Using relative OH ≥7% as the threshold of volume overload, we found a prevalence of hemodilution of 63% in the anemic ND-CKD population.
Volume overload, as assessed by bioimpedance spectroscopy devices, has been recognized as an important
contributor to the poor cardiovascular or renal outcomes in hemodialysis and ND-CKD patients.
In addition to the deleterious effects of high blood pressure, circumferential stretch from fluid retention activates endothelial cells, resulting in an increase in proinflammatory cytokines.
In the present study, anemic patients with excess OH had significantly higher levels of interleukin-6 compared with those with true anemia.
Accumulating evidence has shown that inflammation contributes to both the development of CVD and the progression of CKD.
The interaction among hemodilution, CVD, and CKD progression is complex. In our study, patients with hemodilution had a higher proportion of comorbid conditions including diabetes mellitus and CVD, which might confound the association between hemodilution and clinical outcomes.
After adjustment for potential confounders, hemodilution remained an independent predictor of the adverse outcomes. Our findings have important clinical implications, suggesting that a concomitant meticulous correction of volume overload can be considered to be incorporated into the treatment for CKD anemia.
However, our observational study was not able to establish causality, and we caution against translating the results of our study into therapeutic practice.
Future therapeutic trials of CKD anemia should attempt to characterize the patients’ fluid status.