Evidence for increased risk of prediabetes in the uremic patient

Cardiometabolic factors and vitamin D deficiency in pediatric patients with chronic kidney disease

Background

Patients with chronic kidney disease (CKD) are at increased risk for cardiovascular disease. Up to 80% of patients with CKD may exhibit inadequate vitamin D (VD) levels, which have been linked to the presence of cardiometabolic factors (CFs) in the adult population. However, research on this association in the pediatric population is limited.

Objective

To analyze the effects of 25-hydroxyvitamin D3 (25-[OH]D) levels and status on the presence of CFs in children receiving kidney replacement therapy (KRT).

Materials and methods

This cross-sectional study included pediatric patients receiving KRT, aged 8-17 years, who were receiving hemodialysis or peritoneal dialysis from January 2021 to March 2024. We conducted anthropometric measurements, blood pressure assessments, and glucose, 25-(OH)D, and lipid profiling for all participants. The daily dose of cholecalciferol supplementation, as well as other medications affecting bone and lipid metabolism and antihypertensive drugs, were documented. Statistical analyses were performed using Student's t-tests and chi-square tests to compare the CFs between groups with and without VD deficiency.

Results

The study involved 156 patients with an average age of 12.9 years and a mean serum VD level of 22.5 ng/dL. Patients with VD deficiency presented higher levels of total cholesterol and diastolic blood pressure (p < 0.05). No statistically significant differences were found in other biochemical profile variables or in the frequency of cardiometabolic factors.

Conclusion

Vitamin D deficiency seems to increase the risk of dyslipidemia and uncontrolled hypertension in children and adolescents with end-stage CKD.

Use of Glucose-Lowering Agents in Diabetes and CKD

Diabetes is the most common cause of kidney failure worldwide. Patients with diabetes and chronic kidney disease (CKD) are also at markedly higher risk of cardiovascular disease, particularly heart failure (HF), and death. Through the processes of gluconeogenesis and glucose reabsorption, the kidney plays a central role in glucose homeostasis. Insulin resistance is an early alteration observed in CKD, worsened by the frequent presence of hypertension, obesity, and ongoing chronic inflammation, and oxidative stress. Management of diabetes in moderate to severe CKD warrants special consideration because of changes in glucose and insulin homeostasis and altered metabolism of glucose-lowering therapies. Kidney failure and initiation of kidney replacement therapy by dialysis adds to management complexity by further limiting therapeutic options, and predisposing individuals to hypoglycemia and hyperglycemia. Glycemic goals should be individualized, considering CKD severity, presence of macrovascular and microvascular complications, and life expectancy. A general hemoglobin A1c (HbA1c) goal of approximately 7% may be appropriate in earlier stages of CKD, with more relaxed targets often appropriate in later stages. Use of sodium glucose cotransporter2 (SGLT2) inhibitors and glucagon like peptide-1 receptor agonists (GLP-1RAs) meaningfully improves kidney and heart outcomes for patients with diabetes and CKD, irrespective of HbA1c targets, and are now part of guideline-directed medical therapy in this high-risk population. Delivery of optimal care for patients with diabetes and CKD will require collaboration across health care specialties and disciplines.

Comprehensive risk profiles of family history and lifestyle and metabolic risk factors in relation to diabetes: A prospective cohort study

BACKGROUND

Family history of diabetes, unhealthy lifestyles, and metabolic disorders are individually associated with higher risk of diabetes, but how different combinations of the three risk categories are associated with incident diabetes remains unclear. We aimed to estimate the associations of comprehensive risk profiles of family history and lifestyle and metabolic risk factors with diabetes risk.

METHODS

This study included 5290 participants without diabetes at baseline with a mean follow-up of 4.4 years. Five unhealthy lifestyles and five metabolic disorders were each allocated a score, resulting in an aggregated lifestyle and metabolic risk score ranging from 0 to 5. Eight risk profiles were constructed from combinations of three risk categories: family history of diabetes (yes, no), lifestyle risk (high, low), and metabolic risk (high, low).

RESULTS

Compared with the profile without any risk category, other profiles exhibited incrementally higher risks of diabetes with increasing numbers of categories: the hazard ratio (HR, 95% confidence interval [CI]) for diabetes ranged from 1.34 (1.01-1.79) to 2.33 (1.60-3.39) for profiles with one risk category, ranged from 2.42 (1.45-4.04) to 4.18 (2.42-7.21) for profiles with two risk categories, and was 4.59 (2.85-7.39) for the profile with three risk categories. The associations between the numbers of risk categories and diabetes risk were more prominent in women (pinteraction  = .025) and slightly more prominent in adults <55 years (pinteraction  = .052).

