Mortality and Low Serum Bicarbonate Level in Patients on Hemodiafiltration versus Peritoneal Dialysis

Relationship Between Serum Total Carbon Dioxide Concentration and Bicarbonate Concentration in Patients Undergoing Peritoneal Dialysis

Background

Few studies have assessed the relationship between serum total carbon dioxide (CO₂) and bicarbonate ion (HCO₃⁻) concentration in patients undergoing peritoneal dialysis. We determined the agreement between serum total CO₂ and HCO₃⁻ concentration and the diagnostic accuracy of serum total CO₂ for the prediction of low (HCO₃⁻ <24 mEq/L) and high (HCO₃⁻ ≥24 mEq/L) bicarbonate concentrations in patients on peritoneal dialysis.

Methods

We collected 245 samples of venous blood from 51 patients on peritoneal dialysis. Independent factors that correlated with the HCO₃⁻ concentration were analyzed using multiple linear regression analysis. The diagnostic accuracy of serum total CO₂ was evaluated by receiver operating characteristic (ROC) curve analysis and a 2×2 table. Agreement between serum total CO₂ and HCO₃⁻ concentration was assessed by Bland-Altman analysis.

Results

Serum total CO₂ was independently correlated with HCO₃⁻ concentration (β = 0.354, p < 0.001). The area under the curve of serum total CO₂ for the identification of low and high bicarbonate concentrations was 0.909. The diagnostic accuracy of serum total CO₂ for the prediction of low and high bicarbonate concentrations was: sensitivity, 91.5%; specificity, 74.7%; positive predictive value, 53.5%; negative predictive value, 96.5%; and accuracy, 78.8%. Bland-Altman analysis showed a moderate agreement between serum total CO₂ and HCO₃⁻ concentration.

Conclusion

Serum total CO₂ correlated closely with the HCO₃⁻ concentration in patients undergoing peritoneal dialysis. Serum total CO₂ might be useful for predicting low and high bicarbonate in peritoneal dialysis patients.

Relationship between serum total carbon dioxide concentration and bicarbonate concentration in patients undergoing hemodialysis

Background

Few studies have investigated the relationship between serum total carbon dioxide (CO₂) concentration and bicarbonate ion (HCO₃^-) concentration in patients undergoing hemodialysis. We determined the agreement and discrepancy between serum total CO₂ and HCO₃^- concentrations and the diagnostic accuracy of serum total CO₂ for the prediction of low (HCO₃^- < 24 mEq/L) and high (HCO₃^- ≥ 24 mEq/L) bicarbonate concentrations in hemodialysis patients.

Methods

One hundred forty-nine arteriovenous blood samples from 84 hemodialysis patients were studied. Multiple linear regression analysis was used to determine factors correlated with HCO₃^- concentration. Diagnostic accuracy of serum total CO₂ was evaluated using receiver operating characteristic curve analysis and a 2 × 2 table. Agreement between serum total CO₂ and HCO₃^- concentrations was assessed using Bland-Altman analysis.

Results

Serum total CO₂ concentration was closely correlated with HCO₃^- concentration (β = 0.858, P < 0.001). Area under the curve of serum total CO₂ for the identification of low and high bicarbonate concentrations was 0.989. Use of serum total CO₂ to predict low and high bicarbonate concentrations had a sensitivity of 100%, specificity of 50.0%, positive predictive value of 96.5%, negative predictive value of 100%, and accuracy of 96.6%. Bland-Altman analysis showed moderate agreement between serum total CO₂ and HCO₃^- concentrations. Discrepancies between HCO₃^- and serum total CO₂ concentrations (serum total CO₂ - HCO₃^- ≤ -1) were observed in 89 samples.

Conclusion

Serum total CO₂ concentration is closely correlated with HCO₃^- concentration in hemodialysis patients. However, there is a non-negligible discrepancy between serum total CO₂ and HCO₃^- concentrations.

High-volume online haemodiafiltration treatment and outcome of end-stage renal disease patients: more than one mode

The reduction of the dismally high mortality of current end-stage renal disease patients maintained on conventional standard haemodialysis (HD) remains an unmet medical need. Online haemodiafiltration (HDF) modes with various sites of fluid substitution (post-, pre-, mixed- and mid-dilution) are increasingly used worldwide as promising alternatives to conventional HD. Large scale cohort studies, post hoc analyses of randomized trials, and individual participant meta-analyses suggest that post-dilution and pre-dilution, especially with high substitution volumes, improve outcomes compared with conventional standard HD. However, there is no definitive proof of a survival advantage of HDF over standard HD. The different modes of high-volume HDF should be considered a therapeutic platform allowing to personalize and tailor routine HDF treatment. The selection of the HDF mode should be made according to individual patient characteristics. Utilizing high retention onset membranes, expanded haemodialysis (HDx) can achieve the same solute removal performance as HDF. Subgroups of high-volume OL-HDF patients could benefit from HDx. Ongoing and future trials should provide definitive proof for the superiority of high-volume OL-HDF over conventional HD or HDx to give guidance for the most favourable mode of dialytic therapy for clinical use.