Background

People who inject drugs (PWID) are at increased risk for HIV and hepatitis C virus (HCV) infection and also have high levels of homelessness and unstable housing. We assessed whether homelessness or unstable housing is associated with an increased risk of HIV or HCV acquisition among PWID compared with PWID who are not homeless or are stably housed.

Methods

In this systematic review and meta-analysis, we updated an existing database of HIV and HCV incidence studies published between Jan 1, 2000, and June 13, 2017. Using the same strategy as for this existing database, we searched MEDLINE, Embase, and PsycINFO for studies, including conference abstracts, published between June 13, 2017, and Sept 14, 2020, that estimated HIV or HCV incidence, or both, among community-recruited PWID. We only included studies reporting original results without restrictions to study design or language. We contacted authors of studies that reported HIV or HCV incidence, or both, but did not report on an association with homelessness or unstable housing, to request crude data and, where possible, adjusted effect estimates. We extracted effect estimates and pooled data using random-effects meta-analyses to quantify the associations between recent (current or within the past year) homelessness or unstable housing compared with not recent homelessness or unstable housing, and risk of HIV or HCV acquisition. We assessed risk of bias using the Newcastle-Ottawa Scale and between-study heterogeneity using the I² statistic and p value for heterogeneity.

Findings

We identified 14 351 references in our database search, of which 392 were subjected to full-text review alongside 277 studies from our existing database. Of these studies, 55 studies met inclusion criteria. We contacted the authors of 227 studies that reported HIV or HCV incidence in PWID but did not report association with the exposure of interest and obtained 48 unpublished estimates from 21 studies. After removal of duplicate data, we included 37 studies with 70 estimates (26 for HIV; 44 for HCV). Studies originated from 16 countries including in North America, Europe, Australia, east Africa, and Asia. Pooling unadjusted estimates, recent homelessness or unstable housing was associated with an increased risk of acquiring HIV (crude relative risk [cRR] 1·55 [95% CI 1·23–1·95; p=0·0002]; I²= 62·7%; n=17) and HCV (1·65 [1·44–1·90; p<0·0001]; I²= 44·8%; n=28]) among PWID compared with those who were not homeless or were stably housed. Associations for both HIV and HCV persisted when pooling adjusted estimates (adjusted relative risk for HIV: 1·39 [95% CI 1·06–1·84; p=0·019]; I²= 65·5%; n=9; and for HCV: 1·64 [1·43–1·89; p<0·0001]; I²= 9·6%; n=14). For risk of HIV acquisition, the association for unstable housing (cRR 1·82 [1·13–2·95; p=0·014]; n=5) was higher than for homelessness (1·44 [1·13–1·83; p=0·0036]; n=12), whereas no difference was seen between these outcomes for risk of HCV acquisition (1·72 [1·48–1·99; p<0·0001] for unstable housing, 1·66 [1·37–2·00; p<0·0001] for homelessness).

Interpretation

Homelessness and unstable housing are associated with increased risk of HIV and HCV acquisition among PWID. Our findings support the development of interventions that simultaneously address homelessness and unstable housing and HIV and HCV transmission in this population.

Funding

National Institute for Health Research, National Institute on Drug Abuse, National Institute of Allergy and Infectious Diseases, and Commonwealth Scholarship Commission.

中文翻译：

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无家可归、住房不稳定以及注射吸毒者感染艾滋病毒和丙型肝炎病毒的风险：一项系统回顾和荟萃分析

背景

注射吸毒者 (PWID) 感染艾滋病毒和丙型肝炎病毒 (HCV) 的风险增加，并且无家可归和住房不稳定的情况也很严重。我们评估了与非无家可归或住所稳定的 PWID 相比，无家可归或不稳定的住房是否与 PWID 感染 HIV 或 HCV 的风险增加有关。

方法

在此系统回顾和荟萃分析中，我们更新了 2000 年 1 月 1 日至 2017 年 6 月 13 日期间发布的现有 HIV 和 HCV 发病率研究数据库。使用与该现有数据库相同的策略，我们搜索了 MEDLINE、Embase 和PsycINFO 用于研究，包括会议摘要，于 2017 年 6 月 13 日至 2020 年 9 月 14 日期间发表，估计社区招募的 PWID 中的 HIV 或 HCV 发病率，或两者兼而有之。我们仅纳入报告原始结果的研究，不限制研究设计或语言。我们联系了报告 HIV 或 HCV 发病率或两者但未报告与无家可归或不稳定住房相关的研究的作者，以索取原始数据，并在可能的情况下调整效果估计。我们使用随机效应荟萃分析提取效应估计值并汇总数据，以量化近期（当前或过去一年内）无家可归或不稳定住房与非近期无家可归或不稳定住房与 HIV 或 HCV 感染风险之间的关联。我们使用纽卡斯尔-渥太华量表评估偏倚风险，使用 I²异质性的统计量和 p 值。

发现

我们在数据库搜索中确定了 14351 篇参考文献，其中 392 篇与我们现有数据库中的 277 篇研究进行了全文审查。在这些研究中，55 项研究符合纳入标准。我们联系了 227 项研究的作者，这些研究报告了 PWID 中的 HIV 或 HCV 发病率，但没有报告与感兴趣的暴露的关联，并从 21 项研究中获得了 48 个未发表的估计值。删除重复数据后，我们纳入了 37 项研究和 70 项估计值（26 项针对 HIV；44 项针对 HCV）。研究来自北美、欧洲、澳大利亚、东非和亚洲等 16 个国家。汇总未经调整的估计值、近期无家可归或住房不稳定与感染 HIV 的风险增加相关（粗相对风险 [cRR] 1·55 [95% CI 1·23–1·95；p=0·0002]；I ²= 62·7%；n=17) 和 HCV (1·65 [1·44–1·90; p<0·0001]; I 2 ⁼ 44·8%; n=28])稳定安置。当汇集调整后的估计值时，HIV 和 HCV 的关联仍然存在（HIV 的调整后相对风险：1·39 [95% CI 1·06–1·84；p=0·019]；I 2 = 65·5%；ⁿ = 9；对于 HCV：1·64 [1·43–1·89；p<0·0001]；I ² = 9·6%；n=14）。对于感染 HIV 的风险，不稳定住房 (cRR 1·82 [1·13–2·95；p=0·014]；n=5) 的关联高于无家可归者 (1·44 [1·13– 1·83；p=0·0036]；n=12），而这些结果在 HCV 感染风险方面没有差异（1·72 [1·48–1·99；p<0·0001] 对于不稳定住房，1·66 [1·37–2·00；p<0·0001] 表示无家可归）。

解释

无家可归和不稳定的住房与注射吸毒者感染 HIV 和 HCV 的风险增加有关。我们的研究结果支持制定干预措施，同时解决该人群中的无家可归和不稳定的住房以及 HIV 和 HCV 传播问题。

资金

国家健康研究所、国家药物滥用研究所、国家过敏和传染病研究所以及英联邦奖学金委员会。