Frailty and socioeconomic position: A systematic review of observational studies

Background: Frailty, an age-related state of reduced physiological reserve, is often associated with lower socio-economic position (SEP). This systematic review synthesised observational studies assessing (i) the association between SEP and frailty prevalence; (ii) how changes in frailty status over time vary by SEP; and (iii) whether the association between frailty and clinical outcomes is modified by SEP. 

Methods: We searched three electronic databases from 2001 to 2023. We included observational studies measuring early-, mid-, and late-life indicators of SEP (education, income, wealth, housing, occupation, and area-based measures of multiple deprivation) and frailty (assessed using any validated measure). Screening and extraction were performed in duplicate. Findings were synthesised using narrative synthesis. 

Results: We included 383 studies reporting findings from 265 independent samples/cohorts across 64 countries. Lower SEP was associated with higher frailty prevalence across all indicators (childhood deprivation 7/8 studies, education 227/248, occupation 28/32, housing 8/9, income 98/108, wealth 39/44 and area-based deprivation 32/34). Lower SEP was also associated with higher frailty incidence (27/30), with greater odds of transitioning towards a more severe frailty state (35/43), lower odds of frailty reversion (7/11), and (in some studies) with more rapid accumulation of deficits (7/15). The relationship between frailty and mortality was not modified by SEP. 

Interpretation: Preventative measures across multiple levels of individual and structural inequality are likely to be required to reduce the rising levels of frailty. Resourcing of interventions and services to support people living with frailty should be proportionate to needs in the population to avoid widening existing health inequalities.