D espite notable advances in prenatal and neonatal care, respiratory distress syndrome (RDS) and bronchopulmonary dysplasia (BPD) remain important complications of preterm births, frequently resulting in mortality as well as short-term and long-term morbidity. BPD, as originally described by Northway et al (1), is less common today, but it has been replaced by a 'new' disease that typically follows mild to moderate RDS in small preterm infants who respond quickly to surfactant therapy but require prolonged ventilation for apnea and poor respiratory efforts (2). The accurate prediction of the development and severity of lung disease in preterm infants could assist clinicians in making critical decisions quickly (3) and could provide a better idea of the short-term prognosis to the treating team and family members. Identifying factors associated with preventing the onset of BPD is also an important facet of neonatology research.The present study of a large cohort of preterm infants had three objectives: to examine factors associated with the development of RDS and BPD, to examine factors associated with BPD severity and to develop a predictive equation for the occurrence of BPD following a preterm birth.
Methods subjectsThe study population included all preterm infants (defined as a gestational age of younger than 37 weeks) who were admitted to the Montreal Children's Hospital (Montreal, Quebec) between January 1, 1980, and December 31, 1992. The Montreal Children's Hospital is a tertiary paediatric hospital with a specialized neonatal care department that serves as a referral centre for the province of Quebec. No infants are born at the Montreal Children's Hospital, and all study subjects were transferred to this institution following BACKGRoUNd: Despite notable advances in neonatal care, bronchopulmonary dysplasia (BPD) remains an important complication of preterm birth, frequently resulting in prolonged hospital stay and longterm morbidity. Methods: A historical cohort study of all preterm infants (gestational age younger than 37 weeks) admitted to the Montreal Children's Hospital (Montreal, Quebec) between January 1, 1980, and December 31, 1992, was conducted. Information collected included demographic data, maternal and perinatal history, and main neonatal outcomes. Independent risk factors associated with BPD were identified by univariate analysis using one-way ANOVA, t tests or Mantel-Haenszel c 2 testing. Severity of disease was studied using an ordinal multinomial logistic regression model. ResULts: In total, 1192 preterm infants were admitted, of whom 551 developed respiratory distress syndrome and 322 developed BPD. For each additional week of prematurity, the risk of developing BPD increased by 54% (adjusted OR 1.54/week [95% CI 1.45 to 1.64]). For each point subtracted on the 1 min Apgar score, the risk of developing BPD was increased by 16% (OR 1.16 [95% CI 1.1 to 1.3]). BPD was also associated with the presence of patent ductus arteriosus (OR 3.5 [95% CI 2.1 to 6.0]), pneumothorax in the first 48 h ...