Date Published: June 6, 2019
Publisher: Public Library of Science
Author(s): Craig van Rensburg, Rebecca Berhanu, Kamban Hirasen, Denise Evans, Sydney Rosen, Lawrence Long, Petros Isaakidis.
Drug resistant-tuberculosis is a growing burden on the South African health care budget. In response the National Department of Health implemented two important strategies in 2011; universal access to drug-sensitivity testing for rifampicin with Xpert MTB/RIF as the first-line diagnostic test for TB; and decentralization of treatment for RR/MDR-TB to improve access and reduce costs of treatment.
Estimate the costs by treatment outcome of decentralized care for rifampicin and multi-drug resistant tuberculosis under routine conditions. The study was set at an outpatient drug resistant-tuberculosis treatment facility at a public academic hospital in Johannesburg, South Africa. During the study period 18–24 month long course treatment was offered for rifampicin-resistant and multi-drug-resistant tuberculosis.
Data are from a prospective observational cohort study. Costs of treatment were estimated from the provider perspective using bottom-up micro-costing. Costs were estimated as patient-level resource use multiplied by the unit cost of the resource. Clinic visits, drugs, laboratory tests, and total days hospitalized were collected from patients’ medical records. Staff time was estimated through a time and motion study. A successful treatment outcome was defined as cure or completion of the regimen.
We enrolled 124 patients with 52% having a successful outcome. The average total cost/patient for all patients was $3,430 and $4,530 for successfully treated patients. The largest contributors to total cost across all outcomes were drugs (43%) and staff (28%). The average cost to achieve a successful outcome including all patients who started treatment (“production cost”) in the cohort is $6,684.
Decentralized, outpatient RR/MDR-TB care under South Africa’s 2011 strategy costs 74% less per patient than the previous strategy of inpatient care. The treatment cost of RR/MDR-TB is primarily driven by drug and staff costs, which are in turn dependant on treatment length.
Drug-resistant tuberculosis (DR-TB) threatens achievement of global TB control. Despite the decline in new TB cases globally, rates of rifampicin (RIF) resistant and multi-drug resistant tuberculosis (RR/MDR-TB) are increasing . Access to treatment is limited and treatment outcomes remain extremely poor; the World Health Organization (WHO) estimates that only 12% of an estimated 600,0000 annual cases of RR/MDR-TB globally are successfully treated . Along with poorer outcomes, treatment costs of RR/MDR-TB are much higher than those of drug susceptible TB, with the main driver being the cost of inpatient care [1,2].
From patient files we collected the total number and types visits to the main treatment clinic, TB and non-TB drugs dispensed, laboratory tests performed, audiology visits and total inpatient days reported. As patient records do not contain sufficient detail to estimate a unique visit cost based on actual resources used we estimated the average resource use for these resources per visit type (e.g. outpatient treatment facility or local primary health care clinic).
Ethical approval was granted by the Human Research Ethics Committee at the University of Witwatersrand. Participants provided written informed consent to participate in this study.
Baseline demographics and clinical characteristics are presented in Table 1. A total of 124 patients were included in the final cohort. Half were female 62/124 (50%) with a median age 38 (IQR 31–42.5). The majority of patients were HIV co-infected 109/124 (87.8%) with a median CD4 count 107 cells/mm3 (IQR 27–274) at treatment initiation. Half of HIV-positive patients were on ART at time of RR/MDR-TB treatment initiation (n = 54/109; 50.5%), for a median of 11.4 months (IQR 3.8–29.9). Nearly half of the patients in the cohort had rifampicin mono-resistant TB (RMR) 60/124 (48.3%), 38/124 (30.6%) had RR/MDR-TB, and 26/124 (21%) had rifampicin resistant TB diagnosed by Xpert without further confirmatory testing (RR-TB by Xpert). A larger proportion of MDR-TB patients (79%) were referred from outpatient facilities than RMR (57%) and RR-TB by Xpert (54%). RR-TB by Xpert also had the lowest proportion of smear positive (3.8%) vs 17% and 26% for RMR and MDR-TB respectively. RR-TB by Xpert patients were managed as though they were confirmed MDR-TB patients.
We performed a bottom-up micro-costing analysis of treatment of RR/MDR-TB in an outpatient, decentralized model of care in South Africa. The proportion of successfully treated patients in the three groups were not significantly different, with only a 3% range between them. The average cost to successfully treat a patient was $4,530, a 74% reduction in costs compared to the inpatient model, which was shown to cost over $17,000 . As the average success rate was 52%, total cost per treatment success including all patients who started treatment (“production cost”) is $6,684. The difference between these two figures represents costs for patients with unsuccessful outcomes, suggesting that overall treatment program cost will increase by more than the cost of treatment to achieve a higher number of successful treatments, unless a more effective treatment program is implemented.