We aim to expand the CARE75+ cohort study (recruitment target of 2500). It will provide a data resource for researchers and a research platform for additional studies (sub-studies), and in the future it will support randomised controlled trials using a Trials within Cohort (TwiCs) methodology. Specific aims in the next few years include:

• To study longitudinal frailty transitions and health and social care resource use
• To provide data for the next iteration of the electronic Frailty Index (eFI) using prognostic modelling (see project : Development and national implementation of eFI-2)
• Identifying research priorities from the perspectives of older people
• Investigating the feasibility of future trials of interventions to improve health, wellbeing and quality of life outcomes for older people
• Providing blood samples for the bio-bank at Ethical Tissue, University of Bradford https://www.bradford.ac.uk/ethical-tissue/ for frailty and ageing research
• Exploring frailty in rural and coastal areas and how to support people living with frailty in black minority and ethnic communities.

CARE75+ collects health, social and economic data. The cohort has well-characterised frailty status derived from the electronic Frailty Index to allow the identification and severity grading of frailty and to investigate frailty trajectories (how frailty changes over time and what might influence it).

CARE75+ assessments include detailed information on the demographic, health and social circumstances of participants. An extensive range of measures are collected using validated instruments, including assessments of frailty, cognition, mood, health-related quality of life, comorbidity, medications, resilience, loneliness and self-efficacy. Measures have been chosen to ensure that CARE75+ includes measures for applied epidemiological investigation and randomised trial evaluation of future interventions. For the full list of data outcomes see our data dictionary. Data are collected using a bespoke electronic data capture application, the CARE75+app.

Blood samples are collected from consenting Leeds and Bradford participants at baseline and at 12 month follow-up to provide a resource to investigate associations of a range of organ specific, immunological, endocrine and genetic markers with frailty.

As well as providing longitudinal data, CARE75+ has been established using a Trials within Cohort design (TwiCs), to provide a platform for intervention development, feasibility and definitive randomised control trials. To date CARE75+ has supported 5 additional studies (sub-studies). CARE75+ has broad consent for data linkage.

The cohort has sites recruiting nationwide in rural and city locations with varying population demographics and levels of social deprivation: Bradford, Leeds, Hull, Scarborough, Newcastle, Durham, Doncaster, Oswestry, Stafford, Wolverhampton, Exeter and Plymouth.

The study has approval from the National Research Ethics Service Committee, Yorkshire & the Humber – Bradford & Leeds (14/YH/1120).

UKCRN reference 18043