Limited data on microvascular complications in patients with post-transplant diabetes (PTDM) is an obstacle to developing follow-up algorithms.
To evaluate diabetic microvascular complications in patients with long-standing PTDM.
This study included patients with at least a five-year history of PTDM and age-matched renal transplant recipients without PTDM (NDM). Diabetic peripheral neuropathy (PN) was evaluated using the Michigan Neuropathy Screening Instrument (MNSI), the CASE IV device, and in vivo corneal confocal microscopy (CCM). Cardiac autonomic neuropathy (CAN) tests were performed using the heart rate variability. Nephropathy (DN) screening was assessed using spot urine albumin/creatinine ratio and eGFR calculation. Diabetic retinopathy (DR) was evaluated by fundus examination and photography, and optical coherence tomography.
This study included 41 patients with PTDM and 45 patients in the NDM group. The median follow-up was 107.5 months in the PTDM group. PN was significantly higher in the PTDM group than in the NDM group (p = 0.02). In the PTDM patients with PN, the corneal nerve fiber density examined by CCM was significantly lower than in the PTDM patients without neuropathy (p = 0.001). Parasympathetic involvement was observed in 58.5% of the PTDM group and 22% of the NDM group (p = 0.001). Sympathetic involvement was present in 65.9% of the PTDM group and 29.3% of the NDM group (p = 0.001). Retinopathy was observed in 19.5% of patients in the PTDM group, while none were in NDM patients (p < 0.001). Renal functions were similar between the study groups.
CAN and DR can affect patients with PTDM at a high rate. DR was found to be a threat to the vision of PTDM patients. Diabetic PN can be detected early in PTDM patients by CCM.

© The Author(s) 2023. Published by Oxford University Press on behalf of the Endocrine Society.