Social care costs for community-dwelling older people living with frailty.

International evidence indicates that older people with frailty are more likely to access social care services, compared to nonfrail older people. There is, however, no robust evidence on costs of social care provided for community-dwelling older people living with frailty in their own homes. The main objective of this study was to examine the relationship between community-dwelling older people living with frailty, defined using the cumulative deficit model, and annual formal social care costs for the 2012-2018 period. A secondary objective was to estimate formal social care spending for every 1% reduction in the number of older people who develop frailty over 1 year. Secondary analysis of prospective cohort data from two large nationally representative community-based cohort studies in England was performed. Respondents aged ≥75 were used in the main analysis and respondents aged 65-74 in sensitivity testing. We used regression tree modelling for formal social care cost analysis including frailty, age, gender, age at completing education and living with partner as key covariates. We employed a minimum node size stopping criteria to limit tree complexity and overfitting and applied 'bootstrap aggregating' to improve robustness. We assessed the impact of an intervention for every 1% decrease in the number of individuals who become frail over 1 year in England. Results show that frailty is the strongest predictor of formal social care costs. Mean social care costs for people who are not frail are £321, compared with £2,895 for individuals with frailty. For every 1% of nonfrail people not transitioning to frailty savings of £4.4 million in annual expenditures on formal social care in England are expected, not including expenditure on care homes. Given considerably higher costs for individuals classed as frail compared to nonfrail, a successful intervention avoiding or postponing the onset of frailty has the potential to considerably reduce social care costs.