The effect of racial origin on total body water volume in peritoneal dialysis patients

BACKGROUND AND OBJECTIVES

Peritoneal dialysis adequacy is typically assessed by urea clearance corrected for total body water (TBW) on the basis of anthropomorphic equations, which do not readily take into account changes in body composition, which may vary between ethnic groups. To determine whether ethnicity could affect estimates of peritoneal dialysis adequacy, we compared TBW estimated by anthropomorphic equations and that measured by multifrequency bioimpedance spectroscopy.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We calculated TBW in 600 healthy adult peritoneal dialysis outpatient attending two tertiary university hospitals serving an inner-city multiethnic population who had TBW measured by multifrequency bioimpedance spectroscopy performed.

RESULTS

600 adult peritoneal dialysis patients were studied: mean age, 56.7 ± 0.6 years; 54.2% men; 29.7% diabetic; mean body mass index, 26.1 ± 0.2; 47.3% Caucasian; 29.2% South Asian; 12.8% African/Afro-Caribbean. Total body water was calculated using several anthropomorphic equations and was higher than that calculated MEASURED BY MF-BIS for all ethnic groups, apart from African/Afro-Caribbeans, with the greatest difference between Watson calculated TBW and multifrequency bioelectrical impedance spectroscopy 12.3 ± 0.6% for the South Asians, 9.0 ± 2.6% for Far Eastern Asians, 2.8 ± 0.6% Caucasians, and -0.2 ± 1.5% for African/Afro-Caribbeans.

CONCLUSIONS

In this United Kingdom-based multiethnic population, body composition differed particularly for the South Asian patients compared with Caucasians and African/Afro-Caribbeans. Overestimation of TBW by anthropomorphic-based equations would lead to a lower calculation of Kt/V(urea), which may lead to changes in peritoneal dialysis prescription to achieve clinical standard targets and also affect studies examining the relationship between Kt/V and survival.

Catheter access for hemodialysis defines higher mortality in late-presenting dialysis patients

BACKGROUND

This study explores the relationship between mortality and late presentation for dialysis, focusing on the role of catheter access for hemodialysis (HD).

METHODS

We analyzed data from a cohort of 286 patients commencing dialysis in 2000-2001. Survival and factors associated with death were analyzed by univariate and multivariate analysis. Dialysis access was considered in three groups: HD-AVF, HD-Catheter, and peritoneal dialysis (PD). Late referral (LR) was defined as first review by a nephrologist less than 90 days before dialysis.

RESULTS

One-year mortality was low at 10.1%. HD-Catheter patients were older (p < 0.001), more hypoalbuminemic (p < 0.001), more anemic (p = 0.005), and more likely to be LR (p < 0.001). HD-Catheter patients did not have significantly higher comorbidity (p = 0.128). HD-Catheter was strongly associated with late presentation (75% LR vs. 28% early referral, p < 0.001). Factors associated with death by univariate analysis included age (p < 0.0001), comorbidity (p < 0.0001), HD-Catheter (p < 0.0001), LR (p = 0.0001), hypoalbuminemia (p = 0.0011), and diabetes (p = 0.02). When corrected for these factors, HD-Catheter was associated with death (HR 2.226, 95% CI 1.314-3.772, p = 0.003) but LR was not (p = 0.38).

CONCLUSIONS

A predominant feature of LR that predicts mortality is the use of catheter access for HD. This may be modifiable in those LR patients who do not present as uremic emergencies.