Mortality in people experiencing homelessness: a systematic review and meta-analysis

The association between homelessness and the type of homeless experience with all-cause and cause-specific mortality is uncertain.

Published studies were retrieved through a systematic search of MEDLINE, Embase PsycINFO, and Scopus from inception to December 2024. Unpublished data were identified from open-access data archives. We used random-effects meta-analysis to combine the effect estimates from published and unpublished data from 116 studies comprising 2 563 633 homeless people and 129 292 553 population controls. This review is registered at PROSPERO (CRD42023430984).

The risk of all-cause mortality was increased in people exposed to homelessness compared with those unexposed [relative risk (RR) 2.21, 95% confidence interval (CI) 1.91-2.57, P < .001, I2 = 99.7], with risks similar in men (RR 4.04, 95% CI 2.87-5.21) and women (RR 3.58, 95% CI 2.35-4.82). Risks were higher in people who had slept rough (RR 7.63, 95% CI 3.29-11.97) than in those who had slept in homeless hostels/shelters (RR 3.44, 95% CI 2.10-4.77) and also elevated for people staying in low-cost hotels (RR 5.18, 95% CI 1.14-9.23). Summary RR estimates were elevated for 33 of the 36 (92%) causes of death. The highest risk of death was apparent for psychoactive-substance-use disorder (RR 21.38, 95% CI 14.44-31.67), accidental injuries (RR 13.15, 95% CI 5.46-31.69), and drug overdose (RR 11.65, 95% CI 6.97-19.48). Around half of the studies (57%) were of high quality. No studies were found in low-income countries. There was no evidence of publication bias.

Compared with the general population, homeless people experience an increased risk of premature mortality. The most extreme inequalities were from deaths through psychoactive-substance-use disorder, accidents, and drug overdose. There are evidence-based treatments for psychoactive substance use and drug overdose, suggesting that some of these deaths are avoidable.