Effect of Strict Volume Control on Renal Progression and Mortality in Non-Dialysis-Dependent Chronic Kidney Disease Patients: A Prospective Interventional Study

The Effect of Health Literacy on Patient Outcomes in Stage 3b-4 Pre-Dialysis Patients: A Semi-Experimental Study

This study was conducted to investigate the effect of health literacy on patient outcomes in pre-dialysis patients. A semi-experimental study. The study was conducted with 45 intervention and 45 control patients with glomerular filtration rates between 15-44ml/min/1.73m2. The adequate health literacy of the patients in the intervention group increased from 2.2% to 31.1%. Increased health literacy led to a significant decrease in systolic and diastolic blood pressure values and the severity of symptoms. The study showed that increased health literacy in pre-dialysis patients improves patient outcomes. Nursing care is needed in pre-dialysis.

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.

A nationwide cohort study comparing the effectiveness of diuretics and calcium channel blockers on top of renin-angiotensin system inhibitors on chronic kidney disease progression and mortality

It is unknown whether initiating diuretics on top of renin-angiotensin system inhibitors (RASi) is superior to alternative antihypertensive agents such as calcium channel blockers (CCBs) in patients with chronic kidney disease (CKD). For this purpose, we emulated a target trial in the Swedish Renal Registry 2007-2022 that included nephrologist-referred patients with moderate-advanced CKD and treated with RASi, who initiated diuretics or CCB. Using propensity score-weighted cause-specific Cox regression, we compared risks of major adverse kidney events (MAKE; composite of kidney replacement therapy [KRT], experiencing over a 40% eGFR decline from baseline, or an eGFR under 15 ml/min per 1.73m2), major cardiovascular events (MACE; composite of cardiovascular death, myocardial infarction or stroke), and all-cause mortality. We identified 5875 patients (median age 71 years, 64% men, median eGFR 26 ml/min per 1.73m2), of whom 3165 started a diuretic and 2710 a CCB. After a median follow-up of 6.3 years, 2558 MAKE, 1178 MACE and 2299 deaths occurred. Compared to CCB, diuretic use was associated with a lower risk of MAKE (weighted hazard ratio 0.87 [95% confidence interval: 0.77-0.97]), consistent across single components (KRT: 0.77 [0.66-0.88], over 40% eGFR decline: 0.80 [0.71-0.91] and eGFR under 15ml/min/1.73m2: 0.84 [0.74-0.96]). The risks of MACE (1.14 [0.96-1.36]) and all-cause mortality (1.07 [0.94-1.23]) did not differ between therapies. Results were consistent when modeling the total time drug exposure, across sub-groups and a broad range of sensitivity analyses. Thus, our observational study suggests that in patients with advanced CKD, using a diuretic rather than a CCB on top of RASi may improve kidney outcomes without compromising cardioprotection.

Bioimpedance-Guided Monitoring of Volume Status in Patients With Kidney Disease: A Systematic Review and Meta-Analysis

Background and Objective

Bioimpedance technologies are increasingly used to determine fluid status in patients with chronic kidney disease and those with end-stage kidney disease on dialysis. We aimed to determine whether this technology improves clinical outcomes as compared with usual care.

Methods

We performed a systematic review and meta-analysis of trials, comparing fluid management guided by bioimpedance technologies to standard of care in patients with chronic kidney disease. Our primary outcome was all-cause mortality. Secondary outcomes included blood pressure control, all-cause hospitalization, major adverse cardiovascular events, and change in left ventricular mass index.

Results

Our search identified 819 citations of which 12 randomized controlled trials were included (2420 patients). No studies of non-dialysis-dependent chronic kidney disease patients met inclusion criteria. Mean age was 55 years and mean follow-up was 1 year. There was a statistically significant difference in all-cause mortality between both arms studied (risk ratio [RR] 0.64, 95% confidence interval [CI]: 0.44, 0.99). Better blood pressure control was observed in the bioimpedance arm of the included articles, weighted mean differences (WMD) -3.13 mm Hg (95% CI: -5.73, -0.53 mm Hg) for systolic blood pressure and WMD -2.50 mm Hg (95% CI: -4.36, -0.64 mm Hg) for diastolic blood pressure. No difference was observed concerning the other outcomes.

Conclusions

Among patients on maintenance dialysis, bioimpedance-guided volume management showed decreased all-cause mortality and blood pressure but no significant difference in all-cause hospitalization, major adverse cardiac event, or change in left ventricular mass index. This may be due to a younger population sample than previous articles. Moreover, our study identified a knowledge gap by highlighting the lack of studies evaluating this technology in non-dialysis-dependent chronic kidney disease patients.

