Hemodiafiltration: Technical and Medical Insights

Despite the significant medical and technical improvements in the field of dialytic renal replacement modalities, morbidity and mortality are excessively high among patients with end-stage kidney disease, and most interventional studies yielded disappointing results. Hemodiafiltration, a dialysis method that was implemented in clinics many years ago and that combines the two main principles of hemodialysis and hemofiltration-diffusion and convection-has had a positive impact on mortality rates, especially when delivered in a high-volume mode as a surrogate for a high convective dose. The achievement of high substitution volumes during dialysis treatments does not only depend on patient characteristics but also on the dialyzer (membrane) and the adequately equipped hemodiafiltration machine. The present review article summarizes the technical aspects of online hemodiafiltration and discusses present and ongoing clinical studies with regards to hard clinical and patient-reported outcomes.

Disturbances in Insulin-Glucose Metabolism in Patients With Advanced Renal Disease With and Without Diabetes

CONTEXT

Use of insulin in patients with diabetes and advanced chronic kidney disease (CKD; stages 4 to 5) is challenging and shows great variability among individuals. We explored the mechanisms underlying this variability.

EVIDENCE ACQUISITION

PubMed was searched for articles in English from 1960 to 2018 for advanced CKD and diabetes, glucose and insulin metabolism, insulin clearance, secretion and resistance, plasma insulin concentration, glycemic control, hypoglycemia, insulin dosage, and continuous glucose monitoring (CGM) in CKD.

EVIDENCE SYNTHESIS

The evidence shows that in most patients the daily dose of insulin needs to be significantly reduced with a high degree of variability; in some the dose remains unchanged, and rarely it is increased. The premise that the marked reduction in insulin requirement is essentially attributable to decreased insulin clearance by kidneys leading to prolongation of its plasma half-life, elevated blood insulin concentration, and hypoglycemia is not entirely correct. Other factors including decreases in food intake, insulin secretion, insulin clearance by peripheral tissues, and renal gluconeogenesis play important roles. There is also heightened resistance to insulin due to metabolic acidosis, uremic toxins, inflammatory state, and vitamin D deficiency. Importantly, the magnitude of changes in each of these factors varies between individuals with the same degree of CKD.

CONCLUSIONS

In the presence of diabetes with advanced CKD, the insulin regimen should be individualized based on knowledge of the daily glucose patterns. The use of CGM is promising for safer glycemic control in patients with advanced CKD and diabetes and helps prevent extremes of hypoglycemia and hyperglycemia.

Insulin Resistance and Cardiovascular Risks in Different Groups of Hemodialysis Patients: A Multicenter Study

BACKGROUND

To investigate the association between insulin resistance (IR) and cardiovascular disease (CVD) risks among hemodialysis patients.

METHODS

We conducted a cross-sectional study between 2013 and 2017, on 384 hemodialysis patients from seven hospital-based-dialysis centers. HOMA-IR is classified according to median value. The CVD risks were defined by the K/DOQI Guidelines. Logistic regression analysis was used.

RESULTS

Patients' age was 60.9 ± 11.8, 58.1% men, and 40.3% overweight/obese. The median of HOMA-IR was 5.4, 82.8% high systolic blood pressure, and 85.7% hyperhomocysteinemia. In multivariate analysis, IR was significantly associated with higher odds of low high-density lipoprotein cholesterol, high triglyceride, and impaired fasting glucose in groups of normal weight, overweight/obese, nondiabetes, diabetes, and overall sample. IR linked with elevated high-sensitive C-reactive protein in normal weight patients (odd ratio, OR=2.21, 95% confidence interval, 1.16-4.22, p < .05), with hypoalbuminemia in normal weight patients (OR=8.31, 95% CI, 2.35-29.37, p < .01), in nondiabetes patients (OR=6.59, 95% CI, 1.81-23.95, p < .01), and overall sample (OR=3.07, 1.51-6.23, p < .01).

CONCLUSIONS

The level of IR and prevalence of CVD risks were high in hemodialysis patients. IR was independently associated with CVD risks.

Impact of Percent Body Fat on All-Cause Mortality among Adequate Dialysis Patients with and without Insulin Resistance: A Multi-Center Prospective Cohort Study

The association between body fat and mortality in hemodialysis patients remains controversial. We examined the effect of percent body fat (PBF) on all-cause mortality among adequate hemodialysis patients with and without insulin resistance (IR). A prospective cohort study was conducted on 365 adequate hemodialysis patients (equilibrated Kt/V ≥ 1.2) from seven hospitals. Patients’ characteristics and clinical and biochemical parameters were assessed at baseline between September 2013 and April 2017. Patients were followed up for all-cause mortality until April 2018. The median value of homeostatic model assessment (HOMA-IR) was used to classify IR. Cox proportional hazard models were utilized to examine predictors of all-cause mortality. During 1.4 (1.0–3.2) years of follow-up, 46 patients died. In patients with IR (HOMA-IR ≥ 5.18), PBF was significantly higher in the survival group than in the death group (31.3 ± 9.0 vs. 25.4 ± 8.2, p = 0.005). After controlling for confounding factors, PBF was significantly associated with lower risk for all-cause mortality in patients with IR (hazard ratio, 0.94; 95% confidence interval, 0.89–1.00; p = 0.033). The association was not observed in patients without IR. In conclusion, percent body fat shows a protective effect on survival in hemodialysis patients with IR.