Identification of Factors Related to the Severity of Chronic Lung Disease of Infancy in Preterm Infants after Neonatal Intensive Care Unit Discharge through 12 Months Corrected Age

Introduction: Bronchopulmonary dysplasia (BPD; used interchangeably with chronic lung disease of infancy [CLDi]) is a common complication of prematurity. There is a need for improved assessment of the severity of CLDi after discharge from the neonatal intensive care unit (NICU). Therefore, we developed a CLDi severity score (CLDiSS) for preterm infants after NICU discharge through 12 months corrected age (CA). Here, we report on a study conducted to: (1) identify factors that reflect CLDi severity in preterm infants and (2) develop a weighted scoring algorithm to quantify the relative importance of these factors.

Materials and Methods: An online survey utilizing Delphi methodology was conducted. In the first Delphi round, clinicians rated the importance of various factors used to evaluate the severity of CLDi, from 0 (not at all important) to 10 (very important) for the period between discharge home from the NICU and 12 months CA, and ranked the relative importance of these factors in determining severity. Fourteen factors were considered in the survey; these included respiratory-related hospital readmissions after NICU discharge, respiratory-related emergency room (ER) visits without hospital readmissions, use of home mechanical ventilation, bilevel positive airway pressure, nasal intermittent positive pressure ventilation, supplemental oxygen (thresholds of < 2 or ≥ 2 L/min), which includes continuous positive airway pressure, and use of bronchodilators, corticosteroids (inhaled and systemic), diuretics, and pulmonary vasodilators. The round 1 survey was completed by 91 clinicians experienced in treating prematurity-related lung diseases such as CLDi (pediatric pulmonologists, n = 51; pediatricians, n = 20; neonatologists, n = 20). Participants came from 11 countries across North America, Europe, Asia, and South America. Findings from round 1 of the survey indicated that home mechanical ventilation was the most important factor in determining the severity of CLDi, receiving a mean absolute importance rating of 8.38 (on the scale of 0–10). This was followed by supplemental oxygen ≥ 2 L/min (8.14), hospital readmissions (7.97), and ER visits without hospital readmissions (7.82). Physicians considered intermittent use of diuretics to be the least important factor (5.65). Home mechanical ventilation was also ranked highest in terms of the relative importance in determining severity.

Conclusion: Results from the first Delphi round of survey questions indicated the importance of selected factors in the assessment of the severity of CLDi from NICU discharge through 12 months CA. Up to two additional rounds of the survey will be completed to reach consensus among clinicians. The final findings will be used to guide development of the CLDiSS.

Conflict of Interest: R.W., R.S., and M. H. were a paid consultant to Takeda, in connection with this study. E.S. and M.V. are employees of ICON and performed contracted research for Takeda, in connection with this study. A.M., L.H., and S.S. are employees of and own stock/stock options in Takeda.

Funding: This study was funded by Shire, a Takeda company.

Acknowledgment: The authors thank Rosalind Bonomally, MSc, of Excel Scientific Solutions, who provided medical writing assistance funded by Takeda.

Keywords: preterm; chronic lung disease of infancy; bronchopulmonary dysplasia; Delphi