Martín I, Gibert M J, Aulesa C, Alsina M, Casals E, Bauça J M
Servicio de Análisis Clínicos, Hospital Universitario Son Espases, Palma, Mallorca, Spain.
Servicio de Obstetricia y Ginecología, Hospital Universitario Son Espases, Palma, Mallorca, Spain.
Eur J Obstet Gynecol Reprod Biol. 2015 Jun;189:13-8. doi: 10.1016/j.ejogrb.2015.03.016. Epub 2015 Mar 23.
To compare a contingent strategy with a combined strategy for prenatal detection of Down's syndrome (DS) in terms of cost, outcomes and safety.
The contingent strategy was based on a simulation, removing measurement of the free beta subunit of human chorionic gonadotropin (free βhCG) and calculating the DS risk retrospectively in 32,371 pregnant women who had been screened with the combined strategy in the first trimester. In the contingent strategy, a risk between 1:31 and 1:1000 in the first trimester indicated further testing in the second trimester (alpha-fetoprotein, inhibin A, unconjugated oestriol and free βhCG). The cut-off risk values for the contingent and combined strategies in the first trimester were 1:30 and 1:250, respectively, and the cut-off risk value for integrated screening in the second trimester was 1:250. Costs were compared in terms of avoided DS births, and the ratio of loss of healthy fetuses following invasive procedures per avoided DS birth was calculated.
The combined strategy had sensitivity of 40/44 (90.9%) and a false-positive rate of 2.8%. Corresponding values for the contingent strategy were 39/44 (88.6%) and 1.3%, respectively. Only 11% of pregnant women required tests in the second trimester, and the approximate cost reduction for each avoided DS birth was 5000€. The ratio of lost healthy fetuses following invasive procedures per avoided DS birth improved by up to 0.65.
The contingent strategy has similar effectiveness to the combined strategy, but has lower costs and fewer invasive procedures.
在成本、结果和安全性方面，比较唐氏综合征（DS）产前检测的应急策略和联合策略。
应急策略基于一项模拟研究，去除人绒毛膜促性腺激素游离β亚基（游离βhCG）的检测，并对32371例在孕早期采用联合策略进行筛查的孕妇进行回顾性唐氏综合征风险计算。在应急策略中，孕早期风险在1:31至1:1000之间表明需在孕中期进一步检测（甲胎蛋白、抑制素A、非结合雌三醇和游离βhCG）。应急策略和联合策略在孕早期的截断风险值分别为1:30和1:250，孕中期综合筛查的截断风险值为1:250。根据避免的唐氏综合征患儿出生数比较成本，并计算每例避免的唐氏综合征患儿出生所对应的侵入性操作后健康胎儿丢失率。
联合策略的灵敏度为40/44（90.9%），假阳性率为2.8%。应急策略的相应值分别为39/44（88.6%）和1.3%。仅11%的孕妇需要在孕中期进行检测，每例避免的唐氏综合征患儿出生的成本降低约5000欧元。每例避免的唐氏综合征患儿出生所对应的侵入性操作后健康胎儿丢失率改善了0.65。
应急策略与联合策略效果相似，但成本更低，侵入性操作更少。
