Clinical features and burden of new onset diabetic foot ulcers post simultaneous pancreas kidney transplantation and kidney only transplantation.

BACKGROUND

Patients with diabetes and kidney disease are at risk of diabetes-related foot ulcers (DFU). Whether this risk is modified post simultaneous pancreas-kidney (SPK) or kidney only (KO) transplant is unknown.

METHODS

We evaluated the incidence of new onset DFU post SPK and KO transplant in 235 patients with diabetic kidney disease and diabetic neuropathy. In total 90 (51% male) SPK patients and 145 KO (66% male, 26% Type 1 DM) were evaluated in a single centre retrospective study. Median (range) follow up was 6 (3 to 13) years for both cohorts.

RESULTS

We observed that 16 (17%) of SPK and 22 (15%) KO patients respectively developed a DFU during follow up. In both cohorts a history of peripheral arterial disease [37.5% vs. 4%] and pre-transplant history of DFU were associated with post transplant DFU (p ≪ 0.05). In KO cohort, patients who developed a DFU were more likely to have T1DM than T2DM (29% vs. 10%), p ≪ 0.05. There was no impact of DFU on SPK transplant failure. In contrast patients with DFU post KO transplant had more than five fold increased hazard ratio (HR) of transplant failure as compared to those without DFU independent of other risk factors [HR 5.19 95% CI (2.05 to 13.18) p = 0.001].

CONCLUSION

Nearly 1 in 7 patients develop a new onset DFU post KO or SPK transplantation and DFU also significantly increases risk of failure of the transplanted kidney. Our results highlight the need for greater awareness of regular foot examination, DFU prevention and risk evaluation in post-transplant patients.

RESEARCH IN CONTEXT

Evidence before this study Patients with diabetes and kidney disease are at enhanced risk of diabetic foot ulcers (DFU). Whether this risk is modified post successful kidney only (KO) or simultaneous pancreas and kidney (SPK) transplantation is unknown. Small case series and studies with short term follow up report varied rates of incidence and are from historical cohorts before the use of modern anti-transplant medications and treatments. Short term studies also suggest that post SPK the resultant normoglycaemia may reverse some features and risk markers of DFU. There are no long term studies on the incidence and impact of diabetic foot ulcers in patients with diabetic kidney disease post SPK or KO transplantation. Added value of this study We report the long term follow up results on DFU incidence, clinical features and related impact on transplant viability in 235 patients with diabetic kidney disease and neuropathy post successful SPK and KO transplant at a single centre. We observed that nearly 1 in 7 patients developed a DFU during follow up and that in patients who received KO transplant onset of DFU was associated with more than 5 fold increase of transplant failure. Implications of all the available evidence Our results highlight the need for greater awareness of regular foot examination, DFU prevention and risk evaluation in post-transplant patients. Despite normoglycaemia post SPK there is a residual burden and risk of DFU. Our work establishes a clinical rationale for further research to explore putative mechanisms that could explain the association between DFU and renal transplant dysfunction.