Classification and Risk Factors for Chronic Lung Disease(CLD) of Prematurity: Classical CLD Versus Atypical CLD

ABSTRACT

PURPOSE: We tried to classify the different type of CLD and assess the risk factors for classical CLD and atypical CLD. METHODS: Retrospective cohort analysis was done in 120 preterm infants with birth weights less than 1,500 g who were admitted to NICU in Seoul National University Children's Hospital between Jan. 1993 and Dec. 1998 and survived more than 28 days of life. RESULTS: CLD occurred in 44 of all infants(37%). The total subjects were classified into severe respiratory distress syndrome(RDS) group, mild RDS group, and non-RDS group. Multivariative logistic regression analysis was done for the assessment of risk factors for CLD in each groups. The analysis revealed that in severe RDS group, the significant risk factors for CLD were short gestational duration[OR 3.1(per 1 week decrement), 95% CI 1.4-7.0], male sex(OR 11, 95% CI 1.0-121), and poor response to surfactant(initial poor response to surfactant or relapse of RDS after initial good response to surfactant, OR 15, 95% CI 1.3-168). In non-RDS group, the significant risk factors for CLD were male sex(OR 8.9, 95% CI 1.5-51), chorioamnionitis(OR 7.5, 95% CI 1.4-38), and high mean airway pressure during the first 72 hours of life[OR 2.1(per 1 cmH2O increment), 95% CI 1.3-3.3]. CONCLUSIONS: It could be suggested that the poor response to surfactant of RDS might be one of the etiologic factors of classical CLD which occurs following severe RDS, and chorioamnionits might be one of the etiologic factors of atypical CLD which occurs without a history of RDS. Therefore CLD might be an etiologically heterogeneous disease entity.