The Accuracy of Hemoglobin A1c and Fructosamine Evaluated by Long-Term Continuous Glucose Monitoring in Patients with Type 2 Diabetes Undergoing Hemodialysis.

INTRODUCTION: The accuracy of hemoglobin A1c (HbA1c) as a glycemic marker in patients with type 2 diabetes (T2D) receiving hemodialysis (HD) remains unknown. To assess accuracy, we compared HbA1c and fructosamine levels with interstitial glucose measured by continuous glucose monitoring (CGM) in patients with T2D receiving HD. METHODS: Thirty patients in the HD group and 36 patients in the control group (T2D and an estimated glomerular filtration rate >60 mL/min/1.73 m2) completed the study period of 17 weeks. CGM (Ipro2®, Medtronic) was performed 5 times for periods of up to 7 days (with 4-week intervals) during a 16-week period. HbA1c (mmol/mol), the estimated mean plasma glucose from HbA1c (eMPGA1c [mmol/L]) and fructosamine (µmol/L) was measured at week 17 and compared with mean sensor glucose levels from CGM. FINDINGS: In the HD group, mean sensor glucose was 1.4 mmol/L (95% confidence interval [CI]: 1.0-1.8) higher than the eMPGA1c, whereas the difference for controls was 0.1 mmol/L (95% CI: -0.1-[0.4]; p < 0.001). Adjusted for mean sensor glucose, HbA1c was lower in the HD group (-7.3 mmol/mol, 95% CI: -10.0-[-4.7]) than in the control group (p < 0.001), with no difference detected for fructosamine (p = 0.64). DISCUSSION: HbA1c evaluated by CGM underestimates plasma glucose levels in patients receiving HD. The underestimation represents a clinical challenge in optimizing glycemic control in the HD population. Fructosamine is unaffected by the factors affecting HbA1c and appears to be more accurate for glycemic monitoring. CGM or fructosamine could thus complement HbA1c in obtaining more accurate glycemic control in this patient group.

The impact of kidney transplantation on insulin sensitivity.

To investigate the impact of kidney transplantation (KTx) on insulin sensitivity affecting glucose metabolism. 9 nondiabetic patients awaiting living donor KTx were examined prior to transplantation with an oral glucose tolerance test and a 3-h hyperinsulinaemic-euglycaemic clamp. The clamp was repeated 6 months after KTx. Nine age-, gender- and body mass index (BMI)-matched individuals with normal kidney function served as controls. Endogenous glucose production and glucose disappearance rate (N = 6) were measured in a subgroup of patients with corresponding controls. Results presented as mean [range]. Two patients had pretransplant prediabetes, whereas all others had normal glucose tolerance. After KTx, average glucose infusion rate to maintain euglycaemia during clamp declined significantly from 15.1 [9.1-23.7] to 9.8 [2.8-14.6] µmol/kg/min (P < 0.01) with 20.2 [9.9-33.7] µmol/kg/min in controls. Endogenous glucose production increased from 7.0 [4.8-8.5] to 9.4 [7.4-11.8] µmol/kg/min (P < 0.05) with 7.0 [-3.8 to 10.1] µmol/kg/min in controls. Glucose disappearance rate was unchanged (18.1 [12.9-24.5] vs. 17.1 [12.2-22.7] µmol/kg/min, NS) with 22.3 [14.6-34.3] in controls. In conclusion, insulin sensitivity is reduced 6 months after KTx and characterized mainly by impaired suppression of the endogenous glucose production.

Clearance of glucoregulatory peptide hormones during haemodialysis and haemodiafiltration in non-diabetic end-stage renal disease patients.

BACKGROUND: Patients with end-stage renal disease (ESRD) have increased fasting concentrations and disturbed postprandial responses of several glucoregulatory hormones. We aimed to evaluate the impact of high-flux haemodialysis (HD) and high-volume haemodiafiltration (HDF) on fasting and postprandial plasma levels of glucoregulatory pancreatic and gut peptide hormones in ESRD patients. METHODS: Ten non-diabetic HD-treated ESRD patients were included to undergo a 3-h standardized liquid mixed meal test 1 h into an HD and an HDF, respectively. On a third, optional, examination day, the meal test was performed without concurrent dialysis treatment. Concentrations of glucose, C-peptide, insulin, glucagon, glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide were measured in plasma and dialysate. RESULTS: Ten participants completed the meal test during HD, eight completed the meal test during HDF and four completed the optional meal test without dialysis. All plasma hormone concentrations declined significantly during the first fasting hour of dialysis with no differences between HD and HDF. Significant clearance of the investigated hormones was observed for both dialysis modalities with significantly higher clearance of insulin, C-peptide and GIP during HDF compared with HD. The fractional appearance of hormones entering the utilized dialysate was higher during HDF. Both dialysis modalities reduced postprandial plasma hormone concentrations in a similar manner. CONCLUSIONS: Our findings show that HD and HDF, respectively, significantly remove glucoregulatory peptide hormones from plasma of non-diabetic ESRD patients; a phenomenon which may affect the glucose metabolism in dialysis-treated ESRD patients.

