This article is more than 5 years old. Information may no longer be current.

Patients with cystic fibrosis live nearly 10 years longer in Canada than US

Compared with American patients with cystic fibrosis, Canadians with the disorder have a significant survival advantage, most likely due to differences in health care coverage, diet and lung transplantation, according to research published in Annals of Internal Medicine.

“A comprehensive, multidisciplinary approach to medical care; early treatment of pulmonary disease; and aggressive management of malnutrition have translated into longer lives for persons with cystic fibrosis,” Anne L. Stephenson, MD, PhD, of St. Michael’s Hospital in Toronto, and colleagues wrote. “Life expectancy depends on a patient’s characteristics as well as his or her access to medical care and medications, which may vary both within and among countries. Comparisons of national cystic fibrosis registry data have led to important discoveries in cystic fibrosis disease progression and increased our understanding of epidemiologic trends in cystic fibrosis mortality and clinical care.”

In 2011, researchers directly compared estimates of median age of survival in patients with cystic fibrosis between the national registry reports of the United States and Canada and found a survival gap among the two countries (36.8 vs. 48.5 years, respectively); however, this approach did not account for inherent differences in methodologies used, data processing techniques and ascertainment bias, Stephenson and colleagues noted. To provide greater confidence, they sought to estimate cystic fibrosis survival rates and examine the differences between the United States and Canada using a standardized approach. They analyzed data recorded between 1990 and 2013 from the United States Cystic Fibrosis Patient Registry (n = 45,448) and the Canadian Cystic Fibrosis Registry (n = 5,941). They used Cox proportional hazards models to compare survival between the two countries and multivariable models to adjust for survival-associated factors, such as age and severity of disease.

While there was an increase in the median age of survival for cystic fibrosis in both countries between 1990 and 2013, survival improved more rapidly in Canada than the United States in 1995 and 2005. Based on data from 2009 to 2013, Canada had a 10-year greater median age of survival than the United States (50.9 vs. 40.6 years, respectively). Adjusted analysis indicated that the risk for death was 34% lower in Canada compared with the United States (HR = 0.66; 95% CI, 0.54 to 0.81). The researchers noted that more Canadians received lung transplants than Americans (10.3% vs. 6.5%, respectively [standardized difference, 13.7]).

In addition, based on United States patients’ insurance, there was a variation in survival differences between the two countries. Canadians, who have universal, publicly funded health care coverage, had a 44% lower death risk than Americans receiving continuous Medicaid or Medicare coverage, a 36% lower death risk than those receiving intermittent Medicaid or Medicare and a 77% lower death risk than those with unknown or no health insurances. However, similar survival rates were observed among Americans with private health insurance and Canadians.

“Our study confirms a significant survival gap between Canada and the United States in persons living with cystic fibrosis,” Stephenson and colleagues concluded.

“Differential access to transplantation related to the referral or donor lung allocation process; variable posttransplant survival; and differences in health care systems, including access to insurance, may, in part, explain the Canadian survival advantage,” they added. “Further studies are necessary to specifically test these hypotheses.”

In an accompanying editorial, Patrick A. Flume, MD, of the Medical University of South Carolina, and Donald R. VanDevanter, PhD, of the Case Western Reserve University School of Medicine in Cleveland, wrote that Stephenson and colleagues took great lengths to ensure commonality and therefore, the striking disparity among survival rates found between the United States and Canada is a “hard reality” that must be accepted.

“Cystic fibrosis registries have again demonstrated their power to identify important opportunities to improve the health and well-being of our patients,” they concluded. “The U.S. Cystic Fibrosis Foundation and Cystic Fibrosis Canada are to be commended not only for supporting these valuable tools but for being bold enough to compare the data within them to demonstrate such a significant survival difference between the two populations. Now we are faced with the more difficult task of trying to identify and implement solutions to bridge this survival gap, which seems to be based on fundamental differences in the two nations' health care systems.” – by Alaina Tedesco

Disclosures: Stephenson and colleagues report primary funding by the U.S. Cystic Fibrosis Foundation. Flume reports receiving grants and personal fees from the Cystic Fibrosis Foundation. VanDevanter reports receiving personal fees from the Cystic Fibrosis Foundation.