Survival after adult liver transplantation does not correlate with transplant center case volume in the MELD era

It has been demonstrated that low-volume orthotopic liver transplant centers have poorer outcomes compared to high-volume centers. In light of the recent significant changes in liver transplantation, we performed an analysis of transplant center procedure volume and mortality with data from the Model for End-stage Liver Disease (MELD) era. We analyzed 9909 adult liver transplants performed in the United States since the beginning of the MELD allocation system. Transplant centers were categorized by volume of transplants performed per year. Multivariate survival models were constructed with raw survival as the primary endpoint for both high- and low-volume centers. Thirty percent of centers were categorized as low volume (<= 20 liver transplants per year) and 8.2% of all transplants were performed at low-volume centers. The unadjusted raw mortality rate at 1-year post-transplant at high-volume centers (9.5%, 95% CI 9.4-9.5) was significantly lower than the rate at low-volume centers (10.9%, 95% CI 10.4-11.4), p < 0.001. However, after adjusting for disease severity and multiple donor and recipient factors, transplant center volume was no longer a significant predictor of post-transplant survival (HR 0.99, 95% CI 0.99-1.00, p = 0.22). We conclude that transplant center case volume is no longer a significant predictor of post-transplant survival in the MELD era and factors which are currently unaccounted for in present survival models should be investigated.