The Health Care Module of the European Health Interview Survey (EHIS) is aimed to obtain comparable information on the use of inpatient and ambulatory care in all EU member states. The aim of this study was to assess the validity of self-reported information on the use of health care, collected according to the Eurostat guidelines, in the Belgian population.MethodsSelf-reported use of health care, based on EHIS questions, was compared with registered information on reimbursed health care through a linkage of data from the Belgian Health Interview Survey 2008 with data from the compulsory Belgian health insurance. Outcome indicators included the probability of a contact with a GP, specialist, dentist and a physiotherapist, as well as inpatient and day patient hospitalisation. The concordance between the two data sources was assessed by calculating the percentage of agreement and Cohen's kappa. Correlates of over and underreporting were investigated via a multinomial logistic regression.ResultsCompared to health insurance data, the survey results underestimated the percentage of people with a specialist contact in the past year (50.5% versus 65.0%) and a day patient hospitalisation (7.8% versus 13.0%). Inversely, survey results overestimated the percentage of people having visited a dentist in the past year: 58.3% versus 48.6%. The best concordance was obtained for an inpatient hospitalisation (kappa 0.75). The validity of self-reported use of health care varied by region. After adjustment for a range of covariates, overreporting a contact with a GP in the past year occurred significantly more often in Brussels (OR 1.93; 95% CI 1.37-2.73) and Wallonia (OR 1.55; 95% CI 1.14-2.11) than in Flanders.ConclusionThe validity of self-reported use of health care, based on EHIS questions, varies by type of health service. Regional differences in the use of self-reported health care may be influenced by regional differences in the validity of the self-reported information.