On the importance of pedal edema in hemodialysis patients

Abstract

Background and objectives: Volume control is a key component of treatment of hemodialysis patients. The role of pedal edema as a marker of volume is unknown. The objective of this study was to determine factors that are associated with edema.

Design, setting, participants, & measurements: A cross-sectional study of asymptomatic hemodialysis patients (n = 146) in four university-affiliated hemodialysis units was conducted. Echocardiographic variables, blood volume monitoring, plasma volume markers (plasma renin and aldosterone and N-terminal pro B-type natriuretic peptide), and inflammation markers (C-reactive protein and IL-6) were measured as exposures, and edema was measured as outcome.

Results: In a multivariate logistic regression analysis, age, body mass index, and left ventricular hypertrophy were independent determinants of edema. Compared with patients with normal or low weight, overweight patients had odds ratio for edema of 5.7 (95% confidence interval [CI] 1.0 to 31.8), and obese patients of 44.8 (95% CI 9.0 to 223). Patients in the top quartile of left ventricular mass index and normal to low weight had odds ratio of edema of 7.7 (95% CI 2.3 -25.9), those who were overweight of 43.5 (95% CI 3.9 to 479.8), and those who were obese of 344.8 (95% CI 33.8 to 3515). Inferior vena cava diameter, blood volume monitoring, plasma volume markers, and inflammation markers were not determinants of edema.

Conclusions: Pedal edema correlates with cardiovascular risk factors such as age, body mass index, and left ventricular mass but does not reflect volume in hemodialysis patients.

Figure 1.

Dot plots of age, left ventricular mass, body mass index, and pulse pressure with home BP monitoring in relation to edema. The horizontal lines represent medians and the interquartile range.