Rethinking social pathways between tuberculosis stigma to treatment outcomes: A gender-stratified mediation analysis of social support

The mechanisms through which tuberculosis-related stigma (TB-stigma) influences treatment outcomes-and whether pathways differ by gender-remain incompletely understood. Social support (SS) has been proposed to mediate pathways linking TB-stigma to treatment vulnerability, although this assumption has rarely been empirically tested. We evaluated associations between TB-stigma and treatment success, with perceived SS as a mediator. We analyzed data from 620 adults receiving tuberculosis treatment in South Africa. We measured isolation- and disclosure-related stigma using validated scales and assessed SS using the Multidimensional Scale of Perceived Social Support. The primary outcome was treatment success. Gender-stratified regression models estimated associations between stigma, SS, and treatment success, and we assessed mediation using bootstrapped confidence intervals. Treatment success was higher among women (92.3%) than men (86.6%) (p = 0.04). Among men, higher isolation-related stigma was associated with lower family-based SS (standardized β=-0.18, 95% CI: -0.31, -0.05) but not treatment success. Among women, isolation-related stigma was associated with higher odds of treatment success (adjusted odds ratio [aOR]: 1.55, 95% CI: 1.05-2.30), whereas disclosure-related stigma was associated with lower odds of treatment success (aOR: 0.76, 95% CI: 0.59-0.98). No evidence of mediation by SS was observed. These findings suggest the relationship between TB-stigma and treatment outcomes is gender- and stigma-dimension-specific and is not explained by perceived SS as currently operationalized. Rather than indicating an absence of social mechanisms, these results suggest that current measures of SS may not adequately capture how TB-stigma shapes treatment experiences, highlighting the need to better measure gendered and relational vulnerability mechanisms.