Section of Psychiatry, Department of Neuroscience, Reproductive Science, and Odontostomatology, Federico Ii University of Naples, Naples, Italy.
Pain and Rehabilitation Centre, and Department of Medical and Health Sciences, Linköping University, SE-581 85, Linköping, Sweden.
BMC Med. 2022 Jul 12;20(1):224. doi: 10.1186/s12916-022-02423-z.
Homelessness has been associated with multiple detrimental health outcomes across observational studies. However, relatively few randomized controlled trials (RCTs) have been conducted on people who experience homelessness (PEH). Thus, this umbrella review ranked the credibility of evidence derived from systematic reviews (SRs) and meta-analyses (MAs) of observational studies investigating the associations between homelessness and any health outcome as well as RCTs targeting health needs in this population.
Several databases were systematically searched from inception through April 28, 2021. Any SR and/or MA reporting quantitative data and providing a control group were eligible for inclusion. The credibility of the evidence derived from observational studies was appraised by considering the significance level of the association and the largest study, the degree of heterogeneity, the presence of small-study effects as well as excess significance bias. The credibility of evidence was then ranked in five classes. For SRs and/or MAs of RCTs, we considered the level of significance and whether the prediction interval crossed the null. The AMSTAR-2 and AMSTAR-plus instruments were adopted to further assess the methodological quality of SRs and/or MAs. The Newcastle-Ottawa Scale (NOS) was employed to further appraise the methodological quality of prospective cohort studies only; a sensitivity analysis limited to higher quality studies was conducted.
Out of 1549 references, 8 MAs and 2 SRs were included. Among those considering observational studies, 23 unique associations were appraised. Twelve of them were statistically significant at the p≤0.005 level. Included cases had worst health-related outcomes than controls, but only two associations reached a priori-defined criteria for convincing (class I) evidence namely hospitalization due to any cause among PEH diagnosed with HIV infection, and the occurrence of falls within the past year among PEH. According to the AMSTAR-2 instrument, the methodological quality of all included SRs and/or MAs was "critically low." Interventional studies were scant.
While homelessness has been repeatedly associated with detrimental health outcomes, only two associations met the criteria for convincing evidence. Furthermore, few RCTs were appraised by SRs and/or MAs. Our umbrella review also highlights the need to standardize definitions of homelessness to be incorporated by forthcoming studies to improve the external validity of the findings in this vulnerable population.
多项观察性研究表明，无家可归与多种不良健康结果相关。然而，针对无家可归者（PEH）的随机对照试验（RCT）相对较少。因此，本伞状综述对系统评价（SR）和荟萃分析（MA）中观察性研究评估无家可归与任何健康结果之间关系的证据的可信度进行了评估，并对针对该人群健康需求的 RCT 进行了评估。
从成立到 2021 年 4 月 28 日，系统地在多个数据库中进行了搜索。任何报告定量数据并提供对照组的 SR 和/或 MA 都符合纳入标准。通过考虑关联的显著性水平和最大研究、异质性程度、小研究效应的存在以及过度显著性偏差，评估来自观察性研究的证据的可信度。然后将证据的可信度分为五个等级。对于 RCT 的 SR 和/或 MA，我们考虑了显著性水平以及预测区间是否穿过零。采用 AMSTAR-2 和 AMSTAR-plus 工具进一步评估 SR 和/或 MA 的方法学质量。仅使用纽卡斯尔-渥太华量表（NOS）进一步评估前瞻性队列研究的方法学质量；进行了仅限于高质量研究的敏感性分析。
在 1549 条参考文献中，纳入了 8 项 MA 和 2 项 SR。在考虑观察性研究的情况下，评估了 23 个独特的关联。其中 12 个在 p≤0.005 水平具有统计学意义。纳入的病例比对照组的健康相关结局更差，但只有两个关联达到了预先定义的可信（I 类）证据标准，即诊断为 HIV 感染的无家可归者因任何原因住院，以及过去一年内无家可归者发生跌倒。根据 AMSTAR-2 工具，所有纳入的 SR 和/或 MA 的方法学质量均为“极低”。干预性研究很少。
尽管无家可归与不良健康结果反复相关，但只有两个关联符合可信证据的标准。此外，很少有 RCT 通过 SR 和/或 MA 进行评估。本伞状综述还强调需要标准化无家可归的定义，以便即将到来的研究纳入，以提高该弱势群体研究结果的外部有效性。
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