Changes in waist circumference following haemodialysis: a brief report

BACKGROUND

Waist circumference (WC) is a known indicator of cardiovascular disease in the haemodialysis (HD) population. However it is not known if HD results in clinically significant changes in WC.

OBJECTIVE

The study purpose was to quantify the degree of change in WC induced by HD.

METHODS

This was a prospective cohort study with 27 patients on HD. Height, body weight, WC, hip circumference (HC), body mass index (BMI) and waist to hip ratio (WHR) were measured immediately prior to and following HD over three consecutive treatments. Differences between three-day average pre- and post-HD weight, BMI, WC, HC and WHR were assessed.

RESULTS

Post-HD WC was significantly lower than that measured pre-HD. Differences in pre-post HD body weight, BMI, HC and WHR were also observed.

CONCLUSIONS

All of the traditional clinical indicators of body composition (WC, HC, WHR, body weight and BMI) were lower following HD.

New method of predicting dry weight using bioelectrical impedance analysis in haemodialysis patients

AIM

There were significant differences in the slopes of the ultrafiltration (UF) amount removed during haemodialysis (HD) sessions versus the percentage change in the extracellular fluid/total body water ratio for the right lower extremity (ECF/TBW(right leg)) plot in normohydrated (NH) and overhydrated states. The purpose of this study was to develop and validate a method for predicting dry weight (DW) using these results.

METHODS

It was hypothesized that for patients to become NH, the slope of the UF amount versus the percentage changes in ECF/TBW(right leg) plot should be same as that of NH patients and a method for predicting DW was developed. To validate the accuracy of this method, the ECF/TBW(right leg) was measured by eight-point tactile-electrode bioelectrical impedance analysis before and after HD in 17 newly enrolled NH patients. Using the current DW (cDW) of subjects as a reference, we compared the accuracies of pDW1 (our devised method) and pDW2 (the normovolaemia/hypervolaemia slope method).

RESULTS

The mean cDW, pDW1 and pDW2 values were 56.8 +/- 7.9, 56.4 +/- 7.7 and 56.3 +/- 8.0 kg, respectively. No significant differences existed between cDW, pDW1 and pDW2. pDW1 had a lower root mean square error than pDW2 (1.12 vs 1.69). On the Bland-Altman plot, differences between pDW1 and cDW were closer to zero than between pDW2 and cDW.

CONCLUSION

A new method was developed of predicting the DW using the relationship between the UF amount and the percentage change in the ECF/TBW ratio of the lower extremities after HD. The devised method appears to be as accurate as the normovolaemia/hypervolaemia slope method.