We identified
some potential misclassification between
deaths due to the respiratory distress syndrome
and deaths due to bronchopulmonary dysplasia
(e.g., deaths attributed to bronchopulmonary
dysplasia within the first 28 postnatal days or to
the respiratory distress syndrome after 28 postnatal
days); however, the overall results of a sensitivity
analysis to account for this misclassification
were consistent with those of the primary
analysis (Table S4 in the Supplementary Appendix).
In addition, the percentage of deaths attributed
to infection increased substantially from the
first postnatal week (3.5% of all deaths) to the
second postnatal week (15.3% of all deaths).