Glucose variability in maintenance hemodialysis patients with type 2 diabetes: Comparison of dialysis and nondialysis days.

INTRODUCTION: Hemodialysis (HD) induces several physiological changes that can affect plasma glucose levels in patients with diabetes and in turn their glycemic control. Studies using continuous glucose monitoring (CGM) to assess glucose variations on dialysis days compared with nondialysis days report conflicting results. Here, we used CGM to examine glucose variations induced by HD in patients with type 2 diabetes. METHODS: Patients with type 2 diabetes undergoing maintenance HD were included. CGM (Ipro2®, Medtronic) was performed at baseline and Week 4, 8, 12, and 16 for up to 7 days at each visit. CGM profiles on days where participants received HD were compared with days without HD using a linear mixed model. FINDINGS: Twenty-seven patients were included. The median number of CGM days performed was 8 (interquartile range [IQR] 6-10) for dialysis days and 16 (IQR 12-17) for nondialysis days. The median sensor glucose was 9.4 (95% confidence interval [CI] 8.8-10.2) mmol/L on dialysis days compared with 9.5 (95% CI 8.9-10.2) mmol/L on nondialysis days (p = 0.58). Nocturnal mean sensor glucose was higher on dialysis days compared with nondialysis days: 8.8 (95% CI 8.0-9.6) mmol/L versus 8.4 (95% CI 7.7-9.2) mmol/L (p = 0.029). DISCUSSION: Similar median sensor glucose values were found for days on and off HD. Nocturnal glucose levels were modestly increased on dialysis days. Our findings indicate that antidiabetic treatment does not need to be differentiated on dialysis versus nondialysis days in patients with type 2 diabetes undergoing maintenance HD.

The Glycemic Effect of Liraglutide Evaluated by Continuous Glucose Monitoring in Persons with Type 2 Diabetes Receiving Dialysis.

AIMS: The aim of this study was to evaluate the effect of liraglutide treatment on glucose variability and the risk of hypoglycemia by continuous glucose monitoring (CGM) in persons with type 2 diabetes (T2D) and dialysis-dependent end-stage renal disease (ESRD). MATERIALS AND METHODS: We assessed CGM data from a previous trial where 24 persons with T2D and dialysis-dependent ESRD were allocated (1:1) to 12 weeks of double-blinded treatment with liraglutide (titrated to maximum tolerable dose up to 1.8 mg) or placebo as an add-on to preexisting antidiabetic treatment. CGM (Ipro2®; Medtronic) was performed for up to 7 days at baseline and at weeks 2, 6, and 10. A linear mixed model was used to compare the 2 study arms. RESULTS: A CGM was worn at baseline by 12 persons in the liraglutide group and 10 in the placebo group (7 and 9 completed week 10, respectively). Glycated hemoglobin A1c (p = 0.81) and glucose variability was similar between the groups (standard deviation, p = 0.33; coefficient of variation, p = 0.16). Comparing baseline and week 10, the number of hypoglycemic events (glucose values between <3.9 and 3.0 mmol/L) increased in the liraglutide group compared with the placebo group (p = 0.02). The occurrence of hypoglycemic events below 3.0 mmol/L was similar between the groups (p = 0.36). CONCLUSIONS: In the present cohort of persons with T2D and dialysis-dependent ESRD, liraglutide treatment increased the risk of hypoglycemic events as compared to placebo (no difference was found for hypoglycemic events below 3.0 mmol/L). The majority of participants were co-treated with insulin.

Effect of the Incretin Hormones on the Endocrine Pancreas in End-Stage Renal Disease.

