(Reuters Health) - Canadians with cystic fibrosis, a life threatening inherited disorder of the lungs and digestive system, tend to survive about a decade longer than American patients, a new study suggests.

Researchers examined national registry data collected from 1990 to 2013 for 5,941 patients with cystic fibrosis in Canada and another 45,456 patients in the U.S.

Half of the Canadians survived past age 51, whereas half of the U.S. patients had died by age 41.

“There was a significant difference in survival between the two countries even after accounting for differences in patient characteristics related to disease severity,” said lead study author Dr. Anne Stephenson, a researcher at the University of Toronto and the Adult Cystic Fibrosis Center at St. Michael’s Hospital in Toronto.

Even though researchers didn’t have data to explore all the factors that might contribute to differing survival rates, it’s possible that insurance might explain at least some of the gap.

“We used insurance status as a surrogate marker for the U.S. health care system compared to the universal health care system in Canada,” Stephenson said by email. “We found that U.S. patients with private health insurance had similar survival to Canadians, however, insurance status in the U.S. is a complex construct and may reflect a combination of other unmeasured factors such as socioeconomic status.”

Overall, the risk for death was 34 percent lower in Canada than in the U.S., researchers report in the Annals of Internal Medicine.

Compared to U.S. patients continuously insured by Medicaid or Medicare, which are government health programs for the poor and disabled, Canadians had a 44 percent lower risk of death, the study found.

And, relative to American patients without any insurance, Canadians had a 77 percent lower risk of death.

Diet may also explain part of the survival advantage for Canadians. Cystic fibrosis affects the ability of the digestive system to absorb fat, which leads to malnutrition.

A high-fat diet, associated with better survival for cystic fibrosis patients, has been recommended in Canada since the 1970s but wasn’t implemented in the U.S. until the 1980s.

Differences in selecting patients for lung transplantation - which was also associated with better survival odds - may explain the longer lifespans in Canada as well, the researchers note.

“There are fundamental differences between Canada and the U.S. with respect to health care systems - universal care versus market based - but also with education and other developmental needs,” said Dr. Patrick Flume, a researcher at the Medical University of South Carolina in Charleston who wrote an accompanying editorial.

“I think that the overall survival differences between Canada and the U.S., and the large survival gap especially in cystic fibrosis patients, is an outcome that demonstrates how the market based approach is less successful,” Flume added by email.

The study was funded by the U.S. Cystic Fibrosis Foundation.

SOURCE: bit.ly/2mFpQMj Annals of Internal Medicine, online March 13, 2017.