Population Study Center, University of Pennsylvania, USA.
Demography. 2010 Aug;47(3):651-65. doi: 10.1353/dem.0.0115.
Despite the increasing number of population-based surveys in sub-Saharan Africa that provide testing and counselingfor HIV over the past decade, understanding the nature ofnonresponse in these surveys, especially panel HIV surveys, is still limited. This article uses longitudinal HIV data collected from rural Malawi in 2004 and 2006 to examine nonresponse in repeat population-based testing. It shows that nonresponse in repeat testing led to significant bias in the estimates of HIV prevalence and to inconsistent conclusions about the predictors of HIV status. In contrast, previous cross-sectional analyses found that nonresponse does not significantly bias the estimates of HIV prevalence. The difference in conclusions from cross-sectional and longitudinal analyses of nonresponse can be attributed to two factors. the different definitions of what constitutes nonresponse in both contexts, and the risk profiles of the missed populations. In particular, although refusal and temporary absence are the major sources ofnonresponse in the cross-sectional contexts, attrition attributable to mortality and out-migration are additional sources of nonresponse in repeat testing. Evidence shows that out-migrants have higher HIV prevalence than nonmigrants, which could account for significant bias in the estimates ofprevalence among participants in both tests observed in this study.
尽管过去十年间，撒哈拉以南非洲地区开展了越来越多的基于人群的调查，为艾滋病毒检测和咨询提供了便利，但对这些调查（特别是面板艾滋病毒调查）中无应答现象的本质仍了解有限。本文利用 2004 年和 2006 年在马拉维农村收集的纵向艾滋病毒数据，考察了重复人群检测中的无应答现象。结果表明，重复检测中的无应答导致艾滋病毒流行率的估计值出现显著偏差，并且对艾滋病毒状况预测因素的结论也不一致。相比之下，之前的横断面分析发现，无应答并不会显著影响艾滋病毒流行率的估计值。横断面和纵向无应答分析得出的结论存在差异，这可以归因于两个因素：两种情况下无应答的定义不同，以及错过人群的风险特征不同。具体而言，虽然拒绝和暂时缺席是横断面情况下无应答的主要原因，但由于死亡和迁移导致的失访也是重复检测中无应答的额外原因。有证据表明，移民的艾滋病毒流行率高于非移民，这可能导致本研究中两次检测参与者的流行率估计值出现显著偏差。
