Institutional volume affects long-term survival following lung transplantation in the USA

OBJECTIVES The aim of this study was to evaluate the impact of institutional volume on long-term outcomes following lung transplantation (LTx) in the USA. METHODS Adults undergoing LTx were identified in the United Network for Organ Sharing registry. Patients were divided into equal size tertiles according to the institutional volume. All-cause mortality following LTx was evaluated using the risk-adjusted multivariable Cox regression and the Kaplan–Meier analyses, and compared between these volume cohorts at 3 points: 90 days, 1 year (excluding 90-day deaths) and 10 years (excluding 1-year deaths). Lowess smoothing plots and receiver-operating characteristic analyses were performed to identify optimal volume thresholds associated with long-term survival. RESULTS A total of 13 370 adult LTx recipients were identified. The mean annual centre volume was 33.6 ± 20.1. After risk adjustment, low-volume centres were found to be at increased risk for 90-day mortality, [hazard ratio (HR) 1.56, P < 0.001], 1-year mortality excluding 90-day deaths (HR 1.46, P < 0.001) and 10-year mortality excluding 1-year deaths (HR 1.22, P < 0.001). These findings persisted when the centre volume was modelled as a continuous variable. The Kaplan–Meier analysis also demonstrated significant reductions in survival at each of these time points for low-volume centres (each P < 0.001). The 10-year survival conditional on 1-year survival was 37.4% in high-volume centres vs 28.0% in low-volume centres (P < 0.001). The optimal annual volume threshold for long-term survival was 26 LTx/year. CONCLUSIONS The institutional volume impacts long-term survival following LTx, even after excluding deaths within the first post-transplant year. Identifying the processes of care that lead to longer survival in high-volume centres is prudent.