The relationship between deprivation and frailty trajectories over 1 year and at the end of life: a case-control study.

BACKGROUND We investigated the association between area-level, multi-domain deprivation and frailty trajectories in the last year of life and over 1 year in a matched non-end-of-life sample. METHODS A 1-year longitudinal case-control study using primary care electronic health records from 20 460 people age ≥ 75. Cases (died 1 January 2015 to 1 January 2016) were 1:1 matched to controls by age, sex and practice location. Monthly interval frailty measured using a 36-item electronic frailty index (eFI: range 0-1, lower scores mean less frailty). Deprivation measured using Index of Multiple Deprivation (IMD) quintiles. We used latent growth curves to model the relationship between IMD and eFI trajectory. RESULTS Living in a less deprived area was associated with faster increase in eFI for cases (0.005% per month, 95%confidence interval [CI]: 0.001, 0.010), but not controls, and was associated with lower eFI at study baseline in cases (-0.29% per IMD quintile, 95%CI -0.45, -0.13) and controls (-0.35% per quintile, 95%CI -0.51, -0.20). CONCLUSIONS Overall, greater area-level deprivation is associated with higher levels of frailty, but people who survive to ≥75 have similar 1-year frailty trajectories, regardless of area-level deprivation. Interventions to reduce frailty should target younger age groups, especially those living in the most deprived areas.