Abstract
Background:
People with HIV disproportionately experience homelessness and other forms of housing instability. Understanding how housing status influences HIV clinical outcomes remains limited, especially among individuals engaged in care.
Methods:
We evaluated associations between housing status and HIV care markers using clinical data and patient-reported measures from the Centers for AIDS Research Network of Integrated Clinical Systems (CNICS) cohort of adults receiving HIV care across the US, between 2019–2025. We used relative risk regression and linear regression to estimate associations between self-perceived housing instability and outcomes including HIV viral suppression (<200 copies/mL), self-reported antiretroviral therapy (ART) use and adherence (visual analog scale), and CD4 cell count, adjusted for demographic characteristics, year, and site.
Results:
Among 6,873 individuals in clinical care, nearly 10% reported some form of housing instability at their most recent visit: 4.6% “Unstable,” 3.3% “Homeless,” and 1.7% “Don’t know.” Compared to stably housed individuals, the prevalence of viral suppression was lower among those experiencing homelessness (PR=0.82, 95% CI: 0.77–0.89) and unstable housing (PR=0.94, 95% CI: 0.90–0.98), as was the prevalence of ART use, mean ART adherence, and mean CD4 count. Results were similar when stratified by substance use and depression and when compared to a community-based cohort of people with HIV.
Conclusion:
Housing instability is associated with a lower prevalence of HIV viral suppression even among individuals engaged in clinical care. These results highlight lack of access to stable housing as a structural barrier to successful management of HIV and to ending the HIV epidemic in the US.
Introduction
The United States (US) is currently experiencing a housing crisis marked by rising housing instability, with potential health consequences for highly impacted populations including people with HIV (PWH).1 Housing instability refers to a range of challenges such as difficulty affording housing, overcrowding, moving frequently, or, in severe cases, experiencing homelessness.2,3 A total of 771,480 people across the US experienced sheltered or unsheltered homelessness on a single night in January 2024, reflecting an 18% increase from 2023 and the highest number ever recorded since reporting began in 2007.4 Among PWH, an estimated 9.3% nationally experienced homelessness at some point in the past year, with the prevalence increasing to 17.9% when including those experiencing any type of housing instability.5 New HIV infections are increasingly concentrated among members of vulnerable populations, including unhoused and unstably housed individuals.6,7 Housing instability and HIV are intersecting epidemics, with overlapping factors including stigma and discrimination that may serve as barriers to HIV care.8
Previous research demonstrates that housing instability is associated with worse outcomes across the HIV care continuum, including lower linkage to in care, poor retention, suboptimal adherence to antiretroviral therapy (ART), and lack of viral suppression,9–18 which can lead to onward HIV transmission19 and lower survival.20 However, most research on this topic has been constrained by small sample sizes, restricted geographic range, or a focus on specific sub-populations. In particular, previous studies primarily focused on PWH who were not in care or newly initiating care, leaving uncertainty about the role of housing instability as a barrier to adherence among PWH with established HIV care. Additionally, questions remain regarding the dynamics between different forms of housing instability and HIV care outcomes. Housing is not a binary exposure by nature; housing stability exists along a spectrum, with different levels of housing instability potentially having different impacts on HIV clinical care. Yet, to date, the majority of research has not made the distinction between unhoused and unstably housed individuals. The most recent meta-analysis on housing instability among PWH reported that 78% of the 152 included studies used “a dichotomized indicator of housing status—most often ‘homeless’ versus ‘not homeless,’”10 with investigators often grouping those who identify as being homeless with those reporting unstable housing conditions, such as temporary hotels, treatment centers, and halfway houses.
The importance of understanding and addressing housing instability among PWH is underscored by the goal of the “Ending the HIV Epidemic in the US” (EHE) initiative: “Ending the HIV epidemic in the United States requires implementing integrated solutions that address the comprehensive health, social services, and housing needs of people with HIV and people who could benefit from HIV prevention so they can stay healthy and prevent HIV acquisition or transmission.”21 To better understand the association between housing instability and HIV care outcomes, we examined the prevalence of HIV viral suppression among PWH reporting different categories of housing stability in a large, geographically and sociodemographically diverse cohort of adult PWH engaged in HIV care across the US. In addition, we conducted a comparative analysis within a long-standing community-based cohort of PWH to contrast outcomes between PWH in care to those in the general community in order to elucidate whether housing instability has similar implications regardless of whether PWH have established HIV care.
