Obesity and gender-biased access to deceased donor kidney transplantation

Abstract

Background: Despite the survival advantage of transplantation over dialysis, obese patients are less likely to be listed on the deceased donor waiting list and subsequently transplanted. This study aimed to determine the association between obesity and access to deceased donor transplantation and whether any association observed was applicable to men and women equally.

Methods: Cox proportional hazards models were conducted to determine the association between obesity and waitlisting for transplantation and then subsequent receipt of a kidney transplant using data from the Australian and New Zealand Dialysis and Transplant Registry (2007-14).

Results: Of 11633 patients included, 4408 (37.9%) were obese. Over a follow-up period of 26306 patient-years during waitlisting and 5607 patient-years from waitlisting to transplantation, 3515 candidates were listed (28.4% obese) and 1662 were transplanted (29.3% obese). Obesity was associated with a reduced likelihood of waitlisting {adjusted hazard ratio [aHR] 0.66 [95% confidence interval (CI) 0.58-0.76]} but not kidney transplantation once waitlisted [aHR 1.10 (95% CI 0.97-1.24)]. The impact of obesity and waitlisting was modified by gender (P-value for interaction = 0.01). Women who were obese were 34% less likely to be listed than normal-weight women [aHR 0.66 (95% CI 0.58-0.76)], compared with obese men who were 14% less likely [aHR 0.86 (95% CI 0.77-0.97)].

Conclusions: Overall, obesity reduces the likelihood of being listed for deceased donor transplantation, especially among women, but not transplantation once listed. Transplant physicians who regulate access to the deceased donor waiting list should be aware of this apparent inequity and seek to understand and ameliorate contributing factors.

Keywords: chronic kidney disease; kidney transplantation; obesity; sex; waitlisting.