Timing of Lung Function Decline in Cystic Fibrosis Reveals More Insights Than Just the Extent

Published August 15, 2017 | American Journal of Respiratory and Critical Care Medicine

For generations, pediatric physicians did not concern themselves much with treatment of adult cystic fibrosis (CF). Why would they? In the 1980s, for instance, the average life expectancy was 12 years.

Adult CF was virtually unheard-of. Today, more than half of CF patients are adults.

Overall, the genetic disorder affects about 30,000 people in the U.S. Now, a longitudinal cohort study illustrates the many treatment advancements of recent years, identifies phenotypes of rapid pulmonary decline, and suggests how to look for differences in risk factors among adult patients.

The study, led by John Clancy, MD, Pulmonary Medicine, and Rhonda Szczesniak, PhD, Biostatistics and Epidemiology, used a novel statistical approach to tease out lung function declines over time.

Of early-, middle- and late-stage declines, the average level of decline did not differ widely among phenotypes, but the timing did (ages 12.9, 16.3, and 18.5, respectively.)

“The surprising thing was that the people who declined later in life actually lost the most because they started with the highest lung function,” Szczesniak says. “Work at our local CF center has shown that applying certain interventions and increasing the number of clinic visits and tests corresponds to improved lung function. So knowing the timing of the rapid decline can help inform your treatment path.”

The study explored data about CF patients, ages 6-21 years, gathered from the Cystic Fibrosis Foundation Patient Registry.

“When we think about pulmonary decline, it’s not so much a question of ‘if’ as it is ‘when,’ ” says Clancy. “This work helps identify the key characteristics that can help identify those at risk, and when. This is the first step to tailoring treatments, particularly for adolescents.”