Changes in the fluid volume balance between intra- and extracellular water in a sample of Japanese adults aged 15-88 yr old: a cross-sectional study.

The fluid volume balance between intracellular water (ICW) and extracellular water (ECW) gradually changes with age and various medical conditions. Comprehension of these physiological changes would aid in clinical decision-making related to body fluid assessments. A total of 1,992 individuals (753 men and 1,239 women) aged ≥15 yr included in this study had their body composition measurements performed at training gyms in 2014. We developed a regression formula to assess the association of age with the ratio of ECW to ICW in these subjects. The mean ages of male and female subjects were 51.2 ± 15.2 and 57.4 ± 15.2 yr, and their mean body mass indexes were 23.4 ± 3.3 and 21.1 ± 2.8 kg/m2, respectively. The total fluid volumes of male and female subjects were 39.6 ± 4.9 and 27.7 ± 3.0 liters, whereas the percent body fat mass per kilogram of body weight were 19 and 26%, respectively. The ECW-to-ICW ratio increased with age because of the steeper decrease in the ICW content than in the ECW content, especially after the age of 70 yr. The regression formulas used for calculating the age-adjusted ECW/ICW ratio were as follows: 0.5857 + 7.4334 × 10-6 × (age)2 in men and 0.6062 + 5.5775 × 10-6 × (age)2 in women. In conclusion, the fluid imbalance between ICW and ECW contents is driven by decreased cell volume associated with aging and muscle attenuation. Therefore, our proposed formula may serve as a useful assessment tool for the calculation of body fluid composition.

Association between Low Dietary Protein Intake and Geriatric Nutrition Risk Index in Patients with Chronic Kidney Disease: A Retrospective Single-Center Cohort Study.

Reduced dietary protein intake in malnourished patients with chronic kidney disease (CKD) may be associated with adverse clinical outcomes, which may mask any efficacy of a low-protein diet. The study included 126 patients with CKD who attended a dedicated dietary counseling clinic in 2005-2009 and were systematically followed until January 2015. Of these patients, 20 (15.9%) had moderate or severe nutrition-related risk of geriatric nutritional risk index (GNRI) < 92; these patients were more likely to be older, have a greater proteinuria, and have lower body mass index and serum albumin concentration. Dietary protein intake was significantly lower in older patients (r = -0.33, p < 0.001) and those with lower glomerular filtration rate (r = 0.47, p < 0.001). The non-protein to nitrogen calorie ratio was independently associated with GNRI. Reduced GNRI was significantly associated with mortality (hazard ratio (HR) = 4.94; 95% confidence interval (CI) = 1.61-15.42, p = 0.012) and cardiovascular events (HR = 9.37; 95% CI = 2.49-37.34, p = 0.006), but not with adverse renal outcomes. Restricting protein intake may be harmful to patients with any nutrition-related risk, suggesting that improvement of nutritional status should be a high priority.

Brain Natriuretic Peptide and Body Fluid Composition in Patients with Chronic Kidney Disease: A Cross-Sectional Study to Evaluate the Relationship between Volume Overload and Malnutrition.

BACKGROUND/AIM: Fluid volume overload occurs in chronic kidney disease (CKD), leading to the compensatory release of natriuretic peptides. However, the elevated cardiac peptides may also be associated with malnutrition as well as volume overload. METHODS: Body fluid composition was measured in 147 patients with CKD between 2009 and 2015, and its relationship to brain natriuretic peptide (BNP) levels was examined. Body fluid composition was separated into three components: (a) a water-free mass consisting of muscle, fat, and minerals; (b) intracellular water (ICW) content, and (c) extracellular water (ECW) content. Excess fluid mass was calculated using Chamney's formula. RESULTS: The measured BNP levels in the tertile groups were 10.9 ± 5.4, 36.3 ± 12.5, and 393 ± 542 pg/ml, respectively. Patients in a higher log-transformed BNP level tertile were more likely to be older, to have a higher frequency of cardiac comorbidities, pulse pressure, C-reactive protein levels, and proteinuria, and to have lower serum sodium, kidney function, and serum albumin (p < 0.05). In body fluid composition, decreased body mass was significantly associated with the ECW-to-ICW ratio in relation to the downward ICW slope (r = -0.235, p = 0.004) and was strongly correlated with excess fluid mass (r = -0.701, p < 0.001). The ECW-to-ICW ratio and excess fluid mass was independently associated with the BNP levels. CONCLUSION: Fluid volume imbalance between intra- and extracellular water regulated by decreased cell mass was independently associated with BNP levels, which may explain the reserve capacity for fluid accumulation in patients with CKD.

Association between ratio of measured extracellular volume to expected body fluid volume and renal outcomes in patients with chronic kidney disease: a retrospective single-center cohort study.

