Data from: Association between total dose of ritodrine hydrochloride and pulmonary edema in twin pregnancy: a retrospective cohort study in Japan

Objective
Pulmonary edema is recognized as a severe side effect of ritodrine hydrochloride. Recently, the number of twin pregnancies has been increasing. Few studies have reported the association between total dose of ritodrine hydrochloride prior to delivery and pulmonary edema in twin pregnancy. We aimed to examine this association and determine the optimal cutoff threshold of total ritodrine hydrochloride dose to predict the incidence of pulmonary edema in twin pregnancy, based on obstetric records.
Design
Retrospective cohort study.
Setting
Yamanashi Prefectural Central Hospital, Japan
Participants
Two hundred twenty-six women with twin pregnancy who delivered at Yamanashi Prefectural Central Hospital between September 2009 and November 2016
Methods
The obstetric records of the participants were analyzed. We defined one unit of ritodrine hydrochloride as 72 mg per 24 h continuous transfusion at 50 µg/min to calculate the dose of ritodrine used for tocolysis.
Outcome measures
Multivariable logistic regression analysis was performed to examine the association between total dose of ritodrine hydrochloride used for threatened preterm labor and pulmonary edema, while controlling for potential confounding factors. Then, a receiver-operating characteristic curve was used to determine the optimal cutoff of total ritodrine dose to predict pulmonary edema incidence.
Results
Mean maternal age was 32 (range, 18-46) years; 143 participants were nulliparous (63.3%), 109 had (48.2%) term deliveries, and 194 (85.8%) had cesarean deliveries. The overall incidence of pulmonary edema was 13.7% (31/226). Multivariable analysis showed that the total dose of ritodrine was significantly associated with pulmonary edema (adjusted odds ratio 1.02; 95% confidence interval, 1.004-1.03). The best cut-off point to predict the incidence of pulmonary edema was 26 units (1872 mg) (sensitivity, 61.3%; specificity, 87.8%).
Conclusion
Our results suggest that consideration of the total dose of ritodrine hydrochloride is helpful in the management of patients with threatened preterm labor in twin pregnancy.

研究目的：肺水肿（pulmonary edema）是盐酸利托君（ritodrine hydrochloride）公认的严重不良反应。近年来，双胎妊娠（twin pregnancy）的发生率呈上升趋势。目前鲜有研究探讨双胎妊娠孕妇分娩前盐酸利托君总剂量与肺水肿发生的相关性。本研究旨在基于产科病历，分析该相关性，并确定可预测双胎妊娠孕妇肺水肿发生的盐酸利托君总剂量最佳截断值。
研究设计：回顾性队列研究。
研究地点：日本山梨县立中央医院（Yamanashi Prefectural Central Hospital）
研究对象：2009年9月至2016年11月期间于日本山梨县立中央医院分娩的226名双胎妊娠孕妇。
研究方法：对研究对象的产科病历进行回顾分析。本研究将每24小时以50μg/min的速率持续输注的72mg盐酸利托君定义为1个单位，以此计算宫缩抑制治疗（tocolysis）所用的盐酸利托君剂量。
结局指标：采用多变量logistic回归分析，在控制潜在混杂因素的前提下，探讨先兆早产（threatened preterm labor）患者所用盐酸利托君总剂量与肺水肿的相关性；随后采用受试者工作特征曲线（receiver-operating characteristic curve）确定预测肺水肿发生的盐酸利托君总剂量最佳截断值。
研究结果：孕妇平均年龄为32岁（范围：18~46岁）；其中初产妇（nulliparous）143名，占比63.3%；足月分娩109名，占比48.2%；剖宫产分娩194名，占比85.8%。总体肺水肿发生率为13.7%（31/226）。多变量分析显示，盐酸利托君总剂量与肺水肿发生显著相关（校正后比值比为1.02；95%置信区间：1.004~1.03）。预测肺水肿发生的最佳截断值为26个单位（1872mg），灵敏度为61.3%，特异度为87.8%。
研究结论：本研究结果提示，在双胎妊娠先兆早产患者的临床管理中，考量盐酸利托君总剂量具有重要临床参考价值。