Late cystic fibrosis care negatively impacts infant weight, height

Key takeaways:

• Delayed cystic fibrosis care contributed to reduced weight and height-for-age in infancy through age 5 years.
• Researchers emphasized timely newborn screening to combat poor nutritional outcomes.

Infants with cystic fibrosis who received care at 47 days old had decreased weight and height-for-age during infancy compared with infants who received care at 10 days old, according to results published in The Journal of Pediatrics.

Stacey L. Martiniano

“This finding is especially important for the everyday clinician because, typically, an infant’s primary care provider is the person receiving the information about an out-of-range newborn screen result and needs to refer to a [cystic fibrosis (CF)] care center for further testing and treatment initiation,” Stacey L. Martiniano, MD, pulmonary specialist at Children’s Hospital Colorado, told Healio. “CF is a rare disease, so many providers are not familiar with the newborn screening process for CF and the impact of delayed referral.”

In a risk-factor matched cohort study, Martiniano and colleagues assessed 1,102 infants from the Cystic Fibrosis Foundation patient registry diagnosed with CF through newborn screening to see if age at the start of CF care impacts nutritional, pulmonary and health outcomes.

Researchers classified CF care as undergoing a sweat test or having a CF care center encounter or hospitalization, using age at first CF event as a proxy for the date when such CF care likely commenced.

Patient characteristics

Half of the total cohort (n = 551) was aged younger than 14 days when they had their first CF event, with a median age of 10 days, whereas the remaining half (n = 551) had their first event when aged 33 days or older, with a median age of 47 days.

Infants from the younger cohort received their CF diagnosis earlier than the older cohort (8 days vs. 33 days; P < .001) and commonly experienced a clinical encounter as their first instance of CF care, differing from the older cohort who more often experienced CF care first through a sweat test.

Both cohorts rarely experienced hospitalizations as their first instance of CF care; however, it occurred more in the younger cohort.

Notably, researchers found that infants from the older cohort more frequently had detection of only one CFTR variant on the 23-variant panel (28% vs. 22%; P = .01) and the 39-variant panel (26% vs. 17%; P < .001) compared with infants from the younger cohort.

Nutritional outcomes

Despite similar birth weight and length z scores, the older infant cohort had significantly reduced median weight-for-age z scores at the time of the first encounter vs. the younger cohort (–1.05; range, –1.94 to –0.22 vs. –0.85; range, –1.71 to –0.17; P = .01). This trend persisted at age 1 year (–0.05; range, –3.88 to 2.4 vs. 0.11; range, –4.8 to 2.5; P = .05).

In terms of median height-for-age, infants diagnosed at an older age also had significant declines in this z score compared with infants diagnosed at a younger age at the first encounter (–1.06; range, –1.82 to –0.17 vs. –0.46; range, –1.35 to 0.22; P < .001), 1 year (–0.6; range, –4.2 to 3.6 vs. –0.42; range, –4.9 to 2.8; P = .01), 3 to 4 years (–0.23; range, –3.4 to 2.6 vs. –0.11; range, –2.8 to 2.6; P = .01) and 5 to 6 years (–0.26; range, –3.8 to 2.6 vs. –0.12; range, –2.4 to 2.3; P = .03).

“We were surprised that a delay in initial care at a CF center from just 10 days of life to 47 days of life was associated with worse short-term and long-term growth outcomes,” Martiniano told Healio. “This is a seemingly short amount of time, but shows how critical treatment in the first month of life is for babies with CF.”

Additionally, researchers found significantly fewer infants from the older vs. younger cohort being breastfed at 2 months (50.9% vs. 62.4%; P = .002) and 6 months (29.5% vs. 41.3%; P < .001).

Pulmonary, health outcomes

Percent predicted FEV₁ did not significantly differ between the two cohorts at 7 years of age, but researchers noted that this result was “likely limited by missing data.”

The rate of Pseudomonas aeruginosa infections at age 1 year and age 1 to 3 years also was comparable in both cohorts, with a nearly significant difference at age 6 years showing more infections among infants from the late diagnosis cohort.

“This study has been paired with ongoing efforts to educate providers about the need for urgent referral for these babies, along with process improvement work by many newborn screen programs and CF care centers nationwide,” Martiniano told Healio. “Also, as disease-modifying CFTR modulator treatments become available for infants and young children with CF, we will be able to study how timeliness of diagnosis and initial care impacts clinical response to these medications.

“Based on our results, we hypothesize that expanding the number of CF gene variants tested on newborn screen panels may help to shorten time to diagnosis and treatment initiation for more babies,” Martiniano added. “Updated national guidelines about CF newborn screening are also under development.”

Reference:

• New study findings underscore the importance of timely newborn screenings in early care for cystic fibrosis. https://www.luriechildrens.org/en/news-stories/new-study-findings-underscore-the-importance-of-timely-newborn-screenings-in-early-care-for-cystic-fibrosis/. Published July 28, 2023. Accessed July 31, 2023.

For more information:

Stacey L. Martiniano, MD, can be reached at stacey.martiniano@childrenscolorado.org.