Disability trajectories in the last years of life: a Swedish longitudinal multi-cohort study

The patterns and determinants of late-life functional decline are not fully understood. We examined disability trajectories in relation to proximity to death among decedents aged 70 years and older, and investigated their associations with sex, age at death, education, cognitive impairment, and chronic conditions.

Harmonised data from six Swedish longitudinal ageing studies (1997-2016) within the National E-infrastructure for Aging Research (NEAR) were used. Participants who died at age 70 years or older and had data on activities of daily living (ADL) from at least two assessments were included (N = 2294, 62% women, mean age at death 89.8 years [SD 6.5]). ADL limitations (0-5 scale) were analysed across four time intervals before death (0-2, >2-4, >4-6, and 6-12 years). Group-based trajectory modelling identified disability trajectories, multinomial logistic regression examined demographic associations, and generalized estimating equations assessed associations of cognitive impairment and chronic conditions with trajectory membership.

Three trajectories were identified: constantly low (53%), low-sharply increasing (36%), and high-increasing (11%). Women, those with lower education, and individuals dying at older ages were more likely to follow increasing or persistently high disability trajectories. High-increasing trajectory was associated with higher likelihood of cognitive impairment.

For most, ADL limitations remained low until the final two years of life, though distinct trajectories with steady or sharp increases also emerged. Identifying demographic and health-related factors associated with functional decline may inform targeted interventions and help anticipate care needs.