School of Public Health, The University of Queensland, Herston 4006, Australia.
School of Public Health, The University of Queensland, Herston 4006, Australia; School of Social Sciences, The University of Queensland, St. Lucia 4067, Australia.
J Psychiatr Res. 2019 Mar;110:127-142. doi: 10.1016/j.jpsychires.2018.12.022. Epub 2018 Dec 24.
Survey research frequently involves missing cases attributable to refusals to participate, lack of success in accessing all potential respondents or loss to follow-up in longitudinal studies. There is concern that those not recruited or those lost are a select group whose absence from a study may bias the findings of the study. This study provides a test of the extent to which selective loss to follow-up in a longitudinal study may lead to biased findings. The Mater-University Study of Pregnancy collected baseline information for 7718 pregnant women. Follow-ups occurred five years, 14 years, 21 years and 27 years after the birth, for 6753 eligible women. Participants at baseline were partitioned according to follow-up status for each follow-up. We compare baseline (at recruitment) measures of association, with these same measures of association for those retained in the study (Group A) and those lost to follow-up (Group B) at each phase of data. Using univariate logistic regression we compared the strength of association between maternal mental health and various baseline socio-demographic factors for different rates of loss to follow-up. Estimates of association at baseline, and at each follow-up are similar irrespective of the rate of loss to follow-up and whether the comparison is with those retained in the study or those lost to follow-up. There were no statistically significant differences in 90.8% of baseline comparisons with Group A, and 96.9% of comparisons with Group B measures of association. We conclude that differential loss to follow-up rarely affects estimates of association. We suggest that loss to follow-up may produce misleading findings only in circumstances where loss to follow-up is combined with a number of other sources of bias.
调查研究经常涉及由于拒绝参与、未能成功联系到所有潜在受访者或纵向研究中随访失败而导致的缺失案例。人们担心那些未被招募或失去联系的人是一个选择群体，他们的缺席可能会使研究结果产生偏差。本研究检验了纵向研究中选择性随访缺失在多大程度上可能导致有偏差的研究结果。Mater-University 妊娠研究为 7718 名孕妇收集了基线信息。对于 6753 名符合条件的女性，在分娩后 5 年、14 年、21 年和 27 年进行了随访。根据每次随访的随访情况，将基线参与者进行分组。我们比较了基线（招募时）的关联度量，以及在每个阶段研究中保留的参与者（A 组）和随访丢失的参与者（B 组）的相同关联度量。我们使用单变量逻辑回归比较了母亲心理健康与各种基线社会人口因素之间的关联强度，以确定不同的随访丢失率。基线和每次随访的关联估计值与随访丢失率无关，无论比较对象是研究中保留的参与者还是随访丢失的参与者，结果都是相似的。与 A 组相比，90.8%的基线比较和 96.9%的与 B 组比较的关联估计没有统计学差异。我们得出结论，随访丢失率差异很少影响关联估计。我们认为，只有在随访丢失与其他一些来源的偏差相结合的情况下，随访丢失才会产生误导性的研究结果。
