The latest medical research on Nephrology

The research magnet gathers the latest research from around the web, based on your specialty area. Below you will find a sample of some of the most recent articles from reputable medical journals about nephrology gathered by our medical AI research bot.

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Combination of Changes in Estimated GFR and Albuminuria and the Risk of Major Clinical Outcomes.

Clinical Journal of the American

Whether combining changes in eGFR and urine albumin-to-creatinine ratio (UACR) is more strongly associated with outcomes compared with either change alone is unknown.

We analyzed 8766 patients with type 2 diabetes in the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation Observational (ADVANCE-ON) study. Changes in eGFR and UACR (baseline to 2 years) were defined as ≥40% decrease, minor change, and ≥40% increase. The primary outcome was the composite of major macrovascular (nonfatal or fatal myocardial infarction, nonfatal or fatal stroke, or cardiovascular death), major kidney events (requirement for kidney replacement therapy or kidney death), and all-cause mortality.

Over a median of 7.7 years of follow-up, 2191 primary outcomes were recorded. Strong linear associations between eGFR and UACR changes and subsequent risk of the outcome were observed. For eGFR, the hazard ratios were 1.58 (95% confidence interval [95% CI], 1.27 to 1.95) for a decrease ≥40% and 0.82 for an increase ≥40% (95% CI, 0.64 to 1.04) compared with minor change. For UACR, the hazard ratios were 0.96 (95% CI, 0.85 to 1.07) for a decrease ≥40% and 1.32 (95% CI, 1.19 to 1.46) for ≥40% increase compared with minor change. Compared with dual minor changes, both an eGFR decrease ≥40% and a UACR increase ≥40% had 2.31 (95% CI, 1.67 to 3.18) times the risk of the outcome, with evidence of interaction between the two markers.

Clinically meaningful decreases in eGFR and increases in UACR over 2 years, independently and in combination, were significantly associated with higher risk of major clinical outcomes.

Use of a Medical-Alert Accessory in CKD: A Pilot Study.

Clinical Journal of the American

Poor disease recognition may jeopardize the safety of CKD care. We examined safety events and outcomes in patients with CKD piloting a medical-alert accessory intended to improve disease recognition and an observational subcohort from the same population.

We recruited 350 patients with stage 2-5 predialysis CKD. The first (pilot) 108 participants were given a medical-alert accessory (bracelet or necklace) indicating the diagnosis of CKD and displaying a website with safe CKD practices. The subsequent (observation) subcohort (n=242) received usual care. All participants underwent annual visits with ascertainment of patient-reported events (class 1) and actionable safety findings (class 2). Secondary outcomes included 50% GFR reduction, ESKD, and death. Cox proportional hazards assessed the association of the medical-alert accessory with outcomes.

Median follow-up of pilot and observation subcohorts were 52 (interquartile range, 44-63) and 37 (interquartile range, 27-47) months, respectively. The frequency of class 1 and class 2 safety events reported at annual visits was not different in the pilot versus observation group, with 108.7 and 100.6 events per 100 patient-visits (P=0.13), and 38.3 events and 41.2 events per 100 patient visits (P=0.23), respectively. The medical-alert accessory was associated with lower crude and adjusted rate of ESKD versus the observation group (hazard ratio, 0.42; 95% confidence interval, 0.20 to 0.89; and hazard ratio, 0.38; 95% confidence interval, 0.16 to 0.94, respectively). The association of the medical-alert accessory with the composite endpoint of ESKD or 50% reduction GFR was variable over time but appeared to have an early benefit (up to 23 months) with its use. There was no significant difference in incidence of hospitalization, death, or a composite of all outcomes between medical-alert accessory users and the observational group.

The medical-alert accessory was not associated with incidence of safety events but was associated with a lower rate of ESKD relative to usual care.

Association of CKD with Incident Tuberculosis.

Clinical Journal of the American

The incidence and risk of Mycobacterium tuberculosis in people with predialysis CKD has rarely been studied, although CKD prevalence is increasing in certain countries where Mycobacterium tuberculosis is endemic. We aimed to investigate the association between predialysis CKD and active Mycobacterium tuberculosis risks in a nation with moderate Mycobacterium tuberculosis risk.

