Quantifying the attributable burden of economic inequality on under-five mortality across ten African countries: a WHO HEAT-based analysis.

INTRODUCTION: Despite global declines in under-five mortality, African countries continue to experience high rates, with socioeconomic disparities undermining progress toward Sustainable Development Goal 3.2. While wealth gradients in child survival are well documented, the proportion of deaths directly attributable to inequality remains poorly quantified across national contexts. METHODS: We conducted a cross-national secondary analysis using the WHO Health Equity Assessment Toolkit (HEAT) v.6.0. Data from ten African countries for the 2022 reference year were included, comprising a total study population of over 6.5 million live births. Under-five mortality rates were obtained from United Nations Inter-agency Group for Child Mortality Estimation (UN IGME) datasets, disaggregated by wealth quintile and sex. Inequality was assessed using Difference, Ratio, Population Attributable Risk, Population Attributable Fraction, Slope Index of Inequality, and Relative Index of Inequality. RESULTS: National under-five mortality ranged from 38.0 per 1,000 live births in Rwanda to 117.3 in Niger, with all countries exceeding the SDG target of ≤ 25. Wealth gradients were present in all settings: the absolute difference between poorest and richest quintiles ranged from 11.3 (South Sudan) to 67.0 (Mali). Inequality-attributable burdens were highest in Mali (PAR - 41.9; PAF - 44.7%), Togo (PAR - 25.6; PAF - 42.5%), and Madagascar (PAR - 22.7; PAF - 34.5%). Gradient measures confirmed steep inequities in Mali and Togo (SII ≤ -56.3; RII 2.3). Male children had higher mortality, but sex-attributable fractions were negligible. CONCLUSION: Up to 45% of under-five deaths in high-burden African countries are attributable to economic inequality. Embedding equity metrics into child survival strategies and targeting the poorest households are essential to accelerate progress toward ending preventable child deaths. Precision public health targeting the poorest quintiles is crucial to reducing preventable child deaths in Africa.