Challenges of Glycemic Control in People With Diabetes and Advanced Kidney Disease and the Potential of Automated Insulin Delivery

Diabetes is the leading cause of chronic kidney disease (CKD) and end-stage kidney disease in the world. It is known that maintaining optimal glycemic control can slow the progression of CKD. However, the failing kidney impacts glucose and insulin metabolism and contributes to increased glucose variability. Conventional methods of insulin delivery are not well equipped to adapt to this increased glycemic lability. Automated insulin delivery (AID) has been established as an effective treatment in patients with type 1 diabetes mellitus, and there is emerging evidence for their use in type 2 diabetes mellitus. However, few studies have examined their role in diabetes with concurrent advanced CKD. We discuss the potential benefits and challenges of AID use in patients with diabetes and advanced CKD, including those on dialysis.

Impact of dialysis modality on major adverse cardiovascular events and all-cause mortality: a national population-based study

BACKGROUND

Only few studies with inconsistent results comparing the relative risk of cardiac mortality between peritoneal dialysis (PD) and hemodialysis (HD). Switches between renal replacement therapy (RRT) modalities render objective assessment of survival benefits a greater challenge.

METHODS

Data were retrieved from Taiwan's National Health Insurance Database from 1 January 2006 to 31 December 2015. We included 13 662 and 41 047 long-term dialysis patients in a propensity score matching study design and a time-varying study design, respectively, to compare major adverse cardiovascular events (MACEs) between patients receiving PD and HD. We also included 109 256 dialysis patients to compare the all-cause mortality among different RRT modalities.

RESULTS

For MACE, the hazard ratio (HR) for PD patients compared to HD patients was 0.95 [95% confidence interval (CI) 0.89-1.02] in the propensity score study design and 1.06 (95% CI 1.01-1.12) in the time-varying study design. For all-cause mortality, the HR for PD patients compared to HD patients was 1.09 (95% CI 1.05-1.13) in the propensity score study design and 1.13 (95% CI 1.09-1.17) in the time-varying study design. The HR for death was higher at a level of statistical significance for females (1.21, 95% CI 1.15-1.28), patients ≥65 years old (1.30, 95% CI 1.24-1.36) and diabetes mellitus (DM; 1.28, 95% CI 1.22-1.34).

CONCLUSIONS

The HR for MACE is significantly higher among PD patients in time-varying design analysis. In addition, all-cause mortality was higher in PD patients compared to patients with HD, especially in those who were aged ≥65 years, female or DM.

Day and night changes in energy expenditure of patients on automated peritoneal dialysis

RATIONALE

Automated peritoneal dialysis (APD) treatment for end-stage kidney disease affords patients a degree of autonomy in everyday life. Clinical investigations of their energy expenditure (EE) are usually based on resting EE, which could mask day and night variations in EE. The aim of this study, therefore, was to compare the components of EE in APD patients and healthy control (C) subjects.

MATERIAL AND METHOD

Patients treated with APD for more than 3 months were compared with C volunteers matched for age and lean body mass (LBM). Biochemical analyses were performed and body composition was determined by DEXA to adjust EE to LBM. Total EE, its different components and respiratory quotients (RQ) were measured by a gas exchange method in calorimetric chambers. Spontaneous total and activity-related EE (AEE) were also measured in free-living conditions over 4 days by a calibrated accelerometer and a heart rate monitor.

RESULTS

APD (n = 7) and C (n = 7) patients did not differ in age and body composition. REE did not differ between the two groups. However, prandial increase in EE adjusted for dietary energy intake was higher in APD patients (+57.5 ± 12.71 kcal/h) than in C subjects (+33.8 ± 10.5 kcal/h, p = 0.003) and nocturnal decrease in EE tended to be lower in APD patients undergoing dialysis sessions (- 4.53 ± 8.37 kcal/h) than in subjects (- 11.8 ± 7.69 kcal/h, p = 0.059). Resting RQ (0.91 ± 0.09 vs 0.81 ± 0.04, p = 0.032) and nocturnal RQ (0.91 ± 0.09 vs 0.81 ± 0.04, p = 0.032) were significantly higher in APD patients, indicating a preferential use of glucose substrate potentially absorbed across the peritoneum. AEE was lower in APD patients (595.9 ± 383.2 kcal/d) than in C subjects (1205.2 ± 370.5 kcal/d, p = 0.011). In contrast, energy intakes were not significantly different (1986 ± 465 vs 2083 ± 377 kcal/d, p = 0.677).

CONCLUSION

Although the two groups had identical resting EE, APD patients had a higher prandial increase in EE, a lower activity-related EE and higher resting and nocturnal RQ than healthy subjects.