In this nationwide retrospective cohort study, we reviewed the National Health Insurance Database of Korea, screening 17,020,339 people who received a national health screening two or more times from 2012 to 2016. Predialysis CKD was identified with consecutive laboratory results indicative of CKD (e.g., persistent eGFR <60 ml/min per 1.73 m2 or dipstick albuminuria). People with preexisting active Mycobacterium tuberculosis or kidney replacement therapy were excluded. A 1:1 matched control group without CKD was included with matching for age, sex, low-income status, and smoking history. The risk of incident active Mycobacterium tuberculosis, identified in the claims database, was assessed by the multivariable Cox regression model, which included both matched and unmatched variables (e.g., body mass index, diabetes, hypertension, places of residence, and other comorbidities).

We included 408,873 people with predialysis CKD and the same number of controls. We identified 1704 patients with active Mycobacterium tuberculosis (incidence rate =137.5/100,000 person-years) in the predialysis CKD group and 1518 patients with active Mycobacterium tuberculosis (incidence rate =121.9/100,000 person-years) in the matched controls. The active Mycobacterium tuberculosis risk was significantly higher in the predialysis CKD group (adjusted hazard ratio, 1.21; 95% confidence interval, 1.13 to 1.30). The risk factors for active Mycobacterium tuberculosis among the predialysis CKD group were old age, men, current smoking, low income, underlying diabetes, chronic obstructive pulmonary disease, and Kidney Disease Improving Global Outcomes CKD stage 1 (eGFR≥90 ml/min per 1.73 m2 with persistent albuminuria) or stage 4/5 without dialysis (eGFR<30 ml/min per 1.73 m2).

In the Korean population, the incidence of active Mycobacterium tuberculosis was higher in people with versus without predialysis CKD.

Blood Pressure and Incident Atrial Fibrillation in Older Patients Initiating Hemodialysis.

Clinical Journal of the American

We examined the association of predialysis systolic and diastolic BP and intradialytic hypotension with incident atrial fibrillation in older patients initiating hemodialysis.

We used the US Renal Data System linked to the records of a large dialysis provider to identify patients aged ≥67 years initiating hemodialysis between January 2006 and October 2011. We examined quarterly average predialysis systolic BP, diastolic BP, and proportion of sessions with intradialytic hypotension (i.e., nadir systolic BP <90 mm Hg). We applied an extended Cox model to compute adjusted hazard ratios (HRs) of each exposure with incident atrial fibrillation.

Among 17,003 patients, 3785 developed atrial fibrillation. When comparing predialysis systolic BP to a fixed reference of 140 mm Hg, lower predialysis systolic BP was associated with a higher hazard of atrial fibrillation, whereas higher systolic BP was associated with a lower hazard of atrial fibrillation. When comparing across a range of systolic BP for two hypothetical patients with similar measured covariates, the association varied by mean systolic BP: at systolic BP 190 mm Hg, each 10 mm Hg lower systolic BP was associated with lower atrial fibrillation hazard (HR, 0.94; 95% confidence interval, 0.90 to 1.00), whereas at systolic BP 140 mm Hg, a 10 mm Hg lower systolic BP was associated with a higher atrial fibrillation hazard (HR, 1.12; 95% confidence interval, 1.10 to 1.14). Lower diastolic BP was associated with higher atrial fibrillation hazards. Intradialytic hypotension was weakly associated with atrial fibrillation.

In this observational study of older patients initiating hemodialysis, lower predialysis systolic BP and diastolic BP were associated with higher incidence of atrial fibrillation.

A new mouse model of CKD transitioned from ischemic AKI.

American Journal of

Acute kidney injury (AKI) significantly increases the risk of development of chronic kidney disease (CKD), which is closely associated with the sev...

Reduced endothelial nitric oxide synthase activation contributes to cardiovascular injury during chronic kidney disease progression.

American Journal of

Major cardiovascular events are a common complication in chronic kidney disease (CKD) patients. Endothelial dysfunction can contribute to the cardi...

Postdialysis Hypokalemia and All-Cause Mortality in Patients Undergoing Maintenance Hemodialysis.

