ESTIMATING CAUSAL EFFECTS OF HIV PREVENTION INTERVENTIONS WITH INTERFERENCE IN NETWORK-BASED STUDIES AMONG PEOPLE WHO INJECT DRUGS

• 成果类型: Article
• 署名作者: Lee, Tingfang; Buchanan, Ashley L.; Katenka, Natallia, V; Forastiere, Laura; Halloran, M. Elizabeth; Friedman, Samuel R.; Nikolopoulos, Georgios
• 署名单位: University of Rhode Island; University of Rhode Island; Yale University; Fred Hutchinson Cancer Center; University of Washington; University of Washington Seattle; New York University; University of Cyprus
• 刊物名称: ANNALS OF APPLIED STATISTICS
• ISSN/ISSBN: 1932-6157
• DOI: 10.1214/22-AOAS1713
• 发表日期: 2023
• 页码: 2165-2191
• 关键词: inference; RISK; epidemiology; infection; athens; users

摘要

Evaluating causal effects in the presence of interference is challenging in network-based studies of hard-to-reach populations. Like many such populations, people who inject drugs (PWID) are embedded in social networks and one person's treatment can affect the outcomes of others in the network. In our setting, the study design is observational with a nonrandomized network based HIV prevention intervention. Information is available on each participant and their connections that confer possible HIV risk through injection and sexual behaviors. We considered two inverse probability weighted (IPW) estimators to quantify the population-level spillover effects of nonrandomized interventions on subsequent health outcomes. We demonstrated that these two IPW estimators are consistent, asymptotically normal, and derived a closed form estimator for the asymptotic variance, while allowing for overlapping interference sets (groups of individuals in which the interference is assumed possible). A simulation study was conducted to evaluate the finite-sample performance of the estimators. We analyzed data from the Transmission Reduction Intervention Project which ascertained a network of PWID and their contacts in Athens, Greece, from 2013 to 2015. We evaluated the effects of community alerts on subsequent HIV risk behavior in this observed network, where the connections or links between participants were defined by using substances or having unprotected sex together. In the study, community alerts were distributed to inform people of recent HIV infections among individuals in close proximity in the observed network. The estimates of the risk differences for spillover, using either IPW estimator demonstrated a protective effect. The results suggest that HIV risk behavior could be mitigated by exposure to a community alert when an increased risk of HIV is detected in the network.