Center volume effects in pediatric renal transplantation. A report of the North American Pediatric Renal Transplant Cooperative Study.
An inverse relationship between mortality and center volume has been established for several surgical procedures. Given the distinctiveness of pediatric renal transplantation and the large variation in center volume, investigation for relationships between center volume and graft outcome was pursued using the North American Pediatric Transplant Cooperative Study database. Center volume groups were based on the total number of pediatric transplants reported from 1987 to 1995. Centers reporting > 100, 51-100, or < or = 50 transplants were grouped as high- (n=11), moderate- (n=28), or low-volume (n=65), respectively. Differences between groups included increasing rates of cadaver donor graft thrombosis (2.4%, 4.3%, and 5.7%, P<0.01) and acute tubular necrosis (ATN) (10.2%, 11.5%, and 14.0%, P<0.01) with decreasing center volume. Treatment differences included a higher rate of induction with an anti-T-cell antibody preparation in the larger-volume groups, 60.2%, 51.8%, and 39.2% (P<0.001). Decreasing graft survival for decreasing center size groups was noted at 3 months post transplant, 90.4%, 90.2%, and 88.4%. These differences were significant only with the exclusion of anti-T-cell induction from the proportional hazards model (relative risk=0.81 and =0.70 for the moderate- and high-volume groups, P<0.02). Superior graft survival in the high-volume centers noted at 3 months post transplant appears predominantly the result of lower rates of cadaver donor graft thrombosis and ATN. Analysis points to the need for low-volume centers to identify risk factors influencing these outcomes.