Global Trends in Leprosy-Related Incidence and Disease Burden from 1990 to 2021: A Secondary Analysis of the Global Burden of Disease Study

Background Despite substantial progress in reducing incidence, considerable challenges to global leprosy elimination persist. This study sought to elucidate longitudinal trends in the global leprosy-associated disease burden through multiple stratifications. Methods Using data from the Global Burden of Disease Study, we analyzed the age-standardized incidence rate (ASIR) and Disability-Adjusted Life Years (DALYs) rate (ASDR) per 100,000 population for leprosy, stratified by geography (seven super-regions in the GBD regional classification), age (focusing on the pediatric population), income level (World Bank classification), and Healthcare Access and Quality (HAQ) index. The ICD codes used to identify leprosy were A30–A30.9 and B92 for ICD-10, and 030–030.9 and V74.2 for ICD-9. A locally weighted regression (LOESS) model was applied to estimate long-term trends, and joinpoint regression analysis was used to identify significant trend change points. Results Data from 204 countries were included in the analysis. From 1990 to 2021, favorable decreases in the LOESS estimates of ASIR were observed in South Asia (6.307 to 1.321), followed by Sub-Saharan Africa (2.789 to 0.808) and Latin America and the Caribbean (2.605 to 1.506), with a global average annual percent change (AAPC) of -3.301. AAPCs of ASDR also showed significant declining trends across all geographic regions, with a global AAPC of -2.638. Among children and adolescents, global AAPCs of ASIR and ASDR also decreased favorably. By income level, lower-middle- and low-income country groups demonstrated consistent declining trends in ASIR and ASDR. Strong correlations between ASIR and ASDR and the HAQ index were observed in each country at the beginning and the end of the study period. Conclusions Globally, the leprosy-associated disease burden has declined over the last three decades, including among children and adolescents in endemic regions.