Haataja P, et al. - Researchers planned this study to assess the frequency and predictors of hospital admissions for lower respiratory tract infections (LRTIs) in moderately preterm (MP, 32⁺⁰ to 33⁺⁶ weeks) and late preterm (LP, 34⁺⁰ to 36⁺⁶ weeks) infants compared to term (T ≥37 weeks) and very preterm (VP, <32⁺⁰ weeks) infants. In addition to VP birth, MP and LP births, seemed to have a significant impact on respiratory infectious morbidity and the need of hospital admissions for LRTIs.

Methods

• All infants born in Finland in 1991-2008 were covered in this national register-based study.
• Researchers analyzed data on 1,018,256 infants in four gestational age-based groups: VP (n = 6,329), MP (n = 6,796), LP (n = 39,928), and T (n = 965,203) groups.
• Collection of data on hospital admissions due to bronchiolitis/bronchitis and pneumonia was performed up to the age of 7 years.

Results

• For LRTIs, hospital admissions in the MP and LP groups were more common than in the T group but less frequent than in the VP group: bronchiolitis/bronchitis (VP 24.4%, MP 13.9%, LP 9.5%, and T 5.6%) and pneumonia (VP 8.8%, MP 4.5%, LP 3.3%, and T 2.4%).
• MP and LP birth predicted bronchiolitis/bronchitis (MP OR 1.89; 95%CI 1.75-2.03, LP 1.51; 1.45-1.56) and pneumonia (MP 1.49; 1.32-1.67, LP 1.25; 1.18-1.33) admissions compared to the term group.
• For LRTIs, statistically relevant risk factors were maternal smoking, cesarean section, male sex, admission to a neonatal unit and ventilator therapy.
• Furthermore, being first-born, being born SGA and neonatal antibiotic therapy seemed correlated with bronchiolitis/bronchitis.