Clinical Journal of the American

Almost half of patients on dialysis demonstrate a postdialysis serum potassium ≤3.5 mEq/L. We aimed to examine the relationship between postdialysis potassium levels and all-cause mortality.

We conducted a cohort study of 3967 participants on maintenance hemodialysis from the Dialysis Outcomes and Practice Patterns Study in Japan (2009-2012 and 2012-2015). Postdialysis serum potassium was measured repeatedly at 4-month intervals and used as a time-varying variable. We estimated the hazard ratio of all-cause mortality rate using Cox hazard regression models, with and without adjusting for time-varying predialysis serum potassium. Models were adjusted for baseline characteristics and time-varying laboratory parameters. We also analyzed associations of combinations of pre- and postdialysis potassium with mortality.

The age of participants at baseline was 65±12 years (mean±SD), 2552 (64%) were men, and 96% were treated with a dialysate potassium level of 2.0 to <2.5 mEq/L. The median follow-up period was 2.6 (interquartile range, 1.3-2.8) years. During the follow-up period, 562 (14%) of 3967 participants died, and the overall mortality rate was 6.7 per 100 person-years. Compared with postdialysis potassium of 3.0 to <3.5 mEq/L, the hazard ratios of postdialysis hypokalemia (<3.0 mEq/L) were 1.84 (95% confidence interval, 1.44 to 2.34) in the unadjusted model, 1.44 (95% confidence interval, 1.14 to 1.82) in the model without adjusting for predialysis serum potassium, and 1.10 (95% confidence interval, 0.84 to 1.44) in the model adjusted for predialysis serum potassium. The combination of pre- and postdialysis hypokalemia was associated with the highest mortality risk (hazard ratio, 1.72; 95% confidence interval, 1.35 to 2.19, reference; pre- and postdialysis nonhypokalemia).

Postdialysis hypokalemia was associated with mortality, but this association was not independent of predialysis potassium.

Proteomic Analysis of Urinary Microvesicles and Exosomes in Medullary Sponge Kidney Disease and Autosomal Dominant Polycystic Kidney Disease.

Clinical Journal of the American

Microvesicles and exosomes are involved in the pathogenesis of autosomal dominant polycystic kidney disease. However, it is unclear whether they also contribute to medullary sponge kidney, a sporadic kidney malformation featuring cysts, nephrocalcinosis, and recurrent kidney stones. We addressed this knowledge gap by comparative proteomic analysis.

The protein content of microvesicles and exosomes isolated from the urine of 15 patients with medullary sponge kidney and 15 patients with autosomal dominant polycystic kidney disease was determined by mass spectrometry followed by weighted gene coexpression network analysis, support vector machine learning, and partial least squares discriminant analysis to compare the profiles and select the most discriminative proteins. The proteomic data were verified by ELISA.

A total of 2950 proteins were isolated from microvesicles and exosomes, including 1579 (54%) identified in all samples but only 178 (6%) and 88 (3%) specific for medullary sponge kidney microvesicles and exosomes, and 183 (6%) and 98 (3%) specific for autosomal dominant polycystic kidney disease microvesicles and exosomes, respectively. The weighted gene coexpression network analysis revealed ten modules comprising proteins with similar expression profiles. Support vector machine learning and partial least squares discriminant analysis identified 34 proteins that were highly discriminative between the diseases. Among these, CD133 was upregulated in exosomes from autosomal dominant polycystic kidney disease and validated by ELISA.

Our data indicate a different proteomic profile of urinary microvesicles and exosomes in patients with medullary sponge kidney compared with patients with autosomal dominant polycystic kidney disease. The urine proteomic profile of patients with autosomal dominant polycystic kidney disease was enriched of proteins involved in cell proliferation and matrix remodeling. Instead, proteins identified in patients with medullary sponge kidney were associated with parenchymal calcium deposition/nephrolithiasis and systemic metabolic derangements associated with stones formation and bone mineralization defects.

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2019_04_24_CJASNPodcast_19_06_.mp3.

Plant-Based Diets and Incident CKD and Kidney Function.