Methods
Study population
The primary analysis was conducted among adult PWH in clinical HIV care at seven Centers for AIDS Research Network of Integrated Clinical Systems (CNICS) cohort sites that collected relevant data between 2019–2025. The CNICS cohort integrates comprehensive demographic and clinical data from electronic medical records and other institutional data sources, as well as standardized clinical assessments of patient-reported measures and outcomes (PROs).22 Participants in CNICS must have established HIV care, defined as having attended at least two HIV primary care visits within the past 12 months at the time of enrollment in the CNICS cohort. CNICS participants complete an approximately 10 minute clinical assessment of PROs via touch-screen tablet every ~6 months in conjunction with a clinical visit.23 For inclusion in these analyses, PWH had to have completed a PRO assessment on housing status and have a recent HIV viral load measure (Supplementary Figure 1).
Housing status assessment
Housing status was assessed as self-perceived housing stability reported on the most recent PRO assessment via the following question: “In the past month, how would you describe your living situation?” with response options of “Homeless,” “Unstable,” “Stable,” or “Don’t know.” The housing status question, including recall period and response options, was specifically developed to appropriately assess housing instability in the CNICS population through a participatory process involving 1:1 cognitive interviews conducted with PWH to ensure comprehension and uniform interpretation of content.
Outcomes
The primary outcome of interest was HIV viral suppression, defined as a viral load <200 copies/mL based on the most recent viral load measure within 1 month before or after the housing status assessment. Secondary outcomes included other key HIV clinical care markers: (1) CD4 cell count; (2) self-reported use of current ART; and (3) self-reported ART adherence in the past month, assessed using the Visual Analog Scale (VAS).24
Covariates
Covariates of interest in this analysis included demographic factors (age, sex, race and ethnicity, years in CNICS), illicit drug use, and depressive symptoms. Drug use and depression were self-reported measures collected via the CNICS clinical PRO assessment; drug use was assessed using a modified version of the ASSIST25 and depressive symptoms via the Patient Health Questionnaire (PHQ-9).26,27 For this analysis, current drug use was defined as self-reported use of any illicit drugs in the past three months, including methamphetamine, cocaine/crack, illicit opioids (heroin, fentanyl, narcotic pain medications not as prescribed), sedatives, prescription stimulants, inhalants, and psychedelics. Moderate-to-severe depression was defined as PHQ-9 score of ≥10. We used PRO measures from the same day as the housing assessment, or from the closest preceding assessment in a minority of cases (Supplementary Table 1).
Statistical analysis
Associations between self-perceived housing status and HIV clinical care markers were evaluated as prevalence ratios (PR) with 95% confidence intervals (CI) estimated from relative risk regression for binary outcomes28 (HIV viral suppression and ART use) and as mean differences with 95% CIs estimated from linear regression for continuous outcomes (CD4 cell count and ART adherence). All models were adjusted for age, sex, race and ethnicity, year of housing status assessment, and site.
We also conducted several sensitivity and secondary analyses. First, analyses were repeated expanding to PWH with outcomes measured within a broader window of 6 months before or after the housing status assessment. Additionally, analyses for HIV viral suppression were stratified by (1) current drug use and (2) depressive symptoms. Finally, to understand how findings from our clinical cohort of PWH in care compared to a community-based cohort (including PWH both in and out of care), we conducted a parallel analysis among PWH in the AIDS Linked to the IntraVenous Experience (ALIVE) study29 in Baltimore, Maryland from 2010–2024. The ALIVE study assesses housing status as self-reported homelessness or sleeping unsheltered for at least 1 night in the past 6 months. In order to compare across cohorts, this analysis evaluated housing status as a binary variable for self-reported homelessness (vs. combined “stable,” “unstable,” and “don’t know” in CNICS). Secondary analyses controlled for the same covariates as in the primary analysis. All analyses were conducted in Stata version 19.5 (StataCorp, College Station, TX).
