Risk factors and clinical outcomes of pulmonary hypertension associated with bronchopulmonary dysplasia in extremely premature infants: A systematic review and meta‐analysis

This systematic review and meta-analysis evaluated the risk factors for bronchopulmonary dysplasia associated pulmonary hypertension (BPD-PH) in extremely premature infants (gestational age < 32 weeks) and its impact on outcomes. A computerized search of eight databases was performed, from the time of library construction to February 2024. The quality of the included studies was assessed with the Newcastle‒Ottawa scale. Statistical analyses were performed using RevMan 5.4.1 and Stata 16.0 software. Meta-analysis of 2137 extremely premature infants revealed that oligohydramnios (OR = 2.21, 95% CI 1.06-4.61), low gestational age (SMD = -0.36, 95% CI -0.47 to -0.24), low birth weight (SMD = -0.54, 95% CI -0.74 to -0.35), small for gestational age (OR = 1.61, 95% CI 1.06-2.44), neonatal respiratory distress syndrome (OR = 2.05, 95% CI 1.45-2.91), grade III bronchopulmonary dysplasia (OR = 4.67, 95% CI 1.34-16.30), and sepsis (OR = 2.25, 95% CI 1.69-4.66) were risk factors for BPD-PH, whereas antenatal steroids (OR = 0.66, 95% CI 0.49-0.88) were protective factors. BPD-PH led to the extension of oxygen therapy (SMD = 0.67, 95% CI 0.42-0.92) and hospital stay (SMD = 0.77, 95% CI 0.14-1.40), and elevated the risk of discharged on oxygen (OR = 2.77, 95% CI 1.35-5.70) and death (OR = 4.38, 95% CI 2.21-8.69). BPD-PH is a multifactorial disease. In this study, a total of seven risk factors, and one protective factor for BPD-PH were identified in extremely premature infants. By managing and mitigating these factors, it is possible to decrease the occurrence of BPD-PH. Furthermore, BPD-PH may increase the risk of a poor prognosis in extremely premature infants.