It predicts prognosis in chronic liver disease and can be used to prioritize for liver transplantation.

The United Kingdom Model for End-Stage Liver Disease (UKELD) is a clinical scoring system used specifically within the British National Health Service (NHS) to prioritize adult patients for liver transplantation. Developed by the Liver Advisory Group, it was introduced in 2008 to ensure that donor organs are allocated to those with the highest “transplant benefit” and greatest risk of mortality while on the waiting list (Barber et al., 2011).

Unlike the standard MELD score used in the United States, which primarily focuses on bilirubin, creatinine, and INR, the UKELD score incorporates serum sodium—a potent predictor of mortality in patients with cirrhosis and ascites.

The UKELD Equation

The UKELD score is calculated using four biochemical markers. It is a logarithmic formula designed to predict the 1-year mortality risk of a patient with chronic liver disease.

The Formula

$$\text{UKELD} = \left( 5.395 \times \ln(\text{INR}) \right) + \left( 1.485 \times \ln(\text{Bilirubin}) \right) + \left( 1.857 \times \ln(\text{Creatinine}) \right) – \left( 0.439 \times \text{Sodium} \right) + 50.39$$

• INR: International Normalized Ratio (clotting function).
• Bilirubin: Measures jaundice/hepatic excretory function ($\mu\text{mol/L}$).
• Creatinine: Measures renal function ($\mu\text{mol/L}$).
• Sodium: Measures electrolyte balance and fluid status ($\text{mmol/L}$).

Clinical Interpretation and Thresholds

The UKELD score is used to determine if a patient has reached the “minimal listing criteria” for liver transplantation in the UK.

The Magic Number: 49

A UKELD score of 49 is the standard threshold for elective liver transplant listing.

• UKELD < 49: The 1-year mortality risk of the patient is generally lower than the risk associated with the transplant surgery itself (~9%). At this stage, the patient is usually monitored rather than listed.
• UKELD $\ge$ 49: The patient’s 1-year mortality risk without a transplant exceeds 9%, meaning they are likely to derive a survival benefit from a new liver.

UKELD vs. MELD: Key Differences

While both models aim to reduce waiting-list mortality, the UKELD provides specific advantages within the UK population:

1. Inclusion of Sodium: Low serum sodium (hyponatremia) is a frequent complication of cirrhosis and a strong independent predictor of death. Including sodium makes the UKELD more sensitive than the original MELD (Biggins et al., 2006).
2. Specific to the UK Cohort: The model was derived from and validated using data from the UK Liver Transplant Registry, making it highly accurate for the specific demographics and disease etiologies (such as Alcohol-related Liver Disease and PSC) common in Britain.

Limitations and Exceptions

The UKELD is an excellent tool for many, but it does not capture the urgency of all patients. “Points” or “Exceptions” are often granted for:

• Hepatocellular Carcinoma (HCC): Patients with liver cancer may have low UKELD scores but require urgent transplantation to prevent tumor spread.
• Intractable Symptoms: Patients with severe pruritus (itching) or recurrent hepatic encephalopathy that isn’t reflected in blood tests.
• Variant Syndromes: Such as Hepatopulmonary Syndrome.

References

1. Barber, K., et al. (2011). UKELD: the development and implementation of a new model for predicting mortality on the liver transplant waiting list. Liver Transplantation, 17(2).
2. Neuberger, J., et al. (2008). Selection of patients for liver transplantation and allocation of donated livers in the UK. Gut, 57(2), 252-257. https://doi.org/10.1136/gut.2007.131730
3. Biggins, S. W., et al. (2006). Evidence-based incorporation of serum sodium concentration into MELD. Gastroenterology, 130(6), 1652-1660.
4. NHS Blood and Transplant (2022). Liver Transplantation: Selection Criteria and Recipient Registration. [Policy Document POL185].