Cost-effectiveness of Xpert MTB/RIF for tuberculosis diagnosis in South Africa: a real-world cost analysis and economic evaluation

Abstract

SummaryBackgroundIn 2010 a new diagnostic test for tuberculosis, Xpert MTB/RIF, received a conditional programmatic recommendation from WHO. Several model-based economic evaluations predicted that Xpert would be cost-effective across sub-Saharan Africa. We investigated the cost-effectiveness of Xpert in the real world during national roll-out in South Africa.MethodsFor this real-world cost analysis and economic evaluation, we applied extensive primary cost and patient event data from the XTEND study, a pragmatic trial examining Xpert introduction for people investigated for tuberculosis in 40 primary health facilities (20 clusters) in South Africa enrolled between June 8, and Nov 16, 2012, to estimate the costs and cost per disability-adjusted life-year averted of introducing Xpert as the initial diagnostic test for tuberculosis, compared with sputum smear microscopy (the standard of care).FindingsThe mean total cost per study participant for tuberculosis investigation and treatment was US$312·58 (95% CI 252·46–372·70) in the Xpert group and $298·58 (246·35–350·82) in the microscopy group. The mean health service (provider) cost per study participant was $168·79 (149·16–188·42) for the Xpert group and $160·46 (143·24–177·68) for the microscopy group of the study. Considering uncertainty in both cost and effect using a wide range of willingness to pay thresholds, we found less than 3% probability that Xpert introduction improved the cost-effectiveness of tuberculosis diagnostics.InterpretationAfter analysing extensive primary data collection during roll-out, we found that Xpert introduction in South Africa was cost-neutral, but found no evidence that Xpert improved the cost-effectiveness of tuberculosis diagnosis. Our study highlights the importance of considering implementation constraints, when predicting and evaluating the cost-effectiveness of new tuberculosis diagnostics in South Africa.FundingBill & Melinda Gates Foundation.

Standardized framework for evaluating costs of active case-finding programs: An analysis of two programs in Cambodia and Tajikistan

“…To assess validity of our unit cost estimates, we compared our results with previously published estimates of TB diagnostics and interventions. [16,[24][25][26][27] Focusing on cost per Xpert test, we find our estimates consistent and comparable to the existing evidence (between $12 and $42 per test) factoring operational settings, costing methods, consumables costs, and testing volumes. In comparing our cost per program yield estimates, we found one study that reported costs of program operation and yields of the CATA program that overleaped with our assessment period but reporting much lower cost estimate.…”

“…Therefore, we were not able to capture uncertainties in cost estimates that may arise due to variabilities in operations and workloads that may depend on operational settings conditions. [24,26,30] This limitation can be overcome by designing costing studies alongside the program development and implementation to include staff timeuse surveys or time and motion and tracking operational statistics so that these data can help inform cost allocation mechanisms, describe uncertainties in cost estimates associated with operational variabilities and activity-specific inefficiencies [24,31]. Subsequently, we recommend that costs be routinely evaluated so that variability in operations and settings can be captured and reflected as part of the cost reports.…”

Incremental cost-effectiveness of the second Xpert MTB/RIF assay to detect Mycobacterium tuberculosis

“…Xpert was superior over microscopic determination of drug susceptibility (MODS) in high TB/HIV prevalence setting (18). Whereas, Vassall et al (19) reported that Xpert was cost-neutral and did not improve the cost-effectiveness of TB diagnosis in South Africa. Budgetary constraint is a major consideration influencing the choice of diagnostics in developing countries.…”

REASSURED diagnostics to inform disease control strategies, strengthen health systems and improve patient outcomes

“…This includes a careful assessment of acceptability and feasibility linked to possible increased stresses on the health system/provider when testing is introduced into settings where thus far no or limited testing was performed. Studies using the GeneXpert MTB/RIF TB test showed that new diagnostic tests would not have the expected impact on outcomes if test introduction is not accompanied by changes in patient pathways or practices 72,73 . These studies highlight the importance of programmatic monitoring of the impact of novel technologies beyond studies that are usually conducted under controlled conditions.…”