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. Copyright (c) 2009 John Wiley & Sons, Ltd.