Supplemental health insurance and equality of access in Belgium.

The effects of supplemental health insurance on health-care consumption crucially depend on specific institutional features of the health-care system. We analyse the situation in Belgium, a country with a very broad coverage in compulsory social health insurance and where supplemental insurance mainly refers to extra-billing in hospitals. Within this institutional background, we find only weak evidence of adverse selection in the coverage of supplemental health insurance. We find much stronger effects of socio-economic background. We estimate a bivariate probit model and cannot reject the assumption of exogeneity of insurance availability for the explanation of health-care use. A count model for hospital care shows that supplemental insurance has no significant effect on the number of spells, but a negative effect on the number of nights per spell. We comment on the implications of our findings for equality of access to health care in Belgium.