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Public health
Protocol
Mortality among people who have experienced homelessness: protocol for a systematic review and meta-analysis
  1. Jessica Heerde1,2,3,
  2. Rohan Borschmann2,4,5,6,
  3. Jesse Young2,4,7,8,
  4. Stuart A Kinner2,4,9,10,
  5. Susan M Sawyer1,2,
  6. George C Patton1,2
  1. 1Department of Paediatrics, The University of Melbourne, Parkville, Victoria, Australia
  2. 2Centre for Adolescent Health, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
  3. 3School of Social Work, The University of Melbourne, Parkville, Victoria, Australia
  4. 4Justice Health Unit, Centre for Health Equity, Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Victoria, Australia
  5. 5Melbourne School of Psychological Sciences, The University of Melbourne, Parkville, Victoria, Australia
  6. 6Department of Psychiatry, Warneford Hospital, University of Oxford, Oxford, UK
  7. 7School of Population and Global Health, The University of Western Australia, Perth, Western Australia, Australia
  8. 8National Drug Research Institute, Curtin University, Perth, Western Australia, Australia
  9. 9Griffith Criminology Institute, Griffith University, Brisbane, Queensland, Australia
  10. 10School of Population Health, Curtin University, Perth, Western Australia, Australia
  1. Correspondence to A/Prof Jessica Heerde; jessica.heerde{at}unimelb.edu.au

Abstract

Introduction Homelessness is a major contributor to health inequalities. People who experience homelessness are at markedly increased risk of multiple and complex health morbidities which likely increase their susceptibility to early, preventable death. Despite this, the mortality burden in this group remains poorly understood, limited in part by insufficient synthesis of data at a global level. This systematic review will synthesise international literature examining rates of risk and protective factors for mortality among people who have experienced homelessness.

Methods and analysis We will search MEDLINE, PsycINFO, Embase and PubMed for peer-reviewed cohort studies examining mortality among people who have experienced homelessness. No study eligibility restrictions will be placed on the date, country of origin, or language of publications, or age of the sample. We will assess the quality of included studies using the Methodological Standards for Epidemiological Research scale. Our measures of mortality will include: (A) incidence—all cause and cause specific, expressed as a crude mortality rate (CMR) per 1000 person-years, with 95% CI and (B) all cause and cause specific, indirectly standardised mortality ratios (SMRs) with 95%CI. Associations between risk and protective factors and all-cause and cause-specific mortality will be reported using pooled relative risk ratios with 95% CI. Where there are sufficient data, the influence of subgroup and methodological factors on CMRs, SMRs and predictive factors will be examined using meta-regression.

Ethics and dissemination This study does not require institutional ethics review or approval as it will synthesise findings from published studies that have previously been granted relevant ethics approvals. Study findings will be disseminated through a peer-reviewed journal article, conference and seminar presentations. A plain language summary will be distributed through the authors’ academic and professional networks.

PROSPERO registration number CRD42021272937.

  • public health
  • epidemiology
  • primary care
http://creativecommons.org/licenses/by-nc/4.0/

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.

https://doi.org/10.1136/bmjopen-2022-067182

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    STRENGTHS AND LIMITATIONS OF THIS STUDY

    • The global systematic review will be conducted and reported in line with best practice guidelines (Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols 2015) and is registered with PROSPERO (CRD42021272937).

    • Our methods have been specified a priori, and a comprehensive search strategy across four key health, medicine and biomedical databases has been developed in consultation with a research librarian.

    • If sufficient data are available, our planned meta-analysis will permit reliable estimation of the pooled risk for mortality (crude mortality rates and standardised mortality ratios), and its potentially modifiable (risk and protective) factors (relative risk ratios), among people who have experienced homelessness.

    • While global in scope, it is anticipated that reviewed studies will predominantly come from high-income countries and will be published in English language, limiting the representativeness and generalisability of the derived estimates.

    • Most reviewed studies are expected to be observational and, as such, we may have limited capacity to draw causal inferences.

    Introduction

    International estimates suggest that over 1.6 billion people are inadequately housed, with over 100 million people worldwide having no housing.1 This is likely to be an underestimate given vast differences in global socialeconomic, structural, cultural and political contexts. People who have experienced homelessness face health inequalities and are at markedly increased risk for preventable morbidity and premature mortality.2 3 The large and increasing number of people who experience homelessness worldwide4 5 presents a strong imperative for understanding the extent and nature of the health burden in this group, including mortality. Yet, our understanding of mortality among people who experience homelessness is limited.