Results
A total of 6,873 PWH engaged in HIV clinical care were included in the primary analysis, the majority of whom were male (81.2%) with a mean age of 50.4 years (SD: 13.1; Table 1). Most PWH described their housing situation as “stable” (90.5%), however nearly 10% of PWH reported some form of housing instability: 4.6% “unstable” housing situation, 3.3% “homeless”, and 1.7% did not know the stability of their housing situation. On average, PWH reporting forms of housing instability were somewhat younger than those with stable housing and more often identified as non-Hispanic Black or Hispanic/Latine. Male PWH comprised a larger proportion of those experiencing homelessness (88.4%) or unstable housing (85.1%) and a smaller proportion of those not knowing the stability of their housing situation (73.9%).
Table 1.
Demographic and clinical characteristics of people with HIV across the US in the CNICS cohort by self-reported housing status, 2019–2025.
| Self-reported housing status | |||||
|---|---|---|---|---|---|
| Total (N=6,873) |
Stable (n=6,218, 90.5%) |
Unstable (n=315, 4.6%) |
Homeless (n=225, 3.3%) |
Don’t know (n=115, 1.7%) |
|
| Age, mean (SD) | 50.4 (13.1) | 50.9 (13.1) | 44.5 (12.1) | 45.9 (12.4) | 46.2 (12.8) |
| Male | 5,580 (81.2%) | 5,028 (80.9%) | 268 (85.1%) | 199 (88.4%) | 85 (73.9%) |
| Race and ethnicity | |||||
| Non-Hispanic Black | 3,169 (46.1%) | 2,808 (45.2%) | 174 (55.2%) | 107 (47.6%) | 80 (69.6%) |
| Non-Hispanic White | 2,702 (39.3%) | 2,508 (40.3%) | 102 (32.4%) | 69 (30.7%) | 23 (20.0%) |
| Hispanic/Latine | 684 (10.0%) | 603 (9.7%) | 31 (9.8%) | 41 (18.2%) | 9 (7.8%) |
| Other | 318 (4.6%) | 299 (4.8%) | 8 (2.5%) | 8 (3.6%) | 3 (2.6%) |
| Years in CNICS, mean (SD) | 11.2 (7.5) | 11.5 (7.5) | 8.9 (6.6) | 8.4 (6.9) | 9.9 (7.3) |
| Current ART prescription | 6,672 (97.1%) | 6,040 (97.1%) | 299 (94.9%) | 218 (96.9%) | 115 (100.0%) |
| Illicit drug useb | |||||
| No current use | 5,406 (78.7%) | 4,997 (80.4%) | 207 (65.7%) | 118 (52.4%) | 84 (73.0%) |
| Current use | 1,380 (20.1%) | 1,151 (18.5%) | 102 (32.4%) | 102 (45.3%) | 25 (21.7%) |
| Missing | 87 (1.3%) | 70 (1.1%) | 6 (1.9%) | 5 (2.2%) | 6 (1.3%) |
| Depression | |||||
| PHQ-9 score <10 | 5,096 (74.2%) | 4,757 (76.5%) | 149 (47.3%) | 118 (52.4%) | 72 (62.6%) |
| PHQ-9 score ≥10 | 975 (14.2%) | 770 (12.4%) | 106 (33.7%) | 74 (32.9%) | 25 (21.7%) |
| Missing | 802 (11.7%) | 691 (11.1%) | 60 (19.1%) | 33 (14.7%) | 18 (15.7%) |
Data are n (%) or mean (SD).
Abbreviations: PWH, people with HIV; CNICS, Center for AIDS Research (CFAR) Network of Integrated Clinical Systems; ART, antiretroviral therapy; PHQ, Patient Health Questionnaire.
Among PWH who self-reported current, non-injectable ART use.
Use in the prior 3 months. Includes methamphetamine, cocaine/crack, opioids [heroin, fentanyl, narcotic pain medications], sedatives, prescription stimulants, inhalants, and/or psychedelics. Does not include cannabis use.
Overall, 92.8% of PWH had suppressed HIV viral loads (<200 copies/mL), with lower proportions virally suppressed among PWH reporting forms of housing instability (unstable: 86.0%; homeless: 76.0%; don’t know: 84.4%) compared to PWH with stable housing (93.9%; Figure 1). Similarly, PWH experiencing housing instability had lower CD4 cell counts on average than those with stable housing (570–577 vs. 697 cells/mm3, respectively). While over 95% of PWH in every housing category had a current prescription for ART, those experiencing housing instability reported lower ART use (89.3%−93.0% vs. 97.1%) and lower average ART adherence among those on ART (VAS score: 84.5–89.1 vs. 93.9).
