Body composition, hydration, and related parameters in hemodialysis versus peritoneal dialysis patients.

AIMS

Maintaining euvolemia is an important goal in patients on renal replacement therapy. However, adequate assessment of volume status in clinical practice is hampered by a lack of accurate measuring tools. A new multifrequency bioimpedance tool has recently been validated. This study compares volume status in peritoneal dialysis (PD) and hemodialysis (HD) patients in a single center.

METHODS

Body Composition Monitoring (BCM; Fresenius Medical Care, Bad Homburg, Germany) was performed in all patients on PD or HD without contraindication. PD patients were measured with a full abdomen; HD patients were measured at the midweek session, once immediately before and once 20 minutes after dialysis. Clinical overhydration was defined as an overhydration-to-extracellular water ratio of >0.15.

RESULTS

Total body water, extracellular water, and intracellular water were 33.7 +/- 6.9 L versus 31.8 +/- 8.1 L vs 33.9 +/- 6.7 L, 16.4 +/- 3.9 L vs 15.3 +/- 4.9 L vs 16.8 +/- 3.3 L, and 17.1 +/- 6.2 L vs 16.5 +/- 4.6 L vs 17.2 +/- 3.9 L in the pre-HD, post-HD, and PD patients, respectively (p = NS). In the pre-HD and the PD patients, overhydration was 1.9 +/- 1.7 L and 2.1 +/- 2.3 L, whereas post-HD this was only 0.6 +/- 1.7 L (p < 0.001). Clinical overhydration was more prevalent in pre-HD and PD patients compared to post-HD patients (24.1% vs 22.3% vs 10%, p < 0.001). In multivariate models, overhydration was related to age, male gender, and post-HD status.

CONCLUSION

Although much clinical attention is paid to volume status, 24% of patients still have clinically relevant volume overload. Implementation of a reliable and clinically applicable tool to assess volume status is therefore necessary. It is possible to obtain comparable volume status in PD and HD patients.