Canadian Study Finds Lung Transplant Survival Rates Good For Persons With Cystic Fibrosis

The five-year survival rate for Canadians with cystic fibrosis who have received a lung transplant is 67% and half of those who have had transplants live beyond 10 years, new research has found.

The encouraging statistics were published today in the Journal of Heart Lung Transplantation by Dr. Anne Stephenson MD, PhD, of the Adult CF Program, at St. Michael’s Hospital, in Toronto, Ontario St. Michael’s Hospital. In a release, Dr. Stephenson says this was the first time anyone had used the Canadian Cystic Fibrosis Registry, of which she is the director, to examine outcomes following lung transplantation at a national level in Canada. Previous studies have reported outcomes at single transplant sites.

The paper, entitled “Clinical and demographic factors associated with post–lung transplantation survival in individuals with cystic fibrosis“ (The Journal of Heart and Lung Transplantation, 2015; DOI: 10.1016/j.healun.2015.05.003)is coauthored by Dr. Stephenson with Jenna Sykes, MMath, Yves Berthiaume, MD, Lianne G. Singer, MD, Shawn D. Aaron, MD, George A. Whitmore, PhD, and Sanja Stanojevic, PhD, who note that contemporary studies evaluating post-transplant survival are limited and often include data from single centers or selected sub-groups. They explain that the purpose of this study was to evaluate overall transplant survival and identify risk factors associated with death after transplant.

The coauthors used the Canadian Cystic Fibrosis Registry (CCFR) , a population-based cohort, to describe survival after lung transplant. Pre-transplant factors associated with post-transplant survival were estimated using Cox proportional hazards models.

They report that between 1988 and 2012, 580 patients referenced in the CCFR received lung transplants, with a median post-transplant 1-year survival rate if 87.8 percent. Across the entire cohort, 5-year survival was 66.7 percent, and 10-year survival was 50.2 percent. Median post-transplant survival was 3.3 years in patients infected with Burkholderia cepacia complex compared with 12.36 years in patients without B cepacia infection. After adjustment, there was a non-significant trend toward better post-transplant survival with increasing year of transplant. Factors associated with poorer survival rates in the overall CF population, such as being female, early age of diagnosis, malnutrition and CF-related diabetes, did not significantly impact post-transplant survival, but other factors such as pancreatic sufficiency or being infected with certain bacteria that can live in the lungs of people with CF, such as B. cepacia, had a detrimental impact on survival.

Dr. Stephenson found a patient’s age at the time of the transplant was a significant predictor of survival. Pancreatic sufficiency and age at transplant such that youngest and oldest had the poorest survival were significant negative predictors of survival. The youngest and oldest patients had poorer survival rates compared to those in the middle age-range. In the first 10 years after transplant, survival rates were similar between those under and over age 18 years, but if someone survived beyond 10 years, there was a four-fold increase in risk of death for those under 18 years of age. The risk of death after transplant for patients infected with B cepacia was highest within the first year, but remained elevated >1 year after transplant compared with patients without B cepacia infection.

The researchers conclude that after lung transplantation, five-year survival in Canadians with CF is 67 percent and 50 percent of patients live >10 years, but despite these impressive probabilities, age at transplant, pancreatic sufficiency and B cepacia infection remain important determinants of survival after lung transplantation.

“People think when you have cystic fibrosis and need a transplant it’s a death sentence,” observes Dr. Stephenson. “But our paper shows that one-, three-, and five-year survival rates following lung transplantation are really quite high.”

Photo Caption: The five-year survival rate for Canadians with cystic fibrosis who have received a lung transplant is 67 percent and half of those who have had transplants live beyond 10 years, according to new research by Dr. Anne Stephenson of St. Michael’s Hospital. – Image Courtesy St. Michael’s Hospital

Cystic fibrosis is a rare, genetic, life-shortening chronic disease that that affects the lungs and digestive systems. Approximately 30,000 Americans are living with CF, and it is the most common fatal genetic disorder affecting Canadian children and young adults. In persons with CF a defective gene and its protein product cause the body to produce unusually thick, sticky mucus that clogs the lungs and leads to life-threatening lung infections, obstructs the pancreas, and stops natural enzymes from helping the body break down and absorb food. Patients with CF typically live only into their mid-20s, but that metric has been improving with greater understanding of the disease and development of better treatments, and a trend toward improved survival in more recent decades as persons who received transplants in 2000 or later were 23 per cent less likely to die compared to those transplanted before 2000.

The Journal of Heart and Lung Transplantation paper is the second piece of good news for cystic fibrosis patients Dr. Stephenson has published recently. In November, a paper she published in the European Respiratory Journal showed that Canadians with cystic fibrosis are living almost 20 years longer than they did two decades ago.

The median survival age was 49.7 years in 2012, up from 31.9 years in 1990. Since the paper was written, Dr. Stephenson has updated the median survival age to include Cystic Fibrosis Canada data from 2013 and reported the median age of survival has in fact reached 50.9 years. She says there are few therapies that can impact survival as dramatically as lung transplantation, which has likely contributed to the increasing survival in Canadians with CF. However, even lung transplants are not a cure for CF because the defective gene that causes the disease is found in all the cells of the body, with the exception of the newly transplanted lungs.

This study received funding from the Canadian Institutes of Health Research.

St. Michael’s Hospital is dedicated to providing compassionate care to all who enter its doors, and also provides outstanding medical education to future health care professionals in 27 academic disciplines. Critical care and trauma, heart disease, neurosurgery, diabetes, cancer care, care of the homeless and global health are among the hospital’s recognized areas of expertise. Through the Keenan Research Centre and the Li Ka Shing International Healthcare Education Centre, which make up the Li Ka Shing Knowledge Institute, research and education at St. Michael’s Hospital are recognized and make an impact around the world. Founded in 1892, the hospital is fully affiliated with the University of Toronto.

Sources:
St. Michael’s Hospital
The Journal of Heart and Lung Transplantation

Image Credit:
St. Michael’s Hospital