haematology infectious-disease

4C Mortality Score for COVID-19

Validated prognostic score predicting in-hospital mortality in adults hospitalised with COVID-19. Uses 8 readily available clinical variables at admission. Validated in multiple national and international cohorts.

Score interpretation

Low Risk -- 4C Score 0-3 (~1.2% in-hospital mortality) 0–3

4C low risk -- very low probability of in-hospital mortality from COVID-19

→ Consider outpatient or early discharge pathway (with safety netting); monitor SpO2 at home (alert return if SpO2 < 94% or rapid decline); antipyretics and symptomatic management; ensure vaccination status reviewed; antivirals: nirmatrelvir-ritonavir (Paxlovid) or sotrovimab if high-risk immunocompromised patient (NICE COVID therapeutics; refer via COVID Medicines Delivery Unit); no specific antiviral for low-risk admitted patients; dexamethasone NOT indicated unless requiring supplemental O2.

Intermediate Risk -- 4C Score 4-8 (~9.9% mortality) 4–8

4C intermediate risk -- moderate mortality probability; active inpatient management

→ Inpatient admission; supplemental O2 if SpO2 < 92%; dexamethasone 6 mg OD x10 days if requiring supplemental oxygen (RECOVERY: deaths reduced by about one fifth on oxygen and one third on invasive ventilation); remdesivir 200 mg IV day 1 then 100 mg IV days 2-5 if SpO2 <= 94% requiring supplemental O2 (EMA approved); baricitinib 4 mg OD x14 days if on O2 + dexamethasone (RECOVERY, COV-BARRIER trials); VTE prophylaxis (therapeutic or prophylactic based on D-dimer/risk); prone awake positioning if tolerated; NEWS2 monitoring; escalation criteria pre-agreed (ICU if RR > 30, SpO2 < 90 on O2, or haemodynamic compromise).

High Risk -- 4C Score 9-14 (~31.4% in-hospital mortality) 9–14

4C high risk -- in-hospital mortality 31.4% in the validation cohort (Knight 2020); intensive management and escalation planning

→ Senior review and ICU/HDU consideration; high-flow nasal oxygen (HFNO) 40-60 L/min or CPAP 5-10 cmH2O for moderate-severe hypoxaemic respiratory failure (CPAP reduced intubation or death in RECOVERY-RS); dexamethasone 6 mg OD x10 days; baricitinib 4 mg OD; remdesivir if within 10 days of symptom onset and not on invasive ventilation; intubation and invasive ventilation if: RR > 35, PaO2/FiO2 < 100, signs of fatigue; lung-protective ventilation (6 mL/kg IBW, plateau pressure < 30 cmH2O); prone ventilation > 12 hours/day (PROSEVA); VTE: standard prophylactic-dose anticoagulation for patients on high-flow oxygen, CPAP, NIV or invasive ventilation (therapeutic-dose heparin benefited only non-critically ill patients -- ATTACC/ACTIV-4a/REMAP-CAP; NICE NG191); ECMO if severe refractory ARDS; goals of care discussion; DNACPR consideration; palliative care early involvement for very high risk patients.

Very High Risk -- 4C Score >= 15 (~61.5% in-hospital mortality) 15–21

4C very high risk -- in-hospital mortality 61.5% in the validation cohort (Knight 2020)

Interpretation bands for the 4C Mortality Score. Apply clinical judgement and local guidance.

References

Knight SR et al. Risk stratification of patients admitted to hospital with covid-19 using the ISARIC WHO Clinical Characterisation Protocol: development and validation of the 4C Mortality Score. BMJ. 2020;370:m3339.
NICE COVID-19 rapid guideline: managing COVID-19. NICE NG191. 2021 (updated 2023).

Curated clinical cross-links plus same-class fallbacks.

Drugs

Pathways

Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.

Score interpretation

References

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