Silva Ana Paula, Greco Marília, Fausto Maria Arlene, Carneiro Mariângela
Programa de Pós-Graduação em Ciências da Saúde: Infectologia e Medicina Tropical. Faculdade de Medicina. Universidade Federal de Minas Gerais. Belo Horizonte, MG, Brasil.
Projeto Horizonte. Universidade Federal de Minas Gerais. Belo Horizonte, MG, Brasil.
Rev Saude Publica. 2017 Jun 26;51:60. doi: 10.1590/S1518-8787.2017051006681.
The objective of this study is to estimate the attrition rates and evaluate factors associated with loss to follow-up between 1994 and 2011 in an open cohort of HIV-negative men who have sex with men.
The Project Horizonte is an open cohort study that aimed to assess the incidence of HIV infection, evaluate the impact of educational interventions, and identify potential volunteers for HIV vaccine trials. The rates of losses to follow-up were estimated for three periods (1994-1999, 2000-2005, and 2006-2011). The variables analyzed were collected in a psychosocial questionnaire. Volunteers who dropped out were compared with the ones who remained in the study using a Cox regression model.
A total of 1,197 volunteers were recruited. The median follow-up time in the study (n = 626) was 4.2 years. The median follow-up time for the volunteers who dropped out of the study (n = 571) was 1.46 years. The overall rate of loss to follow-up was 11.6/100 person-years. Attrition rates by period were: 12.60 (1994-1999), 11.80 (2000-2005), and 9.00 (2006-2011) per 100 person-years. Factors associated with losses to follow-up were: age group of 21-30 years old, monthly per capita income of more than six or less than one Brazilian minimum wage, having more than two dependents, report of bisexual practice, and inconsistent use of condoms for receptive anal sex.
A slight decrease of the loss to follow-up was observed over time. Higher attrition rates happened in the first three years of follow-up. It is possible that the link of the volunteers were not yet well established. Those who reported inconsistent condom use in receptive anal sex were more likely to leave the study, suggesting an underestimation of the incidence of HIV infection in a cohort population. For greater effectiveness, retention strategies must be reassessed considering the connection between the characteristics of homosexual and bisexual behavior and the motivations to engage in health research.
本研究的目的是估计1994年至2011年间，一个男男性行为HIV阴性开放队列中的失访率，并评估与失访相关的因素。
地平线项目是一项开放队列研究，旨在评估HIV感染的发生率，评估教育干预措施的影响，并识别HIV疫苗试验的潜在志愿者。估计了三个时期（1994 - 1999年、2000 - 2005年和2006 - 2011年）的失访率。分析的变量收集于一份社会心理调查问卷中。使用Cox回归模型将退出的志愿者与留在研究中的志愿者进行比较。
共招募了1197名志愿者。研究中（n = 626）的中位随访时间为4.2年。退出研究的志愿者（n = 571）的中位随访时间为1.46年。总体失访率为11.6/100人年。各时期的失访率分别为：1994 - 1999年每100人年12.60、2000 - 2005年每100人年11.80、2006 - 2011年每100人年9.00。与失访相关的因素有：年龄在21 - 30岁之间、月人均收入高于或低于一个巴西最低工资、有两个以上受抚养人、报告有双性恋行为以及在接受肛交时避孕套使用不一致。
随着时间的推移，观察到失访率略有下降。随访的前三年失访率较高。可能是志愿者之间的联系尚未很好地建立。那些报告在接受肛交时避孕套使用不一致的人更有可能离开研究，这表明在队列人群中对HIV感染发生率的估计可能偏低。为了提高有效性，必须重新评估留存策略，考虑同性恋和双性恋行为特征与参与健康研究动机之间的联系。