    To our knowledge, there are only two prior systematic reviews of mortality among homeless people.2 5 A review and meta-analysis by Aldridge et al2 analysed mortality outcomes across four groups experiencing social exclusion from studies published between January 2005 and October 2015. Of the 337 studies they reviewed, only 3 included measures of mortality for homeless people. The Aldridge study2 confirmed excess mortality associated with experiencing homelessness but it was limited by the small body of evidence reviewed meaning that neither pooled crude mortality rates (CMRs) nor pooled standardised mortality ratios (SMRs) for mortality among homeless people could be calculated. A more recent systematic review6 analysed data from eight studies examining mortality rates among homeless people, all set within the USA and published between 2009 and 2019. These studies analysed selected samples, such as data collected from samples based on community-based shelter records or convenience samples of homeless people participating in healthcare programmes, and most studies focused on adults. A meta-analysis was not conducted as a part of this review.

    Several international studies from Denmark,7 8 Sweden,9 Ireland,10 Scotland11 12 and the Netherlands,13 which were either not included in prior reviews or published after the Aldridge review, used data linkage to estimate mortality among those who are homeless or have experienced homelessness. Data linkage addresses issues of low power in small retrospective studies and, if appropriately designed, permits the comparison of mortality rates between people experiencing homelessness and the general population. Among the findings of these European and Scandinavian studies are that (1) rates of mortality were greater among those who experienced homelessness than in the general population, with suicide and overdose among the leading causes and that (2) at least one recorded episode of homelessness is associated with increased risk of death. Stratified by sex, SMRs among those who have experienced homelessness are higher for females than males; and stratified by age, SMRs are generally higher for younger than for older people.7–11 13–17

    There is now an important opportunity to synthesise the international literature and quantify the association between homelessness and mortality. This is because at present, knowledge of the extent and causes of premature death relative to the general population, and the contribution of associated risk and protective factors, limits effective, comprehensive responses. Accordingly, the aim of this systematic review is to synthesise the peer-reviewed evidence to investigate: (A) the incidence of all-cause and cause-specific mortality among people who have experienced homelessness; (B) how these rates compare to age-matched and sex-matched general populations and (C) historical (static) and potentially modifiable factors that are associated with all-cause and cause-specific mortality among people who have experienced homelessness. These factors may be associated with increased (risk) or decreased (protective) mortality rate.

    Methods and analysis

    Protocol and registration

    This systematic review and meta-analysis will be conducted in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis for Protocols 2015.18 19 This protocol is registered with the International Prospective Register of Systematic Reviews (PROSPERO; CRD42021272937).

    Search strategy

    We will search the following electronic health, medicine and biomedical databases of peer-reviewed research: MEDLINE, PsycINFO, Embase and PubMed, using variations and combinations of database-specific controlled subject vocabulary (ie, MESH terms and subject headings) relating to homelessness and mortality. This method will ensure uniformity in search terms across each database. Given that no restrictions will be placed on the date of publication, databases will be searched from their inception until the date of the search. The MEDLINE search strategy is presented in table 1. The search strategy was developed in consultation with a research librarian at the Royal Children’s Hospital (RCH) Melbourne, Australia.

    View this table:
    Table 1

    MEDLINE Search Strategy

    Inclusion criteria

    Eligible peer-reviewed studies are prospective and/or retrospective cohort studies, as defined by the Cochrane study design guide,20 which report at least one estimate of mortality among a sample of people who have experienced homelessness, or provide sufficient information to permit calculation of such an estimate. The types of homelessness and causes of mortality that will be considered for inclusion are described below (see the Participants and Outcome measure sections, respectively). Study eligibility will not be restricted by the date or the country of origin, or the age of the sample. No restrictions will be placed on the language of publications. Where identified, the abstracts of non-English publications will be translated into English and reviewed for eligibility.

    Exclusion criteria

    Case reports, cross-sectional studies and case–control studies will be excluded, as will commentaries, editorials, practice guidelines and letters. Dissertations, conference abstracts and grey literature (book chapters, government reports/guidelines) will also be excluded. Previous reviews of the literature will be excluded; however, the reference lists of any previous reviews will be screened to identify additional eligible studies not identified in our search strategy.

