Nhs Blood and Transplant

NHS BLOOD AND TRANSPLANT

RELATIVE CHANCE OF TRANSPLANT SOFTWARE (R-CoT)

INFORMATION ON WAITING TIMES TO KIDNEY TRANSPLANT

1INTRODUCTION

1.1The UK Kidney Allocation Scheme used to prioritise patients and allocate kidneys considers a number of clinically relevant factors and is complex in design.For this reason it can be extremely difficult for patients and clinicians to understand and manage expectations concerning waiting times to kidney transplantation. It is well known that, on average, adult patients can expect to wait approximately three to four years for a deceased donorkidney transplant but that is only truly informative for ‘the average patient’. R-CoT is computer software that is able to provide more meaningful waiting time information tailored to an individual patient’s circumstance.

1.2R-CoT is based on a statistical analysis carried out by the Statistics and Clinical Audit Department within the organisation NHS Blood and Transplant.

2STARTING UP THE R-CoT SOFTWARE

2.1R-CoT was developed in Microsoft (MS) Excel Professional Edition (2003). To use the software MS Excel 2003 or later versions will be required although there may be other conversion software available capable of running this programme.

2.2Macros and security settings:On opening the software in MS Excel, and depending on your security settings, you may be prompted to “Enable Macros” or you may be presented with a warning message that alerts you to the fact that the software has embedded macros. If you do not choose to enable or accept macros then it will not be possible to use this software. If security settings are set at ‘High’ the software can still be used but you may not be able to make use of the ‘Reset’ button embedded within the software.

1 of 5

3USER INSTRUCTIONS

3.1Once opened, the screen should look like that shown in Figure 1.

Figure 1:Opening screen shot

3.2On the left hand side of the screen you will see a number of drop-down boxes. A selection must be made in each drop-down box before a result will be shown. If you are unsure of the most appropriate response to select then you will still need to choose an option before a result will be shown. In such circumstances you can at least get a feel for the relative chance of transplant but it may not be as accurate as it could be. Equally some of the variables can change over time and this software can be used to understand their potential impact on anticipated waiting times.

3.3To help select the correct information, further information on each of the variables listed can be found in the definitions section that follows. Once all the relevant information has been selected the software should present the results almost instantaneously. If you would like to reset all variables simply press the reset button.

1 of 5

4DEFINITION OF INFORMATION REQUIRED

Recipient Blood Group: Select either O, A, B or AB.

Matchability: Matchability is calculated from a standardised pool of 10,000 recent donors. From that pool the number of blood group identical donors that the patient is well or favorably HLA-mismatched is counted. This number is converted to a standardised score between one and ten and that number is used to group patients into one of three groups; easy, moderate or difficult to match.

Registration age: Recipient age at point of being actively listed onto the National Kidney Transplant List.

Transplant centre: Centre at which the patient will be receiving their transplant. Not necessarily their dialysis centre.

Sensitisation: Please enter the appropriate group as defined by the standardised calculated reaction frequency percentage.

Previous failed graft (within 180 days): If the patient has not received a previous kidney transplant or if the patients previous kidney functioned for more than 180 days then please enter ‘no’. If the patients previous kidney transplant failed within 180 days of the graft date then please enter ‘yes’.

Patient ethnicity: Select white, Asian, black or other as appropriate.

Suspensions: Patients that are suspended for a significant proportion of their registration have decreased access to transplant. It is recognised that many periods of suspension are often unavoidable, for example the patient may be too sick to undergo surgery. At the point of listing it is not necessarily known how often the patient will be suspended from the list. It may however be useful to look at the best and worst case scenario by examining the effect of the patient being suspended for less than a quarter of their registration against the situation if they are suspended for at least a quarter of their total registration period.

HLA-DR homozygous: Select ‘no’ if the patient is HLA-DR heterozygous or ‘yes’ if the patient is HLA-DR homozygous.

HLA-B homozygous: Select ‘no’ if the patient is HLA-B heterozygous or ‘yes’ if the patient is HLA-B homozygous.

Number of previous grafts:The number of previous solid organ transplants should be entered. If a patient has been listed for their first ever solid-organ transplant then ‘0’ should be entered.

5INTERPRETING THE RESULTS DISPLAYED

5.1An example of how the results are presented is shown in Figure 2 and an explanation of how to interpret the results is shown in paragraphs 5.2 to 5.4.

Figure 2:Example results

1 of 5

5.2The Chart:

The chart indicates that, in patients that fit the selected criteria, around 15% are typically transplanted within just one-year of listing. However, and more importantly perhaps, 85% of this type of patient is typically not transplanted within one-year of listing. As we move along the x-axis we can see that in most cases (around 97%) this patient type can expect to receive a DBD kidney transplant within five years of listing, although again 3% typically do not and the patient could well be one of those 3%.

5.3Percentiles

Percentiles are also shown in the bottom left corner of the screen. Three times are shown in years and months. In this example it is shown that 25%, of this patient type, typically receive a transplant within 1 year and 6 months of listing, 50% within 2 years and 6 months of listing and 75% within 3 years 5 months.

5.4The results show ‘greater than 5 years’ (> 5) only, why is that?

A statistical model based on real historical data is used to calculate the results shown. It is, to some extent, possible to predict what is likely to happen in the future based on what we have observed in the past. Because the existing kidney allocation scheme was introduced in 2006 we have only observed sufficient numbers of patient waiting times under the era of the 2006 scheme five years beyond there initially registration. It is therefore not possible to provide robust and meaningful results beyond five years.

6FURTHER INFORMATION

National Kidney Allocation Scheme

NHS Blood and Transplant

2012

1 of 5