Bioimpedance Indices of Fluid Overload and Cardiorenal Outcomes in Heart Failure and Chronic Kidney Disease: a Systematic Review

BACKGROUND

Bioimpedance-based estimates of fluid overload have been widely studied and systematically reviewed in populations of those undergoing dialysis, but data from populations with heart failure or nondialysis chronic kidney disease (CKD) have not.

METHODS AND RESULTS

We conducted a systematic review of studies using whole-body bioimpedance from populations with heart failure and nondialysis CKD that reported associations with mortality, cardiovascular outcomes and/or CKD progression. We searched MEDLINE, Embase databases and the Cochrane CENTRAL registry from inception to March 14, 2022. We identified 31 eligible studies: 20 heart failure and 11 CKD cohorts, with 2 studies including over 1000 participants. A wide range of various bioimpedance methods were used across the studies (heart failure: 8 parameters; CKD: 6). Studies generally reported positive associations, but between-study differences in bioimpedance methods, fluid overload exposure definitions and modeling approaches precluded meta-analysis. The largest identified study was in nondialysis CKD (Chronic Renal Insufficiency Cohort, 3751 participants), which reported adjusted hazard ratios (95% confidence intervals) for phase angle < 5.59 vs ≥ 6.4 of 2.02 (1.67-2.43) for all-cause mortality; 1.80 (1.46-2.23) for heart failure events; and 1.78 (1.56-2.04) for CKD progression.

CONCLUSIONS

Bioimpedance indices of fluid overload are associated with risk of important cardiorenal outcomes in heart failure and CKD. Facilitation of more widespread use of bioimpedance requires consensus on the optimum device, standardized analytical methods and larger studies, including more detailed characterization of cardiac and renal phenotypes.

Identification of fluid overload in elderly CKD Patients using bioimpedance techniques

Diagnosis of fluid overload (FO) in early stage is essential to manage chronic kidney disease (CKD) patients' fluid balance and to prevent cardiovascular disease (CVD). However, identification of fluid status in CKD patient is largely dependent on physician's clinical acumen. The ratio of fluid overload to extracellular volume (FO/ECV) has been used as a reference to assess fluid status. The primary aim of this study was to compare FO/ECV with other bioimpedance methods and clinical assessment in CKD patients. Whole body ECV, intracellular volume (ICV), total body water (TBW) and calf normalized resistivity (CNR) were measured (Hydra 4200). Thresholds of FO utilizing CNR and ECV/TBW were derived by receiver operator characteristic (ROC) analysis based on data from pooled CKD patients and healthy subjects (HS). Clinical assessments of FO in CKD patients were performed by nephrologists . CKD (stage 3 and stage 4) patients (n=50) and HS (n=189) were studied. The thresholds of FO were ≤ 14.3 (10^-2 Ωm³/kg) for females and ≤ 13.1 (10^-2 Ωm³/kg) for males using CNR and ≥ 0.445 in females and ≥ 0.434 in males using ECV/TBW. FO was diagnosed in 78%, 62% and 52% of CKD patients by CNR, FO/ECV and ECV/TBW, respectively while only 24% of CKD patients were diagnosed to be FO by clinical assessment . The proportion of FO in non-dialysis CKD patients was largely underestimated by clinical assessment compared to FO/ECV, CNR and ECV/TBW. CNR, and FO/ECV methods were more sensitive than ECV/TBW in identifying fluid overload in these CKD patients.

Estimated Glomerular Filtration Rate in Chronic Kidney Disease: A Critical Review of Estimate-Based Predictions of Individual Outcomes in Kidney Disease

Chronic kidney disease (CKD) is generally regarded as a final common pathway of several renal diseases, often leading to end-stage kidney disease (ESKD) and a need for renal replacement therapy. Estimated GFR (eGFR) has been used to predict this outcome recognizing its robust association with renal disease progression and the eventual need for dialysis in large, mainly cross-sectional epidemiological studies. However, GFR is implicitly limited as follows: (1) GFR reflects only one of the many physiological functions of the kidney; (2) it is dependent on several non-renal factors; (3) it has intrinsic variability that is a function of dietary intake, fluid and cardiovascular status, and blood pressure especially with impaired autoregulation or medication use; (4) it has been shown to change with age with a unique non-linear pattern; and (5) eGFR may not correlate with GFR in certain conditions and disease states. Yet, many clinicians, especially our non-nephrologist colleagues, tend to regard eGFR obtained from a simple laboratory test as both a valid reflection of renal function and a reliable diagnostic tool in establishing the diagnosis of CKD. What is the validity of these beliefs? This review will critically reassess the limitations of such single-focused attention, with a particular focus on inter-individual variability. What does science actually tell us about the usefulness of eGFR in diagnosing CKD?

