Share your view on how livers are offered
While not everyone with PSC will need a liver transplant, some do. For those people, the system for prioritising people on the liver transplant waiting list is of utmost importance. We live in a time where demand for donated organs exceeds the supply, and care must be taken so that each precious liver donated is used in the fairest way possible with the goal of saving and improving lives.
The current system, called the National Liver Offering Scheme (NLOS), is under review, and we have a chance to influence how NLOS evolves and improves.
Warning: This page mentions survival rates and touches on the chance of death.
The National Liver Offering Scheme
The National Liver Offering Scheme (NLOS) was introduced in 2018. Since its introduction it has only been applied to donation after brain death (DBD) donor organs. It uses factors relating to every donor (and the liver) and the potential recipient to decide who to offer a liver to.
What is important about this scheme is that it combines an individual’s need for a transplant (how poorly they are) with how long someone will live after transplant (utility) to create a benefit score which is used to decide who is the best match for the next available liver.
There have been criticisms of this system. For example, in 2022 some patients reported to PSC Support that they were being told that the NLOS system disadvantages people with PSC. Very long wait times were being reported from patients with PSC.
It was determined that no reports or concerns about PSC were highlighted by the Monitoring Committee for the scheme. However, since then, age has since been shown to have an effect: 'The UK liver offering algorithm prioritises older patients for transplantation by predicting that advancing age increases the benefit from liver transplantation.'1
The current system allocates a benefit score to people on the waiting list to determine who is the best match for a particular liver. Many factors are taken into account. This study shows that the people aged 25 – 55 years have a lower liver benefit score compared to those outside this range when all else is equal.
Mark Chatterley, Operations Manager at PSC Support said: 'Despite the system being checked for bias, PSC patients wait a long time for a liver offer. This could be a result of PSC patients often being younger. I can personally attest that the quality of life of PSC patients while on the list is often very poor and I would like to see quality of life measures being involved in the offering scheme.'
Need, Utility and Benefit
Determining who gets a potential liver is a tough decision. This is one of the elements that the patient survey is looking at. There are three main ways to think about this: Need, utility and benefit.
Need
How likely someone is to die.
The sicker a patient is on the list, the higher their need.
An offering system based solely on need would always offer a liver to the sickest person on the list.
Issues:
- How long someone may live after transplant is not taken into account. While someone may have the highest need, they may not be able to survive the surgery or live for very long after.
- This only measures physical need. Mental and social need is not taken into account.
Utility
How long someone will live after transplant.
The better the predicted outcome for a patient on the list, the higher their utility score.
An offering system based solely on utility would offer a liver to the person with the best statistical chance for survival.
Issues:
- Survival measurements only go up to 5 years.
- Someone who may gain an additional 30 years of life from a transplant is rated the same as someone who may gain 6 due to the use of 5-year survival for this factor.
Benefit
The greatest increase in additional life expectancy
This is best explained with an example. Say there is a liver that could give anyone two years of life and we have two potential recipients on the waiting list: One who will only live another week and one another year.
The first person would get an additional life expectancy of two years. The second person would only get an additional 1 year.
Issues:
- Quality of life is not taken into account on both the pre- and post- transplant sides.
- Survival measurements only go up to 5 years.
Martine Walmsley, Head of Research Strategy at PSC Support said, 'NLOS was intended to be a more equitable system for deciding who gets the next liver on the transplant list. Previously this was only largely based on need (in blunt terms, who is most likely to die first without a transplant) and there was general agreement that it needed to be changed.
'NLOS was set up with a limit of only five years when calculating how long someone will live after their transplant due to lack of longer term data. People with PSC do very well after transplant, and can live for decades longer than five years but, because of the 5-year limit, this doesn’t get taken into account. This unintentionally disadvantages young people (with any liver disease, not just PSC). There is more data today than when the scheme was first set up and so an updated scheme should now place greater emphasis on potential life years gained.
'Furthermore, quality of life should be factored into the algorithm, especially for those who will be offered livers as part of the variant* scheme.'
*'Variant' refers to patients for whom the benefit score is not appropriate and so their position on the waiting list will be prioritised according to waiting time.
Survey
This button will open the survey in another tab so you can refer back to this page to see definitions of need, utility and benefit.
Videos
This video has Professor Douglas Thorburn, Consultant Hepatologist and chair of the NHSBT Liver Advisory Group, and Laura Stamp, Lead Nurse Recipient Coordinator at NHS Blood and Transplant answering questions about the National Liver Offering Scheme review.
This video is our Ask the Expert session with Professor Douglas Thorburn, Consultant Hepatologist and chair of the NHSBT Liver Advisory Group who kindly gave us an overview of the current scheme and answered your questions.
References
1. Effect of recipient age on prioritisation for liver transplantation in the UK: a population-based modelling study
Attia, Anthony et al.
The Lancet Healthy Longevity, Volume 5, Issue 5, e346 - e355