Clinical Outcomes in Combined Lung-Liver Transplants Vs Isolated Lung-Transplants: A Systematic Review and Meta-Analysis

The combined lung-liver transplant is an infrequent but established therapy for patients with end-stage lung and liver disease. Recent evidence suggests that the liver may reduce rates of graft rejection and increase overall graft survival for cotransplanted organs. To establish a comprehensive summary of safety and efficacy data and explore whether there may be a tolerogenic effect conferred by the liver in combined lung-liver transplants (CLuLi), we systematically searched 4 databases (Medline, Embase, Cochrane, OVID Transplant library) for all studies comparing clinical outcomes between CLuLi and lung transplants alone (LTA). The primary outcome for this study was overall survival at 1 and 5 years. 3 observational studies were deemed eligible for inclusion including a total of 21, 608 transplant patients- 86 CLuLi and 21,522 LTA. The most common indications for CLuLi included cystic fibrosis (50%) and noncholestatic liver disease (23%). 1- and 5-yr survival rates for CLuLi ranged from 80-91% and 59-84%, respectively, and were not significantly different to LTA in any of the studies. A random effects inverse variance meta-analysis demonstrated an insignificant difference in hospital stay length for CLuLi compared to LTA (95% CI -8.10 to +19.52, p=0.42). 1 study reported on acute rejection and found comparable rates between CLuLi and LTA (40% vs 46%). Overall, our study has shown CLuLi transplants to be at least as safe and effective as lung transplants alone. At present, there is insufficient quality evidence to evaluate the tolerogenic effect of the liver in CLuLi transplants.