Longitudinal assessment of loss and gain of lung function in childhood asthma

Abstract

Background: The Childhood Asthma Management Program study revealed that\n25.7% of children with mild to moderate asthma exhibit a loss of lung\nfunction. The objective was to assess the trajectories of function by\nmeans of serial FEV1 in asthmatic children participating in\nout-of-hospital follow-up. Methods: A total of 295 children (199 boys)\nwho had undergone at least 10 spirometry tests from the age of 8 were\nselected from a single-center open cohort. The annualized rate of change\n(slope) for prebronchodilator FEV1 (percent predicted) was estimated for\neach participant and three patterns were defined: significantly positive\nslope, significantly negative slope, and null slope (non-significant\nP-value in the Pearson test). The standard deviation (SD) of each\nindividual slope was recorded as a variability criterion of FEV1.\nResults: The median (25th and 75th percentile) age at inclusion and the\nlast visit was 8.5 (8.2, 9.3) and 15.4 (14.8, 16.0) years, respectively.\nTracking of function (null slope) was observed in 68.8% of the\nchildren, while 27.8% showed a loss of function (negative slope) and\n3.4% showed a gain in function (positive slope). The children\ncharacterized by loss of function depicted a better initial function and\na lower FEV1 variability during their follow-up than children with\ntracking or gain of lung function. At the last visit, these children\nwere characterized by a lower lung function than children with tracking\nor gain of lung function. Conclusion: Children with a better initial\nFEV1 value and less FEV1 variability are more prone to loss of lung\nfunction.