title: Assessment of body composition using dry mass index and ratio of total body water to estimated volume based on bioelectrical impedance analysis in chronic kidney disease patients.
abstract: OBJECTIVE
  Body mass index (BMI) is commonly used for assessment of nutritional status. However, changes in BMI in chronic kidney disease (CKD) patients are affected not only by muscle and fat but also by fluid volume. The ratio of extracellular water (ECW(BIA)) to total body water (TBW(BIA)) in multifrequency bioelectrical impedance analysis is commonly used for assessing abnormal fluid status. This study reexamines ECW(BIA)/TBW(BIA) and evaluates the reliability of TBW(BIA)/TBW(watson) and dry mass index (DMI) in the assessment of fluid and nutritional status.
  
  
  METHODS
  TBW(BIA), intracellular water (ICW(BIA)), and ECW(BIA) were measured in 45 randomly selected CKD patients. Participants were surveyed for age, gender, BMI, blood pressure, serum albumin, estimated glomerular filtration rate, and proteinuria. DMI was calculated by the formula ([weight--TBW(BIA)]/height(2)) and TBW(BIA)/TBW(watson) using an anthropometric formula (Watson). Fluid and nutritional status were assessed using ECW(BIA)/TBW(BIA), TBW(BIA)/TBW(watson), and DMI.
  
  
  RESULTS
  TBW(BIA)/TBW(watson) positively correlated with weight, BMI, and diastolic blood pressure and negatively correlated with age and serum albumin level. In contrast, ECW(BIA)/TBW(BIA) correlated with ICW deficit, aging, and body weight loss. On the basis of DMI and TBW(BIA)/TBW(watson), participants were categorized as follows: 1 obese patient with hypovolemia and 2 with euvolemia; 17 overweight patients with hypovolemia (n = 6), euvolemia (n = 8), or hypervolemia (n = 3); 24 patients of optimal weight with hypovolemia (n = 10), euvolemia (n = 9), or hypervolemia (n = 5); and 1 underweight patient with euvolemia.
  
  
  CONCLUSIONS
  A combination of DMI, BMI, and TBW(BIA)/TBW(watson) makes it possible to include assessment of fluid volume to the physique index. In addition, ECW(BIA)/TBW(BIA) is not a reliable marker of edematous state in CKD patients.
authors.affiliation: Department of Nephrology, Toho University School of Medicine, Tokyo, Japan. ys-0084@med.toho-u.ac.jp
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Ohashi
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Otani
authors.forename: Reibin
authors.initials: R
authors.lastname: Tai
authors.forename: Yoshihide
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Ken
authors.initials: K
authors.lastname: Sakai
authors.forename: Atsushi
authors.initials: A
authors.lastname: Aikawa
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure; D001823:Body Composition; D015992:Body Mass Index; D001834:Body Water / Q000378:metabolism; D001835:Body Weight; D017097:Electric Impedance; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009752:Nutritional Status; D011507:Proteinuria / Q000503:physiopathology; D051436:Renal Insufficiency, Chronic / Q000503:physiopathology*; D015203:Reproducibility of Results; D012709:Serum Albumin / Q000032:analysis; D014883:Water-Electrolyte Imbalance / Q000503:physiopathology
chemical_list: D012709:Serum Albumin