Ioannidis J P, Taha T E, Kumwenda N, Broadhead R, Mtimavalye L, Miotti P, Yellin F, Contopoulos-Ioannidis D G, Biggar R J
HIV Research Branch, Division of AIDS, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA.
Int J Epidemiol. 1999 Aug;28(4):769-75. doi: 10.1093/ije/28.4.769.
Large simple trials which aim to study therapeutic interventions and epidemiological associations of human immunodeficiency virus (HIV) infection, including perinatal transmission, in Africa may have substantial rates of loss to follow-up. A better understanding of the characteristics and the impact of women and children lost to follow-up is needed.
We studied predictors and the impact of losses to follow-up of infants born in a large cohort of delivering women in urban Malawi. The cohort was established as part of a trial of vaginal cleansing with chlorhexidine during delivery to prevent mother-to-infant transmission of HIV.
The HIV infection status could not be determined for 797 (36.9%) of 2156 infants born to HIV-infected mothers; 144 (6.7%) with missing status because of various sample problems and 653 (30.3%) because they never returned to the clinic. Notably, the observed rates of perinatal transmission were significantly lower in infants who returned later for determination of their infection status (odds ratio = 0.94 per month, P = 0.03), even though these infants must have had an additional risk of infection from breastfeeding. In multivariate models, infants of lower birthweight (P = 0.003) and, marginally, singletons (P = 0.09) were less likely to return for follow-up. The parents of infants lost to follow-up tended to be less educated (P < 0.001) and more likely to be in farming occupations, although one educated group, teachers and students, were also significantly less likely to return. Of these variables, infant birthweight, twins versus singletons, and maternal education were also associated with significant variation in the observed risk of perinatal transmission among infants of known HIV status.
Several predictors of loss to follow-up were identified in this large HIV perinatal cohort. Losses to follow-up can impact the observed transmission rate and the risk associations in different studies.
旨在研究人类免疫缺陷病毒（HIV）感染的治疗干预措施及流行病学关联（包括围产期传播）的大型简单试验在非洲可能存在较高的失访率。有必要更好地了解失访妇女和儿童的特征及其影响。
我们研究了马拉维城市地区一大群分娩妇女所生婴儿失访的预测因素及其影响。该队列是作为一项在分娩期间用洗必泰进行阴道清洗以预防HIV母婴传播试验的一部分而建立的。
在2156名HIV感染母亲所生婴儿中，797名（36.9%）的HIV感染状况无法确定；144名（6.7%）因各种样本问题而状态缺失，653名（30.3%）是因为他们再也没有回到诊所。值得注意的是，后来回来确定感染状况的婴儿的围产期传播观察率显著较低（优势比为每月0.94，P = 0.03），尽管这些婴儿肯定有因母乳喂养而增加的感染风险。在多变量模型中，低出生体重婴儿（P = 0.003）以及单胎婴儿（边缘显著，P = 0.09）回来接受随访的可能性较小。失访婴儿的父母往往受教育程度较低（P < 0.001），且更有可能从事农业工作，不过有一个受过教育的群体，即教师和学生，回来的可能性也显著较低。在这些变量中，婴儿出生体重、双胞胎与单胎以及母亲教育程度也与已知HIV感染状况婴儿的围产期传播观察风险的显著差异有关。
在这个大型HIV围产期队列中确定了几个失访的预测因素。失访会影响不同研究中观察到的传播率和风险关联。