Comparison of Cardiovascular Outcomes by Dialysis Modality: A Systematic Review and Meta-Analysis

Debates exist regarding the merit of starting one dialysis modality over the other for improved cardiovascular outcomes. Five previously published prospective and retrospective cohort studies have reported inconsistent conclusions on this topic. The aim of this systematic review and meta-analysis is to evaluate the influence initiation of hemodialysis (HD) vs peritoneal dialysis (PD) may have on the relative risk (RR) of subsequent development of adverse cardiovascular events (ACVE) in patients with end-stage renal disease (ESRD). Of the 518 records identified, 5 cohort studies, assessing a total of 47,062 patients were included in the meta-analysis. With regard to the subsequent development of ACVE following initiation on the different dialysis modalities, the pooled RR was found to be non-significant. Peritoneal dialysis is a suitable and cost-effective alternative to HD for ESRD patients at risk of cardiovascular disease.

Measurement and Correlation of Indices of Insulin Resistance in Patients on Peritoneal Dialysis

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BACKGROUND

Insulin resistance (IR) is common in maintenance dialysis patients and is associated with excess mortality. Hyperinsulinemic euglycemic glucose clamp (HEGC) is the gold standard for measuring IR. There are limited studies using HEGC for comparison to other indirect indices of IR in peritoneal dialysis (PD) patients, nor have there been direct comparisons between patients receiving PD and those on maintenance hemodialysis (MHD) with regard to severity of IR, methods of measurement, or factors associated with the development of IR. ♦

METHODS

This is a cross-sectional, single-center study performed in 10 prevalent PD patients of median age 48 years (range 41 - 54); 50% were female and 60% were African American. Insulin resistance was assessed by HEGC (glucose disposal rate [GDR]), homeostatic model assessment of IR (HOMA-IR), HOMA-IR corrected by adiponectin (HOMA-AD), leptin adiponectin ratio (LAR), quantitative insulin sensitivity check index (QUICKI), McAuley's index, and oral glucose tolerance test (OGTT) at each time point for a total of 18 studies. Retrospective analysis compared this cohort to 12 hemodialysis patients who had previously undergone similar testing. ♦

RESULTS

The median GDR was 6.4 mg/kg/min (interquartile range [IQR] 6.0, 7.8) in the PD cohort compared with the MHD group, which was 5.7 mg/kg/min (IQR 4.3, 6.6). For both the PD and MHD cohorts, the best predictors of GDR by HEGC after adjusting for age, gender, and body mass index (BMI), were HOMA-AD (PD: r = -0.69, p = 0.01; MHD: r = -0.78, p = 0.03) and LAR (PD: r = -0.68, p < 0.001; MHD: r = -0.65, p = 0.04). In both groups, HOMA-IR and QUICKI failed to have strong predictive value. Eight of 10 PD patients had at least 1 abnormal OGTT, demonstrating impaired glucose tolerance. ♦

CONCLUSIONS

Insulin resistance is highly prevalent in PD patients. The adipokine based formulas, HOMA-AD and LAR, correlated well in both the PD and MHD populations in predicting GDR by HEGC, outperforming HOMA-IR. The use of these novel markers could be considered for large-scale, epidemiological outcome studies.

Glucose challenge test (50-g GCT) in detection of glucose metabolism disorders in peritoneal dialysis patients: preliminary study

BACKGROUND

The aim was to evaluate the clinical utility of the oral glucose tolerance screening test (50-g GCT--glucose challenge test) for the detection of glucose metabolism disorders (GMD) in peritoneal dialysis (PD) patients with normal fasting glucose levels.

METHODS

The 50-g GCT was performed in 20 prevalent patients without history of diabetes before PD treatment onset, who had been on dialysis for a median time of 15.34 months. In addition, other indicators of glucose metabolism were measured: C-peptide, fasting insulin serum concentration, and the glycated hemoglobin level (HbA1c). The patients were prospectively followed for a median time of 25.8 months.

RESULTS

50-g GCT revealed GMD in 15 studied patients (75%)--impaired glucose tolerance in 11 patients (55%) and diabetes mellitus in four patients (20%). HbA1c and insulin resistance, estimated by homeostasis model assessment, were elevated in two (10%) and seven (35%) patients, respectively. In patients with GMD, dietetic and pharmacologic interventions were performed. When the 50-g GCT was repeated at the end of the observation period, 12 (60%) patients reported GMD, with no case of diabetes.

CONCLUSION

50-g GCT appears to be a simple and practical tool for the detection of GMD in PD patients with normal fasting glucose. Timely therapeutic intervention can effectively inhibit the progression of glucose intolerance during PD treatment.

