Picking the low-hanging fruit: the cost-effectiveness of opportunistic diabetes screening during tuberculosis contact investigations on the Texas-Mexico border.

Objective: There is a known association between type 2 diabetes (diabetes) and tuberculosis (TB), and TB clinics have become hubs for new diabetes diagnosis among active patients with TB. However, despite the potential to identify diabetes patients, resources limit diabetes screening opportunities to close TB contacts. We assessed the cost-effectiveness of adding opportunistic screening for diabetes during the routine TB contact investigations conducted at TB clinics. Research design and methods: We used a Markov-based model to simulate the costs of diabetes screening, management and health outcomes, including the incidence of complications and death. All costs were considered from a health system perspective. One-way sensitivity analyses were conducted to assess the robustness of the results to various assumptions. Interventions that fall below US$50 000 per quality-adjusted life years (QALYs) are commonly considered very cost-effective, while those between $50 000 and $100 000 are considered moderately cost-effective. Results: Simulation of diabetes screening among TB contacts resulted in not only increased survival and reduced complications but also increased costs of diabetes management. The resulting incremental cost-effectiveness ratio was $32 642 per QALY added, which is well within commonly used willingness-to-pay thresholds for cost-effectiveness. Compared with no screening, screening increased the costs by $8633 and resulted in an increase in QALYs by 0.26 per patient. Conclusions: In the base case analysis, screening was very cost-effective given that none of the sensitivity analyses resulted in a cost-effectiveness ratio above $50 000 per QALY. Our results indicate that the expansion of diabetes screening in TB clinics is a cost-effective strategy to improve health outcomes.