CONCLUSIONS

This study delineated associations between comprehensive risk profiles with diabetes risk, with stronger associations observed in women and slightly stronger associations in adults younger than 55 years.

Plasma Metabolomics Reveals Metabolic Profiling For Diabetic Retinopathy and Disease Progression

BACKGROUNDS

Diabetic retinopathy (DR), the main retinal vascular complication of DM, is the leading cause of visual impairment and blindness among working-age people worldwide. The aim of this study was to investigate the difference of plasma metabolic profiles in patients with DR to better understand the mechanism of this disease and disease progression.

METHODS

We used ultrahigh-performance liquid Q-Exactive mass spectrometry and multivariate statistical analyses to conduct a comprehensive analysis of plasma metabolites in a population with DR and proliferative DR (PDR). A risk score based on the level of the selected metabolite was established and evaluated using the least absolute shrinkage and selection operator regularization logistic regression (LASSO-LR) based machine learning model.

RESULTS

22 differentially expressed metabolites which belonged to different metabolic pathway were identified and confirmed to be associated with the occurrence of DR. A risk score based on the level of the selected metabolite pseudouridine was established and evaluated to strongly associated with the occurrence of DR. Four circulating plasma metabolites (pseudouridine, glutamate, leucylleucine and N-acetyltryptophan) were identified to be differentially expressed between patients with PDR and other patients, and a risk score formula based on these plasma metabolites was developed and assessed to be significantly related to PDR.

CONCLUSIONS

Our work highlights the possible use of the risk score assessment based on the plasma metabolites not only reveal in the early diagnosis of DR and PDR but also assist in enhancing current therapeutic strategies in the clinic.

Association and risk factors of chronic kidney disease and incident diabetes: a nationwide population-based cohort study

AIMS/HYPOTHESIS

Chronic kidney disease (CKD) is a known complication of diabetes mellitus, and insulin resistance is a well-known complication of CKD. However, there is no consensus in the published data on the association of CKD with incident diabetes.

METHODS

A total of 15,403 people with CKD were identified from the Taiwan National Health Insurance Research Database to determine their risk of incident diabetes compared with that of 15,403 matched individuals without CKD. Fine and Gray regression models using death as a competing risk were performed to calculate adjusted HRs and 95% CIs. Risk factors for incident diabetes in people with CKD were also determined.

RESULTS

The CKD cohort had a higher incidence rate of diabetes compared with the non-CKD cohort (11.23/1000 person-years vs 8.93/1000 person-years). In the fully adjusted model, CKD was a significant and independent predictor of incident diabetes (adjusted HR 1.204; 95% CI 1.11, 1.31). The influence of CKD on incident diabetes showed consistent results in three levels of sensitivity analysis. In the CKD cohort, the significant risk factors for incident diabetes included increased age, geographical location, hypertension, hyperlipidaemia and gout. Of these, hypertension was associated with the highest risk of developing incident diabetes (adjusted HR 1.682; 95% CI 1.47, 1.93).

CONCLUSIONS/INTERPRETATION

People with CKD were at higher risk of developing incident diabetes. People with CKD and hypertension, hyperlipidaemia, increased age or gout and who lived in certain geographical regions of Taiwan were more likely to develop diabetes as a complication compared with people without those characteristics.

A Pharmacometabolomic Approach to Predict Response to Metformin in Early-Phase Type 2 Diabetes Mellitus Patients

Metformin is a first-line medication for type 2 diabetes mellitus (T2DM). Based on its universal use, the consideration of inter-individual variability and development of predictive biomarkers are clinically significant. We aimed to identify endogenous markers of metformin responses using a pharmacometabolomic approach. Twenty-nine patients with early-phase T2DM were enrolled and orally administered metformin daily for 6 months. A total of 22 subjects were included in the final analysis. Patients were defined as responders or non-responders based on changes in their glycated haemoglobin A1c (HbA1c) from baseline, over 3 months. Urine metabolites at baseline, as well as at the 3 and 6 month follow-ups after the start of treatment were analysed using gas chromatography-mass spectrometry and evaluated with multivariate analyses. Metabolites distinguishable between the two response groups were obtained at baseline, as well as at the 3 and 6 month follow-ups, and significantly different metabolites were listed as markers of metformin response. Among the identified metabolites, citric acid, myoinositol, and hippuric acid levels showed particularly significant differences between the non-responder and responder groups. We thus identified different metabolite profiles in the two groups of T2DM patients after metformin administration, using pharmacometabolomics. These results might facilitate a better understanding and prediction of metformin response and its variability in individual patients.

