Voge Gretchen A, Katusic Slavica K, Qin Rui, Juhn Young J
Department of Pediatrics, Hennepin County Medical Center, Minneapolis, Minn.
Department of Health Sciences Research, Mayo Clinic, Rochester, Minn.
J Allergy Clin Immunol Pract. 2015 Nov-Dec;3(6):905-10. doi: 10.1016/j.jaip.2015.03.018. Epub 2015 May 2.
The risk of asthma, specifically in former late preterm infants, has not been well defined. Covariate imbalance and lack of controlling for this has led to inconsistent results in prior studies.
The objective of this study was to determine the risk of asthma in former late preterm infants using a propensity score approach.
The study was a population-based birth cohort study. Study subjects were all children born in Rochester, Minn, between 1976 and 1982. Asthma status during the first 7 years of life was assessed by applying predetermined criteria. The propensity score was formulated using 15 covariates by fitting a logistic regression model for late preterm birth versus term birth. We applied the propensity score method to match late preterm infants (34 0/7 to 36 6/7 weeks of gestation) to term infants (37 0/7 to 40 6/7 weeks of gestation) within a caliper of 0.2 standard deviation of logit of propensity score.
Of the eligible 7040 infants, 5915 children had complete data. Before propensity score matching, late preterm infants had a higher risk of asthma (20 of 262, 7.6%) compared with full-term infants (272 of 5653, 4.8%) (P = .039). There was significant covariate imbalance between comparison groups. After matching with propensity scores, we found that former late preterm infants had a similar risk of asthma to the matched full-term infants (6.6% vs 7.7%, respectively, P = .61), and the result was consistent with covariate-adjustment Cox regression models controlling for significant covariates (P = .57).
A late preterm birth history is not independently associated with childhood asthma, as the reported risk of asthma among former late preterm infants appears to be due to covariate imbalance.
哮喘风险，尤其是既往晚期早产儿的哮喘风险，尚未得到明确界定。协变量不平衡以及对此缺乏控制导致既往研究结果不一致。
本研究的目的是采用倾向评分法确定既往晚期早产儿患哮喘的风险。
本研究为基于人群的出生队列研究。研究对象为1976年至1982年在明尼苏达州罗切斯特市出生的所有儿童。通过应用预定标准评估生命最初7年的哮喘状况。通过对晚期早产与足月出生拟合逻辑回归模型，使用15个协变量制定倾向评分。我们应用倾向评分法在倾向评分对数的0.2标准差范围内，将晚期早产儿（妊娠34⁰/₇至36⁶/₇周）与足月儿（妊娠37⁰/₇至40⁶/₇周）进行匹配。
在符合条件的7040名婴儿中，5915名儿童有完整数据。在倾向评分匹配前，晚期早产儿患哮喘的风险（262例中的20例，7.6%）高于足月儿（5653例中的272例，4.8%）（P = .039）。比较组之间存在显著的协变量不平衡。在进行倾向评分匹配后，我们发现既往晚期早产儿患哮喘的风险与匹配的足月儿相似（分别为6.6%和7.7%，P = .61），并且该结果与控制显著协变量的协变量调整Cox回归模型一致（P = .57）。
晚期早产史与儿童哮喘无独立关联，因为既往晚期早产儿中报告的哮喘风险似乎是由于协变量不平衡所致。
