Healthcare use patterns before Alzheimer's disease and related diseases identification and future healthcare trajectory.

<bold>Objectives: </bold>A frequent late Alzheimer's Disease and Related Diseases (ADRD) identification is described and may induce erratic health resource use. We aimed to describe healthcare use patterns preceding ADRD identification.<bold>Methods: </bold>We studied persons aged 65 or older, identified with incident ADRD in 2012 in the French health insurance database. Healthcare use covering a wide range of care in ambulatory and hospital settings during the period ranging from 18 to six months before ADRD identification was studied. The main dimensions of healthcare use patterns before ADRD identification were investigated in three age groups (65-74, 75-84, ≥85) through a multiple correspondence analysis. These dimensions were secondarily interpreted according to the 5-year healthcare trajectory following ADRD identification, qualified as favorable (or not) by experts in the field.<bold>Results: </bold>This research studied 36,990 subjects. Four dimensions raised in each age group. Two dimensions' interpretations were retrieved in all age groups: intensity of healthcare use, functional dependency. However, their rank differed along with the qualification of the future healthcare trajectory. Some specificities appeared in some age group. In the 65-74 and 75-84 years groups, there were dimensions reflecting healthcare use related to psychiatric or psycho-behavioral disorders. In the ≥85 group, two dimensions reflected dependency related to other comorbidities, and organised medical follow-up.<bold>Conclusion: </bold>Several dimensions emerged in line with erratic trajectories before ADRD identification. They underlined the need for actions towards ADRD identification. [ABSTRACT FROM AUTHOR]