Evans D J, Levene M I
Centre for Reproduction, Growth and Development, University of Leeds, D Floor Clarendon Wing, The General Infirmary at Leeds, Leeds LS2 9NS, UK.
Arch Dis Child Fetal Neonatal Ed. 2001 Mar;84(2):F79-84. doi: 10.1136/fn.84.2.f79.
To determine by how much selection bias in preterm infant cohort studies results in an overestimate of survival.
Systematic review of studies reporting survival in infants less than 28 weeks of gestation published 1978-1998. Studies were graded according to cohort definition: A, stillbirths and live births; B, live births; C, neonatal unit admissions. Proportions of infants surviving to discharge were calculated for each week of gestation.
Sixty seven studies report data on 55 cohorts (16 grade A, 23 grade B, 16 grade C). Studies that are more selective report significantly higher survival between 23 and 26 weeks of gestation (grade C > grade B > grade A, p < 0.01), exaggerating survival by 100% and 56% at 23 and 24 weeks respectively.
To minimise the potential for overestimating survival around the limits of viability, future studies should endeavour to report the outcome of all pregnancies for each week of gestation (terminations, miscarriages, stillbirths, and all live births).
确定早产婴儿队列研究中的选择偏倚会使生存估计值高估多少。
对1978年至1998年发表的有关妊娠小于28周婴儿生存情况的研究进行系统综述。根据队列定义对研究进行分级：A组，死产和活产；B组，活产；C组，新生儿病房入院病例。计算每孕周存活至出院的婴儿比例。
67项研究报告了55个队列的数据（16个A组、23个B组、16个C组）。选择性更强的研究报告在妊娠23至26周之间的生存率显著更高（C组>B组>A组，p<0.01），在23周和24周时分别将生存率高估了100%和56%。
为尽量减少在生存能力极限附近高估生存率的可能性，未来的研究应努力报告每孕周所有妊娠的结局（终止妊娠、流产、死产和所有活产）。