Figure 1.
HIV clinical care outcomes by self-reported housing status, CNICS cohort, 2019–2025.
Data are n (%) or mean (SD).
Abbreviations: ART, antiretroviral therapy; VAS, visual analog scale.
In the primary adjusted analysis, experiencing homelessness was associated with an 18% lower prevalence of viral suppression (95% CI: 0.77–0.89) and unstable housing was associated with a 6% lower prevalence of HIV viral suppression (95% CI: 0.90–0.98) compared to stable housing (Table 2). PWH who reported that they did not know the stability of their housing situation also had an 8% lower prevalence of viral suppression, however results were imprecise because of small numbers (95% CI: 0.85–1.00). Associations between housing instability and CD4 cell count, ART use, and adherence generally mirrored viral suppression results, with poorer outcomes among PWH experiencing forms of housing instability compared to stable housing (Table 2). Sensitivity analyses expanded to additional PWH with outcomes measured within a broader 6-month timeframe of the housing status assessment yielded similar results to the primary analyses (Supplementary Table 2).
Table 2.
Associations between self-reported housing status & HIV clinical care outcomes in the CNICS cohort, 2019–2025.
| HIV viral suppression (<200 copies/mL) (N=6,873) |
CD4 count (cells/mm3) (N=3,952) |
|||
|---|---|---|---|---|
| Housing status | n | PR (95% CI)a | n | β (95% CI)b |
| Stable (ref) | 6,218 | — | 3,521 | — |
| Unstable | 315 | 0.94 (0.90, 0.98) | 199 | −98 (−147, −48) |
| Homeless | 225 | 0.82 (0.77, 0.89) | 159 | −82 (−137, −27) |
| Don’t know | 115 | 0.92 (0.85, 1.00) | 73 | −96 (−175, −16) |
| Self-reported ART use (N=6,809) |
ART adherence (VAS)c (N=6,018) |
|||
| Housing status | n | PR (95% CI)a | n | β (95% CI)b |
| Stable (ref) | 6,165 | — | 5,516 | — |
| Unstable | 312 | 0.96 (0.93, 0.99) | 257 | −8.1 (−10.0, −6.2) |
| Homeless | 220 | 0.91 (0.86, 0.95) | 167 | −6.4 (−8.7, −4.0) |
| Don’t know | 112 | 0.93 (0.87, 0.99) | 78 | −3.4 (−6.8, 0.0) |
Abbreviations: PR, prevalence ratio; CI, confidence interval; ART, antiretroviral therapy; VAS, visual analog scale.
Relative risk regression with robust standard errors adjusted for age, sex, race and ethnicity, year, and site.
Linear regression adjusted for age, sex, race and ethnicity, year, and site.
Among PWH who reported current, non-injectable ART use; measured using the visual analog scale (VAS).
Results from secondary analyses stratified by substance use and mental health also showed a similar pattern. Regardless of current illicit drug use or depressive symptoms, experiencing unstable housing or homelessness was associated with a lower prevalence of HIV viral suppression (Table 3). Associations were slightly more pronounced among PWH experiencing homelessness who reported drug use (PR=0.79, 95% CI: 0.70–0.90) or depression (PR=0.78, 95% CI: 0.67–0.91) than in the primary analysis, but associations persisted among PWH experiencing homelessness without drug use (PR=0.87, 95% CI: 0.80–0.95) and without depression (PR=0.83, 95% CI: 0.76–0.92). Among PWH with unstable housing, point estimates were similar across strata of drug use and depression (PR=0.91 to 0.97) but with larger confidence intervals as a result of smaller sample sizes.
Table 3.
