Comparative Effectiveness between Expanded Hemodialysis (Hemodialysis Using a Medium Cut-Off Dialyzer) and Mixed-Dilution Online Hemodiafiltration Using a High-Flux Dialyzer in Removing Middle-Molecule Uremic Toxins.

INTRODUCTION: Expanded hemodialysis (HD using a medium cut-off dialyzer [HD + MCO]) provides comparable or better removal of various uremic toxins, particularly large middle-molecule uremic toxins, than post-dilution online hemodiafiltration (olHDF). Uremic toxin-removing effectiveness between HD + MCO and mixed-dilution olHDF, one of the currently most efficient olHDF modalities, has not been assessed. METHOD: This randomized controlled trial was conducted in 14 prevalent thrice-a-week HD patients with blood flow rate above 400 mL/min. The patients were randomized into two sequences of 2-week treatment periods of HD + MCO and later mixed-dilution olHDF or vice versa. The reduction ratio (RR) values of small-molecule as well as middle-molecule uremic toxins and protein-bound uremic toxins were measured at baseline and at the end of the treatment. RESULTS: When compared with mixed-dilution olHDF, HD + MCO provided slightly lower ß2M RR, but the value was still higher than 75%; showed similar κFLC RR, IS RR, and URR; and yielded significantly higher RR values of α1M (p < 0.001) and λFLC (p < 0.001). Despite higher albumin loss in HD + MCO, the serum albumin levels at the end of the study were comparable between both groups. CONCLUSION: Expanded HD (HD + MCO) provided similar effectiveness in removing various uremic toxins and could exhibit greater removal of large middle-molecule uremic toxins, such as α1M and λFLC. Expanded HD can be used as an effective alternative option for mixed-dilution olHDF.

The role of serum cystatin C in estimation of renal function in survivors of critical illness.

PURPOSE: Estimating renal function by serum creatinine after critical illness is a challenging problem. However, the role of cystatin C for estimation of the renal function in survivors of critical illness is unknown. We aimed to compare the performance of serum cystatin C- and serum creatinine-based eGFR against a reference GFR using 99mTc-diethylenetriaminepentaacetic acid (99mTc-DTPA) in survivors of critical illness. MATERIAL AND METHODS: Survivors of critical illness with stable hemodynamics and renal functions were recruited. Their serum creatinine and cystatin C levels were measured. eGFR were calculated by using various equations: 1)CKD-EPI SCysC; 2) Thai eGFR SCysC; 3)CKD-EPI SCr; 4)Thai eGFR SCr; 5)MDRD Caucasian SCr; 6)CKD-EPI SCr-SCysC. The 99mTc-DTPA plasma clearance was used as a standard eGFR. RESULTS: Forty-two patients were included. The bias (median percentage difference) between standard GFR and SCysC-based eGFR were 41.97% (95%CI 33.1% to 48.5%) for CKD-EPI SCysC and 31.72% (95%CI 21.1% to 34.9%) for Thai eGFR SCysC. While, the bias between standard GFR and SCr-based eGFR were -11.37 (95%CI -20.9 to 1.6) for CKD-EPI SCr, -18.30 (95%CI -26.3 to -10.6) for Thai eGFR SCr, and -27.17 (-43.7 to -19.1) for MDRD Caucasian SCr. CONCLUSION: In survivors of critical illness, we demonstrated limitations of estimating GFR by both currently available SCysC and SCr-based equations. Therefore, further studies are still needed to develop better eGFR equations.