Perinatal risk-indicators for long-term respiratory morbidity among preterm or very low birth weight neonates

Objectives: To develop prediction models for long-term respiratory morbidity. To explore if respiratory distress syndrome (RDS) is a risk-indicator for long-term respiratory morbidity and to identify other perinatal risk-indicators for long-term respiratory morbidity. Study design: In the Dutch POPS cohort 1338 live born infants delivered in The Netherlands in 1983, either before 32 completed weeks gestation and/or with a birth weight below 1500 g, were followed prospectively. We used multivariable logistic regression analyses to construct three prediction models for respiratory morbidity at 2, 5 and 19 years of age. Results: At 2 years of age, maternal smoking (adjusted OR 1.5, 95% CI 1.0-2.4), prolonged rupture of membranes (adjusted OR 2.3, 95% CI 1.3-4.1), pre-eclampsia (adjusted OR 1.9, 95% CI 1.1-4.1), male gender (adjusted OR 1.5, 95% CI 1.1-2.0) and BPD (adjusted OR 1.9, 95% CI 1.1-3.2) were significantly associated with respiratory morbidity. Prolonged rupture of membranes (adjusted OR 3.7, 95% CI 1.6-8.5), family history of asthma (adjusted OR 5.9, 95% CI 2.7-13.0) and BPD (adjusted OR 1.8, 95% CI 1.1-3.0) were significantly associated with respiratory morbidity at 5 years of age. At 19 years of age only higher social class was associated with decreased respiratory morbidity (adjusted OR 0.64, 95% CI 0.41-0.99). The areas under the curves (AUC) were 0.65, 0.71 and 0.61 respectively. The prediction models for respiratory morbidity at 2 and 5 years of age showed a good calibration, while the calibration plot for respiratory morbidity at 19 year was less optimal. Conclusions: RDS is not a risk-indicator for long-term respiratory morbidity at 2, 5 and 19 years in this cohort (OR 1.2, 95% 0.88-1.7; 1.3, 95% 0.88-2.0; OR 0.91, 95% 0.56-1.5 respectively). Future obstetric studies interested in the effect of a specific perinatal intervention on long-term respiratory morbidity, should consider taking bronchopulmonary dysplasia (BPD) as primary outcome instead of RDS.