The prevalence of homelessness and its associated factors among people who inject drugs in Iran: results from nationwide bio-behavioral surveillance surveys in 2020 and 2023

Homelessness among people who inject drugs (PWID) represents a significant and complex public health challenge. However, few studies have investigated the factors contributing to its prevalence, particularly in the Middle East and North Africa region. We aimed to determine homelessness’s prevalence and associated factors among PWID in Iran from July 2019 to March 2020 and between May and August 2023. This study analyzed data from two national surveys (2020 and 2023) in Iran, focusing on PWID aged over 18. Participants were interviewed about their demographics, substance use, health behaviors, and experiences with homelessness. Multinomial logistic regression determined homelessness-related factors in the past 12 months or over 12 months for merged data of both years. In 2020, 2632 participants, and in 2023, 2371 PWID were included in the analysis. The prevalence of homelessness in the past 12 months was 43.2% (95% Confidence Intervals [CI]: 41.3, 45.1) in 2020 and 47.6% (95% CI: 45.6–49.6) in 2023. Multivariable multinomial logistic regression showed that being aged ≥ 30 years (adjusted Odds Ratio [aOR]: 2.13, 95% CI: 1.66–2.72), having high school education or higher (aOR: 0.74, 95% CI: 0.65–0.85), age of first drug use < 18 years (aOR: 1.61, 95% CI: 1.41–1.85), and the lifetime history of HIV testing (aOR: 1.36, 95% CI: 1.17–1.58) were significantly associated with homelessness in the past 12 months. Being aged ≥ 30 years (aOR: 1.62, 95% CI: 1.14–2.31), having high school education or higher (aOR: 0.71, 95% CI: 0.59–0.87), age of first drug use < 18 years (aOR: 1.47, 95% CI: 1.21–1.78), and lifetime history of HIV testing (aOR: 1.76, 95% CI: 1.40–2.22) also had significant associations with homelessness in more than 12 months. Our findings suggest that sociodemographic characteristics, substance use patterns, and health behaviors significantly contribute to the likelihood of homelessness among PWID. Housing-supportive programs integrated with harm reduction interventions are recommended to mitigate homelessness and its related challenges.