Heterogeneous Long-Term Trajectories of Dependency in Older Adults: The PAQUID Cohort, a Population-Based Study over 22 years

Background: A critical step toward successful aging is to identify opportunities for prevention of functional decline. Our aim was to describe the heterogeneity in trajectories of dependency preceding death in elders and to identify factors associated with this heterogeneity.

Methods: The study relied on 3,238 participants of the prospective population-based PAQUID cohort aged 65+ at baseline in 1988. Dependency was defined from an 11-item scale of basic and instrumental activities of daily living (ADL: bathing, dressing, toileting, continence, eating, and transferring; instrumental activities of daily living (IADL): telephoning, shopping, using transport, handling medication, and managing finances) collected over 22 years. Heterogeneous trajectories were estimated using a longitudinal item response theory model including latent classes.

Results: Five distinct profiles of functional dependency were identified over the two last decades of life: persistently high (12%), moderate (26%), persistently low (40%), and accelerated high dependency (15%), and no dependency (8%). Main factors associated with heterogeneity included age at death, sex, education, initial cognition (Mini-Mental State Examination [MMSE] score and dementia), initial disability, and poly-medication.

Conclusions: In the two last decades of life, more than 9 elders in 10 were characterized as functional decliners. On average, around half of the elders died with no or mild dependency, while 27% live several years with a high level of limitations and would need assistance in activities of daily living, at least for 2-4 years preceding death. The identified factors associated with these trajectories are important to understand functional heterogeneity in elders and to propose interventions to postpone or prevent "chronic" disability.