Economic support to improve TB treatment outcomes in South Africa : a pragmatic cluster randomized controlled trial

[摘要] ENGLISH ABSTRACT: This thesis focused on the provision of economic support to improve the outcomes of patients on TB treatment. Although the association between poverty and tuberculosis is generally acknowledged, there is little evidence to guide the use of economic interventions to improve tuberculosis control. In South Africa, a high burden country with extensive poverty, such evidence is particularly important.The first part of this thesis is a Cochrane systematic review of evidence from randomized controlled trials regarding the effectiveness of economic support among patients with tuberculosis. Eleven trials were included: ten conducted among marginalised groups in the United States on economic support for people on prophylactic treatment for latent TB; and one from Timor-Leste on economic support for patients with active TB. The review found that the use of economic interventions in patients with latent TB may increase the return rate for reading tuberculin skin test results, probably improves clinic re-attendance for initiation or continuation of prophylaxis and may improve completion of prophylaxis, compared to normal care. However, it is uncertain if economic support improves treatment completion in patients with active TB (low quality evidence).The second part of the thesis reports the findings of a pragmatic, cluster randomized controlled trial to evaluate the feasibility and effectiveness of delivering economic support to patients on treatment for active TB in South Africa. Patients with drug sensitive pulmonary TB were offered a monthly voucher valued at ZAR120 until completion of treatment or a maximum of eight months. Patients in control clinics received usual TB care. A parallel process evaluation provided contextual information to explain the trial findings. The qualitative component of this evaluation consisted of in-depth interviews with a sample of trial participants, including patients, nurses and health managers, to assess responses to the voucher and its administration. The quantitative component included a survey of patients' household expenditure to assess patients' levels of poverty and the effects of the voucher on these, and an analysis of the goods on which patients spent their vouchers.4091 patients were included in the trial: 1984 in the control arm (10 clinics) and 2107 in the intervention arm (10 clinics). Intention to treat analysis showed a small but non-significant improvement in treatment success rates in intervention clinics (intervention 76.2%; control 70.7%; risk difference 5.6% (-1.2; 12.3%), p = 0.107). Fidelity to the intervention was low, partly because nurses preferred to issue vouchers based on perceived financial need, rather than on eligibility. Logistical difficulties in delivering vouchers to clinics also undermined fidelity. The vouchers did not significantly increase patients' household expenditure, but were experienced by patients as helpful, especially in providing more food with which to take their tablets.Factors related to the administration of economic support may undermine its effectiveness in improving TB treatment outcomes. Further research is needed to explore how best to deliver such economic support to those eligible to receive it, particularly in low and middle income countries where the burden of tuberculosis is highest.

[发布机构] Stellenbosch University