly unlikely that they would need a blood transfusion given the 5% transfusion rate published in the literature. With our population-based data, we would now tell patients that their risk of requiring a transfusion is around 20%, so that if a patient does not want a transfusion for whatever reason—religious or otherwise—he or she is better informed about that risk before providing informed consent.”
He cautioned that a possible study limitation is the lack of pathology data. “For example, we don't know if the patient's renal mass was large or small because the information was not included in the data set we looked at,” he said.
Additionally, the investigators did not have information on patients' preoperative hemoglobin values. “So, a certain percentage of these patients may have had low values to begin with which would have necessitated transfusion, regardless of the nature of their procedure,” he explained.