New BPD predicts lung function at school age: Follow-up study and meta-analysis

New treatment practices have improved survival of preterm infants and decreased airway pathology in bronchopulmonary dysplasia (BPD). Our aim was to investigate whether preterm birth, BPD, and the severity of BPD predict lung function in school children that are born in surfactant era. We studied pulmonary function of 88 school-aged children born very preterm (gestational age <32 weeks) and paired them with 88 age- and sex-matched controls born at term. Spirometry and diffusion capacity were recorded. We also performed a meta-analysis covering the era of antenatal corticosteroid and surfactant treatment. BPD was defined as oxygen dependence for ≥ 28 days and it was severity-graded by oxygen requirement at 36 weeks postmenstrual age (mild, none; moderate, FiO2 = 0.22-0.29; severe, FiO2 ≥ 0.30). Preterm children had lower forced expiratory volume in 1 sec (FEV1 ) 86.4 ± 11.8 versus 94.9 ± 10.1 (mean % predicted ± SD; P < 0.001), and lower diffusion capacity (DLCO) 87.6 ± 13.9 versus 93.7 ± 12.0 (P = 0.005) compared with term controls. BPD group differed in both FEV1 (P = 0.037) and DLCO (P = 0.018) from those without BPD. For meta-analysis, search identified 210 articles. Together with present results, six articles met the inclusion criteria. FEV1 of no BPD, all BPD, and moderate to severe BPD groups differed from that in term controls by -7.4, -10.5, and -17.8%, respectively. According to meta-analysis and follow-up study, the adverse effects of prematurity on pulmonary function are still detectable in school-age. BPD was associated with reductions in both diffusion capacity and spirometry. New interventions are required to document a further decrease in the life-long consequences of prematurity.