Glucose tolerance before and after renal transplantation

Background. Renal insufficiency predisposes to insulin resistance, hyperparathyroidism and derangements in calcium phosphate and nitrogenous compound balance, leading to pre-transplant hyperglycaemia. These metabolic risk factors are not fully corrected after renal transplantation. The present study aimed to assess the role of pre-transplant glycaemia and the named metabolic risk factors in post-transplant hyperglycaemia [PHYG; impaired fasting glucose (IFG), impaired glucose tolerance (IGT) or diabetes mellitus (DM)]. Methods. This is a retrospective cohort study involving 301 patients without pre-transplant DM. Measurements included a pre- and post-transplant oral glucose tolerance test (OGTT) as well as glomerular filtration rate (GFR), parathyroid hormone (PTH), phosphate, calcium and urea measured 10 weeks post-transplant. The risk of PHYG at 10 weeks post-transplant was analysed using multiple logistic regression. Results. Ninety-three patients (31%) had PHYG (two IFG, 52 IGT, 39 DM). Variables associated with PHYG included pre-transplant 2-h glycaemia [OR 1.26, 95% CI (1.09, 1.46)] and post-transplant urea levels [OR 1.14, 95% CI (1.02, 1.27)]. Older age, non-Caucasian ethnicity, previous transplants, ≥3 HLA class 1 mismatches and high prednisolone doses were likewise associated with an increased PHYG risk (all P < 0.05). Conclusions. Pre-transplant glycaemia and high post-transplant levels of urea were associated with a greater risk of PHYG. This seemed to be independent of GFR, PTH, phosphate, calcium and traditional risk factors such as age and glucocorticoid load.