What contributes to out-of-pocket health expenditure in Cambodia's uncovered population? A distributional and...

Out-of-pocket health expenditures (OOPE) are an inefficient and inequitable means of health financing. Identifying the factors driving these expenditures is crucial to design effective prepayment schemes. This study uses Cambodia-a country with high OOPE and prevalent informal employment-as a case study to analyse the relative contributions of healthcare, health, and social factors to OOPE and the OOPE budget share (OOPE as a proportion of total annual household expenditure) across different points in their distribution.

We used data from a 2023 cross-sectional survey among 3254 households engaged in informal employment with no access to prepayment schemes (uncovered households). We employed unconditional quantile regression to investigate the distributional effects of healthcare, health, and social factors on OOPE and the OOPE budget share. To examine the heterogeneity in the contributions of these factors to the explained variance in OOPE and the OOPE budget share at different quantiles, we combined unconditional quantile regression with Shapley decomposition.

Uncovered households incurred high OOPE, leading to elevated incidences of financial hardship. Healthcare factors, including levels of care, private providers, medications, and visits were the largest contributors to the explained variance in OOPE and the OOPE budget share. Health factors, including severity, days lost to illness/injury, noncommunicable diseases, and injuries, also contributed substantially. Social factors contributed less overall, with wealth being the primary driver. Contributions of these factors varied across different points in the outcome distributions.

These findings underscore the need to improve financial protection for uncovered households. The Cambodian government should consider expanding prepayment schemes that directly address the main healthcare drivers identified in this study. Schemes should provide effective access to comprehensive outpatient care and essential medications, and necessary services at higher care levels, including in the private sector. Addressing the rising burden of noncommunicable diseases alongside multisectoral efforts to reduce injuries may also be important.