Alzheimer's disease: Estimating its prevalence rate in a French geographical unit using the National Alzheimer Data Bank and national health insurance information systems.

BACKGROUND: Reliable epidemiological data on Alzheimer's disease are scarce. However, these are necessary to adapt healthcare policy in terms of prevention, care and social needs related to this condition. To estimate the prevalence rate in the Alpes-Maritimes on the French Riviera, with a population of one million, we present a capture-recapture procedure applied to cases of Alzheimer's disease, based on two epidemiological surveillance systems. METHODS: To estimate the total number of patients affected by Alzheimer's disease, a capture-recapture study included a cohort of patients with Alzheimer's disease or receiving medications only eligible for use for this condition, recorded by a specific health insurance information system (Health Insurance Cohort, HIC), and those registered in the French National Alzheimer's Data Bank ("Banque Nationale Alzheimer", BNA) in 2010 and 2011. We applied Bayesian estimation of the Mt ecological model, taking into account age and gender as covariates, i.e. factors of inhomogeneous catchability. RESULTS: Overall, 5,562 patients with Alzheimer's disease were recorded, of whom only 856 were common to both information systems. Mean age and F/M sex ratio differed between BNA and HIC surveillance systems, 81 vs 84 years and 2.7 vs 3.2, respectively. A Bayesian estimation, with age and gender as covariates, yields an estimate of 15,060 cases of Alzheimer's disease [95%HPDI: 14,490-15,630] in the Alpes-Maritimes. The completeness of the HIC and BNA databases were respectively of 25.4% and 17.2%. The estimated prevalence rate among the population over 65 years old was 6.3% in 2010-2011. CONCLUSIONS: This study demonstrates that it is possible to determine the number of subjects affected by Alzheimer's disease in a geographical unit, using available data from two existing surveillance systems in France, i.e. 15,060 cases in the Alpes-Maritimes. This is the first stage of a population-based approach in view of adapting available resources to the population's needs.

The French National Alzheimer database: a fast growing database for researchers and clinicians.

BACKGROUND: Alzheimer's disease (AD) is a major public health issue. The French National Alzheimer database (BNA) registers all medical acts performed by memory units and independent specialists throughout France. This article describes the national coverage, the registered patient characteristics and illustrates research possibilities. METHODS: All data transmitted up to December 2012 were analyzed. The following patient characteristics were studied: age, sex, educational level, place of living, diagnosis, Mini-Mental State Examination score and existence of pharmacological or psychosocial interventions. RESULTS: At the end of 2012, the BNA included 84% (n = 357) of all French memory units, contained 341,498 patients and more than 800,000 medical acts. AD accounted for 26.4% of all registered diagnoses, related disorders for 21.7% and mild cognitive impairment for 8.7%. CONCLUSION: The BNA offers a multitude of research possibilities. In the coming years, the BNA will play a major role in monitoring trends and related risk factors in AD.