Lower serum potassium combined with lower sodium concentrations predict long-term mortality risk in hemodialysis patients

Association between serum potassium and risk of all-cause mortality among chronic kidney diseases patients: A systematic review and dose-response meta-analysis of more than one million participants

We aimed to perform a meta-analysis, using prospective cohort studies, to test the association between serum potassium and all-cause mortality among chronic kidney diseases (CKD) patients. A systematic search was performed using PubMed-MEDLINE and Scopus, up to July 2020. Prospective cohort studies which reported risk estimates of all-cause mortality in CKD patients with different serum potassium levels were included in the present meta-analysis. Thirteen studies were included in the analysis. A nonlinear dose-response meta-analysis suggested that there is a J-shaped association between serum potassium levels and the risk of all-cause mortality, with a nadir at serum potassium of 4.5 mmol/L. Subgroup analyses indicated that the strength and shape of the association between serum potassium and all-cause mortality may be influenced by age. Our meta-analysis provides supportive evidence that there is a J-shape association between serum potassium and all-cause mortality among CKD patients.

Xerostomia, thirst, sodium gradient and inter-dialytic weight gain in hemodialysis diabetic vs. non-diabetic patients

Background

In hemodialysis (HD) patients, xerostomia and hyposalivation may intensify sensations of thirst, and contribute to the intake of fluids and excessive inter-dialytic weight gain (IWG). Since IWG is regarded to be higher in diabetic patients than in non-diabetics HD enhancing their mortality, it is crucial to define plausible underlying causes. Therefore, the study investigates factors contributing to the increased IWG in diabetic HD patients.

Material and Methods

The study included 97 HD patients (38 diabetics) receiving hemodialysis. All participants completed surveys comprising the Dialysis Thirst Inventory (DTI) and Xerostomia Inventory. Unstimulated whole saliva flow rate (USWFR) was measured, with USWFR below 0.1 mL/min being regarded as hyposalivation. Additionally, pre- and post-dialysis serum sodium concentration, sodium gradient and IWG were assessed. In diabetic HD patients, hemoglobin A1c (HbA1c) level was measured.

Results

Significantly higher scores were found in diabetic than non-diabetic HD patients with regard to DTI (21.2±7.7 vs. 17.1±6.2: Z=2.44, p=0.03) and xerostomia (40.5±6.1 vs. 29.9±14.4: Z=4.15, p=0.003). Hyposalivation was observed more often in diabetic HD patients (Z=2.23, p=0.04). IGW was significantly higher in participants with diabetes (Z=2.44, p=0.03), as was the pre-dialysis sodium serum (Z=3.4, p=0.008). High levels of HbA1c were associated with lower levels of serum sodium (r=-0.67 p<0.05). HbA1c positively correlated with pre-dialysis sodium gradient (r=0.66 p<0.05). However, multiple regression analysis found that the only predictors of increased IWG (>4.8 IWG%) in diabetic patients remained saliva flow rate and pre-dialysis sodium gradient.

Conclusions

Concomitant diabetes in hemodialysis patients appears to intensify subjective xerostomia and thirst sensation. It also leads to excessive IWG by the increase of pre-dialysis serum sodium gradient.

Key words:Diabetes mellitus, hemodialysis, hyposalivation, inter-dialytic weight gain, sodium gradient.

Clinical implications and outcome prediction in chronic hemodialysis patients with lower serum potassium×uric acid product

BACKGROUND

The aims of this study were to evaluate correlations between serum potassium (S[K]) and uric acid (S[UA]) in hemodialysis patients and to determine whether lower levels of both S[K] and S[UA] were associated with poor long-term prognoses in these patients.

METHODS

A cohort of 424 maintenance hemodialysis patients (58±13 years of age; 47% male; 39% with diabetes) from a single center were divided into tertiles based on the product of S[K]×S[UA] (K×UA): Group 1: low K×UA: n=141; Group 2: median K×UA: n=141; and Group 3: high K×UA: n=142. The longest observation period was 60 months.

RESULTS

S[K] showed a positive linear correlation with S[UA] (r=0.33; p<0.001). In multivariate logistic regression analysis, Group 1 was characterized by hypoalbuminemia (odds ratio [OR]=0.20, 95% confidence interval (CI)=0.11-0.35) and lower levels of normalized protein catabolism [nPCR] (OR=0.10, 95%CI=0.05-0.22) and phosphate levels (OR=0.41, 95%CI=0.33-0.51). In contrast, Group 3 was associated with higher nPCR (OR=6.07, 95%CI=2.93-12.50) and albumin levels (OR=2.12, 95% CI=2.12-7.00). Compared to the reference (Group 1), the hazard ratio (HR) for long-term mortality was significantly lower in Groups 2 (HR=0.65, 95%CI=0.43-0.99) and 3 (HR=0.56, 95%CI=0.36-0.89). In multivariate Cox proportional analysis, the risk of mortality decreased by 2% (HR=0.98; 95%CI=0.96-0.99) per 1 unit increase in K×UA product.

CONCLUSION

Hemodialysis patients with lower S[K] and [UA] levels were characterized by hypoalbuminemia and lower nPCR, and they were associated with a long-term mortality risk.