Fluid overload as a therapeutic target for the preservative management of chronic kidney disease:

Loop diuretics improve conditions of dialysis inception in advanced CKD: an observational cohort study

BACKGROUND

Diuretics can reduce fluid overload but their effects on conditions of dialysis start remain elusive. We aimed to determine whether loop diuretics exposure in the year before inception can delay the need for dialysis, affect the conditions of dialysis start, and cause early mortality three months after initiation in pre-dialysis patients.

METHODS

All adult patients starting dialysis from 2009 to 2015 in the REIN registry were included. Three subgroups were defined according to diuretics exposure: "continuous", "stopped", or "no diuretics" over the year before inception and compared for pre-dialysis hospitalization rates, and 3-month mortality after dialysis.

RESULTS

Among 59,302 patients, we found fewer emergency initiations of dialysis in the continuous diuretics group than in the stopped diuretics and no diuretics groups: 9492 (27.5%) vs 1905 (32.3%) and 5226 (35.0%), respectively; p < 0.0001. In the continuous diuretics group, there were fewer starts on central venous catheters than in the stopped diuretics and no diuretics groups: 16,677 (49.4%) vs. 3246 (56.0%) vs. 8,639 (58.4%); p < 0.0001. Patients with continuous diuretic exposure had a lower hospitalization rate than the stopped diuretics group in the year prior to dialysis, except for heart failure. The unadjusted 3-month hazard ratio of mortality after dialysis inception was significantly higher in the "no diuretics" or "stopped diuretics" groups compared with "continuous diuretics", but the excess of risk was blunted after adjustment for emergency start and pre-dialysis visits to a nephrologist.

CONCLUSION

Continuous loop diuretics exposure in the year before dialysis was associated with better conditions of dialysis inception, and possibly lower mortality rates in the three months after inception.

Assessment of Hydration, Nutritional Status and Arterial Stiffness in Hypertensive Chronic Kidney Disease Patients

The aim of this cross-sectional study was to determine the body fluid volume in patients diagnosed with both chronic kidney disease (CKD) and arterial hypertension (AH), and to investigate the relationship between fluid overload (FO), nutritional status and arterial stiffness in this specific patient population. A total of 169 participants with CKD and AH were enrolled in the study, and data on general parameters, comorbidities, medication use, and laboratory parameters were collected. Body composition was assessed with a Tanita MC 780 device, and data on the central and peripheral systolic and diastolic blood pressure, as well as pulse wave velocity (PWV) and the augmentation index (AIx) were collected with an IEM Mobil-O-Graph 24 h ambulatory blood pressure monitor, which was based on oscillometry. The Mediterranean Diet Serving Score (MDSS) questionnaire was used to determine the adherence to the Mediterranean diet (MeDi). Our results showed that the significant positive predictors of hydration status were the use of diuretics and oral hypoglycemic agents, whereas the negative predictors were female sex, higher body mass index level and use of two or more antihypertensives in the form of a single-pill combination. We also found differences in blood pressure and arterial stiffness parameters in relation to volume status, along with differences based on the presence of diabetes mellitus (DM). In conclusion, these results call for a higher awareness of volume status in the care of CKD patients with AH, especially in those with diabetes mellitus.

Natriuretic peptides, extracellular volume, and subclinical cardiovascular changes in chronic kidney disease stages 1-3: a pilot study

Natriuretic peptide levels are elevated in persons with chronic kidney disease (CKD) stages 1-3, but it remains unclear whether this is associated with extracellular volume excess or early cardiovascular changes. We hypothesized that patients with CKD stages 1-3 would have evidence of cardiovascular changes, which would associate with brain natriuretic peptide (BNP), amino-terminal-pro-BNP (NT-pro-BNP), and patient-reported symptoms.Outpatients with CKD stages 1-3 and non-CKD controls were enrolled. Cardiovascular parameters included extracellular water (ECW) normalized to body weight measured using whole-body multifrequency bioimpedance spectroscopy, and total peripheral resistance index (TPRI) and cardiac index measured by impedance cardiography. Dyspnea, fatigue, depression, and quality of life were quantified using questionnaires.Among 21 participants (13 with CKD), median (IQR) BNP was 47.0 (28.0-302.5) vs 19.0 (12.3-92.3) pg/mL, p=0.07, and NT-pro-BNP was 245.0 (52.0-976.8) vs 26.0 (14.5-225.8) pg/mL, p=0.08, in the CKD and control groups, respectively. Those with CKD had higher pulse pressure (79 (66-87) vs 64 (49-67) mm Hg, p=0.046) and TPRI (3721 (3283-4278) vs 2933 (2745-3198) dyn×s/cm5/m2, p=0.01) and lower cardiac index (2.28 (2.08-2.78) vs 3.08 (2.43-3.37) L/min/m2, p=0.02). In the overall cohort, natriuretic peptides correlated with pulse pressure (BNP r=0.59; NT-pro-BNP r=0.58), cardiac index (BNP r=-0.76; NT-pro-BNP r=-0.62), and TPRI (BNP r=0.48), p<0.05 for each, but not with ECW/weight. TPRI and blood pressure correlated moderately with symptoms.Elevated natriuretic peptides may coincide with low cardiac index and elevated peripheral resistance in patients with CKD stages 1-3. The role of these biomarkers to detect subclinical cardiovascular changes needs to be further explored.

