Institute for Global Health, University College London, 30 Guilford Street, London WC1N 1EH, UK.
Univ. Grenoble Alpes, CNRS, INRAE, Grenoble INP, GAEL, 38000 Grenoble, France.
Health Policy Plan. 2020 May 1;35(4):408-415. doi: 10.1093/heapol/czz155.
Social desirability bias, which is the tendency to under-report socially undesirable health behaviours, significantly distorts information on sensitive behaviours that is gained from self-reports. As a result, self-reported condom use among high-risk populations is thought to be systematically over-reported, and it is impossible to identify the determinants of condom use. The main objective of the article is to elicit unbiased information on condom use among female sex workers (FSWs) using the double list experiment method to analyse the role of HIV infection and exposure to HIV prevention methods in condom use. More specifically, the difference in levels of condom use between HIV-positive and HIV-negative FSWs is estimated. In addition, the role of FSWs' registration and participation in a pre-exposure prophylaxis (PrEP) demonstration project in condom use is considered. A list experiment was designed to elicit condom use information from 786 FSWs in Senegal who were surveyed in 2015 and 2017. Using the list experiment method, participants were randomly assigned to one of two groups (treatment or control) and were asked to report the number of statements they agreed with. Respondents assigned to the control group were presented with three non-sensitive items, whereas those allocated to the treatment group were presented with the same three statements plus the sensitive item (e.g. 'I used a condom during my last intercourse with a client'). Comparing the average number of sentences that were agreed with in both groups provides an estimation of the condom use rate in the treatment group and estimating such prevalence for several sub-groups allows the role of HIV infection risk in condom use to be identified. The percentage of FSWs using condoms in their last sexual intercourse with a client was 80% in 2015 and 78% in 2017, which was significantly lower than the 97% obtained in the face-to-face surveys in both waves. When estimating condom use among sub-groups with the list experiment method, we found that condom use among HIV-positive FSWs was only 34%, which was 47 percentage points lower than condom use among HIV-negative FSWs. We also found that registered FSWs are more likely to use condoms than clandestine FSWs. However, we did not find any difference in condom use between FSWs who were enrolled in the PrEP demonstration project and those who were not enrolled. Health policies should therefore aim to increase condom use among HIV-positive FSWs.
社会期望偏差，即倾向于少报社会上不受欢迎的健康行为，会严重扭曲通过自我报告获得的敏感行为信息。因此，高风险人群中自我报告的避孕套使用情况被认为是系统地被高估了，并且无法确定避孕套使用的决定因素。本文的主要目的是使用双列表实验方法获取关于女性性工作者（FSW）避孕套使用的无偏信息，以分析 HIV 感染和接触 HIV 预防方法在避孕套使用中的作用。更具体地说，估计 HIV 阳性和 HIV 阴性 FSW 之间的避孕套使用水平差异。此外，还考虑了 FSW 登记和参与暴露前预防（PrEP）示范项目在避孕套使用中的作用。设计了一个列表实验，以从 2015 年和 2017 年在塞内加尔接受调查的 786 名 FSW 中获取避孕套使用信息。使用列表实验方法，参与者被随机分配到两组（处理组或对照组），并被要求报告他们同意的陈述数量。对照组的受访者被呈现三个非敏感项目，而分配到处理组的受访者则被呈现三个相同的陈述加上敏感项目（例如，“我在与客户的最后一次性交中使用了避孕套”）。比较两组中同意的陈述的平均数量，可以估计处理组中避孕套的使用率，并对几个亚组进行这种流行率估计，可以确定 HIV 感染风险在避孕套使用中的作用。2015 年和 2017 年，FSW 在与客户的最后一次性交中使用避孕套的比例分别为 80%和 78%，明显低于两个波次的面对面调查中获得的 97%。使用列表实验方法估计亚组中的避孕套使用情况时，我们发现 HIV 阳性 FSW 中避孕套的使用率仅为 34%，比 HIV 阴性 FSW 低 47 个百分点。我们还发现，注册的 FSW 使用避孕套的可能性大于秘密的 FSW。然而，我们没有发现参加 PrEP 示范项目的 FSW 和未参加的 FSW 之间在避孕套使用方面有任何差异。因此，卫生政策应旨在提高 HIV 阳性 FSW 中避孕套的使用。
