The association of demographics, frailty and multiple health conditions with outcomes from acute medical admissions to hospitals in England: exploratory analysis of an administrative dataset

Abstract

Emergency and acute hospital services in England are under increasing pressure. The aim of this study was to investigate the association between key case-mix indicators and outcomes for adults admitted to hospital with an acute medical condition in England. All patients aged ≥16 years admitted to hospital in England as an acute unselected medical admission and who survived to discharge during the financial year 2021-2022 were included. Length of hospital stay was the primary outcome of interest. Data were available for 1,586,168 unique patients. A case-mix index was developed with a score that ranged from 0 to 12. Frailty was the most important variable in the index, followed by multiple health conditions and patient age. The mean case-mix score across hospital trusts in England ranged from 5.3 to 7.8. The case-mix index will support initiatives to better understand factors contributing to outcomes from acute medical admissions to hospital.

Keywords: case-mix; emergency care; quality improvement; unwarranted variation.

Fig 1.

Funnel plot of adjusted mean length of stay in NHS hospital trusts in England for patients with a discharge date from 1 April 2021 to 31 March 2022.

Fig 2.

Mean emergency admission case-mix index score across NHS hospital trusts in England for patients with a discharge date from 1 April 2021 to 31 March 2022.