Modelling the Long-Term Economic Burden of HIV on Households and Health Systems Across Nigeria’s Six Geopolitical Zones

The economic burden of HIV on Nigerian households and the national health system is multidimensional, encompassing direct treatment costs, productivity losses, caregiver burden, and long-term systemic financing pressures, yet comprehensive cross-geopolitical zone economic modelling is absent from the literature. This study models the long-term economic burden of HIV at household and health system levels across Nigeria's six geopolitical zones using a Markov disease progression model calibrated to Nigerian epidemiological, clinical, and economic data. A mixed-methods design combines a household economic survey of 1,800 people living with HIV (300 per zone), health facility costing analyses in 60 antiretroviral therapy sites, and expert elicitation through a Delphi panel of 25 HIV economists, clinicians, and programme managers. Primary data inform model parameter estimation, with secondary data from the National Agency for the Control of AIDS, Nigeria Health Sector Budget, and the Global Burden of Disease Study 2022 supplementing the dataset. The Markov model is coded in R using the heemod package, with probabilistic sensitivity analysis performed to quantify parameter uncertainty. Catastrophic health expenditure, impoverishment rates, and health system fiscal space impacts are calculated across 10-year projection scenarios. The Human Capital and Capabilities Approach provides the welfare economics theoretical foundation. Original contributions include a validated Nigeria-specific HIV economic burden model and geopolitical zone disaggregated projections not previously available in the literature. Findings will inform National HIV financing strategy under the Nigeria National AIDS Spending Assessment. Keywords: economic burden, HIV, Markov modelling, household finance, Nigeria.