A Multi-Country Evaluation of Patient Preferences for Tuberculosis Diagnostics: A Discrete Choice Experiment to Inform WHO Target Product Profiles

Abstract

Abstract Background Recognizing new and improved diagnostics as a key step to reducing the global tuberculosis (TB) burden, the World Health Organization (WHO) publishes target product profiles (TPPs) to guide development of novel TB diagnostics; however, TPPs have not included the preferences of people undergoing TB testing. Understanding their preferences is crucial for optimizing the acceptability and uptake of TB diagnostic services. Design/methods We conducted a discrete choice experiment (DCE) among adults with presumptive or microbiologically confirmed TB in 5 countries (Philippines, Vietnam, South Africa, Uganda, and India). The DCE evaluated preferences for 5 TB diagnostic test attributes (sample type, accuracy, cost, location, time to result) with 3-4 levels per attribute. We estimated mean preference weights for attribute levels using Hierarchical Bayesian models and conducted willingness-to-trade analyses for preferred test features. Results Among 1,033 participants (median age 43 years, Interquartile Range: 30-55), 52% were female, 10% had HIV, 14% had diabetes, 36% had current or prior TB), the most strongly valued test features were free cost, high diagnostic accuracy, and rapid (within 15 minutes) result availability. Among less valued attributes, facility-based testing (location) and sputum (sample type) were most preferred. The relative importance of attributes and their levels differed by country. In willingness-to-trade simulations, participants in each country were willing to trade 10-20% lower accuracy for the availability of rapid tests but were unwilling to trade accuracy for alternative sample types (e.g., tongue-swab, urine, blood) or testing locations (e.g., home- or community-based); participants in India and Vietnam were willing to pay $3.20 and $4.00 USD, respectively, for tests with rapid results. Conclusions Persons accessing TB services in five high-burden countries universally value free cost, high diagnostic accuracy, and rapid result availability. However, many were willing to accept lower test accuracy and some were willing to incur small out-of-pocket costs to access rapid tests. To align with preferences of TB-affected communities, future TPP updates and new test development should prioritize rapid results while maintaining high accuracy and minimizing costs.