Volume overload correlates with cardiovascular risk factors in patients with chronic kidney disease

Volume overload is a predictor of mortality in dialysis patients. However, the fluid status of patients with chronic kidney disease (CKD) but not yet on dialysis has not been accurately characterized. We used the Body Composition Monitor, a multifrequency bioimpedance device, to measure the level of overhydration in CKD patients, focusing on the association between overhydration and cardiovascular disease risk factors. Overhydration was the difference between the amount of extracellular water measured by the Body Composition Monitor and the amount of water predicted under healthy euvolemic conditions. Volume overload was defined as an overhydration value at and above the 90th percentile for the normal population. Of the 338 patients with stages 3-5 CKD, only 48% were euvolemic. Patients with volume overload were found to use significantly more antihypertensive medications and diuretics but had higher systolic blood pressures and an increased arterial stiffness than patients without volume overload. In a multivariate analysis, male sex, diabetes, pre-existing cardiovascular disease, systolic blood pressure, serum albumin, TNF-α, and proteinuria were independently all associated with overhydration. Thus, volume overload is strongly associated with both traditional and novel risk factors for cardiovascular disease. Bioimpedance devices may aid in clinical assessment by helping to identify a high-risk group with volume overload among stages 3-5 CKD patients.