How to Interpret and Discuss KDPI with Patients
What is the Kidney Donor Profile Index (KDPI)?
The kidney donor profile index (KDPI) combines a variety of donor factors into a single number that summarizes the likelihood of graft failure after deceased donor kidney transplant.
What is the KDPI trying to tell me?
The KDPI tells you how long a deceased donor kidney is expected to function relative to all of the kidneys recovered in the U.S. during the last year. Lower KDPI scores are associated with longer estimated function, while higher KDPI scores are associated with shorter estimated function. For example, a kidney with a KDPI of 20% is expected to have shorter longevity than 20% of recovered kidneys (i.e., longer function than 80% of recovered kidneys).
How much difference in expected longevity exists between low, medium, and high KDPI kidneys?
Figure 1 shows that a deceased donor kidney with KDPI of 0-20% is expected to function, on average, nearly 11 and a half years after transplant, compared to over 12 years for a living donor kidney. The majority (65%) of deceased donor kidneys have KDPI between 21 and 85% and are expected to function for about 9 years. Kidneys with KDPI exceeding 85% are expected to function for more than five and a half years.
Since living donor kidneys have tended to be transplanted into lower-risk patients (e.g., younger, non- diabetic), and KDPI > 85% kidneys have tended to go to higher-risk patients, the actual differences in half-lives for a given patient may not be as great as shown in Figure 1. And of course, the actual graft survival for any given patient depends on patient-specific factors such as age, diagnosis, HLA mismatching, compliance with treatment protocols, and other factors.
How can I use KDPI to evaluate organ offers?
Historically, the kidney allocation system has used two designations to describe kidneys; they are either from a standard criteria donor (SCD) or an expanded criteria donor (ECD). It turns out there are wide variations of expected kidney function within these two broad categories. KDPI provides more granularity in how each kidney is expected to function relative to other available kidneys. Use KDPI as an element in your evaluation of the kidney as you consider other donor characteristics, and remember that candidates need to consent to receive kidneys with KDPI over 85%. KDPI is not intended to serve as the only metric for determining donor suitability.
Kidney Donor Profile Index (KDPI) Guide for Clinicians: How to Interpret and Discuss KDPI with Patients
Will a patient’s waiting time be affected by their willingness to accept offers of higher KDPI kidneys?
Yes. It is possible that limiting a patient’s access to only kidneys from donors with lower KDPI scores will increase the patient’s waiting time. However, given their lower expected longevity (Figure 1), opting to accept a high KDPI kidney may not be the best choice for all patients. This decision depends on a variety of factors, including your transplant center’s expected waiting times, the patient’s clinical characteristics, whether living donation is a possibility, and quality of life considerations. In the same way the ECD list was intended to help transplant more quickly patients that may not require a high-longevity kidney, consenting and listing a patient as willing to accept a KDPI>85% kidney is also expected to expand opportunities for transplantation.
What additional information is available?
Access professional and patient education materials about the new kidney allocation system, including the following.
- Instructional videos and guidance for professionals
- Links to allocation calculators and supporting materials
- Kidney brochure for patients https://www.unos.org/wp-content/uploads/unos/Kidney_Eval_Brochure.pdf