Microvascular Complications of Posttransplant Diabetes Mellitus in Kidney Transplant Recipients: A Longitudinal Study

Objective: To assesses microvascular complications in renal transplant recipients with posttransplant diabetes mellitus (PTDM). Research Design and Methods: In this observational study, patients with >= 5 years of PTDM were included from a cohort of 895 kidney recipients transplanted from 2000 through 2011. Diabetic retinopathy was evaluated by fundus photographs and optical coherence tomography (OCT). Diabetes kidney disease was evaluated by protein to creatinine ratio (PCR) and estimated glomerular filtration rate (eGFR). Distal polyneuropathy was assessed by Michigan Protocol and 10 g-monofilament feet examinations. The Ewing protocol identified cardiovascular autonomic neuropathy. Renal transplant recipients without PTDM diagnosis (NPTDM) were considered controls. Results: After 144.5 months of follow-up, 135 (15%) patients developed PTDM, and 64 had a PTDM duration >= 5 years. None of the patients with PTDM presented diabetic retinopathy at fundus photographs, but thinning of inner retinal layers was observed with OCT. More than 60% of patients with PTDM had distal polyneuropathy (OR, 1.55; 95% CI, 1.26 to 1.91; P < 0.001). Cardiovascular reflex tests abnormalities were similar between patients with PTDM and NPTDM (P = 0.26). During the first year and 8.5 +/- 3.0 years after renal transplantation, eGFR and PCR did not differ significantly between patients with PTDM or NPTDM. Conclusions: This longitudinal study assesses microvascular complications in renal transplant patients with PTDM. A lower than expected prevalence as well as a different clinical course of the complications was observed. PTDM seems to be a unique type of diabetes, and its consequences may be milder than expected in type 1 and type 2 diabetes.