PP102 Selecting The Sequence Of Diagnostic Tests For Leprosy In Brazil

Abstract

IntroductionHansen’s disease, or leprosy, is a chronic bacterial infection that affects the nerves, skin, eyes, and nose lining. In 2019, there were 202,256 new cases reported globally, and nearly 28,000 new cases are diagnosed each year in Brazil. The best way to prevent the spread of Hansen’s disease is early diagnosis and treatment of infected individuals. Most diagnoses are done clinically, but only the microscopic analysis of slit-skin smears is funded in Brazil. Serologic and polymerase chain reaction (PCR) tests have also been developed to aid in the diagnosis. The goal of this study was to identify the most cost-effective strategy for increasing the diagnosis of Hansen’s disease in Brazil.MethodsWe examined the impact of the following four strategies using a decision tree model: (i) slit-skin smear only; (ii) PCR test only; (iii) serologic testing followed by slit-skin smear for positive samples; and (iv) serologic testing followed by slit-skin smear for positive samples and PCR test for negative serologic tests and negative slit-skin smears. The accuracy of the tests was determined using a systematic review and meta-analysis and validated by experts. The costs were calculated from the Brazilian health system perspective. Univariate and probabilistic analyses were also conducted.ResultsSerologic testing or PCR followed by slit-skin smear was dominated in the economic model (more false-negative samples and more costly). The addition of serologic testing and PCR to the diagnostic sequence made the strategy more expensive than slit-skin smears alone, but it significantly reduced the percentage of false negative results (from 7.3 to 2.9%) at an estimated cost of USD 533.61 per incremental diagnosis. Disease prevalence was the most important variable in the sensitivity analysis.ConclusionsThis is the first cost-effectiveness model undertaken for Hansen’s disease. The results indicate that incorporating serology and PCR testing into the Brazilian health system could be an appealing option for reducing the spread of Hansen’s disease in Brazil.