In patients with type 1 diabetes simultaneous pancreas and kidney transplantation preserves long-term kidney graft ultrastructure and function better than transplantation of kidney alone.

AIMS/HYPOTHESIS: In patients with type 1 diabetes and end-stage renal disease (ESRD) we aimed to determine whether long-term normoglycaemia, as achieved by successful simultaneous pancreas and kidney (SPK) transplantation, would preserve kidney graft structure and function better than live donor kidney (LDK) transplantation alone. METHODS: Estimated GFR (eGFR) was calculated in SPK (n = 25) and LDK (n = 17) recipients in a stable phase 3 months after transplantation and annually during follow-up. Kidney graft biopsies were obtained at follow-up for measurement of glomerular volume (light microscopy), glomerular basement membrane (GBM) and podocyte foot process widths and mesangial volume fraction (electron microscopy). RESULTS: SPK and LDK recipients were similar in age and diabetes duration at engraftment. Donor age was higher in the LDK group. Median follow-up time was 10.1 years. Mean HbA1c levels during follow-up were 5.5 ± 0.4% (37 ± 5 mmol/mol) and 8.3 ± 1.5% (68 ± 16 mmol/mol) in the SPK and LDK group, respectively (p < 0.001). Compared with SPK recipients, LDK recipients had wider GBM (369 ± 109 nm vs 281 ± 57 nm; p = 0.008) and increased mesangial volume fraction (median 0.23 [range 0.13-0.59] vs 0.16 [0.10-0.41]; p = 0.007) at follow-up. Absolute eGFR change from baseline was -11 ± 21 and -23 ± 15 ml min(-1) 1.73 m(-2) (p = 0.060), whereas eGFR slope was -1.1 (95% CI -1.7, -0.5) and -2.6 (95% CI -3.1, -2.1) ml min(-1) 1.73 m(-2) per year in the SPK and LDK group, respectively (p = 0.001). CONCLUSIONS/INTERPRETATION: In patients with type 1 diabetes and long-term normoglycaemia after successful SPK transplantation, kidney graft ultrastructure and function were better preserved compared with LDK transplantation alone.