Estimation of fluid status using three multifrequency bioimpedance methods in hemodialysis patients

INTRODUCTION

Segmental eight-point bioimpedance has been increasingly used in practice. However, whether changes in bioimpedance analysis components before and after hemodialysis (HD) using this technique in a standing position is comparable to traditional whole-body wrist-to-ankle method is still unclear. We aimed to investigate the differences between two eight-point devices (InBody 770 and Seca mBCA 514) and one wrist-to-ankle (Hydra 4200) in HD patients and healthy subjects in a standing position.

METHODS

Thirteen HD patients were studied pre- and post-HD, and 12 healthy subjects once. Four measurements were performed in the following order: InBody; Seca; Hydra; and InBody again. Electrical equivalent models by each bioimpedance method and the fluid volume estimates by each device were also compared.

FINDINGS

Overall, total body water (TBW) was not different between the three devices, but InBody showed lower extracellular water (ECW) and higher intracellular water (ICW) compared to the other two devices. When intradialytic weight loss was used as a surrogate for changes in ECW (∆ECW) and changes in TBW (∆TBW), ∆ECW was underestimated by Hydra (-0.79 ± 0.89 L, p < 0.01), InBody (-1.44 ± 0.65 L, p < 0.0001), and Seca (-0.32 ± 1.34, n.s.). ∆TBW was underestimated by Hydra (-1.14 ± 2.81 L, n.s.) and InBody (-0.52 ± 0.85 L, p < 0.05) but overestimated by Seca (+0.93 ± 3.55 L, n.s.).

DISCUSSION

Although segmental eight-point bioimpedance techniques provided comparable TBW measurements not affected by standing over a period of 10-15 min, the ECW/TBW ratio appeared to be significantly lower in InBody compared with Seca and Hydra. Results from our study showed lack of agreement between different bioimpedance devices; direct comparison of ECW, ICW, and ECW/TBW between different devices should be avoided and clinicians should use the same device to track the fluid status in their HD population in a longitudinal direction.

Impact of Overhydration on Left Ventricular Hypertrophy in Patients With Chronic Kidney Disease

Objective

Volume overload is a frequent feature related to left ventricular hypertrophy (LVH) in dialysis patients, but its influence on patients with chronic kidney disease (CKD) not on dialysis has not been accurately uncovered. This article was to examine the relationship between overhydration (OH) and LVH in patients with CKD not yet on dialysis.

Methods

A total of 302 patients with CKD stages 1–4 were included. Participants were divided into different subgroups according to occurring LVH or not, and OH tertiles. Clinical and laboratory parameters were compared among groups. Spearman correlation analyses were adopted to explore the relationships of echocardiographic findings with the clinical and laboratory characteristics. Binary logistic regression models were performed to estimate the odds ratios (ORs) for the associations between OH and LVH. Restricted cubic splines were implemented to assess the possible non-linear relationship between OH and LVH. LVH was defined as left ventricular mass index (LVMI) &gt;115 g/m2 in men and &gt;95 g/m2 in women.

Results

Of the enrolled patients with CKD, the mean age was 45.03 ± 15.14 years old, 165 (54.6%) cases were men, and 65 (21.5%) cases had LVH. Spearman correlation analyses revealed that OH was positively correlated with LVMI (r = 0.263, P &lt; 0.001). After adjustment for age, gender, diabetes, body mass index (BMI), systolic blood pressure (SBP), hemoglobin, serum albumin, estimated glomerular filtration rate (eGFR), and logarithmic transformation of urinary sodium and urinary protein, multivariate logistic regression analyses demonstrated that both the middle and highest tertile of OH was associated with increased odds of LVH [OR: 3.082 (1.170–8.114), P = 0.023; OR: 4.481 (1.332–15.078), P = 0.015, respectively], in comparison to the lowest tierce. Restricted cubic spline analyses were employed to investigate the relationship between OH and LVH, which unfolded a significant non-linear association (P for non-linear = 0.0363). Furthermore, patients were divided into two groups according to CKD stages. The multivariate logistic regression analyses uncovered that increased odds of LVH were observed in the middle and the highest tertile of OH [OR: 3.908 (0.975–15.670), P = 0.054; OR: 6.347 (1.257–32.054), P = 0.025, respectively] in patients with stages 1–2.

Conclusion

These findings suggest that a higher level of OH was associated with a higher occurrence of LVH in patients with CKD not on dialysis, especially in patients with CKD stages 1–2.

The Dietary Approach to the Treatment of the Rare Genetic Tubulopathies Gitelman's and Bartter's Syndromes

Gitelman’s (GS) and Bartter’s (BS) syndromes are rare, inherited autosomal recessive tubulopathies characterized by hypokalemia, metabolic alkalosis, renal sodium, chloride, and potassium and magnesium-wasting. While the treatment based on potassium, sodium, chloride, and magnesium supplementation in addition to other pharmacologic options are widely established, recommendations about the dietary approach to GS and BS still remain generic. In this review we focus on the dietary strategies to increase sodium, potassium, and magnesium intake in GS and BS patients. Potassium and magnesium-rich foods and supplements are considered together with those that may reduce through different mechanisms the potassium and magnesium plasma level. Magnesium supplementation is often poorly tolerated, causing abdominal pain and diarrhea in most patients. New formulations using liposome and, in particular, sucrosomial technology have been recently proposed for magnesium supplementation in order to increase magnesium supplement tolerability and intestinal absorption. The dietary approach to GS and BS may be very important in the therapeutic approach to these syndromes. Due to the relevance of the dietary approach to these syndromes, a nutritional counseling should always be recommended and the nutritionist should join nephrologists in the follow-up of GS and BS patient care.