Every decision, both in life and in medicine, involves a balance of risk: the decision to go on holiday balances the risk of travelling to and staying in a foreign country against the benefit of a fortnight’s sunshine and relaxation; the decision to treat bacterial pneumonia balances the risk of anaphylaxis against the benefit of antibiotic therapy. Consciously and subconsciously, we make decisions for ourselves and our patients every day based on our perception of risk. Humans, however, are not good at accurately assessing risk. In 1990, research comparing people’s anxiety about nine different risks concluded that “there is no generally applicable dynamic relationship between perceived and actual risk”.  So what influences our perception of risk? The answer is that we overestimate the risk of events that stimulate fear and emotion (such as terrorist attacks, child abduction and aeroplane crashes) while underestimating the risk associated with less emotive factors (such as obesity, smoking and car travel).
This is also true in medicine. Kidney transplantation is unarguably the optimal treatment for end stage kidney disease. The single modifiable factor which has the greatest impact on how long recipients survive with a kidney transplant is the length of time they spend on dialysis prior to transplantation.[2,3] Some individuals develop antibodies to non-self HLA following pregnancy, blood transfusion, and transplantation resulting in a long waiting time for an organ offer as many donors have incompatible HLA types.  This equates to a prolonged period on dialysis with the associated risk of death and becoming unfit for a kidney transplant. For these patients, HLA incompatible living donor transplantation may be an option; although the risk of rejection is higher, the long term survival outcomes are comparable to deceased donor transplantation and significantly better than remaining on dialysis. 
Despite this, many centres are reluctant to accept kidneys associated with increased immunological risk for these patients. Why is this? Fear. Treating a patient with aggressive antibody mediated rejection following a kidney transplant can be a terrifying experience; there is the anxiety associated with the potential for loss of the transplant (for the donor, recipient, and transplant team), the distressing side effects of the intensive immunosuppressive treatment that is required and, for some, the major disincentive of immediate finger pointing and criticism when the short term risk fails to deliver.
On the other hand, when a patient deteriorates after many years on dialysis that may not stimulate the same emotive response or critical reception. However the reality remains that the median survival for a 40 year old patient commencing dialysis in the UK is approximately ten years and that transplantation may double or even triple that survival time. [5-8] Objectively, the risk of transplanting highly sensitised patients after a short time on dialysis with a kidney associated with increased immunological risk has a favourable risk: benefit ratio. Subjectively, physicians fear the potential for rejection and graft loss so patients wait. And wait.
As clinicians, we need to have insight into our own biases in risk perception. Unpleasant and stressful cases in the past can distort our decision making in the present. This has the potential to result in suboptimal patient management. The ability to objectively balance the many aspects (surgical, anaesthetic, medical, immunological, psychological) of the risk associated with a treatment against that of avoiding the treatment is an essential skill for physicians. The capacity to do this effectively for each individual patient is the cornerstone of personalised medicine and an attribute of the exceptional clinician.
Jennifer McCaughan is a final year nephrology trainee in Northern Ireland. Her interest is in kidney transplantation and in higher immunological risk transplants in particular. She is currently undertaking a fellowship in renal transplantation and HLA in Toronto.
Aisling E Courtney is a consultant nephrologist, Belfast City Hospital.
Competing interests: None declared.
Not commissioned, peer reviewed.
- Loewenstein G MJ. Dynamic Processes in Risk Perception. Journal of RIsk and Uncertainty 1990;3:155-75
- Meier-Kriesche HU, Port FK, Ojo AO, et al. Effect of waiting time on renal transplant outcome. Kidney Int 2000;58:1311-7
- Helantera I, Salmela K, Kyllonen L, Koskinen P, Gronhagen-Riska C, Finne P. Pretransplant dialysis duration and risk of death after kidney transplantation in the current era. Transplantation 2014;98:458-64
- Fuggle SV, Martin S. Tools for human leukocyte antigen antibody detection and their application to transplanting sensitized patients. Transplantation 2008;86:384-90
- Orandi BJ, Garonzik-Wang JM, Massie AB, et al. Quantifying the risk of incompatible kidney transplantation: a multicenter study. Am J Transplant 2014;14:1573-80
- NHSBT. Annual Report in Kidney Transplantation. 2010;
- Wolfe RA, Ashby VB, Milford EL, et al. Comparison of mortality in all patients on dialysis, patients on dialysis awaiting transplantation, and recipients of a first cadaveric transplant. N Engl J Med 1999;341:1725-30
- Neovius M, Jacobson SH, Eriksson JK, Elinder CG, Hylander B. Mortality in chronic kidney disease and renal replacement therapy: a population-based cohort study. BMJ Open 2014;4:e004251