CONTEXT: The insulin-stimulating and glucagon-regulating effects of the 2 incretin hormones, glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), contribute to maintain normal glucose homeostasis. Impaired glucose tolerance occurs with high prevalence among patients with end-stage renal disease (ESRD). OBJECTIVE: To evaluate the effect of the incretin hormones on endocrine pancreatic function in patients with ESRD. DESIGN AND SETTING: Twelve ESRD patients on chronic hemodialysis and 12 matched healthy controls, all with normal oral glucose tolerance test, were included. On 3 separate days, a 2-hour euglycemic clamp followed by a 2-hour hyperglycemic clamp (3 mM above fasting level) was performed with concomitant infusion of GLP-1 (1 pmol/kg/min), GIP (2 pmol/kg/min), or saline administered in a randomized, double-blinded fashion. A 30% lower infusion rate was used in the ESRD group to obtain comparable incretin hormone plasma levels. RESULTS: During clamps, comparable plasma glucose and intact incretin hormone concentrations were achieved. The effect of GLP-1 to increase insulin concentrations relative to placebo levels tended to be lower during euglycemia in ESRD and was significantly reduced during hyperglycemia (50 [8-72]%, P = 0.03). Similarly, the effect of GIP relative to placebo levels tended to be lower during euglycemia in ESRD and was significantly reduced during hyperglycemia (34 [13-50]%, P = 0.005). Glucagon was suppressed in both groups, with controls reaching lower concentrations than ESRD patients. CONCLUSIONS: The effect of incretin hormones to increase insulin release is reduced in ESRD, which, together with elevated glucagon levels, could contribute to the high prevalence of impaired glucose tolerance among ESRD patients.

Safety and Efficacy of Liraglutide in Patients With Type 2 Diabetes and End-Stage Renal Disease: An Investigator-Initiated, Placebo-Controlled, Double-Blind, Parallel-Group, Randomized Trial.

OBJECTIVE: To evaluate parameters related to safety and efficacy of liraglutide in patients with type 2 diabetes and dialysis-dependent end-stage renal disease (ESRD). RESEARCH DESIGN AND METHODS: Twenty-four patients with type 2 diabetes and ESRD and 23 control subjects with type 2 diabetes and normal kidney function were randomly allocated to 12 weeks of double-blind liraglutide (titrated to a maximum dose of 1.8 mg) or placebo treatment (1:1) injected subcutaneously once daily as add on to ongoing antidiabetic treatment. Dose-corrected plasma trough liraglutide concentration was evaluated at the final trial visit as the primary outcome measure using a linear mixed model. RESULTS: Twenty patients with ESRD (1:1 for liraglutide vs. placebo) and 20 control subjects (1:1) completed the study period. Dose-corrected plasma trough liraglutide concentration at the final visit was increased by 49% (95% CI 6-109, P = 0.02) in the group with ESRD compared with the control group. Initial and temporary nausea and vomiting occurred more frequently among liraglutide-treated patients with ESRD compared with control subjects (P < 0.04). Glycemic control tended to improve during the study period in both liraglutide-treated groups as assessed by daily blood glucose measurements (P < 0.01), and dose of baseline insulin was reduced in parallel (P < 0.04). Body weight was reduced in both liraglutide-treated groups (-2.4 ± 0.8 kg [mean ± SE] in the group with ESRD, P = 0.22; -2.9 ± 1.0 kg in the control group, P = 0.03). CONCLUSIONS: Plasma liraglutide concentrations increased during treatment in patients with type 2 diabetes and ESRD, who experienced more gastrointestinal side effects. Reduced treatment doses and prolonged titration period may be advisable.

Elimination and degradation of glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide in patients with end-stage renal disease.

CONTEXT: The affect of the kidneys in elimination and degradation of intact incretin hormones and their truncated metabolites is unclear. OBJECTIVE: To evaluate elimination and degradation of glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) in patients with dialysis-dependent kidney failure. SETTING AND DESIGN: Twelve non-diabetic patients treated with chronic hemodialysis and 12 control subjects were examined in a double-blind, randomized, matched observational study at the Department of Nephrology, Rigshospitalet, University of Copenhagen, Denmark. Over 4 separate study days, synthetic human GIP or GLP-1 was infused with or without concurrent inhibition of dipeptidyl peptidase 4 using sitagliptin or placebo. Plasma concentrations of glucose, insulin, glucagon, and intact and total forms of GLP-1 or GIP were measured repeatedly. Plasma half-life (T1/2), metabolic clearance rate (MCR), area under curve, and volume of distribution for intact and metabolite levels of GLP-1 and GIP were calculated. RESULTS: Fasting concentrations of intact GLP-1 and GIP were increased in dialysis patients (P < .001) whereas fasting levels of GLP-1 and GIP metabolites did not differ between groups (P > .738). MCRs of intact GLP-1 and GIP, and the GLP-1 metabolite were reduced in dialysis patients on the placebo day (P < .009), and T1/2 of intact and metabolite forms of GLP-1 and GIP were comparable between groups (P > .121). CONCLUSIONS: Unexpectedly, degradation and elimination of the intact and metabolite forms of GLP-1 and GIP seemed preserved, although reduced, in patients with dialysis-dependent kidney failure.