[Use of national French health insurance register to identify the current address of a cohort].
BACKGROUND: The aim of the study was to assess the efficiency of the Registre National Inter-régimes des bénéficaires de l'Assurance-Maladie (RNIAM), which is the French register of health insurance, in order to identify the present address of subjects who have lived in the Beaumont-Hague county, France, between 1978 and 1998, when they were less than 25 years old. METHODS: A cohort of 4,118 persons was defined by consulting school and civil status registers from three villages. We drew at random 824 subjects and between October 2000 and August 2001, we asked the RNIAM to locate them. For each subject, the usual identification parameters (first name, last name, birth date and eventually birth place) were provided. In case of a doubt concerning these parameters, a second request was undertaken with a slight modification. RESULTS: Altogether, 94.5% of the included people were identified by the RNIAM. Identification was better for people born in France than for those born abroad (97% versus 52%) and 84.5% of people were linked to a health insurance regimen. The RNIAM was able to identify a correct address for 68.7% of the subjects. CONCLUSION: The RNIAM seems promising for further epidemiological investigations. Nonetheless, it still remains insufficient by itself to identify addresses. Other means (tax records) should be evaluated and associated with the register data.