Advanced oxidation protein products promote NADPH oxidase-dependent β-cell destruction and dysfunction through the Bcl-2/Bax apoptotic pathway

The accumulation of plasma advanced oxidation protein products (AOPPs) has been linked with diverse disorders, including diabetes, chronic kidney disease, obesity, and metabolic syndrome. The aim of the present study was to evaluate the pathophysiological relevance of AOPPs in β-cell destruction and dysfunction. Exposure of cultured rat β-cells (INS-1) to AOPPs induced an increase in Bax expression, caspase-3 activity, and apoptosis as well as a decrease in Bcl-2 expression in a dose- and time-dependent manner. AOPP challenge rapidly increased the production of intracellular superoxide by activation of NADPH oxidases, demonstrated by p47^phox translocation and interaction with p22^phox and gp91^phox, and this in turn led to apoptosis. AOPPs treatment resulted in β-cell apoptosis, AOPPs accumulation, and decreased insulin content in pancreas and plasma in unilateral nephrectomized rats. Chronic inhibition of NADPH oxidase by apocynin prevented β-cell apoptosis and ameliorated insulin deficiency in AOPP-challenged rats. This study demonstrates for the first time that accumulation of AOPPs promotes NADPH oxidase-dependent β-cell destruction and dysfunction by the Bcl-2/Bax-caspase apoptotic pathway. This finding may provide a mechanistic explanation for β-cell destruction and dysfunction in patients with diverse disorders.

Urea impairs β cell glycolysis and insulin secretion in chronic kidney disease

Disorders of glucose homeostasis are common in chronic kidney disease (CKD) and are associated with increased mortality, but the mechanisms of impaired insulin secretion in this disease remain unclear. Here, we tested the hypothesis that defective insulin secretion in CKD is caused by a direct effect of urea on pancreatic β cells. In a murine model in which CKD is induced by 5/6 nephrectomy (CKD mice), we observed defects in glucose-stimulated insulin secretion in vivo and in isolated islets. Similarly, insulin secretion was impaired in normal mouse and human islets that were cultured with disease-relevant concentrations of urea and in islets from normal mice treated orally with urea for 3 weeks. In CKD mouse islets as well as urea-exposed normal islets, we observed an increase in oxidative stress and protein O-GlcNAcylation. Protein O-GlcNAcylation was also observed in pancreatic sections from CKD patients. Impairment of insulin secretion in both CKD mouse and urea-exposed islets was associated with reduced glucose utilization and activity of phosphofructokinase 1 (PFK-1), which could be reversed by inhibiting O-GlcNAcylation. Inhibition of O-GlcNAcylation also restored insulin secretion in both mouse models. These results suggest that insulin secretory defects associated with CKD arise from elevated circulating levels of urea that increase islet protein O-GlcNAcylation and impair glycolysis.

Glycaemic changes in patients with chronic kidney disease

In Argentina, there have been no studies aimed at establishing the prevalence of dysglycaemia (impaired fasting glucose [IFG], impaired glucose tolerance [IGT] and diabetes mellitus [DM]) in patients with chronic kidney disease (CKD). Our group decided to conduct an observational study to evaluate the frequency with oral glucose tolerance test (OGTT) in CKD patients with no previous data for dysglycaemia in their medical records. OGTT was performed in 254 patients (60.62% male) with stage 3, 4 and 5 CKD under conservative treatment, haemodialysis or transplantation. Results for DM were found in 10 patients according to fasting glucose alone (3.94%; 95% CI: 1.35-6.53%), 11 patients with exclusively the second hour criterion (4.33%; 95% CI: 1.63-7.03%), 15 with both criteria (5.91%; 95% CI: 2.81-9.00%) and 36 patients with at least one criteria (14.17%; 95% CI: 9.69-18.66%). In a multivariate analysis, DM was associated with waist circumference (OR=1.033 per cm; 95% CI, 1.005 to 1.062; P=.019) and with conservative treatment vs. replacement therapy (OR=0.41; 95% CI: 0.19-0.92; P=.028). IGT was evident in 24.6% and 20.3 on conservative vs. replacement therapy, with no statistically significant difference. IFG (ADA criteria) was 19.75 vs. 9.24% in conservative vs. replacement therapy, with a statistically significant difference. OGTT is suggested for all CKD patients since it is able to detect the full range of unknown dysglycaemias, which avoids underdiagnoses and favours performing treatments to prevent progression in DM risk groups (IFG and/or IGT). It also aids in the selection of the most appropriate medication for transplantation or treatment initiation in new cases of undiagnosed DM to decrease morbidity and mortality.

