Cost Effectiveness analysis of GeneXpert Omni compared to GeneXpert MTB/Rif for point of care diagnosis of Tuberculosis among presumptive cases in Pingire health center III, Serere district

Abstract

Insufficient case detection is a persistent obstacle to furthering the WHO’s stated goal of eliminating TB by 2035. Introduction and implementation of Xpert MTB/Rif with improved sensitivity and turnaround time has provided substantial improvements in TB case detection. Xpert Omni that uses an Ultra cartridge with a sensitivity that is 5% higher than standard Xpert MTB/Rif cartridge is a potential portable battery powered POC test for used in resource constrained settings. However, it is not known whether its increased sensitivity and reduced specificity would translate into diagnostic cost saving and improved clinical outcomes. Objective: This study sought to determine the cost-effectiveness of Xpert MTB/Rif compared to Xpert Omni for point of care diagnosis of tuberculosis among presumptive cases. It further compared treatment initiation, pre-treatment loss to follow up and time-to-start treatment of Xpert at POC with Xpert by referral and microscopy in Pingire Health centre III, Serere district. Methodology: A decision-analysis model that compares the Xpert MTB/RIF and Xpert Omni test Cost-effectiveness analysis was performed in TreeAge software by in-putting respective model parameters. Sensitivity analysis was done by modifying the parameters in the model. Logistic regression was used to analyse pre-treatment lost to follow-up, median time-to-start treatment was compared using survival analysis approach by Kaplan-Meier curves and Box plots. Results: the study demonstrated that GeneXpert Omni was more effective but more costly. It requires US$30.72 for every additional TB case diagnosed by Xpert Omni. Results of 1,161 of presumptive TB cases were analysed. The median time to treatment initiation was 1 day for Xpert at POC and 14 days for Xpert by referral. The likelihood of loss to follow was four fold among the patients whose samples were referred to the GeneXpert laboratory compared to when the Xpert was at the point of care. Conclusion: The deployment of Xpert Omni is moderately cost effective POC test compared to Xpert MTB/Rif. Xpert at POC has reduced pre-treatment loss to follow up and reduced time-to-start treatment.