Associations between self-reported housing status & HIV viral suppression (<200 copies/mL) stratified by substance use and mental health, CNICS cohort, 2019–2025.
| Illicit drug usea (N=6,765) |
No current useb
(N=5,390) |
Current useb (N=1,375) |
||||
|---|---|---|---|---|---|---|
| Housing status | n | Viral suppression, n (%)c | PR (95% CI)d | n | Viral suppression, n (%)c | PR (95% CI)d |
| Stable (ref) | 4,982 | 4,714 (94.6%) | — | 1,148 | 1,044 (90.9%) | — |
| Unstable | 206 | 182 (88.4%) | 0.96 (0.91, 1.00) | 102 | 83 (81.4%) | 0.91 (0.83, 1.00) |
| Homeless | 118 | 96 (81.4%) | 0.87 (0.80, 0.95) | 101 | 70 (69.3%) | 0.79 (0.70, 0.90) |
| Don’t know | 84 | 69 (82.1%) | 0.89 (0.80, 0.98) | 24 | 21 (87.5%) | —e |
| Depression (N=6,071) |
PHQ-9 score <10 (N=5,096) |
PHQ-9 score ≥10 (N=975) |
||||
| Housing status | n | Viral suppression, n (%)c | PR (95% CI)d | n | Viral suppression, n (%)c | PR (95% CI)d |
| Stable (ref) | 4,757 | 4,518 (95.0%) | — | 770 | 700 (90.9%) | — |
| Unstable | 149 | 129 (86.6%) | 0.93 (0.87, 0.99) | 106 | 92 (86.8%) | 0.97 (0.90, 1.05) |
| Homeless | 118 | 92 (78.0%) | 0.83 (0.76, 0.92) | 74 | 51 (68.9%) | 0.78 (0.67, 0.91) |
| Don’t know | 72 | 62 (86.1%) | 0.93 (0.85, 1.02) | 25 | 20 (80.0%) | —e |
Abbreviations: PR, prevalence ratio; CI, confidence interval; PHQ, Patient Health Questionnaire.
Includes methamphetamine, cocaine/crack, opioids [heroin, fentanyl, narcotic pain medications], sedatives, prescription stimulants, inhalants, and/or psychedelics. Does not include cannabis.
Prior 3-month use.
Unadjusted prevalence of HIV viral suppression (<200 copies/mL) within strata of housing status and substance use or mental health.
Relative risk regression with robust standard errors adjusted for age, sex, race and ethnicity, year, and site.
Too few observations to generate a stable estimate.
Lastly, the analysis comparing results from PWH engaged in care (CNICS) to those in a community-based cohort (ALIVE) showed similar findings (Table 4). The prevalence of reporting homelessness was higher among PWH in the ALIVE cohort (11.7% homeless in the past 6 months) than in the Johns Hopkins HIV Clinical Cohort (JHHCC, 2.9% homeless in the past month)—both based in Baltimore—or across the other 6 CNICS sites (3.3% homeless in the past month). However, across these clinical and community-based cohorts when adjusting for the same covariates, experiencing homelessness (versus not experiencing homelessness) was associated with a lower prevalence of viral suppression. This association was slightly stronger in the ALIVE cohort (PR=0.79, 95% CI: 0.64–0.98) than in CNICS sites apart from JHHCC (PR=0.85, 95%CI: 0.79–0.91), while the association was similar but less precise in JHHCC (PR=0.86, 95% CI: 0.69–1.07).
Table 4.
Associations between self-reported housing status & HIV viral suppression (<400 copies/mL)a across different US cohorts.
| CNICS (6 sites):Clinical Cohortb (N=6,312) |
Johns Hopkins (Baltimore): Clinical Cohortc (N=755) |
ALIVE Study (Baltimore): Community Cohortd (N=623) |
||||
|---|---|---|---|---|---|---|
| Housing status | n (%) | PR (95% CI)e | n (%) | PR (95% CI)e | n (%) | PR (95% CI)e |
| Housed (ref) | 6,102 (96.7%) | — | 733 (97.1%) | — | 550 (88.3%) | — |
| Homelessf | 210 (3.3%) | 0.85 (0.79, 0.91) | 22 (2.9%) | 0.86 (0.69, 1.07) | 73 (11.7%) | 0.79 (0.64, 0.98) |
Abbreviations: PR, prevalence ratio; CI, confidence interval. CNICS, Centers for AIDS Research (CFAR) Network of Integrated Clinical Systems; ALIVE, AIDS Linked to the IntraVenous Experience.