Low-Polydispersity Glucose Polymers as Osmotic Agents for Peritoneal Dialysis

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BACKGROUND

Peritoneal dialysis (PD) solutions containing icodextrin as the osmotic agent have advantages during long dwells. The glucose polymers that constitute icodextrin are a heterogeneous mix of molecules with a polydispersity [ratio of weight-average to number-average molecular weight (Mw/Mn)] of approximately 2.6. The present study evaluates whether modifications in the polydispersity and concentration of glucose polymers can improve ultrafiltration (UF) without an associated increase in carbohydrate absorption (CA). ♦

METHODS

Computer simulations using a three-pore model of peritoneal transport during a long dwell in PD patients predict that, in general, compared with 7.5% icodextrin, glucose polymers with a Mw greater than or equal to 7.5 kDa, a polydispersity less than 2.6, and concentrations greater than 7% could achieve higher UF without higher CA. Based on the simulations, we hypothesized that, compared with 7.5% icodextrin, glucose polymers with a Mw of 18 - 19 kDa and a polydispersity of 2.0 at 11% concentration could achieve higher UF without a higher CA. We tested this hypothesis in experimental studies using 8-hour dwells in New Zealand White rabbits. In those studies, UF was measured by complete fluid collection, and CA was measured by subtracting the total carbohydrate in the collected fluid from the carbohydrate initially infused. ♦

RESULTS

The UF was higher with 11% 19 kDa glucose polymer than with 7.5% icodextrin (mean ± standard deviation: 89 ± 31 mL vs 49 ± 15 mL; p = 0.004) without higher CA (5.2 ± 0.9 g vs 5.0 ± 0.9 g, p = 0.7). Similar results were seen with the 11% 18 kDa glucose polymer, which, compared with 7.5% icodextrin, resulted in higher UF (mean ± standard deviation: 96 ± 18 mL vs 66 ± 17 mL; p < 0.001) without higher CA (4.8 ± 0.7 g vs 5.2 ± 0.6 g, p = 0.2). ♦

CONCLUSIONS

The findings demonstrate that, compared with 7.5% icodextrin solution, long-dwell PD solutions containing 11% glucose polymers with a Mw of 18-19 kDa and a polydispersity of 2.0 can provide higher UF without higher CA.

Association of body fat with inflammation in peritoneal dialysis

Peritoneal dialysis (PD) frequently leads to body weight gain, which appears to be a potential cause of the chronic inflammation frequently present in these patients. The consequences of this inflammation are impaired nutritional status, accelerated atherosclerosis, and increased mortality. To assess the association between inflammation and body fat in female patients treated with PD. Nineteen female patients on PD for at least 6 months with no infectious complications or malignant or acute inflammatory diseases. Nutritional status was determined by measuring weight, height, body mass index (BMI), waist (WC), and mid-arm circumferences (MAC), mid-arm muscle area, and tricipital fold (TCF). Bioelectrical impedance (BIA) was used to determine body composition. Biochemical evaluation included the determination of serum albumin, urea, creatinine, and C-reactive protein (CRP). The glucose absorbed from the dialysis solution was quantitated. According to BMI, two patients were classified as malnourished and ten as overweight/obese. Sixteen individuals had high WC measurements and 12 had excess body fat (BF) as measured by BIA. High CRP levels were observed in 12 patients, who had higher WC, MAC, BMI, TCF, and BF measurements compared to non-inflamed patients. Positive associations were detected between CRP and BMI, MAC, WC, and TCF. Associations between BF and CRP suggest that adiposity may be a potent exacerbating factor of inflammation in this population, especially visceral fat. Thus, obesity may be considered to be one more factor responsible for the early atherosclerosis and high cardiovascular mortality observed in these patients.

Metabolic syndrome in peritoneal dialysis patients: choice of diagnostic criteria and prognostic implications

BACKGROUND AND OBJECTIVE

In the general population, metabolic syndrome (MES) is associated with cardiovascular risk. However, the definition of MES and its prognostic implication among patients undergoing peritoneal dialysis (PD) remain controversial.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We studied 329 prevalent PD patients from April 2008 to April 2011 and compared four sets of diagnostic criteria: the original World Health Organization (WHO) criteria, the International Diabetes Federation (IDF) criteria, the original National Cholesterol Education Program (NCEP) criteria, and the modified NCEP criteria. Nutritional status, body composition, and arterial pulse-wave velocity were measured. Patients were followed for 31.7 ± 15.5 months.

