TOPLINE:

A new score for forced expiratory volume in 1 second (FEV₁) called the conditional change score identified that a notable share of children with asthma developed impaired lung growth during childhood, and better initial lung function was associated with this risk. The score also significantly correlated with FEV₁ variability and BMI.

METHODOLOGY:

• Previous research indicates that approximately 25% of children with asthma exhibit impaired lung growth, with better initial function identified as a potential risk factor. A conditional change score for FEV₁, accounting for time intervals between measurements and independent of baseline values, has been proposed.
• Researchers analyzed data of 295 children with confirmed asthma to determine whether the conditional change score can identify a subgroup with impaired lung growth and to identify risk factors for impaired lung growth.
• Asthma was confirmed by either a significant bronchodilator response or a diagnosis of an asthma exacerbation; children had undergone at least 10 spirometry tests beginning at nearly 8 years of age.
• For each child, the annualized change in prebronchodilator FEV₁ percent predicted was estimated, and conditional change scores were calculated; scores between -1.96 and +1.96 indicated normal growth, scores below -1.96 indicated impaired growth, and scores above +1.96 indicated enhanced growth.
• Median follow-up durations for children with enhanced, normal, or impaired growth were 5.9, 6.5, and 6.6 years, respectively.

TAKEAWAY:

• Overall, 16% of the children exhibited impaired lung growth during the follow-up period. These participants also experienced a greater decline in lung function over time and had lower FEV1 at the final visit than those in other groups.
• The conditional change score showed significant correlations with the slope of annualized rate of change in FEV₁ (correlation coefficient [R], 0.74), FEV₁ variability (R, 0.21), z-score of FEV₁ at the first visit (R, -0.22), and BMI at the final visit (R, 0.16).
• These variables remained independently associated with the conditional change score in the multiple regression analysis.

IN PRACTICE:

“The calculation of the conditional change score of FEV₁ should be implemented in daily practice to allow the early identification of children with asthma who are at increased risk of loss of lung function,” the authors wrote.

SOURCE:

The study was led by Bruno Mahut, Clinique La Berma, Antony, France. It was published online on September 16, 2025, in Pediatric Pulmonology.

LIMITATIONS:

The study was limited by its single-center design. The use of prebronchodilator FEV₁ values, although supported by multiple measurements per child, could have been affected by reversible factors such as acute bronchoconstriction. Moreover, the findings are generalizable only to children with asthma who received outpatient follow-up care.

DISCLOSURES:

The study did not receive specific funding. The authors declared having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.