Tuberculosis Disease Prevalence Among People Who Smoke Illicit Drugs: A Respondent- Driven Sampling Study in the Western Cape, South Africa

BACKGROUND: Tuberculosis (TB) transmission is heterogenous, yet high-risk populations remain poorly defined. We aimed to assess whether people who smoke drugs (PWSD) have elevated TB disease rates in a high-burden setting. METHODS: We recruited PWSD from a rural community in the Western Cape, South Africa, using respondent-driven sampling (RDS). Participants were ≥15 years old, tested positive for methamphetamine and/or methaqualone, and completed TB and HIV testing and biobehavioral surveys. We defined TB disease as culturable TB, Xpert MTB/RIF Ultra (Ultra) MTB detected with no history of TB, Ultra traceamong persons with HIV (PWH) >2 years from any prior diagnosis, or currently on TB treatment. We summarized population-level characteristics and estimated TB prevalence using the RDS-II estimator. We identified characteristics associated with TB using logistic regression. RESULTS: Between April 2021 and October 2023, we enrolled 750 PWSD. Overall, 71.5% (95% CI, 66.1%-76.8%) were male and the mean age was 34 years (95% CI, 33%-36%); 17.5% (95% CI, 13.0%-22.0%) were PWH, of whom 31.6% were newly diagnosed. RDS-adjusted TB prevalence was 10.4% (95% CI, 6.5%-14.3%). TB prevalence among PWSD without HIV was 8.1% (95% CI, 4.4%-11.9%), compared to 20.9% (95% CI, 8.4%-33.4%) with HIV. PWH had 3.3-fold greater adjusted odds of having TB disease (95% CI, 1.9%-5.8%). CONCLUSIONS: PWSD identified through RDS had substantially elevated TB and HIV rates, with 20% of PWSD with HIV having TB. We successfully engaged PWSD in TB screening using peer recruitment. These findings highlight opportunities for community transmission identification and interventions.