Late cystic fibrosis diagnosis linked to lower weight, shorter height in early years

Infants with a late diagnosis for cystic fibrosis were more likely to be behind in their weight and height at 1 year and height at 3 and 5 years, according to a poster presented at the North American Cystic Fibrosis Conference.

“Newborn screening (NBS) for cystic fibrosis was fully implemented in the United States in 2010, but delays in timeliness of evaluation for infants with positive NBS tests persist,” Stacey L. Martiniano, MD, MSCS, associate professor of pediatrics at the University of Colorado and Children’s Hospital Colorado, and colleagues wrote.

Martiniano and colleagues assessed 3,607 infants diagnosed with cystic fibrosis (CF) before age 1 from the Cystic Fibrosis Foundation Patient Registry to observe the characteristics and health outcomes of those treated later for CF, according to the study abstract.

Researchers grouped infants based on their age at first evaluation, or the earliest age of a sweat test, CF center clinical encounter and/or care episode that was longer than 24 hours.

Researchers then matched for several covariates and assessed the differences between the youngest (early) and oldest (late) age at first evaluation quartiles, with 551 infants in each cohort.

Median age at first evaluation was 10 days (interquartile range [IQR], 8-12 days) for the early group compared with 47 days (IQR, 37-72 days) for the late group (P < .001).

Infants in the late diagnosis cohort had a higher likelihood of having one sole CF transmembrane conductance regulator variant than early infants detected on both the commercial 23-variant (28% vs. 22%; P = .01) and 39-variant (26% vs. 17%; P < .001) panels.

In terms of the type of evaluation, 70% of late infants had a sweat test as their first CF event compared with 50% of early infants (P < .001). Early infants were more likely to have a clinical encounter as their first event (61% vs. 49%; P < .001).

Additionally, infants who were diagnosed late were less likely to be breastfed at age 2 and 6 months and, despite similar birthweight and length, they had lower median weight-for-age and height-for-age z scores at both their first encounter with CF and at 1 year, and lower height-for-age z scores at 3 to 5 years old, according to the abstract.

Researchers also found that parent education may factor into a late diagnosis as infants in this cohort had a lower likelihood of having parents with reported college or graduate school education.

However, between both late and early diagnosis CF groups, researchers found no variations in Pseudomonas aeruginosa infection, pulmonary function at age 7 years or hospitalization rates.

“This study highlights ongoing delays in timely NBS in the United States, with resultant long-term consequences,” Martiniano and colleagues wrote. “Qualitative studies and improvement work that evaluate more specific system factors in NBS follow-up programs are essential to ensure equitable, timely evaluation at CF care centers for all infants.”