Postprandial responses of incretin and pancreatic hormones in non-diabetic patients with end-stage renal disease

BACKGROUND

Patients with end-stage renal disease (ESRD) have glucometabolic disturbances resulting in a high prevalence of prediabetes. The underlying pathophysiology remains unclear, but may prove important for the strategies employed to prevent progression to overt diabetes. Meal-induced release of the insulinotropic gut-derived incretin hormones and pancreatic hormones play a critical role in the maintenance of a normal postprandial glucose tolerance.

METHODS

We studied patients with ESRD and either normal (n = 10) or impaired (n = 10) glucose tolerance, and control subjects (n = 11). Plasma concentrations of glucose, insulin, glucagon, glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP) and paracetamol were measured repeatedly during a standardized 4-h liquid meal including 1.5 g paracetamol (added for evaluation of gastric emptying).

RESULTS

Fasting glucose and postprandial glucose responses were comparable between groups (P > 0.082). Patients with ESRD exhibited higher fasting levels of GIP and glucagon compared with controls (P < 0.001). Baseline-corrected GLP-1 and glucagon responses were enhanced (P < 0.002), baseline-corrected insulin responses and insulin excursions were reduced (P < 0.035), and paracetamol excursions were delayed (P < 0.024) in patients with ESRD compared with controls. None of the variables differed between the two ESRD subgroups.

CONCLUSIONS

Non-diabetic patients with ESRD were characterized by reduced postprandial insulin responses despite increased secretion of the insulinotropic incretin hormone GLP-1. Fasting levels and baseline-corrected responses of glucagon were elevated and gastric emptying was delayed in the ESRD patients. These perturbations seem to be caused by uraemia per se and may contribute to the disturbed glucose metabolism in ESRD patients.

Gastrointestinal factors contribute to glucometabolic disturbances in nondiabetic patients with end-stage renal disease

Nondiabetic patients with end-stage renal disease (ESRD) have disturbed glucose metabolism, the underlying pathophysiology of which is unclear. To help elucidate this, we studied patients with ESRD and either normal or impaired glucose tolerance (10 each NGT or IGT, respectively) and 11 controls using an oral glucose tolerance test and an isoglycemic intravenous glucose infusion on separate days. Plasma glucose, insulin, glucagon, and incretin hormones were measured repeatedly, and gastrointestinal-mediated glucose disposal (GIGD) based on glucose amounts utilized, and incretin effect based on incremental insulin responses, were calculated. The GIGD was significantly reduced in both ESRD groups compared with controls. Incretin effects were 69% (controls), 55% (ESRD with NGT), and 41% (ESRD with IGT), with a significant difference between controls and ESRDs with IGT. Fasting concentrations of glucagon and incretin hormones were significantly increased in patients with ESRD. Glucagon suppression was significantly impaired in both groups with ESRD compared with controls, while the baseline-corrected incretin hormone responses were unaltered between groups. Thus, patients with ESRD had reduced GIGD, a diminished incretin effect in those with IGT, and severe fasting hyperglucagonemia that seemed irrepressible in response to glucose stimuli. These factors may contribute to disturbed glucose metabolism in ESRD.

The frequency of prediabetes and contributing factors in patients with chronic kidney disease

AIMS

Uremia is a prediabetic state, but abnormal glucose metabolism and relative risk factors in non-diabetic chronic kidney disease (CKD) patients are not studied extensively. This study aimed to evaluate prediabetes and contributing factors in patients with CKD.

METHODS

We studied the frequency of prediabetes (defined as fasting plasma glucose 100-125 mg/dl and 2-h plasma glucose 140-199 mg/dl) and contributing risk factors in 91 (34 women and 57 men) non-diabetic CKD (GFR < 60) patients who were referred to Sina Hospital between November 2010 and November 2011. Impaired fasting glucose and impaired glucose tolerance were regarded as prediabetic state.

RESULTS

Thirty-eight patients (41.8%), 28 male and 10 female, with mean age of 57.4 ± 17.1 yr, had prediabetes. Among these, 18.7% had impaired fasting glucose, 7.7% impaired glucose tolerance, and 15.4% combined impaired fasting glucose and impaired glucose tolerance. CKD patients with impaired glucose tolerance had more frequently hypertriglyceridemia (85.7% vs. 42.0%, p = 0.001), hypertension (66.6% vs. 31.4%, p = 0.004), and metabolic syndrome according to National Cholesterol Education Program Adult Treatment Panel III (52.3% vs. 25.7%, p = 0.02). Also, mean systolic blood pressure (134.2 ± 13.9 vs. 124.5 ± 20.0, p = 0.004) was higher in CKD patients with impaired glucose tolerance compared to CKD patients with normal glucose.

