A Mixed-Methods Study of the Lagos State Social Health Insurance Scheme and Catastrophic Health Expenditure Among Informal Sector Traders in Alimosho Local Government Area

Catastrophic health expenditure remains a significant barrier to universal health coverage in many African settings, particularly for informal sector workers. The Lagos State Social Health Insurance Scheme was introduced to improve financial protection, but its impact on this vulnerable group is not well documented. This study assessed the impact of the Lagos State Social Health Insurance Scheme on the incidence of catastrophic health expenditure among informal sector traders in Alimosho Local Government Area. Specific objectives were to quantify changes in catastrophic expenditure and to explore participants' experiences and perceptions of the scheme. A concurrent mixed-methods design was employed. A longitudinal survey tracked healthcare expenditure and insurance status in a cohort of 412 informal traders. Concurrently, 24 in-depth interviews and six focus group discussions were conducted to explore qualitative themes regarding scheme accessibility and utilisation. Quantitative data were analysed using logistic regression, while qualitative data underwent thematic analysis. Quantitative results indicated a statistically significant reduction in the incidence of catastrophic health expenditure among scheme enrollees compared to non-enrollees. The proportion of enrolled traders experiencing catastrophic expenditure fell substantially over the study period. Qualitatively, key themes included improved financial predictability for routine care, but persistent concerns about the scheme's coverage of chronic conditions and complex referrals. The scheme demonstrated a protective effect against catastrophic health expenditure for enrolled informal sector traders in this setting. However, design limitations may undermine its full potential for providing comprehensive financial risk protection. Policy reforms should focus on expanding the scheme's benefit package to cover a wider range of conditions, particularly chronic diseases. Enhanced community-based sensitisation is needed to improve understanding and uptake. Further research should investigate long-term sustainability and equity impacts. catastrophic health expenditure, health insurance, informal sector, mixed methods, Nigeria, financial protection This study provides empirical evidence on the effect of a sub-national health insurance scheme on financial protection for informal sector workers, highlighting both its benefits and limitations for policy refinement.