Correlation of Kidney Size on Computed Tomography with GFR, Creatinine and HbA1C for an Accurate Diagnosis of Patients with Diabetes and/or Chronic Kidney Disease

Diabetes is considered one of the major causes of chronic kidney disease (CKD), affecting renal blood vessels and nerves. Diagnosis of CKD by traditional biochemical serum and blood analyses is insufficient and insensitive, thus requiring the development of a more robust technique. This novel study aims to propose a new method for the accurate diagnosis of CKD, quantification of kidney damage, and its prognosis by physicians by measuring the kidney volume on computed tomography (CT). In total, 251 patients were enrolled in this retrospective study. They were divided into four groups: control, patients having diabetes, patients having CKD, and patients having both diabetes and CKD. Results showed that kidney volume correlated negatively with both GFR and HbA1C on CT images, in addition to decreasing faster in males than females. Moreover, HbA1C was shown to correlate positively with creatinine and negatively with GFR. Finally, GFR was more robust than creatinine when correlated with age. The association between kidney volume with GFR and HbA1c can be used to accurately anticipate kidney volume in established CKD on CT scan, especially in resource-poor settings. Furthermore, HbA1C can serve as a powerful biomarker for studying renal function in diabetic CKD patients as it correlates with creatinine and GFR.

Association of overhydration and serum pigment epithelium-derived factor with CKD progression in diabetic kidney disease: A prospective cohort study

AIM

Little is known about whether overhydration (OH), measured using bioimpedance assay (BIA), is associated with CKD progression in patients with type 2 diabetes mellitus (T2DM). We hypothesised that OH was a predictor, and pigment epithelium-derived factor (PEDF) was a modifiable risk factor of CKD progression.

METHODS

We conducted a prospective cohort study of 1,065 patients with clinically euvolemic T2DM who attended the diabetes centre in a tertiary hospital or primary care clinic. CKD progression was defined as a combination of the worsening of the KDIGO defined CKD category by eGFR and a ≥25% decline in eGFR compared to baseline.

RESULTS

Patients with T2DM in the highest tertile of OH and relative OH (OH/ extracellular water > 7%) were positively associated with CKD progression (hazard ratio [HR] 1.45 [95% confidence interval (CI) 1.14-1.85; p = 0.003 and HR 1.29 [95%CI 1.05-1.59; p = 0.017]). There were positive associations between PEDF and CKD progression (β = 1.10; p = 0.001) and between OH and CKD progression (β = 0.21; p = 0.036). OH remained positively associated with CKD progression mediated by PEDF.

CONCLUSIONS

OH is an independent risk factor for CKD progression in patients with T2DM. Our study supports the novel definition of PEDF as a positive mediator between OH and CKD progression.

Trajectory of extracellular fluid volume over time and subsequent risks of end-stage kidney disease and mortality in chronic kidney disease: a prospective cohort study

BACKGROUND

Extracellular fluid volume (ECF) is independently associated with chronic kidney disease (CKD) progression and mortality in patients with CKD, but the prognostic value of the trajectory of ECF over time beyond that of baseline value is unknown.

OBJECTIVES

To characterize ECF trajectory and evaluate its association with the risks of end-stage kidney disease (ESKD) and mortality.

METHODS

From the prospective tricentric NephroTest cohort, we included 1588 patients with baseline measured glomerular filtration rate (mGFR) ≥15 mL min^-1 /1.73 m² and ECF measurement. ECF and GFR were measured repeatedly using the distribution volume and clearance of ⁵¹ Cr-EDTA, respectively. ESKD and mortality were traced through record linkage with the national registries. Adjusted shared random-effect joint models were used to analyse the association between the trajectory of ECF over time and the two competing outcomes.

RESULTS

Patients were mean age 58.7 years, 66.7% men, mean mGFR of 43.6 ± 18.6 mL min^-1 /1.73 m² and mean ECF of 16.1 ± 3.6 L. Over a median follow-up of 5.3 [IQR: 3.0;7.4] years, ECF increased by 136 [95%CI 106;167] mL per year on average, whilst diuretic prescription and 24-hour urinary sodium excretion remained stable. ESKD occurred in 324 (20.4%) patients, and 185 (11.6%) patients died before ESKD. A higher current value of ECF was associated with increased hazards of ESKD (adjusted hazard ratio [aHR]: 1.12 [95%CI 1.06;1.18]; P < 0.001 per 1 L increase in ECF), and death before ESKD (aHR: 1.10 [95%CI 1.04;1.17]; P = 0.002).

