Cost-effectiveness analysis of microscopic observation drug susceptibility test versus Xpert MTB/Rif test for diagnosis of pulmonary tuberculosis in HIV patients in Uganda

Abstract

BackgroundMicroscopic Observation Drug Susceptibility (MODS) and Xpert MTB/Rif (Xpert) are highly sensitive tests for diagnosis of pulmonary tuberculosis (PTB). This study evaluated the cost effectiveness of utilizing MODS versus Xpert for diagnosis of active pulmonary TB in HIV infected patients in Uganda.MethodsA decision analysis model comparing MODS versus Xpert for TB diagnosis was used. Costs were estimated by measuring and valuing relevant resources required to perform the MODS and Xpert tests. Diagnostic accuracy data of the tests were obtained from systematic reviews involving HIV infected patients. We calculated base values for unit costs and varied several assumptions to obtain the range estimates. Cost effectiveness was expressed as costs per TB patient diagnosed for each of the two diagnostic strategies. Base case analysis was performed using the base estimates for unit cost and diagnostic accuracy of the tests. Sensitivity analysis was performed using a range of value estimates for resources, prevalence, number of tests and diagnostic accuracy.ResultsThe unit cost of MODS was US$ 6.53 versus US$ 12.41 of Xpert. Consumables accounted for 59 % (US$ 3.84 of 6.53) of the unit cost for MODS and 84 % (US$10.37 of 12.41) of the unit cost for Xpert. The cost effectiveness ratio of the algorithm using MODS was US$ 34 per TB patient diagnosed compared to US$ 71 of the algorithm using Xpert. The algorithm using MODS was more cost-effective compared to the algorithm using Xpert for a wide range of different values of accuracy, cost and TB prevalence. The cost (threshold value), where the algorithm using Xpert was optimal over the algorithm using MODS was US$ 5.92.ConclusionsMODS versus Xpert was more cost-effective for the diagnosis of PTB among HIV patients in our setting. Efforts to scale-up MODS therefore need to be explored. However, since other non-economic factors may still favour the use of Xpert, the current cost of the Xpert cartridge still needs to be reduced further by more than half, in order to make it economically competitive with MODS.

Cost-effectiveness of GeneXpert Compared to Smear Microscopy for Diagnosis of Tuberculosis in Ethiopia

“…Moreover, the study result indicated that if the cost of cartridge reduced by 10%, the unit cost would reduce by 9.75% below the base case. This estimate was similar to a study conducted in South Africa (47%) [19] and Uganda [27] that indicated the most of the costs of GeneXpert were attributed to the high price of the cartridge. This estimate shows that the high cost of cartridges can be the major obstacle to the full implementation of the diagnostic method as a routine test.…”

“…Moreover, this study's result was consistent with a study done in South Africa [34] that found that using a novel diagnostic test (GeneXpert) for TB diagnosis was cost-saving and cost-effective. However, this nding contradicted the study in Uganda that found GeneXpert was not cost-effective [27]. This difference might be due to the algorithm compared with GeneXpert as MODS has almost similar diagnostic accuracy and low cost compared with the GeneXpert diagnostic method.…”

Economic Analyses of Respiratory Tract Infection Diagnostics: A Systematic Review

“…Cost-effectiveness acceptability curves (CEACs) were included in both articles [25,26], using the net benefit regression framework [36]. The reduction in antibiotic prescriptions was expressed in monetary terms 1 (50%) [87] 2 (29%) [89,90] (33%) [98] Middle income 5 (42%) [29,[32][33][34][35] 9 (20%) [38,43,55,58,64,71,75,79,84] 0 (0%) 2 (29%) [92,94] (67%) [96,97] Low income 1 (8%) [35] 5 (11%) [38,[44][45][46]83] 0 (0%) 1 (14%) [93] (33%) [98] as additional costs per patient prescription avoided [25] or additional costs per percentage reduction in antibiotic prescriptions [26]. Nicholson et al conducted a randomised controlled trial and health-economic evaluation of diagnostic tests for influenza, respiratory syncytial virus (RSV) and Streptococcus pneumoniae in adults hospitalised for chronic or acute cardiopulmonary illness in the UK [24].…”

“…The main diagnostic test to detect TB was the Xpert test [38][39][40][41][42][43][44][45], with other articles assessing the lateral flow urine lipoarabinomannan assay Alere Determine™ test [46], the IGRA (Interferon-Gamma Release Assay) test [47] and the T-cell detection test [48]. The target population consisted of patients presenting with symptoms of active pulmonary TB disease [38][39][40][41][42][43]47], in some cases, patients with human immunodeficiency virus specifically [44][45][46]48]. The comparators were sputum smear microscopy [38][39][40][41]45], culture [42][43][44] and chest radiography [41,43,45].…”

“…The target population consisted of patients presenting with symptoms of active pulmonary TB disease [38][39][40][41][42][43]47], in some cases, patients with human immunodeficiency virus specifically [44][45][46]48]. The comparators were sputum smear microscopy [38][39][40][41]45], culture [42][43][44] and chest radiography [41,43,45]. In the case of testing positive, the treatment was a routine TB regime.…”