Pancreas Offering Scheme
During 2018, a working group was established to consider whether any improvements could be made to the 2010 National Pancreas Allocation Scheme.
This review was in response to observed longer waiting times for very highly sensitised patients, changing clinical views on the use of certain donors based on donor age and body mass index (BMI) and proposed changes to the UK Kidney Offering Scheme.
Materials and methods
A number of computer simulations were used to investigate possible changes to the scheme to address the issues raised whilst maintaining the original principles of the 2010 scheme:
- open and transparent set of allocation rules
- optimise use of a scarce resource
- minimise waiting time and cold storage time while ensuring equity of access regardless of sensitisation
The simulations were developed using 550 randomly selected deceased pancreas donors that resulted in a transplant, 248 patients listed for a pancreas or islet transplant and a pool of 992 patients newly registered for a pancreas or islet transplant. Each simulation represented three years of constant activity.
Simulation results of different scheme changes were compared to the current scheme according to the characteristics of the simulated transplant and waiting list pools.
2010 Pancreas Allocation Scheme
All donation after brainstem death (DBD) and donation after circulatory death (DCD) donors allocated by national rules:
- Tier A – blood group identical and preferable patients
- Tier B – other blood group compatible patients
Within tiers patients prioritised by total points score including:
- tissue match
- waiting time
- dialysis status
- travel time
- donor BMI
- age difference
Donors aged <25 years are not offered to pancreas islet patients.
Agreed new Pancreas Offering Scheme
All DBD and DCD donors allocated by national rules:
- Tier A – patients with matchability score 10, 100% cRF or ≥3 years waiting time
- Tier B – blood group identical and preferable patients (see list below)
- Tier C – other blood group compatible patients
Tier A prioritised by matchability score and waiting time.
Tier B and C prioritised by total points score as in 2010 scheme.
Donors aged <25 years and BMI <25kg/m2 are not offered to pancreas islet patients.
Donors with BMI ≥31kg/m2 are not offered to whole pancreas patient.
Blood group information
Blood group preferable patients:
- potential recipient with blood group O – donors from blood group O
- potential recipient with blood group A – donors from blood group O** and A
- potential recipient with blood group B – donors from blood group O* and B
- potential recipient with blood group AB – donors from blood group O**, A, B** and AB
*Patients with a cRF of 75% or more only
**Patients with a cRF of 90% or more only
Matchability points score
Patient matchability points score is a score between 1 and 10 reflecting the difficulty with which a well-matched HLA compatible organ can be found and takes into account sensitisation and rareness of HLA type.
Scores are updated annually such that 10% of waiting list patients who are easiest to match have score=1 and 10% who are most difficult to match have a score=10.
A score of 1, 2 or 3 is classed as 'easy' to match, a score of 4, 5, 6 or 7 is 'moderate' to match and a score of 8, 9 or 10 is 'difficult' to match.
A new Pancreas Offering Scheme in the UK is being developed to reflect changes to the Kidney Offering Scheme, to address the inequity observed for very highly sensitised patients in the current scheme and reflect clinical views on the use of particular donors.
The new scheme is expected to go live during the summer of 2019.