The retrospective review by Lynn et al.1 sought to investigate mortality in homeless individuals in Ireland during 2019. This was a feasibility study aimed at developing a greater understanding of premature mortality among the homeless using the National Drug-Related Death Index (NDRDI), an epidemiological database. The study was commissioned by the Department of Health and sought to provide more complete and accurate data to help inform policy. It is the first Irish study to examine the number and causes of homeless deaths nationally.

Background
Homelessness is a burgeoning social issue in Ireland. Since 2012, the numbers of those in emergency accommodation or sleeping rough have nearly tripled, with as many as 10,975 individuals accessing emergency accommodation in September 2022.2 Homeless people in Ireland tend to be concentrated around the major cities; the 2016 Census revealed that 72.5% of homeless people were recorded in Dublin.3 Young people are also disproportionately represented among the homeless population, with those aged 18–24 years accounting for 16.7% of adults accessing emergency accommodation.4 Other vulnerable groups include people with disabilities, young parents, the elderly, members of the Travelling community, and members of the LGBTQI+ community. Homeless people also experience poorer health and higher rates of mortality when compared with the general population, with global estimates of a three-to-four-time higher risk among this cohort.5 This increased risk of death can be attributed to several factors, including high prevalence of substance use; high rates of mental illness; increased risk of chronic diseases; disproportionate experience of physical assault; and exposure.6

Methods
The study by Lynn et al. was a retrospective review of all deaths in persons categorised as homeless at time of death in 2019. Coronial data were used to extract data on homeless deaths on a nationwide basis. Homelessness was defined using the global definition by Busch-Geertsema et al.7 Cases were defined as homeless if they met one or more of the following criteria:

1. Homeless – without accommodation, e.g. rough sleepers
2. Homeless – temporary or crisis accommodation
3. Homeless – severely substandard or highly insecure accommodation
4. Homeless – unknown.

Key findings
A total of 17,822 deaths were reported to the coroner in 2019; 84 of which were among homeless individuals. This is the equivalent of seven deaths per month in 2019. The majority of deaths (81%) were among males. The median age at death for men and women was 40.5 and 39.5 years, respectively. This illustrates the burden of premature mortality among this cohort. The highest proportion of deaths occurred in Leinster (77.4%), with Dublin being the major focal point with almost 60% of deaths. Nationally, the majority of fatalities (40.5%) took place in either public places, public buildings, or derelict buildings. An additional 32.1% of all homeless deaths occurred in emergency homeless accommodation. Almost all of the deceased (93%) had a history of substance use, with a high level of polydrug use. Of the total 84 deaths, 46 were classified as ‘poisonings’. Poisoning deaths, also known as overdoses, are deaths due to the toxic effects of recent consumption of one or more drugs. More homeless men than homeless women died from poisoning (80.4% vs 19.6%).

Opioids were the most common drug group implicated in these poisonings, followed by benzodiazepines and Z-drugs. Nearly one-quarter (24.3%) of those who died by opioid poisoning had a documented history of a previous overdose. About 4 in 10 (40.5%) opioid-related deaths occurred in homeless accommodation. There were 38 non-poisonings deaths (31 males vs 7 females). Death by hanging was responsible for 23.7% of all non-poisoning deaths, making it the leading cause of non-poisoning deaths among the sexes. About two-thirds of those who died by hanging had a history of mental health issues (66.7%), while about 16% had a history of drug use. Nearly 40% of cases were in contact with medical services, with 69.7% of these in receipt of substance use treatment within the month preceding death. More women than men (62.5% vs 33.8%) engaged with health services prior to death.

Conclusions
The study reported a higher rate of premature mortality among those classified as homeless in 2019. From these data, it is clear that substance use plays a significant role in these deaths. This, coupled with the high levels of mental health and medical issues among those who died, indicates that this is a vulnerable population with complex needs. This feasibility study also showed that it is possible, cost-effective, and a good use of resources to continue to use the NDRDI to collect these data and disseminate findings through published reports. Future linkage of the NDRDI with other national datasets, including the Pobal HP Deprivation Index for Small Areas and the Pathway Accommodation and Support System (PASS), may prove beneficial to improve data completeness. From a policy perspective, several recommendations for harm reduction strategies were proposed by this study. These strategies include decreasing barriers in accessing treatment services and treatment retention, particularly opioid agonist treatment; increasing specialist training (first aid and naloxone administration) for those who work in homeless accommodation; and strengthening mental health supports.

In conclusion, the study highlights that homelessness is a complex social issue and harm reduction strategies should be implemented to prevent excess mortality among this cohort.

1    Lynn E, Devin J, Craig S and Lyons S (2023) Deaths among people who were homeless at time of death in Ireland, 2019: results of the HRB feasibility study. HRB StatLink Series 11. Dublin: Health Research Board. Available from: https://www.drugsandalcohol.ie/38793/

2    Department of Housing, Local Government and Heritage (2022) Homeless Quarterly Progress Report: Quarter 3 2022. Dublin: Department of Housing, Local Government and Heritage. Available from: https://www.gov.ie/en/publication/256fc-homeless-quarterly-progress-report-for-q3-2022/#

3    Central Statistics Office (2017) Census of Population 2016: homeless persons in Ireland. Cork: Central Statistics Office. Available from: https://www.cso.ie/en/releasesandpublications/ep/p-cp5hpi/cp5hpi/hpi/

4    Department of Housing, Local Government and Heritage (2022) Housing for All: Youth homelessness Strategy 2023–2025. Dublin: Government of Ireland. Available from: https://www.drugsandalcohol.ie/37445/

5    Fazel S, Geddes JR and Kushel M (2014) The health of homeless people in high-income countries: descriptive epidemiology, health consequences, and clinical and policy recommendations. Lancet, 384(9953): 1529–1540.

6    O’Connell JJ (2005) Premature mortality in homeless populations: a review of the literature. Nashville, TN: National Health Care for the Homeless Council.

7    Busch-Geertsema V, Culhane D and Fitzpatrick S (2016) Developing a global framework for conceptualising and measuring homelessness. Habitat Int, 55: 124–132.