Clinical characteristics and risk factors of bronchopulmonary dysplasia in premature infants ≤32 weeks at high altitude and low altitude / 中国小儿急救医学

ABSTRACT

Objective:To analyze the risk factors and clinical features of premature infants with bronchopulmonary dysplasia(BPD)at high altitude in Tibet and low altitude in Beijing.Methods:A retrospective case-control study was conducted.The clinical data of children with gestational age ≤32 weeks admitted to the Department of Neonatology of Lhasa People′s Hospital(altitude of 3 600 m)and the Department of Neonatology of Children′s Hospital Affiliated to Capital Institute of Pediatrics(altitude of 50 m)from January 1, 2018 to December 31, 2021 were collected.Cases were divided into BPD group and non-BPD group.Premature infants with BPD were divided into high altitude group and low altitude group according to different altitudes.The clinical characteristics and high risk factors of BPD were analyzed.Results:There were 379 premature infants with gestational age ≤32 weeks, 351 were included in the study, including 110 cases in group and 241 cases in non-BPD group.There were 48 cases in high altitude group and 62 cases in low altitude group.The incidence of BPD in high altitude areas(Lhasa)was 38.7%(48/124), among which mild, moderate and severe BPD accounted for 75.0%(36 cases), 18.8%(9 cases)and 6.3%(3 cases), respectively.The incidence rates of BPD were 100%(2/2), 86.7%(13/15)and 38.7%(33/107) in gestational age <28 weeks, 28 to 29 + 6 weeks and 30 to 32 weeks, respectively.There was a statistically significant difference among different gestational age groups( χ2=19.696, P<0.001). The incidence of BPD in low altitude areas(Beijing)was 27.3%(62/227), among which mild, moderate and severe BPD accounted for 74.2%(46 cases), 4.8%(3 cases)and 21.0%(13 cases), respectively.The incidence rates of BPD in gestational age<28 weeks, 28 to 29 + 6 weeks and 30 to 32 weeks were 100%(15/15), 45.6%(36/79)and 8.3%(11/133), respectively.There was a statistically significant difference among different gestational age groups( χ2=77.474, P<0.001). The incidence of BPD in high altitude areas was significantly higher than that in low altitude areas( χ2=4.841, P=0.028). Multivariate regression analysis showed that high altitude( OR 146.893, 95% CI 19.044-1 133.064), birth weight( OR 0.996, 95% CI 0.993-0.999), asphyxia( OR 4.187, 95% CI 3.020-21.670), non-invasive mechanical ventilation( OR 1.171, 95% CI 1.106-1.240)and invasive mechanical ventilation( OR 1.198, 95% CI 1.065-1.347)were significantly correlated with the occurrence of BPD.The gestational age at birth, small for gestational age infant, the fraction of inspired oxygen and the incidence of pregnancy induced hypertension in pregnant women in high altitude group were higher than those in low altitude group( P<0.05). The incidence of patent ductus arteriosus, the use time of noninvasive and invasive mechanical ventilation, the length of hospital stay, the age of mother, the application of prenatal hormone and the twin ratio in high altitude group were significantly lower than those in low altitude group( P<0.05). Conclusion:High altitude in Tibet is a high-risk factor for the occurrence of BPD in preterm infants.Strengthening maternal health care in high altitude areas of Tibet and doing a good job in asphyxia resuscitation in delivery room may be important measures to reduce BPD in preterm infants.