Financial Incentives and Deposit Contracts to Promote HIV Retesting in Uganda: a randomized trial

Background: Frequent retesting for HIV among persons at increased risk of HIV infection is critical to early HIV diagnosis of persons and delivery of combination HIV prevention services. There are few evidence-based interventions for promoting frequent retesting for HIV. We sought to determine the effectiveness of financial incentives and deposit contracts in promoting quarterly HIV retesting among adults at increased risk of HIV. Methods and Findings: In peri-urban Ugandan communities from October-December 2018, we randomized HIV-negative adults with self-reported risk to one of three strategies to promote HIV retesting: (1) no incentive; (2) cash incentives (US$7) for retesting at 3 and 6 months (total $14); or (3) deposit contracts: participants could voluntarily deposit $6 at baseline and at 3 months that would be returned with interest (total US$7) upon retesting at 3 and 6 months (total $14) or lost if participants failed to retest. The primary outcome was retesting for HIV at both 3 and 6 months. Of 1,482 persons screened for study eligibility following community-based recruitment, 524 participants were randomized to either no incentive (N=180), incentives (N=172), or deposit contracts (N=172): median age was 25 years (IQR: 22-30), 44% were women, and median weekly income was US$13.60 (IQR: $8.16-21.76). Among participants randomized to deposit contracts, 24/172 (14%) made a baseline deposit, and 2/172 (1%) made a 3-month deposit. In intent-to-treat analyses, HIV retesting at both 3 and 6 months was significantly higher in the incentive arm (89/172 [52%]) than either the control arm (33/180 [18%], odds ratio, OR 4.8, 95% CI: 3.0-7.7, p<0.001) or the deposit contract arm (28/172 [16%], OR 5.5, 95% CI: 3.3-9.1, p<0.001). Among those in the deposit contract arm who made a baseline deposit, 20/24 (83%) retested at 3 months; 11/24 (46%) retested at both 3 and 6 months. Study limitations include measurement of retesting at the clinic where baseline enrollment occurred, only offering clinic-based (rather than community-based) HIV retesting and lack of measurement of retesting after completion of the trial to evaluate sustained retesting behavior. Conclusions: Offering financial incentives to high-risk adults in Uganda resulted in significantly higher HIV retesting. Deposit contracts had low uptake and overall did not increase retesting. As part of efforts to increase early diagnosis of HIV among high-risk populations, strategic use of incentives to promote retesting should receive greater consideration by HIV programs.

背景：对于人类免疫缺陷病毒（HIV, Human Immunodeficiency Virus）感染风险升高人群而言，频繁接受HIV检测对于实现感染者早诊断以及提供组合式HIV预防服务至关重要。目前针对推广HIV定期复检测试的循证干预措施相对匮乏。本研究旨在评估经济激励与押金合约策略在促进HIV感染高风险成人每季度接受HIV复检测试中的有效性。

研究对象与研究结果：2018年10月至12月期间，在乌干达城郊社区中，我们将自我报告存在感染风险的HIV阴性成人随机分为三类复检测试推广策略组：(1) 无激励组；(2) 现金激励组：在第3个月和第6个月完成复检测试即可获得7美元现金奖励，总奖励金额为14美元；(3) 押金合约组：参与者可自愿在基线及第3个月缴纳6美元押金，若在第3个月和第6个月完成复检测试，可获得本金及共计7美元的利息返还（总返还金额为14美元），未完成检测者则损失押金。本研究的主要结局为同时在第3个月和第6个月完成HIV复检测试。

通过社区招募渠道共筛选1482名符合研究入组资格的受试者，最终524名参与者被随机分配至无激励组（N=180）、现金激励组（N=172）或押金合约组（N=172）。受试者中位年龄为25岁（四分位距：22~30），其中女性占比44%，周收入中位数为13.60美元（四分位距：8.16~21.76美元）。在押金合约组受试者中，共有24/172（14%）的参与者完成了基线押金缴纳，2/172（1%）的参与者完成了第3个月的押金缴纳。

意向治疗分析结果显示，现金激励组同时在第3个月和第6个月完成HIV复检测试的受试者占比（89/172 [52%]）显著高于无激励组（33/180 [18%]，比值比OR=4.8，95%置信区间CI: 3.0~7.7，p<0.001）与押金合约组（28/172 [16%]，OR=5.5，95%CI: 3.3~9.1，p<0.001）。在押金合约组中完成基线押金缴纳的受试者中，20/24（83%）在第3个月完成了复检测试，11/24（46%）同时在第3个月和第6个月完成了复检测试。

本研究存在以下局限性：仅在基线入组的临床机构进行复检测试结果的统计，仅提供临床而非社区场景下的HIV复检测试服务，且未评估试验结束后的复检测试行为以验证复检测试行为的持续性。

结论：为乌干达的高风险成人提供经济激励可显著提升HIV复检测试率。押金合约组的参与率较低，且整体未能提升复检测试率。在提升高风险人群HIV早诊断能力的相关工作中，HIV防控项目应更战略性地考虑使用激励措施以推广复检测试。