RESULTS

Among the 329 patients, 175 (53.2%) fulfilled the WHO criteria, 177 (53.8%) the IDF criteria, 199 (60.5%) the original NCEP criteria, and 218 (66.3%) the modified NCEP criteria. The agreement among the four sets of criteria was fair to moderate (Cohen κ=0.35-0.58). Patients with MES defined by all four criteria had higher adipose tissue mass than the others, although the difference in adipose tissue mass was most pronounced with the IDF criteria (MES versus no MES, 18.2 ± 7.9 versus 10.7 ± 5.9 kg; P<0.001). Patients with MES, as defined by the IDF criteria, were hospitalized longer than those without MES (3.82 [interquartile range, 0.00-12.61] versus 1.07 [interquartile range, 0.00-6.43]) days per year of follow-up; P=0.01). Overall survival, cardiovascular survival, or technique survival did not differ between patients with and without MES, irrespective of the diagnostic criteria after adjustment for diabetic status.

CONCLUSION

In patients undergoing PD, overall survival, cardiovascular survival, and technique survival did not differ between patients with and without MES, irrespective of diabetic status and diagnostic criteria. Further studies are needed to establish a new definition or clinical scoring system for risk stratification of PD patients.

[Assessment of body weight changes in patients on peritoneal dialysis]

This study had as its main objective to assess the variation in body weight of patients on peritoneal dialysis (DP) during the first year of treatment and as a secondary goal to identify patients with criteria for metabolic syndrome (SM). Observational study conducted with 35 patients of a university hospital. Data were collected on the clinical and demographic status, change of body weight and criteria for SM from the sample. After 12 months of initiation of dialysis, approximately 40% of patients showed overweight and/or obesity. The average variation of body weight after one year was 3.7 Kg, and the largest variation was found in the first three months, with values of 2.2 Kg The prevalence of SM was 30%. It was concluded that the most important change of body weight happened in the first year of treatment and there is a high prevalence of SM in patients on DP.

To eat or not to eat: dietary fat in uremia is the question

Although a diet low in protein is well known to reduce the risk of progression in patients with chronic kidney disease (CKD), the impact of dietary fat content and fat quality has largely been ignored. As a reduced protein intake results in an obligatory reduction in energy intake, and as CKD patients often suffer from energy malnutrition, this issue deserves greater attention. The present review aims to summarize what is currently known about dietary fat intake in CKD and suggests areas for further study. We conclude that although overweight per se is an important risk factor for the development of CKD, the role of obesity as a risk factor for complications in manifest CKD remains unclear. Current data support a balanced increase in dietary fat intake in patients with CKD to compensate for reduced energy intake in protein-restricted diets and anorexic patients. However, patients who are obese should be encouraged to lose weight while maintaining or, preferably, increasing muscle mass.

Glucose-based peritoneal dialysis solution suppresses adiponectin synthesis through oxidative stress in an experimental model of peritoneal dialysis

OBJECTIVE

Accumulation of visceral fat is one of the major risk factors for the development of cardiovascular disease in peritoneal dialysis (PD) patients. Adiponectin, an adipokine commonly regarded as a negative indicator of metabolic disease, is reported to be downregulated in its gene level in end-stage renal disease patients. Since excessive fat deposit is involved in increased reactive oxygen species (ROS), PD solution (PDS) may contribute to ROS production, resulting in dysregulation of adiponectin. In this study, we tested our hypothesis that oxidative stress induced by PDS may play a role in the regulation of adiponectin.

METHODS

Commercial PDS containing 3.86% glucose (20 - 30 mL) was administered to SD rats for 12 weeks with and without N-acetylcysteine (NAC; 10 mmol/L). ELISA was used to quantify adiponectin in plasma and spent dialysate. For in vitro studies, fully differentiated 3T3-L1 adipocytes and adipocytes isolated from abdominal fat were treated with a high glucose solution, PDS, and H(2)O(2). Adiponectin levels in the conditioned media were measured by ELISA and immunoblot assays. The mRNA levels of adiponectin in mature adipocytes were examined using real-time RT-PCR.

RESULTS

The levels of adiponectin in plasma and spent dialysate were significantly downregulated by PDS and this effect was suppressed by NAC. In 3T3-L1 adipocytes, adiponectin secretion was inhibited by 50 mmol/L glucose, PDS diluted 2-fold, and H(2)O(2) (200 μmol/L). In addition, H(2)O(2) downregulated expression of adiponectin mRNA and secretion of adiponectin oligomer complexes.

CONCLUSIONS

Our data suggest that ROS induced by conventional glucose-based PDS may contribute to pathophysiological changes in abdominal fat and downregulate adiponectin secreted from adipocytes during long-term PD.