CONCLUSIONS

The current value of ECF was associated with the risks of ESKD and mortality, independent of multiple potential confounders, including kidney function decline. This highlights the need for a close monitoring and adjustment of treatment to avoid fluid overload in CKD patients.

Overhydration Measured by Bioimpedance Spectroscopy and Urinary Serine Protease Activity Are Risk Factors for Progression of Chronic Kidney Disease

BACKGROUND

Overhydration (OH) is common in chronic kidney disease (CKD) and might be related to the excretion of urinary serine proteases. Progression of CKD is associated with proteinuria; however, the interrelations of urinary serine proteases, OH, and progression of CKD remain unclear.

METHODS

In n = 179 patients with stable nondialysis-dependent CKD of all stages, OH was measured using bioimpedance spectroscopy (Body Composition Monitor; Fresenius), and urinary serine protease activity was determined using the peptide substrate S-2302. After a median follow-up of 5.9 (IQR: 3.9-6.5) years, progression to end-stage renal disease (ESRD) was analyzed retrospectively.

RESULTS

OH correlated with baseline MDRD-eGFR, urinary albumin creatinine ratio (ACR), and urinary aprotinin-sensitive serine protease activity. Progression to ESRD occurred in n = 33 patients (19%) and correlated with OH and urinary serine protease activity as well as MDRD-eGFR and ACR. Patients were divided into 2 groups determined by cutoff values from receiver operating characteristics for MDRD-eGFR (32 mL/min/1.73 m2), ACR (43 mg/g creatinine), urinary serine protease activity (0.9 RU/g creatinine), and OH (1 L/1.73 m2). Across these cutoff values, Kaplan-Meier curves for renal survival showed significant separations of the groups. In Cox regression adjusted for MDRD-eGFR, ACR, P-NT-pro-BNP, systolic blood pressure, and diabetes mellitus, patients with OH >1 L/1.73 m2 had a 3.32 (95% CI: 1.26-8.76)-fold higher risk for progression to ESRD.

CONCLUSIONS

Our results corroborate that OH detected by bioimpedance spectroscopy in CKD patients is an independent risk factor for progression to ESRD in addition to GFR and albuminuria. Urinary serine protease activity is associated with OH and progression of CKD and provides a possible underlying mechanism.

Geriatric Nutritional Risk Index Is Associated with Unique Health Conditions and Clinical Outcomes in Chronic Kidney Disease Patients

Malnutrition is prevalent in patients with chronic kidney disease (CKD). However, current nutrition screening tools are not specific to the CKD population. In the present study, we aimed to investigate whether the geriatric nutritional risk index (GNRI), a simple tool designed for assessing nutrition-related risks in the elderly population, is associated with unique aspects of CKD such as fluid status, residual renal function, proteinuria, and inflammation, and whether it predicts clinical outcomes. The GNRI was calculated by incorporating serum albumin and anthropometric measurements in 326 patients with nondialysis stage 3–5 CKD who were followed up from September 2011 to March 2017 for end-stage renal disease (ESRD) and the composite outcome of all-cause death and cardiovascular events. Patients were stratified into tertiles according to baseline GNRI levels. Patients in the lowest GNRI tertile were more likely to have significantly higher levels of overhydration, proteinuria, and serum inflammatory markers and tended to have lower lean body mass and estimated glomerular filtration rate when compared with patients in the middle and upper GNRI tertiles. In multivariate linear regression analyses, the GNRI was independently associated with overhydration, proteinuria, and interleukin-6. During a median follow-up of 4.9 years, 101 patients developed ESRD; 40 deaths, and 68 cardiovascular events occurred. Patients in the lowest GNRI tertile had significantly increased risks of ESRD (hazard ratio (HR): 3.15, 95% confidence interval (CI): 1.95–5.07, p < 0.001) and the composite outcome (HR: 1.79, 95% CI: 1.10–2.92, p = 0.019) in fully adjusted models (reference: middle and upper GNRI tertiles). The GNRI takes CKD-specific health conditions into account. In addition, CKD patients with lower GNRI scores had a significantly higher risk of adverse clinical outcomes. Our findings suggest that the GNRI is an appropriate tool for nutrition screening and a prognostic predictor among patients with nondialysis stage 3–5 CKD.