For this analysis, viral suppression was defined as <400 copies/mL to account for changes in the lower level of detection over time in ALIVE data (2010–2024).
For this analysis, the CNICS cohort estimate excludes data from the 7th site that was included in primary analyses (Johns Hopkins HIV Clinical Cohort [JHHCC]), which is presented separately here for a Baltimore-based comparison to the ALIVE study.
JHHCC data are from 2023 (when this site began collecting the CNICS housing status question) to 2024, and included the nearest viral load measured within an expanded window of 6 months within the housing assessment to retain a larger sample.
ALIVE is a long-running cohort study of persons who inject drugs; this analysis was restricted to the subset of ALIVE participants with HIV and used data from the most recent visit with observed housing status and viral load.
Adjusted for age, sex, race and ethnicity, and year, along with site for CNICS.
In CNICS and JHHCC, housing status was defined as a self-reported living situation of “homeless” in the past month (vs. housed: stable, unstable, or don’t know). In ALIVE, housing status was defined as self-report of being homeless or sleeping unsheltered for at least 1 night in the past 6 months.
Discussion
In a large cohort including nearly 7,000 PWH engaged in HIV clinical care across the US with measured housing status and viral load, multiple forms of housing instability were associated with lower achievement of HIV viral suppression—the ultimate goal of HIV treatment and a key target for ending the HIV epidemic. The magnitude of this association was especially pronounced for PWH who reported experiencing homelessness, with a 13–22% lower prevalence of viral suppression compared to PWH with stable housing regardless of drug use and mental health status. Additionally, PWH who characterized their housing situation as homeless or unstable had lower average CD4 cell count and self-reported ART use and adherence, revealing additional gaps in the HIV care continuum for PWH across the spectrum of housing instability. These findings underscore the importance of stable housing for PWH to attain optimal HIV-related health outcomes.
Our findings are consistent with prior studies examining housing status in relation to HIV clinical outcomes, which primarily focused on experiencing homelessness and were among PWH who were newly initiating care or who had not established care.9–18 In contrast to common approaches that prescribe a person’s housing status—typically, a binary indicator for homelessness—based on physical location or another individual’s perception, our study captured self-perceived forms of housing instability that may be less visible but nonetheless have important health impacts.30 For example, unstable housing situations could include trouble paying rent, moving frequently, overcrowding, or remaining in harmful relationships due to housing constraints,2 which could impose difficulty adhering to ART.1 Our results emphasize the importance of measuring and addressing multiple forms of housing instability to improve HIV care outcomes.
Our study also expands the literature by focusing on PWH engaged in HIV primary care, with active ART prescriptions in the modern era when ART is better tolerated, and yet we still observed consistent associations between housing instability and suboptimal HIV care outcomes. We studied a large, diverse, nationally distributed sample of PWH receiving care, highlighting that the association between housing and viral suppression is not limited to disparities in engagement in care alone nor specific to subpopulations of PWH. Our comparative analysis showing similar associations in the ALIVE cohort bolsters this conclusion, showing that housing instability is associated with unsuppressed HIV viral load across clinical and community-based cohorts of PWH while controlling for the same set of covariates. Given heterogeneity in housing access across the US, this comparative analysis was further strengthened by examining clinical and community-based cohorts within the same city (ALIVE and JHHCC in Baltimore) and still showing similar findings.
As a whole, these findings exemplify the importance of stable housing to facilitate successful management of HIV. Even among PWH who have established consistent HIV care, housing instability remains a barrier to ART adherence and viral suppression. For example, PWH experiencing housing instability may not have a secure location to keep medications or to take them privately. While less than perfect adherence is more tolerated with newer ART regimens, this is still a clear and actionable intervention point in the HIV care continuum, especially in the context of relatively new long-acting injectable ART (e.g., cabotegravir and rilpivirine). Long-acting ART removes the need for daily medication and has shown unique promise for achieving and sustaining viral suppression among PWH experiencing housing instability.31–33 As long-acting ART becomes more widely accessible, it will provide a powerful tool to address ART adherence barriers together with strategies to improve access to stable, affordable housing.
