Primary and secondary care service use and costs associated with frailty in an ageing population: longitudinal analysis of an English primary care cohort of adults aged 50 and over, 2006-2017.

"Declaration of Conflicts of Interest: HP has received lecture fees or sponsorship from Abbott, Pfizer, HC-UK conferences and UCB pharma outside of the submitted work and is supported by the NIHR Southampton Biomedical Research Centre, Nutrition, and the University of Southampton. S de L has research funding through his University from AstraZeneca, GSK, Moderna, MSD, Sanofi, Seqirus and Takeda. He has been a member of advisory boards for AstraZeneca, GSK, Sanofi and Seqirus, with funding paid to his University. AC is part-funded by the National Institute for Health Research Applied Research Collaboration Yorkshire & Humber, the NIHR Leeds BRC and Health Data Research UK, an initiative funded by UK Research and Innovation Councils, NIHR and the UK devolved administrations and leading medical research charities. Declaration of Sources of Funding: This project is funded by the National Institute for Health Research (NIHR) Health Services and Delivery Research (HSDR) programme, award HS&DR 16/116/43. The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care. These funding bodies had no role in writing of the manuscript or decision to submit for publication."

"Declaration of Sources of Funding: This project is funded by the National Institute for Health Research (NIHR) Health Services and Delivery Research (HSDR) programme, award HS&DR 16/116/43. The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care. These funding bodies had no role in writing of the manuscript or decision to submit for publication."