Increasing airway obstruction from 8 to 18†years in extremely preterm/low-birthweight survivors born in the surfactant era.

BACKGROUND: The evolution of airway obstruction into late adolescence of extremely preterm (gestational age <28 weeks) or extremely low-birthweight (birth weight <1000 g) survivors in the era after surfactant was introduced is unclear. OBJECTIVE: To compare changes in spirometry from 8 to 18 years of age of a geographical cohort of preterm survivors with normal birth weight controls, and to determine higher risk groups within the preterm cohort. METHODS: Of 297 extremely preterm/low-birthweight survivors born in 1991-1992 in the state of Victoria, Australia, 81% and 70% had spirometry at 8 and 18 years of age, respectively. Corresponding rates among 260 normal birth weight controls were 80% and 58%, respectively. Data were analysed using linear mixed models. RESULTS: The preterm group had substantial impairments in airflow at both ages compared with controls (eg, mean differences in z-score for FEV1; 8 years -1.02, 95% CI -1.21 to -0.82; 18 years -0.92, 95% CI -1.14 to -0.71). The preterm group had a greater increase in small airway obstruction between 8 and 18 years compared with controls. Within the preterm group, those who had bronchopulmonary dysplasia in the newborn period and those who were smokers at 18 years had airway obstruction that increased over time compared with those who did not. CONCLUSIONS: Preterm survivors born in the surfactant era had significant impairments in airflow through childhood into late adolescence that increased over time compared with controls. At-risk preterm participants include those who had bronchopulmonary dysplasia, and smokers at 18 years.

Bronchopulmonary dysplasia in very low birth weight subjects and lung function in late adolescence.

OBJECTIVES: The purpose of this work was to determine the relationship between lung function in late adolescence and bronchopulmonary dysplasia, to establish whether lung function changed more from earlier in childhood in those with bronchopulmonary dysplasia, and to assess the effect of different definitions of bronchopulmonary dysplasia on respiratory outcome. METHODS: Subjects were composed of 147 survivors of birth weight <1500 g from the Royal Women's Hospital (Melbourne, Australia) born during 1977-1982 and who had lung function tests at a mean age of 18.9 years. Of the 147 subjects, 33 (22%) had bronchopulmonary dysplasia in the newborn period. Lung function was measured according to American Thoracic Society guidelines. RESULTS: All of the lung function variables reflecting airflow were substantially diminished in the bronchopulmonary dysplasia group, but lung volumes were not significantly different. More subjects in the bronchopulmonary dysplasia group had reductions in airflow in the clinically significant range (eg, forced expired volume in 1 second/forced vital capacity ratio <75%; bronchopulmonary dysplasia: 42.4% [14 of 33]; and no bronchopulmonary dysplasia: 16.4% [18/114]). Results were not substantially affected after adjustment for confounding variables, including intrauterine growth restriction or birth weight. Compared with earlier in childhood, the forced expired volume in 1 second/forced vital capacity ratio deteriorated more in bronchopulmonary dysplasia subjects between 8 and 18 years. Lung function results varied little with different definitions of bronchopulmonary dysplasia. CONCLUSIONS: Subjects of very low birth weight with bronchopulmonary dysplasia in the newborn period have poorer lung function in late adolescence than those without bronchopulmonary dysplasia, and their lung function may be deteriorating at a more rapid rate.