Household- Versus Incentive-Based Contact Investigation for Tuberculosis in Rural South Africa: A Cluster-Randomized Trial.

BACKGROUND: Household contact investigation for people newly diagnosed with tuberculosis (TB) is poorly implemented, particularly in low- and middle-income countries. Conditional cash incentives may improve uptake. METHODS: We conducted a pragmatic, cluster-randomized, crossover trial of 2 TB contact investigation approaches (household-based and incentive-based) in 28 public primary care clinics in South Africa. Each clinic used 1 approach for 18 months, followed by a 6-month washout period, after which the opposite approach was used. Fourteen clinics were randomized to each approach. In the household-based arm, we conducted TB screening and testing of contacts at the household. In the incentive-based arm, both index patients and ≤10 of their close contacts (either within or outside the household) were given small cash incentives for presenting to study clinics for TB screening. The primary outcome was the number of people with incident TB who were diagnosed and started on treatment at study clinics. RESULTS: From July 2016 to January 2020, we randomized 28 clinics to each study arm, and enrolled 782 index TB patients and 1882 contacts in the household-based arm and 780 index patients and 1940 contacts in the incentive-based arm. A total of 1413 individuals started on TB treatment in the household-based arm and 1510 in the incentive-based arm. The adjusted incidence rate ratio of TB treatment initiation in the incentive- versus household-based arms was 1.05 (95% confidence interval: .97-1.13). CONCLUSIONS: Incentive-based contact investigation for TB has similar effectiveness to traditional household-based approaches and may be a viable alternative or complementary approach to household-based investigation.

Conditional Cash Transfers to Incentivize Tuberculosis Screening: Description of a Novel Strategy for Contact Investigation in Rural South Africa.

BACKGROUND: Providing incentives to screen close contacts for tuberculosis (TB) is an alternative to household-based contact investigation. We aimed to characterize patients and contexts where this incentive-based strategy might be preferred. METHODS: This is a secondary analysis of a cluster randomized trial of TB contact investigation in Limpopo District, South Africa, conducted between 2016 and 2020. Twenty-eight clinics were randomly allocated to household-based vs incentive-based contact investigation. In the incentive-based arm, index participants and contacts received transport reimbursement and incentives for TB screening and microbiological diagnosis of contacts. We estimated differences in mean number of contacts per index participant with household-based vs incentive-based contact investigation overall and within subgroups of index participants. RESULTS: A total of 3776 contacts (1903 in the incentive-based and 1873 in the household-based arm) were referred by 2501 index participants. A higher proportion of contacts in the incentive-based than household-based arm were adults (72% vs 59%), reported chronic TB symptoms (25% vs 16%) or ever smoking (23% vs 11%). Index participants who walked or bicycled to a clinic referred 1.03 more contacts per index (95% confidence interval [CI], .48 to 1.57) through incentive-based than household-based investigation. Index participants living with >5 household members referred 0.48 more contacts per index (95% CI, .03 to .94) through household-based than incentive-based investigation. CONCLUSIONS: Relative to household-based investigation, incentive-based investigation identifies contacts likely at higher risk for active TB. Incentive-based investigation may be more appropriate for index participants who can easily access clinics, versus household-based investigation for patients with large households. Clinical Trials Registration. NCT02808507.

A clinical score for identifying active tuberculosis while awaiting microbiological results: Development and validation of a multivariable prediction model in sub-Saharan Africa.