CONCLUSIONS

Prediabetes is a frequent condition in CKD patients. Also, hypertriglyceridemia and hypertension are more prevalent in prediabetic CKD patients than in non-diabetic CKD patients.

New-onset diabetes mellitus after kidney transplantation in Denmark

BACKGROUND AND OBJECTIVES

This study aimed to investigate the development of new-onset diabetes mellitus (NODM) in a prospective study of 97 nondiabetic uremic patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Included were 57 kidney recipients (Tx group, age 39 +/- 13 years) and 40 uremic patients remaining on the waiting list for kidney transplantation (uremic controls, age 47 +/- 11 years). All were examined at baseline before possible transplantation and after 12 months. The prevalence of diabetes, prediabetes, insulin sensitivity index (ISI), and insulin secretion index (Isecr) were estimated using an oral glucose tolerance test with measurements of plasma glucose and plasma insulin.

RESULTS

One year after transplantation NODM was present in 14% (8 of 57) compared with 5% (2 of 40) in the uremic control group (P = 0.01). ISI in the Tx group deteriorated from 6.8 +/- 3.9 before transplantation to 4.9 +/- 2.8 at 12 months after transplantation (P = 0.005), and a slight increase in Isecr from 37 +/- 19 to 46 +/- 22 (P = 0.02) was seen. No significant changes occurred in the uremic controls (ISI was 7.9 +/- 5 and 8.5 +/- 5, and Isecr was 31 +/- 17 and 28 +/- 15). Using multivariate ordinal logistic regression, pre-Tx ISI and age predicted NODM (odds ratios: 0.82, P = 0.01 and 1.06, P = 0.02, respectively).

CONCLUSIONS

One year after kidney transplantation, NODM was present in 14% of patients. This was mainly caused by an increase in insulin resistance and was observed despite improvement in insulin secretion.

Pre-diabetes and arterial stiffness in uraemic patients

BACKGROUND

In order to address factors of relevance for new onset diabetes mellitus and cardiovascular disease after kidney transplantation, we investigated the presence of pre-diabetes, arterial stiffness and endothelial dysfunction in patients with end-stage renal disease (ESRD) accepted for kidney transplantation.

METHODS

Pre-diabetes and an insulin sensitivity index were estimated by an oral glucose tolerance test in 66 consecutive uraemic patients, without diabetes, being on the waiting list for the first renal transplantation. Mean age was 43 +/- 13 years. Duration of ESRD was 32 +/- 27 months. A control group consisted of 14 healthy subjects. Arterial stiffness was measured by aorta pulse wave velocity (PWV) and aorta augmentation index (AIX). Endothelial function was evaluated by flow-mediated vasodilatation (FMD) and plasma concentrations of von Willebrand factor antigen (vWF). Mean arterial blood pressure (MAP) was measured in supine resting position.

RESULTS

Twenty-seven uraemic patients (41%) had pre-diabetes (IFG+IGT), and 39 had normal glucose tolerance. The uraemic patients were more insulin resistant with lower insulin sensitivity index compared to healthy controls (6.1 +/- 3 vs. 15 +/- 7, P < 0.0001) but with no difference between patients with and without pre-diabetes. HbA1c and fasting plasma glucose was comparable in uraemic patients with and without pre-diabetes. PWV was higher in pre-diabetic compared to normoglycaemic uraemic patients (9.1 +/- 3 vs. 7.3 +/- 2 m/s, P = 0.03) and healthy controls (9.1 +/- 3 vs. 6.7 +/- 1, P = 0.01), while AIX did not differ (24.9 +/- 13 vs. 23.2 +/- 12 vs. 17 +/- 16, P = NS). Presence of pre-diabetes was positively associated to PWV in a univariate analysis. Multivariable analysis revealed age and MAP as independent predictors of PWV in uraemic patients. FMD and vWF were impaired in uraemic patients compared to healthy controls (3 +/- 4 vs. 7 +/- 3, P = 0.007 and 1.8 +/- 0.7 vs. 0.96 +/- 0.3 kIU/L, P = 0.0002, respectively) but with no difference between the two groups of uraemic patients. In conclusion, a high prevalence of pre-diabetes, impaired insulin resistance, increased arterial stiffness of aorta as well as impaired augmentation index and vasodilatation was demonstrated in uraemic patients prior to kidney transplantation. Increased arterial stiffness of aorta and augmentation index were independently associated with age and blood pressure.