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PLoS One. 2019 May 6;14(5):e0216221. doi: 10.1371/journal.pone.0216221. eCollection 2019.

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

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Université Côte d'Azur, CHU de Nice, Département de Santé Publique, Centre Hospitalier Universitaire de Nice, Nice, France.
Université Côte d'Azur, CHU de Nice, Centre Mémoire de Ressources et de Recherche, EA CoBTeK, Nice, France.
Direction du Service Médical Régional du Régime Social des Indépendants (RSI) Côte d'Azur, Nice, France.
Direction Régionale du Service Médical de la Caisse Nationale d'Assurance Maladie des Travailleurs Salariés (CNAMTS) PACA-Corse, Marseille, France.



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.


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.


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.


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.

Conflict of interest statement

The authors have declared that no competing interests exist.

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