HbA1c levels at 90 days after renal transplantation in non-diabetic recipients predict de novo pre-diabetes and diabetes at 1 and 3 years after transplantation

Purpose: Pre-diabetes, a risk factor for post-transplant diabetes mellitus (PTDM), represents an early therapeutic target for prevention of PTDM. We evaluated glucose metabolism post-transplantation and the ability to predict pre-diabetes and PTDM from haemoglobin A1c (HbA1c) levels at 90 days, at 1 year, and at 3 years in long-term post-transplantation follow-up.

Methods: HbA1c levels were measured in 71 non-diabetic deceased-donor transplant recipients at four time points (during transplantation, 90-days post-transplantation, 1-year post-transplantion, and at the final post-transplantation follow-up visit 2.71 ± 1.26 years after transplantation). The predictive power of HbA1c levels at 90 days post-transplantation was determined by calculating the sensitivity, specificity, false-positive rates, and false-negative rates. A multivariate logistic regression analysis was performed to determine risk factors for pre-diabetes and PTDM at 1-year post-transplantation and at the last follow-up visit (2.71 ± 1.26 years after renal transplantation).

Results: HbA1c values ≥ 5.7% were seen in 79% of patients at 90 days post-transplant, in 83% at 1 year, and in 69% of patients on follow-up. HbA1c cut-off levels of < 5.7% or ≥ 5.7% showed the highest predictive sensitivity for pathological HbA1c levels (≥ 5.7%) at 1 year post-transplantation (0.83) and at last follow-up (0.86), whereas cut-off levels of < 6.2% or .≥ 6.2% showed the highest specificity (0.97 and 1.00, respectively). The HbA1c level at 90 days was a risk factor for disturbed glucose-metabolism at 1 year (p = 0.000) and at the final follow-up (p = 0.031).

Conclusion: HbA1c levels at 90 days post-transplantation are predictive of disturbed glucose metabolism at 1 year and on long-term follow-up and may serve as predictive tools for early therapeutic interventions to prevent PTDM.