BACKGROUND: Excess extracellular volume is a major clinical problem in patients with chronic kidney disease (CKD). However, whether the extracellular volume status is associated with disease progression is unclear. We investigated the association between the extracellular volume status and renal outcomes. METHODS: We performed a retrospective cohort study of 149 patients with CKD who underwent bioelectrical impedance analysis (BIA) from 2005 to 2009. Patients were categorized according to tertiles of extracellular volume status. The extracellular volume status was assessed by examining the ratio of extracellular water measured by BIA (ECWBIA) to the total body water calculated using the Watson formula (TBWWatson). The main outcomes were adverse renal outcomes as defined by a decline of ≥50% from the baseline glomerular filtration rate or initiation of renal replacement therapy. RESULTS: A higher %ECWBIA/TBWWatson ratio tended to be associated with older age, male sex, diabetes mellitus, resistant hypertension, lower renal function, lower serum albumin levels, higher proteinuria levels, and a higher frequency of furosemide use. In the multivariate analysis, proteinuria remained independently associated with the %ECWBIA/TBWWatson ratio. Both the intracellular and extracellular water volumes decreased with age (correlation between ICW and age, r=-0.30, P<0.001; correlation between ECW and age, r=-0.17, P=0.03). Consequently, the %ECWBIA in the body fluid composition increased with age. During a median follow-up of 4.9 years, patients in the highest tertile of the %ECWBIA/TBWWatson ratio were at greater risk of adverse renal outcomes (16.6 per 100.0 patient years) than were those in the lowest tertile (8.1 per 100.0 patient years) or second tertile (5.6 per 100.0 patient years) (log-rank P=0.005). After adjustment for covariates, the %ECWBIA/TBWWatson ratio was significantly associated with adverse renal outcomes (hazard ratio, 1.21; 95 % confidence interval, 1.10-1.34; P<0.001). CONCLUSIONS: The ECWBIA/TBWWatson ratio was independently associated with adverse renal outcomes. Proteinuria was independently associated with the extracellular volume status. The balance between ICW and ECW changes with age in that the percentage of ECW content in the body fluid composition increases. Elderly patients with CKD may thus be susceptible to volume overload.

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.

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. DESIGN, SETTING, AND SUBJECTS: 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.

Associations of proteinuria, fluid volume imbalance, and body mass index with circadian ambulatory blood pressure in chronic kidney disease patients.

BACKGROUND/AIMS: Obesity and hypervolemic status are the main causes of hypertension in patients with chronic kidney disease (CKD). However, it is difficult to differentiate between them. We aimed to assess the associations of body mass index (BMI) and total body water (TBW) with ambulatory blood pressure (ABP). METHODS: Body composition by bioelectrical impedance analysis (BIA) and 24-h ABP were measured in 40 patients with CKD. TBW was assessed using corrected TBWBIA adjusted for body surface area (cTBWBIA) and the TBWBIA/TBWWatson ratio obtained using an anthropometric formula (Watson). RESULTS: Elevated ABP (average 24-h BP ≥ 135/85 mmHg) was noted in 23 patients, who were more likely to have a higher cTBWBIA and TBWBIA/TBWWatson ratio than patients without elevated BP. Patients with nocturnal non-dipping (<10% drop in BP during sleep) were more likely to have a higher TBWBIA/TBWWatson ratio. Proteinuria and the TBWBIA/TBWWatson ratio were significant independent factors for 24-h ABP. BMI had a positive correlation with the cTBWBIA, TBWBIA/TBWWatson ratio and furosemide use. CONCLUSION: Hypertension is dependent on proteinuria and fluid volume imbalance. The TBWBIA/TBWWatson ratio can serve as an indicator of fluid volume-dependent hypertension. BMI is affected by TBW, in which case BMI can become less involved with 24-h ABP.

Effluent markers related to epithelial mesenchymal transition with adjusted values for effluent cancer antigen 125 in peritoneal dialysis patients.

Objectives. Epithelial mesenchymal transition (EMT) is important for peritoneal deterioration. We evaluated the association between peritoneal solute transport rate (PSTR) and effluent markers related to EMT with adjusted values for effluent cancer antigen 125 (CA125). Methods. One hundred five incident peritoneal dialysis (PD) patients on PD for 25 (12-68) months with biocompatible solutions were included in the study. Fast peritoneal equilibration test was used to evaluate PSTR. Effluent hepatocyte growth factor (HGF), bone morphogenic protein-7 (BMP-7), vascular endothelial growth factor (VEGF), interleukin-6 (IL-6), and CA125 at 4 h were measured. Results. Patients with dialysate/plasma creatinine ≧0.82 showed significantly higher effluent HGF (240 versus 133 pg/mL, P < .001), VEGF, IL-6, and IL6/CA125 levels than the others but no significant differences in effluent HGF/CA125, BMP-7, and BMP7/CA125 were observed. Conclusion. Increase in the effluent HGF levels as a compensatory mechanism is a marker of peritoneal deterioration, but controversy remains regarding adjusted value for CA125.