Background. Glucose intolerance is an untoward side effect of some immunosuppressive and anti‐hypertensive drugs. The primary aim of the present prospective observational study was to test the hypothesis that tapering off prednisolone and cyclosporin (CsA) the first year after transplantation may have beneficial effects on glucose tolerance in renal transplant recipients.

Methods. Ninety‐one non‐diabetic recipients were included, and 87 patients underwent a 75 g oral glucose tolerance test both 10 weeks and 1 year after renal transplantation. The change over time in 2‐h blood glucose was compared with a number of variables potentially influencing glucose tolerance.

Results. The proportion of glucose intolerant recipients was reduced from 55 to 34% during the study. Univariate linear regression analysis showed a significant association between the reduction in daily prednisolone dose down to 5 mg and decline in blood glucose (P=0.001), whereas weight gain was associated with increasing blood glucose (P=0.031). Each 1‐mg reduction of prednisolone dose leads to an estimated decline in 2‐h blood glucose of 0.12 mmol/l based on the multiple linear regression model (P=0.003). Twelve out of 22 patients with post‐transplant diabetes mellitus (PTDM) at baseline improved to normal or impaired glucose tolerance. Ten PTDM‐subjects who remained diabetic 1 year after transplantation had lower serum insulin levels during the oral glucose challenge, and five patients treated with anti‐diabetic drugs at baseline required hypoglycaemic drugs also at follow up. The decline in CsA level of 100 μg/l and the lower number of patients treated with beta‐blockers at follow‐up, did not alter glucose tolerance significantly.

Conclusions. Tapering off prednisolone, but not CsA, significantly improves glucose tolerance during the first year after renal transplantation.