    Participants

    Definitions of homelessness vary internationally, however, it is generally considered within a typology of housing instability.21 22 For this review, people experiencing homelessness include those who are currently, or report a history of (A) being unsheltered (eg, living directly on the streets or in spaces not intended for habitation); and/or (B) residing in emergency shelter (eg, crisis housing, refuge) and/or (C) residing in temporary accommodation (eg, couch-surfing, short-term accommodation such as a rooming or boarding house). Those who are, or have, experienced homelessness may or may not have sought assistance from a specialist homelessness service. Studies of people whose residence is (or has been) threatened due to financial insecurity or poor living standards, and who do not report being unsheltered, residing in an emergency shelter, or residing in temporary accommodation, will be excluded. Studies will only be included where there is a subgroup that (A) is identifiable as experiencing homelessness; (B) meets the inclusion criteria and where (C) their rate of mortality can be disaggregated from the full study sample.

    Outcome measure

    Included studies will report on mortality as an outcome to be eligible for inclusion. Studies of mortality during or after a period of homelessness will be included. There will be no restrictions on the time frame in which mortality is examined after a period of homelessness. Causes of mortality will depend on those reported within the retrieved studies but may include communicable diseases (eg, SARS-CoV-2, HIV, tuberculosis, pneumonia), non-communicable diseases (eg, diabetes, diseases of the circulatory or respiratory system, cancer) and external causes (eg, intentional or unintentional injury). Mortality that results from legal intervention (ie, where a person dies because of interactions with a law enforcement officer in the course of duty, or death in custody) will be included, consistent with the international literature.23–25

    Study selection

    Publication details and abstracts for each of the studies identified through the search of electronic databases will be imported into Endnote26 reference management software. Duplicates will be removed. Next, all remaining eligible studies will be imported into Covidence27 systematic review management software for screening. All remaining articles will undergo title and abstract screening. To ensure that the inclusion and exclusion criteria are consistently applied and in line with current best practice guidelines,28 the titles and abstracts of all identified studies will be independently screened by two authors (JH and RB). A random sample of 10% of these titles and abstracts will first be screened by RB (and inter-rater reliability (Cohen’s kappa statistic29 calculated)), before the remaining 90% of retrieved abstracts are screened. To achieve consensus, a third author (JY) will examine the titles and abstracts of any studies where there is disagreement between the two authors. Inter-rater reliability (Cohen’s kappa statistic) will be calculated for the full title and abstract screening process.29 If reliability is low (<0.40),29 the author team will review and revise the eligibility criteria and double-code a second random 10% of retrieved studies and Cohen’s kappa statistic recalculated. If applicable, the revised eligibility criteria will be used to guide a revised screening process.

    Following title and abstract screening, the full-text version of all remaining potentially eligible studies will be reviewed by two authors (JH and RB) according to the inclusion and exclusion criteria. Any conflicts will be resolved by consensus with a third author (JY). The original study author(s) will be contacted twice via email where further clarification on the study is needed to determine its eligibility for inclusion. Where there is no reply received from the authors, the study will be excluded. In the case where two (or more) eligible studies analyse the same data, only the study with the longer time frame (ie, follow-up duration) will be included.

    Data extraction

    Data will be extracted from the included studies by the lead author, using a prespecified data extraction form (standardised Excel form). Data extraction fields are presented in table 2. Data extracted from the included studies will be checked by a second author (RB) to identify and correct any errors. Any conflicts will be resolved by consensus with a third author (JY).

    View this table:
    Table 2

    Fields for inclusion in the data extraction form

    Risk of bias assessment

    Study quality will be assessed using the Methodological Standards for Epidemiological Research (MASTER) scale.30 31 Two authors (JH and RB) will independently assess each study, with any ambiguity to be resolved by consensus through discussion with a third author (JY). Studies classified as being of low quality will be retained in the review and a sensitivity analysis conducted restricting the meta-analyses to those studies which are above the median MASTER30 31 score (see the Data synthesis and statistical analysis section).

    Data synthesis and statistical analysis

    A detailed descriptive synthesis of all included studies will be conducted, including study identification information (eg, author(s), year of publication, study country of origin), study characteristics (eg, sample size, mean age, sex, length of follow-up), study design (retrospective or prospective; sampling frame) and source(s) of mortality data.