Our findings also indicate that the observed associations between housing status and HIV viral suppression cannot be fully explained by substance use or mental health status. Previous studies have shown that substance use and mental health conditions, particularly depression, are associated with a host of negative health outcomes among PWH, including lower ART adherence and unsuppressed HIV viral load.34–41 Substance use and mental health have also been associated with experiencing homelessness, although these relationships are complex and likely bidirectional.42–47 Thus, substance use and mental health may act as either confounders or mediators of the link between housing instability and HIV viral suppression. Our stratified analyses demonstrate that the associations observed between housing status and HIV viral suppression persist regardless of drug use or depression, indicating that housing instability poses additional barriers to ART adherence (e.g., competing survival needs, adherence to daily medications, stigma, etc.33). Moreover, while longitudinal analyses are needed to better understand the potential mediating roles of substance use and mental health, evidence shows that a focus on ‘Housing First’ (providing immediate access to permanent housing without prerequisites) rather than ‘Treatment First’ (requiring sobriety or substance use treatment before housing is offered) yields better outcomes for housing stability, substance use and mental health, and HIV-related health.48–51
Strengths of our study include the large sample and rich data, a high-quality exposure measurement that distinguishes multiple levels of housing instability, the ability to stratify on covariates that are often assumed to be drivers of associations between housing and health, and a comparative analysis with a community-based cohort to understand consistency in results across PWH regardless of engagement in clinical care. While our multilevel housing measure provides a vital contribution to the literature, we emphasize that housing status is a complex exposure and that future studies should further investigate nuances in the relationship between housing status and HIV care outcomes that may be obscured by categorical measures.
The primary limitation of this study is the cross-sectional nature of our analysis. Use of longitudinal data and methods to assess how changes in housing stability impact viral suppression is crucial to understanding the dynamics and directionality of our observed associations, as well as feasible and effective intervention points, and will be explored in future studies. An additional potential limitation to our study is that housing instability and drug use were collected from self-reported clinical assessments, which could lead to underestimates of their prevalence. However, use of self-administered, tablet-based assessments as part of routine clinical care has been shown to decrease underreporting of risk behaviors due to societal biases.52,53 Outcomes and covariates were not always measured on the same day as the housing assessment, however sensitivity analyses showed little difference in results when using outcomes measured within broader windows of time. Lastly, CNICS is an observational cohort study, so the possibility of residual confounding due to both measured and unmeasured covariates is present.
Conclusions
PWH experience a high prevalence of housing instability, which has been previously associated with negative HIV outcomes in smaller studies of PWH. Our study, among nearly 7,000 PWH receiving regular HIV primary care across the US and confirmed in a community-based study, demonstrated that experiencing homelessness and unstable housing were associated with unsuppressed HIV viremia, lower self-reported ART adherence, and lower CD4 count, regardless of substance use or mental health status. Together with evidence from previous studies, our study indicates that housing instability can interfere with the HIV care continuum even among PWH in established care and that facilitating access to stable, affordable housing is imperative for ending the HIV epidemic.
Supplementary Material
Acknowledgements
The authors acknowledge all CNICS study participants and personnel for their essential contributions to this work.
SOURCES OF SUPPORT:
CNICS and HIV SUCCESS are NIH funded programs made possible respectively by the National Institute of Allergy and Infectious Diseases (NIAID) [R24 AI067039] and the National Institute of Drug Abuse (NIDA) [U24 DA058307]. The CNICS sites involved include Univ of Alabama at Birmingham [P30 AI027767], Univ of Washington [P30 AI027757], Univ of California San Diego [P30 AI036214], Case Western Reserve Univ [P30 AI036219], Johns Hopkins Univ [P30 AI094189], Fenway Health/Harvard [P30 AI060354], and Univ of North Carolina Chapel Hill [P30 AI50410]. The HIV SUCCESS sites involved include ALIVE [U01 DA036297] and Johns Hopkins HIV Clinical Cohort [U01DA036935]. Additional support comes from NIDA [R01 DA058938]. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Footnotes
MEETINGS AT WHICH PARTS OF THE DATA WERE PRESENTED: Society for Epidemiologic Research (SER) Annual Meeting, Austin, TX. June 2024.
CONFLICTS OF INTEREST: The authors report no potential conflicts of interest, including relevant financial interests, activities, relationships, and affiliations.
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