Spatial small-area estimation of under-five mortality in Ethiopia: mapping subnational inequalities to accelerate SDG achievement.

BACKGROUND: Ethiopia has achieved substantial reductions in under-five mortality, but national estimates mask important subnational variation. Reliable zonal estimates are needed to identify high-burden areas and guide local health planning. This study estimated under-five mortality across Ethiopian zones by using a Bayesian spatial small-area estimation (SAE) approach with geospatial covariates. METHODS: An ecological analysis was conducted by using data from the 2019 Mini-Ethiopian Demographic and Health Survey. Under-five mortality risk was estimated at the zonal level through a Bayesian hierarchical spatial SAE model. Associations with selected area-level covariates were assessed. Smoothed relative risks (RRs) with corresponding 95% credible intervals (CrIs) were reported. RESULTS: Marked geographic heterogeneity in under-five mortality was observed. Elevated risks were concentrated in peripheral lowland regions, particularly Somali, Afar, Benishangul-Gumuz, and Gambella. High-burden zones included Afar (Zones 1, 2, and 3), Metekel in Benishangul-Gumuz, Anguak and Nuer in Gambella, and Dollo, Faftan, and Liben in Somali. Population density was inversely associated with mortality (RR: 0.83, 95% CrI: 0.77-0.98), whereas longer travel time to the nearest city was associated with higher under-five mortality (RR: 1.24, 95% CrI: 1.02-1.44). CONCLUSION: Under-five mortality remains unevenly distributed across Ethiopia, with persistent hotspots in remote and underserved regions. Improving geographic access to health services in these areas may help reduce inequalities in child survival and support progress toward the 2030 Sustainable Development Goals.