    The statistical analysis strategy will be led by the author team and developed in consultation with a biostatistician at the Murdoch Children’s Research Institute, Melbourne, Australia. Where there are sufficient data within the included studies (ie, CMRs, SMRs and predictive factors), a meta-analysis will be conducted to produce pooled estimates. It is likely that most, if not all, included studies will be observational, meaning there is no specific exposure to be reviewed. Our measures of mortality will include: (A) incidence of all-cause and cause-specific mortality, expressed as pooled CMRs per 1000 person-years, with 95% CI and (B) all-cause and cause-specific, indirectly SMRs with 95% CI. Associations between risk and protective factors and all-cause and cause-specific mortality will be reported using pooled relative risk ratios with 95% CI. Where CMRs are not reported in an included study, they will be calculated wherever possible, using the method outlined by Zlodre and Fazel.32 We will pool SMRs which compare an exposure (homelessness) to the general population (no homelessness). We will generate a funnel plot and use Egger’s test to assess potential publication bias.33

    Where the data permit, our analyses will be stratified by whether participants were homeless at the time of death. The proportion of total variation across study estimates due to heterogeneity will be examined using the I2 statistic34; an I2 of at least 50% will be considered indicative of substantial heterogeneity.20 Subject to the availability of sufficient data in the included studies, the influence of subgroups and methodological factors on the CMRs, SMRs and/or risk/protective factors will be examined using meta-regression. To further understand potential sources of heterogeneity and where the data permit, subgroup analyses will be conducted by sex, age, study country of origin, study design (ie, retrospective, prospective), type of homelessness (eg, being unsheltered or residing in emergency shelter or residing in temporary accommodation), and length of time homeless. Sensitivity analyses will be conducted which exclude studies assessed as being low quality (based on quality assessment scores below the median on the MASTER scale)30 to examine the potential effect of study quality on outcome measures.

    Patient and public involvement

    There was no patient or public involvement in the design of the study. There will be no patient or public involvement in the conduct, reporting or dissemination plans of this study. Within the author team, however, there is lived experience of homelessness.

    Ethics and dissemination

    This study will analyse the findings of published studies that have already obtained ethics approval, meaning that it does not require institutional ethics review or approval. Despite recognition that people who are homeless, or have experienced periods of homelessness, have poor health outcomes and reduced life chances,2 3 35 efforts to address health inequality and improve health outcomes among this group have long been neglected in health policy. Thus, we will disseminate our findings to academic researchers, key stakeholders in health and other service systems working with people who have experienced homelessness, and policy makers in Australia and internationally. We will publish the findings of our study in an appropriate peer-reviewed journal. We will present our findings at national and international symposia and through seminar presentations. We will also disseminate our findings via a plain language summary distributed among our academic and professional networks, including a link to the main publication. A link to the published review will be circulated via social media.

    Ethics statements

    Patient consent for publication

    Acknowledgments

    The authors express their appreciation to Ms Poh Chua, research librarian at the Royal

    Children's Hospital Melbourne, Australia.

