Risk Factors for Chronic Lung Disease in the Surfactant Era: A North Carolina Population-based Study of Very Low Birth Weight Infants

Abstract

Objective. To identify risk factors for chronic lung disease (CLD) in a population-based cohort of very low birth weight infants, born in an era of surfactant usage. We specifically investigated the effects of antenatal steroids, nosocomial infection, patent ductus arteriosus (PDA), fluid management, and ventilator support strategies. Methods. Data were prospectively collected on 1244 infants born in North Carolina in 1994 with birth weights 500 to 1500 g, and treated at 1 of the 13 intensive care nurseries across the state. The outcome of interest was CLD, defined as dependency on supplemental oxygen at 36 weeks' postmenstrual age. Multivariate odds ratios (OR) and 95% confidence intervals (CI) were estimated with logistic regression models. Results. Among 865 survivors to 36 weeks' postmenstrual age, 224 (26%) had CLD. Nosocomial infection (OR: 2.0; 95% CI: 1.4–3.3), fluid intake on day 2 (OR: 1.06 per 10 mL increase; 95% CI: 1.01–1.11), and the need for ventilation at 48 hours of life (OR: 2.2; 95% CI: 1.3–3.7) were associated with an increased risk of CLD. Among infants ventilated at 48 hours, nosocomial infection (OR: 1.64; 95% CI: 1.02–2.62) and PDA (OR: 1.9; 95% CI: 1.2–3.1) were associated with an increased risk. No association was found with antenatal steroid receipt or increased levels of ventilator support. Conclusion. This analysis suggests that with widespread use of surfactant, nosocomial infection, PDA, and water balance persist as risk factors for CLD.