Multidimensional Poverty and Implementation Reach of Household Contact Tracing for Tuberculosis in South Africa: Analysis of a Randomized Trial

BACKGROUND: Household contact tracing (HHCT) is a widely recommended intervention for tuberculosis (TB) but is poorly implemented. Multidimensional poverty, encompassing deprivations in health, education, and living standards, may hinder implementation success. METHODS: Using a cluster-randomized trial in South Africa, we examined the relationship between household multidimensional poverty as a composite deprivation score and HHCT reach as (1) initiation (at least one household contact screened); (2) continuous proportion of eligible household contacts screened; and (3) completion (all eligible household contacts screened once initiated). We performed multilevel mixed-effects modeling with modified Poisson and ordered beta regression. RESULTS: Despite near-universal comfort with HHCT (97%) among 3392 households, only 43% initiated HHCT and 19% completed screening. Greater multidimensional poverty was significantly associated with lower HHCT initiation in urban households (adjusted prevalence ratio [aPR]: 0.903, 95% confidence interval [CI]: 0.831, 0.984, per 10% higher deprivation; P = .021), but not in rural households (aPR: 1.06, 95% CI: 0.99, 1.13; P = .083). Across all households, we observed a modest but statistically significant association between greater poverty and lower predicted proportion of household contacts screened (adjusted average marginal effect [aAME]: -1.22% [-2.20%, -0.236%], per 10% higher deprivation; P = .015). Among households that initiated HHCT, multidimensional poverty was not significantly associated with screening completion (aPR: 0.945, 95% CI: 0.865, 1.03; P = .207). CONCLUSIONS: Stated comfort with HHCT may not directly translate into implementation success. Multidimensional poverty was a significant structural barrier for HHCT initiation in an urban, South African township. Once initiated, getting all household contacts screened may require targeting additional operational and health system barriers.