    References

    1. ↵
      1. Institute of Global Homelessness
      . Institute of global homelessness: institute of global homelessness 2019. 2022. Available: https://ighomelessness.org/about-us/ [Accessed 13 May 2022].
    2. ↵
      1. Aldridge RW,
      2. Story A,
      3. Hwang SW, et al
      . Morbidity and mortality in homeless individuals, prisoners, sex workers, and individuals with substance use disorders in high-income countries: a systematic review and meta-analysis. Lancet 2018;391:241–50. doi:10.1016/S0140-6736(17)31869-X
      OpenUrlCrossRefPubMed
    3. ↵
      1. Marmot M
      . Inclusion health: addressing the causes of the causes. Lancet 2018;391:186–8. doi:10.1016/S0140-6736(17)32848-9
      OpenUrlCrossRefPubMed
    4. ↵
      1. Organisation for Economic Co-operation and Development (OECD)
      . HC3.1 homeless population. US: OECD social policy division - directorate of employment, labour and social affairs. 2021.
    5. ↵
      1. Australian Institute of Health & Welfare
      . Specialist homelessness services annual report 2020-21. cat. no. HOU 327. Canberra: Australian Institute of Health & Welfare, 2021.
    6. ↵
      1. Funk AM,
      2. Greene RN,
      3. Dill K, et al
      . The impact of homelessness on mortality of individuals living in the United States: a systematic review of the literature. J Health Care Poor Underserved 2022;33:457–77. doi:10.1353/hpu.2022.0035
      OpenUrlCrossRef
    7. ↵
      1. Feodor Nilsson S,
      2. Hjorthøj CR,
      3. Erlangsen A, et al
      . Suicide and unintentional injury mortality among homeless people: a Danish nationwide register-based cohort study. Eur J Public Health 2014;24:50–6. doi:10.1093/eurpub/ckt025
      OpenUrlCrossRefPubMed
    8. ↵
      1. Feodor Nilsson S,
      2. Laursen TM,
      3. Hjorthøj C, et al
      . Homelessness as a predictor of mortality: an 11-year register-based cohort study. Soc Psychiatry Psychiatr Epidemiol 2018;53:63–75. doi:10.1007/s00127-017-1456-z
      OpenUrl
    9. ↵
      1. Beijer U,
      2. Andreasson S,
      3. Agren G, et al
      . Mortality and causes of death among homeless women and men in Stockholm. Scand J Public Health 2011;39:121–7. doi:10.1177/1403494810393554
      OpenUrlCrossRefPubMed
    10. ↵
      1. Ivers J-H,
      2. Zgaga L,
      3. O’Donoghue-Hynes B, et al
      . Five-Year standardised mortality ratios in a cohort of homeless people in Dublin. BMJ Open 2019;9:e023010. doi:10.1136/bmjopen-2018-023010
    11. ↵
      1. Morrison DS
      . Homelessness as an independent risk factor for mortality: results from a retrospective cohort study. Int J Epidemiol 2009;38:877–83. doi:10.1093/ije/dyp160
      OpenUrlCrossRefPubMedWeb of Science
    12. ↵
      1. Tweed EJ,
      2. Leyland AH,
      3. Morrison D, et al
      . Premature mortality in people affected by co-occurring homelessness, justice involvement, opioid dependence, and psychosis: a retrospective cohort study using linked administrative data. Lancet Public Health 2022;7:e733–43. doi:10.1016/S2468-2667(22)00159-1
      OpenUrl
    13. ↵
      1. Termorshuizen F,
      2. van Bergen APL,
      3. Smit RBJ, et al
      . Mortality and psychiatric disorders among public mental health care clients in utrecht: a register-based cohort study. Int J Soc Psychiatry 2014;60:426–35. doi:10.1177/0020764013491942
      OpenUrlCrossRefPubMed
    14. ↵
      1. Beijer U,
      2. Andréasson A,
      3. Agren G, et al
      . Mortality, mental disorders and addiction: a 5-year follow-up of 82 homeless men in Stockholm. Nord J Psychiatry 2007;61:363–8. doi:10.1080/08039480701644637
      OpenUrlCrossRefPubMedWeb of Science
    15. ↵
      1. Nielsen SF,
      2. Hjorthøj CR,
      3. Erlangsen A, et al
      . Psychiatric disorders and mortality among people in homeless shelters in Denmark: a nationwide register-based cohort study. Lancet 2011;377:2205–14. doi:10.1016/S0140-6736(11)60747-2
      OpenUrlCrossRefPubMedWeb of Science
    16. ↵
      1. Seastres RJ,
      2. Hutton J,
      3. Zordan R, et al
      . Long-term effects of homelessness on mortality: a 15-year australian cohort study. Aust N Z J Public Health 2020;44:476–81. doi:10.1111/1753-6405.13038
      OpenUrlPubMed
    17. ↵
      1. Aldridge RW,
      2. Menezes D,
      3. Lewer D, et al
      . Causes of death among homeless people: a population-based cross-sectional study of linked hospitalisation and mortality data in England. Wellcome Open Res 2019;4:49. doi:10.12688/wellcomeopenres.15151.1
    18. ↵
      1. Moher D,
      2. Shamseer L,
      3. Clarke M, et al
      . Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) 2015 statement. Syst Rev 2015;4:1. doi:10.1186/2046-4053-4-1
    19. ↵
      1. Shamseer L,
      2. Moher D,
      3. Clarke M, et al
      . Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) 2015: elaboration and explanation. BMJ 2015;350:g7647. doi:10.1136/bmj.g7647
    20. ↵
      1. Ryan R,
      2. Hill S,
      3. Broclain D, et al
      . Study design guide. Cochrane Consumers and Communication Review Group, 2013.
    21. ↵
      1. Heerde JA,
      2. Hemphill SA
      . Homelessness. In: Schreck CJ, ed. Encyclopaedia of juvenile delinquency and justice. Wiley, 2018.
    22. ↵
      1. Amore K,
      2. Baker M,
      3. Howden-Chapman P
      . The ETHOS definition and classification of homelessness: an analysis. Eur J Homelessness 2011;5:19–37.
      OpenUrl
    23. ↵
      1. Willoughby M,
      2. Young JT,
      3. Spittal MJ, et al
      . Violence-related deaths among people released from incarceration: protocol for a systematic review. BMJ Open 2021;11:e045601. doi:10.1136/bmjopen-2020-045601
    24. ↵
      1. Rutherford A,
      2. Zwi AB,
      3. Grove NJ, et al
      . Violence: a glossary. J Epidemiol Community Health 2007;61:676–80. doi:10.1136/jech.2005.043711
      OpenUrlAbstract/FREE Full Text
    25. ↵
      1. World Health Organization
      . Classification of diseases (ICD). 2018. Available: http://www.who.int/classifications/icd/en/ [Accessed 27 Nov 2021].
    26. ↵
      1. Clarivate Analytics
      . EndNote [program]. endnote X9.3.3 version. Philadelphia, PA, 2013.
    27. ↵
      1. Veritas Health Innovation
      . Covidence [program]. Melbourne, Australia, 2020.
    28. ↵
      1. Polanin JR,
      2. Pigott TD,
      3. Espelage DL, et al
      . Best practice guidelines for abstract screening large‐evidence systematic reviews and meta‐analyses. Res Syn Meth 2019;10:330–42. doi:10.1002/jrsm.1354
      OpenUrl
    29. ↵
      1. McHugh ML
      . Interrater reliability: the kappa statistic. Biochem Med (Zagreb) 2012;22:276–82.
      OpenUrl
    30. ↵
      1. Stone JC,
      2. Glass K,
      3. Clark J, et al
      . A unified framework for bias assessment in clinical research. Int J Evid Based Healthc 2019;17:106–20. doi:10.1097/XEB.0000000000000165
      OpenUrlPubMed
    31. ↵
      1. Stone JC,
      2. Glass K,
      3. Clark J, et al
      . The methodological standards for epidemiological research (master) scale demonstrated a unified framework for bias assessment. J Clin Epidemiol 2021;134:52–64. doi:10.1016/j.jclinepi.2021.01.012
      OpenUrlCrossRefPubMed
    32. ↵
      1. Zlodre J,
      2. Fazel S
      . All-Cause and external mortality in released prisoners: systematic review and meta-analysis. Am J Public Health 2012;102:e67–75. doi:10.2105/AJPH.2012.300764
      OpenUrlCrossRefPubMed
    33. ↵
      1. Egger M,
      2. Davey Smith G,
      3. Schneider M, et al
      . Bias in meta-analysis detected by a simple, graphical test. BMJ 1997;315:629–34. doi:10.1136/bmj.315.7109.629
      OpenUrlAbstract/FREE Full Text
    34. ↵
      1. Higgins JPT,
      2. Thompson SG
      . Quantifying heterogeneity in a meta-analysis. Stat Med 2002;21:1539–58. doi:10.1002/sim.1186
      OpenUrlCrossRefPubMedWeb of Science
    35. ↵
      1. Heerde J,
      2. Patton GC,
      3. Young J, et al
      . Homelessness and the right to life. Parity 2021;34:22–4.
      OpenUrl