BACKGROUND: In highly resource-limited settings, many clinics lack same-day microbiological testing for active tuberculosis (TB). In these contexts, risk of pretreatment loss to follow-up is high, and a simple, easy-to-use clinical risk score could be useful. METHODS AND FINDINGS: We analyzed data from adults tested for TB with Xpert MTB/RIF across 28 primary health clinics in rural South Africa (between July 2016 and January 2018). We used least absolute shrinkage and selection operator regression to identify characteristics associated with Xpert-confirmed TB and converted coefficients into a simple score. We assessed discrimination using receiver operating characteristic (ROC) curves, calibration using Cox linear logistic regression, and clinical utility using decision curves. We validated the score externally in a population of adults tested for TB across 4 primary health clinics in urban Uganda (between May 2018 and December 2019). Model development was repeated de novo with the Ugandan population to compare clinical scores. The South African and Ugandan cohorts included 701 and 106 individuals who tested positive for TB, respectively, and 686 and 281 randomly selected individuals who tested negative. Compared to the Ugandan cohort, the South African cohort was older (41% versus 19% aged 45 years or older), had similar breakdown of biological sex (48% versus 50% female), and had higher HIV prevalence (45% versus 34%). The final prediction model, scored from 0 to 10, included 6 characteristics: age, sex, HIV (2 points), diabetes, number of classical TB symptoms (cough, fever, weight loss, and night sweats; 1 point each), and >14-day symptom duration. Discrimination was moderate in the derivation (c-statistic = 0.82, 95% CI = 0.81 to 0.82) and validation (c-statistic = 0.75, 95% CI = 0.69 to 0.80) populations. A patient with 10% pretest probability of TB would have a posttest probability of 4% with a score of 3/10 versus 43% with a score of 7/10. The de novo Ugandan model contained similar characteristics and performed equally well. Our study may be subject to spectrum bias as we only included a random sample of people without TB from each cohort. This score is only meant to guide management while awaiting microbiological results, not intended as a community-based triage test (i.e., to identify individuals who should receive further testing). CONCLUSIONS: In this study, we observed that a simple clinical risk score reasonably distinguished individuals with and without TB among those submitting sputum for diagnosis. Subject to prospective validation, this score might be useful in settings with constrained diagnostic resources where concern for pretreatment loss to follow-up is high.

Brief Report: Proportion and Predictors of Adult TB Contacts Accepting HIV Testing During an Active TB Case Finding Intervention in South Africa.

BACKGROUND: Many individuals at risk for HIV may be reached through active TB case finding interventions in areas with highly prevalent co-epidemics of TB/HIV. METHODS: We analyzed data from a cluster-randomized trial of 2 TB case finding strategies: facility-based screening and contact investigation of newly identified TB cases. In both arms, on-site rapid HIV testing was offered to all contacts older than 18 months who did not self-report HIV-positive status. Those who were HIV infected were referred appropriately. All contacts 15 years and older were included in this analysis. RESULTS: Among 2179 contacts identified, 50% (1092) accepted HIV testing and counselling, of whom 6.3% (68) tested HIV-positive. Contacts who were unemployed [adjusted prevalence ratio (aPR) 1.14, 95% confidence interval (CI): 1.04 to 1.25], had not been to a clinic (aPR 1.09, 95% CI: 1.02 to 1.18) or HIV tested (aPR 1.25, 95% CI: 1.14 to 1.39) 6 months before, and those reporting gastrointestinal symptoms (aPR 1.22, 95% CI: 0.98 to 1.52) and genitourinary symptoms (aPR 1.30, 95% CI: 1.17 to 1.45) were significantly associated with accepting HIV testing. Women [adjusted odds ratio (aOR) 2.19, 95% CI: 1.26 to 3.81], individuals with a past history of tuberculosis (aOR 1.96, 95% CI: 0.93 to 4.14), and those not HIV tested 6 months before (aOR 2.20, 95% CI: 1.28 to 3.79) were significantly associated with testing HIV-positive. CONCLUSION: Offering HIV testing in the context of active tuberculosis case finding represents an opportunity to identify a large proportion of previously undiagnosed individuals with HIV in a population that might otherwise not seek testing.

Contact tracing versus facility-based screening for active TB case finding in rural South Africa: A pragmatic cluster-randomized trial (Kharitode TB).

