Micro-vascular complications of post-transplant diabetes mellitus in renal transplant recipients- an observational study

Introduction

The incidence of post-transplant diabetes mellitus (PTDM) ranges from 2.5% to 20% in kidney transplant recipients. Diabetic retinopathy (DR), diabetic kidney disease (DKD), and distal symmetric polyneuropathy (DSPN) are the microvascular complications frequently seen in both type 1 and 2 diabetes mellitus (DM). However, the data regarding these complications in patients with PTDM is lacking.

Method

A retrospective and prospective observational study of PTDM conducted at a tertiary care hospital from November 2018 to December 2020. 115 kidney transplant recipients who had PTDM of ≥5 years duration were included and analysed.

Results

The mean duration of PTDM was 8.8 ± 3.0 years, and the mean of all available HbA1c values was 7.0 ± 0.9%. while none of the patients had evidence of diabetic retinopathy on direct ophthalmoscopy, 37.4% of patients (n = 43) had DSPN and this was associated with the duration of PTDM and age. The mean estimated glomerular filtration rate (eGFR) was 59.24 ± 21.82 ml/min/1.73m², and patients had a median proteinuria of 620 mg/day (IQR 1290). Out of 115 patients, 20% of them (n = 23) underwent graft kidney biopsy, and 10 biopsies were diagnosed as de-novo DKD. Patients with biopsy proven DKD had a mean PTDM duration of 143.3 ± 52.4 months; a mean HbA1c level of 7.9 ± 1.3%; a mean eGFR of 44.8 ± 21.8 ml/min; and a median proteinuria of 2653 mg (IQR 2758). An additional analysis of all 23 biopsied patients showed that HbA1c level and degree of proteinuria were significantly associated with de-novo DKD.

Conclusion

PTDM in transplant patients had milder microvascular complications than usually expected in Type 1/2 diabetes in non-transplant patients. DR was not strongly associated with DKD in PTDM patients. Furthermore, de-novo DKD development was associated with poor glycaemic control and increased proteinuria.