Mortality risk in post-transplantation diabetes mellitus based on glucose and HbA1c diagnostic criteria

Abstract

Current diagnostic criteria for post-transplantation diabetes mellitus (PTDM) are either fasting plasma glucose ≥7.0 mmol/l (≥126 mg/dl) or postchallenge plasma glucose ≥11.1 mmol/l (≥200 mg/dl) 2 h after glucose administration [oral glucose tolerance test (OGTT) criterion]. In this retrospective cohort study of 1632 renal transplant recipients (RTRs) without known diabetes mellitus at the time of transplantation, we estimated mortality hazard ratios for patients diagnosed with PTDM by either conventional glucose criteria or the proposed glycated haemoglobin (HbA1c) criterion [HbA1c ≥6.5% (≥48 mmol/mol)]. During a median follow-up of 7.0 years, 311 patients died. Compared with nondiabetic patients and after adjustment for confounders, patients diagnosed with PTDM based on chronic hyperglycaemia early after transplantation (manifest PTDM) or by the OGTT criterion at 10 weeks post-transplant suffered a higher mortality risk (HR 1.59, 95% CI 1.06-2.38, P = 0.02 and HR 1.56, 95% CI 1.04-2.38, P = 0.03, respectively). In contrast, patients diagnosed with PTDM by the HbA1c criterion at 10 weeks or between 10 weeks and 1 year post-transplant were not associated with mortality (HR 0.96, 95% CI 0.61-1.51, P = 0.86 and 1.58, 95% CI 0.74-3.36, P = 0.24 respectively). After adjustment for confounders and competing risks, only patients with manifest PTDM had a significantly higher cardiovascular mortality risk (subdistributional HR 2.31, 95% CI 1.19-4.47, P < 0.001). Since many cases with PTDM were only identified by the OGTT, we recommend monitoring fasting plasma glucose early after renal transplantation followed by an OGTT at 2-3 months post-transplant in patients without overt diabetes mellitus.

Dynamics of Glucose Metabolism After Kidney Transplantation

“…As a retrospective analysis, FPG and HbA1c were available, while OGTT was not. Given that a certain proportion of patients is diagnosed solely via OGTT [48, 49], the incidence of PTDM and prediabetes might be even higher in our population. Diagnostic accuracy of HbA1c in chronic kidney disease [50] and after transplantation [51] is hampered by higher erythrocyte turnover, again underestimating the prevalence of disturbed glucose metabolism.…”

Risk Factors in and Long-Term Survival of Patients with Post-Transplantation Diabetes Mellitus: A Retrospective Cohort Study

“…Res. Public Health 2020, 17, 4581 2 of 11 death in kidney transplant recipients [5]. The incidence of PTDM is 9.1-45.3% after 1 year [1,3,6-9], 10.0-30.0% after 3 years [1,4], and 10.2-15.1% after 5 years [10,11].…”

Management of metabolic alterations in adult kidney transplant recipients: A joint position statement of the Italian Society of Nephrology (SIN), the Italian Society for Organ Transplantation (SITO) and the Italian Diabetes Society (SID)

“…As OGTT for diagnosing PTDM at 10 weeks posttransplantation has demonstrated superiority versus HbA1c with regard to prediction of long-term outcomes (i.e. mortality) in patients without overt diabetes [31], we suggest considering performing an OGTT 2e3 months following KT to screen for PTDM, particularly in those KTRs with combined FPG !5.0 mmol/L (90 mg/dL) and HbA1c ! 5.7% (39 mmol/mol) [30].…”