EVALUation of National Implementation of the ISARIC 4C Mortality Score in United Kingdom hospitals

Project status: Completed

Online pre-print manuscript:


This was a national project aiming to gain a greater understanding of the use of the 4C mortality score in UK hospitals.

The study comprised two parts:

Part 1: An observational, cross-sectional study involved collection of basic information on the existing COVID-19 guidance/protocol at your hospital.

Part 2: A retrospective cohort study to investigate whether or not the 4C mortality score was documented in the case notes of patients presenting to hospital with COVID-19 from 11th to 24thJanuary 2021.

Investigators who submitted part 1 alone were eligible for a certificate of audit participation. Investigators who submitted both parts 1 and 2 were eligible for citable authorship as per NITCAR’s authorship policy.

The study protocol is available here.


The 4C mortality score (ISARIC 4C consortium) has been demonstrated to be a highly effective tool to assess in-hospital mortality risk in COVID-19 patients. Based on eight easy-to-access variables that include patient characteristics, physiological and blood parameters on admission, the 4C score outperformed 15 pre-existing prognostic scores in predicting mortality risk in patients with COVID- 19(1).

Anecdotal evidence suggests that hospitals have started to incorporate the 4C mortality score into their COVID-19 guidance, but no studies have assessed this.

In our study, we were collecting information about how the 4C mortality score has been incorporated into hospital COVID-19 guidance. We were also investigating whether or not the 4C mortality score was documented in patients’ case notes during the January 2021 wave of COVID-19.

No previous studies had explored the use of COVID-19 specific guidance or the application of 4C Score in the assessment of COVID-19 patients. We hope to use this information to provide clinicians with key insights into the use of the 4C score ahead of future waves of COVID-19.


Any infection doctor or junior doctor currently working in the UK with an interest in infection specialties was invited to contribute.

Summary of findings

In our nationwide study, we assessed the use of the 4C score in COVID-19 guidance at 41 hospital sites. We found that most (97.6%) sites recruited utilised COVID-19 guidance, with the 4C score referenced within guidance by 50% sites. Documentation of the 4C score was associated with use of guidance that detailed 4C variables (P= 0.008) or integrated the 4C score within admissions proformas (P=0.02). Integration of the 4C score within clinical pathways may encourage widespread use.

Any questions?

Email us at

Trainee Leads: Dr Andrew Blunsum, Dr Jonathan Perkins

Principal investigator: Dr Antonia Ho