    Footnotes

    • Twitter @DrJessHeerde, @KinnerStuart, @SusanSawyer01

    • Deceased It is with great sadness that we advise Professor George C Patton passed away on the 7th of December 2022.

    • Contributors JH developed the original study proposal. JH, RB, JY, SAK, SMS and GCP contributed to the design of the study. JH developed the initial systematic search strategy in consultation with a research librarian at the Royal Children’s Hospital, Melbourne Australia, and RB, JY, SAK, SMS and GCP. JH wrote the initial draft of the manuscript. JH, RB, JY, SAK, SMS and GCP contributed to redrafting, editing and revising the manuscript. JH, RB, JY, SAK, SMS and GCP approved the final manuscript.

    • Funding JH receives salary and research support from a National Health and Medical Research Council Investigator Grant (2007722). The writing of this protocol was supported by a Mid-Career Seeding Ideas Grant awarded to JH and RB by the Faculty of Medicine, Dentistry and Health Sciences at the University of Melbourne. JH previously received salary support from the Faculty of Medicine, Dentistry and Health Sciences at the University of Melbourne (Momentum Fellowship), the Department of Paediatrics at the University of Melbourne and the Centre for Adolescent Health, Royal Children’s Hospital, Melbourne, Australia. RB receives salary and research support from a National Health and Medical Research Council Emerging Leadership Investigator Grant (2008073). JY receives salary and research support from a National Health and Medical Research Council Investigator Grant (APP1178027). GCP is supported by a National Health and Medical Research Council Senior Principal Research Fellowship (1196999). Apart from the funding sources acknowledged here, this research received no specific grant from any other funding agency in the public, commercial or not-for-profit sectors.

    • Competing interests None declared.

    • Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

    • Provenance and peer review Not commissioned; externally peer reviewed.