An aging population of patients with cystic fibrosis undergoes lung transplantation: An analysis of the ISHLT Thoracic Transplant Registry

Background: Since lung transplantation became a viable option for cystic fibrosis (CF) lung disease, adult transplant recipients with CF have superior survival than all the other major diagnostic indications. However, among adults, recipients with CF have a younger age at transplant than other transplant recipients. Over time, the frequency and proportion of lung transplants for CF has increased for adults compared with children. Using a large international transplant registry, we investigated time trends in numbers of transplants, age at transplant, and post-transplant survival and cause of death for recipients with CF.

Methods: We conducted a retrospective cohort study of primary lung-alone deceased-donor transplants with a primary diagnostic indication of CF reported to the International Society for Heart and Lung Transplantation Thoracic Transplant Registry from January 2005 through December 2014. We assessed outcomes through December 31, 2015. The study defined the pediatric group as age <18 years at transplant and the adult as ≥18 years at transplant. We assessed time trends (Era I 2005-2009, Era II 2010-2014) in age and compared post-transplant outcomes of age sub-groups with Kruskal-Wallis or chi-square tests. Kaplan-Meier survival analysis estimated the incidence of survival, censoring for loss to follow-up, end of study, and retransplant. In addition, we compared outcomes in age groups and transplant eras with the log-rank test.

Results: Of the 5,613 transplanted recipients with CF, the pediatric group comprised 10.9% and the adult group comprised 89.1%. Of the adults, 73.3% were aged 18 to 39 years and 15.9% were ≥40 years old. During Era I, 2,508 of transplant recipients had CF, whereas 3,105 recipients had CF in Era II (p < 0.001). Comparing Era I with Era II, recipient mean age increased from 28.4 years to 29.5 years (p < 0.001) and the proportion of pediatric CF recipients dropped from 12.4% to 9.6% (p < 0.001), whereas the proportion with age ≥40 years increased from 14.2% to 17.2% (p < 0.001). Mean donor age was significantly lower in children than in recipients aged 18 to 39 years and ≥40 years (17.0 vs 37.0 vs 41.0 years, p < 0.001). Pediatric CF transplant recipients had lower survival in the first 3 years post-transplant than adults (p < 0.0001). Chronic graft failure caused most pediatric deaths, whereas infection was the leading cause of death in adult recipients.

Conclusion: As survival of patients with CF has improved in recent decades, the mean age of lung transplant recipients with CF has increased. Currently, an increasing number of adults undergoes lung transplant for this indication. Adult CF transplant recipients continue to have better survival than pediatric recipients, and among adults, older adults have had better survival than younger adults.