Halpern Vera, Obunge Orikomaba, Ogunsola Folasade, Otusanya Sakiru, Umo-Otong John, Wang Chin-Hua, Mehta Neha
Family Health International, Research Triangle Park, NC, USA.
BMC Med Res Methodol. 2009 Jun 23;9:44. doi: 10.1186/1471-2288-9-44.
Lower-than-expected incidence of HIV undermines sample size calculations and compromises the power of a HIV prevention trial. We evaluated the effectiveness of interim monitoring of HIV infection rates and on-going modification of recruitment strategies to enroll women at higher risk of HIV in the Cellulose Sulfate Phase III study in Nigeria.
We analyzed prevalence and incidence of HIV and other sexually transmitted infections, demographic and sexual behavior characteristics aggregated over the treatment groups on a quarterly basis. The site investigators were advised on their recruitment strategies based on the findings of the interim analyses.
A total of 3619 women were screened and 1644 enrolled at the Ikeja and Apapa clinics in Lagos, and at the Central and Peripheral clinics in Port Harcourt. Twelve months after study initiation, the overall incidence of HIV was less than one-third of the pre-study assumption, with rates of HIV that varied substantially between clinics. Due to the low prevalence and incidence rates of HIV, it was decided to close the Ikeja clinic in Lagos and to find new catchment areas in Port Harcourt. This strategy was associated with an almost two-fold increase in observed HIV incidence during the second year of the study.
Given the difficulties in estimating HIV incidence, a close monitoring of HIV prevalence and incidence rates during a trial is warranted. The on-going modification of recruitment strategies based on the regular analysis of HIV rates appeared to be an efficient method for targeting populations at greatest risk of HIV infection and increasing study power in the Nigeria trial.
The trial was registered with the ClinicalTrials.gov registry under #NCT00120770 http://clinicaltrials.gov/ct2/show/NCT00120770.
艾滋病毒感染率低于预期会影响样本量计算，并削弱艾滋病毒预防试验的效力。在尼日利亚进行的硫酸纤维素三期研究中，我们评估了对艾滋病毒感染率进行中期监测以及持续调整招募策略以纳入艾滋病毒感染风险较高女性的有效性。
我们按季度分析了治疗组汇总的艾滋病毒及其他性传播感染的患病率和发病率、人口统计学和性行为特征。根据中期分析结果，就招募策略向各研究点的调查人员提供了建议。
在拉各斯的伊凯贾和阿帕帕诊所以及哈科特港的中心诊所和周边诊所，共筛查了3619名女性，1644名女性入组。研究开始12个月后，艾滋病毒的总体发病率不到研究前假设的三分之一，各诊所之间的艾滋病毒感染率差异很大。由于艾滋病毒的患病率和发病率较低，决定关闭拉各斯的伊凯贾诊所，并在哈科特港寻找新的集水区。这一策略使研究第二年观察到的艾滋病毒发病率增加了近两倍。
鉴于估计艾滋病毒发病率存在困难，在试验期间密切监测艾滋病毒患病率和发病率是必要的。根据艾滋病毒感染率的定期分析持续调整招募策略，似乎是在尼日利亚的试验中针对艾滋病毒感染风险最高人群并提高研究效力的有效方法。
该试验已在ClinicalTrials.gov注册，注册号为#NCT00120770 http://clinicaltrials.gov/ct2/show/NCT00120770 。