BACKGROUND: There is a dearth of comparative effectiveness research examining the implementation of different strategies for active tuberculosis (TB) case finding, particularly in rural settings, which represent 60% of the population of sub-Saharan Africa. METHODS AND FINDINGS: We conducted a pragmatic, cluster-randomized comparative effectiveness trial of two TB case finding strategies (facility-based screening and contact tracing) in 56 public primary care clinics in two largely rural districts of Limpopo Province, South Africa. In the facility-based screening arm, sputum Xpert MTB/RIF was performed on all patients presenting (for any reason) with TB symptoms to 28 study clinics, and no contact tracing was performed. In the contact-tracing arm, contacts of patients with active TB were identified (via household tracing in 14 clinics and using small monetary incentives in the other 14 clinics), screened for TB symptoms, and offered Xpert MTB/RIF testing. The primary outcome was the number of newly identified patients with TB started on treatment. The analysis used multivariable Poisson regression adjusted for historical clinic-level TB case volumes and district. The trial was registered with ClinicalTrials.gov (NCT02808507). From July 18, 2017, to January 17, 2019, a total of 3,755 individuals started TB treatment across 56 study clinics in the 18-month period. Clinic characteristics and clinic-level averages of patient characteristics were similar across the two arms: 40/56 (71%) clinics were in a rural location, 2,136/3,655 (58%) patients were male, and 2,243 (61%) were HIV positive. The treatment initiation ratio comparing the yield of TB patients started on treatment in the facility-based arm compared to that from the contact-tracing arm was 1.04 (95% confidence interval [CI] 0.83-1.30, p = 0. 73). In the contact-tracing arm, 1,677 contacts of 788 new TB index patients were screened, yielding 12 new patients with TB. Prespecified subgroup analyses resulted in similar results, with estimated treatment initiation ratios of 0.96 (95% CI 0.64-1.27; p = 0.78) and 1.23 (95% CI 0.87-1.59; p = 0.29) among historically smaller and historically larger clinics, respectively. This ratio was 1.02 (95% CI 0.66-1.37; p = 0.93) and 1.08 (95% CI 0.74-1.42; p = 0.68) in the Vhembe and Waterberg districts, respectively. The estimated treatment initiation ratio was unchanged in sensitivity analyses excluding 24 records whose TB registration numbers could not be verified (1.03, 95% CI 0.82-1.29; p = 0.78) and excluding transfers-in (1.02, 95% CI 0.80-1.29; p = 0.71). Study limitations include the possibility of imbalance on cluster size owing to changes in catchment population over time and the inability to distinguish the independent effects of the two contact investigation strategies. CONCLUSIONS: Contact tracing based on symptom screening and Xpert MTB/RIF testing did not increase the rate of treatment initiation for TB relative to the less resource-intensive approach of facility-based screening in this rural sub-Saharan setting. TRIAL REGISTRATION: ClinicalTrials.gov NCT02808507.

Improving active case finding for tuberculosis in South Africa: informing innovative implementation approaches in the context of the Kharitode trial through formative research.

BACKGROUND: Tuberculosis (TB) is the leading infectious killer worldwide, with approximately 1.8 million deaths in 2015. While effective treatment exists, implementation of active case finding (ACF) methods to identify persons with active TB in a timely and cost-effective manner continues to be a major challenge in resource-constrained settings. Limited qualitative work has been conducted to gain an in-depth understanding of implementation barriers. METHODS: Qualitative research was conducted to inform the development of three ACF strategies for TB to be evaluated as part of the Kharitode cluster-randomised trial being conducted in a rural province of South Africa. This included 25 semi-structured in-depth interviews among 8 TB patients, 7 of their household members and 10 clinic health workers, as well as 4 focus group discussions (2 rural and 2 main town locations) with 6-8 participants each (n = 27). Interviews and focus group discussions explored the context, advantages and limitations, as well as the implications of three ACF methods. Content analysis was utilised to document salient themes regarding their feasibility, acceptability and potential effectiveness. RESULTS: Study participants (TB patients and community members) reported difficulty identifying TB symptoms and seeking care in a timely fashion. In turn, all stakeholder groups felt that more proactive case finding strategies would be beneficial. Clinic-based strategies (including screening all patients regardless of visit purpose) were seen as the most acceptable method based on participants' preference ranking of the ACF strategies. However, given the resource constraints experienced by the public healthcare system in South Africa, many participants doubted whether it would be the most effective strategy. Household outreach and incentive-based strategies were described as promising, but participants reported some concerns (e.g. stigma in case of household-based and ethical concerns in the case of incentives). Participants offered insights into how to optimise each strategy, tailoring implementation to community needs (low TB knowledge) and realities (financial constraints, transport, time off from work). CONCLUSIONS: Findings suggest different methods of TB ACF are likely to engage different populations, highlighting the utility of a comprehensive approach. TRIAL REGISTRATION: Clinicaltrials.gov ( NCT02808507 ). Registered June 1, 2016. The participants in this formative study are not trial participants.