Lung transplantation in idiopathic pulmonary fibrosis: a systematic review of the literature

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a distinct form of interstitial pneumonia with unknown origin and poor prognosis. Current pharmacologic treatments are limited and lung transplantation is a viable option for appropriate patients. The aim of this review was to summarize lung transplantation survival in IPF patients overall, between single (SLT) vs. bilateral lung transplantation (BLT), pre- and post Lung Allocation Score (LAS), and summarize wait-list survival. METHODS: A systematic review of English-language studies published in Medline or Embase between 1990 and 2013 was performed. Eligible studies were those of observational design reporting survival post-lung transplantation or while on the wait list among IPF patients. RESULTS: Median survival post-transplantation among IPF patients is estimated at 4.5 years. From ISHLT and OPTN data, one year survival ranged from 75% - 81%; 3-year: 59% - 64%; and 5-year: 47% - 53%. Post-transplant survival is lower for IPF vs. other underlying pre-transplant diagnoses. The proportion of IPF patients receiving BLT has steadily increased over the last decade and a half. Unadjusted analyses suggest improved long-term survival for BLT vs. SLT; after adjustment for patient characteristics, the differences tend to disappear. IPF patients account for the largest proportion of patients on the wait list and while wait list time has decreased, the number of transplants for IPF patients has increased over time. OPTN data show that wait list mortality is higher for IPF patients vs. other diagnoses. The proportion of IPF patients who died while awaiting transplantation ranged from 14% to 67%. While later transplant year was associated with increased survival, no significant differences were noted pre vs. post LAS implementation; however a high LAS vs low LAS was associated with decreased one-year survival. CONCLUSIONS: IPF accounts for the largest proportion of patients awaiting lung transplants, and IPF is associated with higher wait-list and post-transplant mortality vs. other diagnoses. Improved BLT vs. SLT survival may be the result of selection bias. Survival pre- vs. post LAS appears to be similar except for IPF patients with high LAS, who have lower survival compared to pre-LAS. Data on post-transplant morbidity outcomes are sparse.