Background: Recently, atypical chronic lung disease (CLD) of prematurity that develops in the absence of preceding respiratory distress syndrome (RDS) have been observed frequently. The specific risk factors for atypical CLD that are presumed to be different from those for classical CLD that develops following RDS were assessed.
Methods: Prospective cohort analysis was done from 115 very low-birthweight infants who were born in Seoul National University Hospital, Seoul, Korea, and survived more than 36 weeks postmenstrual age or 28 days of life. All subjects were classified into either a preceding RDS group (n = 35) or a non-RDS group (n = 80). Logistic regression analysis was done for the multivariate assessment of specific risk factors for CLD in both groups.
Results: The analysis showed that short gestational age (GA; relative risk [RR], 3.1 per 1 week decrement; 95% confidence intervals [CI], 2.7-3.4), of the male gender (RR, 9.8; CI, 0.9-112), and poor response to surfactant (RR, 14; CI, 1.2-156) were significant risk factors for CLD in the preceding RDS group. In the non-RDS group, chorioamnionitis was one of the significant risk factors for CLD (RR, 4.8; CI, 1.1-21) along with short GA and high mean airway pressure (MAP) during the first 3 days of life.
Conclusion: Chorioamnionitis was a risk factor for atypical CLD in addition to short GA and high MAP during the early postnatal period, and poor response to surfactant was a risk factor for classical CLD in addition to short GA and being male. Therefore, CLD is considered to have type-specific risk factors.