Pre-existing diabetes is a risk factor for increased rates of cellular rejection after kidney transplantation: an observational cohort study.

AIM: To investigate whether people with diabetes have an elevated risk of kidney allograft rejection in a well characterized clinical cohort in the setting of contemporary immunosuppression.

METHODS: We conducted a retrospective cohort study including all kidney allograft recipients at a single centre between 2007 and 2015, linking clinical, biochemical and histopathological data from electronic patient records.

RESULTS: Data were analysed for 1140 kidney transplant recipients. The median follow-up was 4.4 years post-transplantation, and 117 of the kidney transplant recipients (10.2%) had diabetes at time of transplantation. Kidney allograft recipients with vs without diabetes were older (53 vs 45 years; P<0.001) and more likely to be non-white (41.0% vs 26.4%; P=0.001). Kidney allograft recipients with vs without diabetes had a higher risk of cellular rejection (19.7% vs 12.4%; P=0.024), but not of antibody-mediated rejection (3.4% vs 3.7%; P=0.564). Graft function and risk of death-censored graft loss were similar in the two groups, but kidney allograft recipients with diabetes had a higher risk of death and overall graft loss than those without diabetes. In a Cox regression model of non-modifiable risk factors at time of transplantation, diabetes was found to be an independent risk factor for cellular rejection (hazard ratio 1.445, 95% CI 1.023-1.945; P=0.042).

CONCLUSIONS: Kidney allograft recipients with diabetes at transplantation should be counselled regarding their increased risk of cellular rejection but reassured regarding the lack of any adverse impact on short-to-medium term allograft function or survival.