Clinical Journal of the American

The association between plant-based diets, incident CKD, and kidney function decline has not been examined in the general population. We prospectively investigated this relationship in a population-based study, and evaluated if risk varied by different types of plant-based diets.

Analyses were conducted in a sample of 14,686 middle-aged adults enrolled in the Atherosclerosis Risk in Communities study. Diets were characterized using four plant-based diet indices. In the overall plant-based diet index, all plant foods were positively scored; in the healthy plant-based diet index, only healthful plant foods were positively scored; in the provegetarian diet, selected plant foods were positively scored. In the less healthy plant-based diet index, only less healthful plant foods were positively scored. All indices negatively scored animal foods. We used Cox proportional hazards models to study the association with incident CKD and linear mixed models to examine decline in eGFR, adjusting for confounders.

During a median follow-up of 24 years, 4343 incident CKD cases occurred. Higher adherence to a healthy plant-based diet (HR comparing quintile 5 versus quintile 1 [HRQ5 versus Q1], 0.86; 95% confidence interval [95% CI], 0.78 to 0.96; P for trend =0.001) and a provegetarian diet (HRQ5 versus Q1, 0.90; 95% CI, 0.82 to 0.99; P for trend =0.03) were associated with a lower risk of CKD, whereas higher adherence to a less healthy plant-based diet (HRQ5 versus Q1, 1.11; 95% CI, 1.01 to 1.21; P for trend =0.04) was associated with an elevated risk. Higher adherence to an overall plant-based diet and a healthy plant-based diet was associated with slower eGFR decline. The proportion of CKD attributable to lower adherence to healthy plant-based diets was 4.1% (95% CI, 0.6% to 8.3%).

Higher adherence to healthy plant-based diets and a vegetarian diet was associated with favorable kidney disease outcomes.

IL-1 Inhibition and Function of the HDL-Containing Fraction of Plasma in Patients with Stages 3 to 5 CKD.

Clinical Journal of the American

Systemic inflammation modulates cardiovascular disease risk and functionality of HDL in the setting of CKD. Whether interventions that modify systemic inflammation can improve HDL function in CKD is unknown.

We conducted a post hoc analysis of two randomized, clinical trials, IL-1 trap in participants with GFR 15-59 ml/min per 1.73 m2 (study A) and IL-1 receptor antagonist in participants on maintenance hemodialysis (study B), to evaluate if IL-1 blockade had improved the anti-inflammatory activity (IL-6, TNF-α, and Nod-like receptor protein 3), antioxidant function (superoxide production), and net cholesterol efflux capacity of HDL. HDL function was measured using LPS-stimulated THP-1 macrophages or peritoneal macrophages of apoE-deficient mice exposed to the apoB-depleted, HDL-containing fraction obtained from the plasma of the study participants, collected before and after the interventions to block IL-1 effects. Analysis of covariance was used for between group comparisons.

The mean age of the participants was 60±13 years, 72% (n=33) were men, and 39% (n=18) were black. There were 32 CKD (16 IL-1 trap and 16 placebo) and 14 maintenance hemodialysis (7 IL-1 receptor antagonist and 7 placebo) participants. Compared with placebo, IL-1 inhibition, in study A and B reduced cellular expression of TNF-α by 15% (P=0.05) and 64% (P=0.02), IL-6 by 38% (P=0.004) and 56% (P=0.08), and Nod-like receptor protein 3 by 16% (P=0.01) and 25% (P=0.02), respectively. The intervention blunted superoxide production in the treated arm compared with placebo, with the values being higher by 17% in the placebo arm in study A (P<0.001) and 12% in the placebo arm in study B (P=0.004). Net cholesterol efflux capacity was not affected by either intervention.

IL-1 blockade improves the anti-inflammatory and antioxidative properties of the HDL-containing fraction of plasma in patients with stages 3-5 CKD, including those on maintenance hemodialysis.

Duration of Dual Antiplatelet Therapy in Patients with CKD and Drug-Eluting Stents: A Meta-Analysis.

Clinical Journal of the American

Whether prolonged dual antiplatelet therapy (DAPT) is more protective in patients with CKD and drug-eluting stents compared with shorter DAPT is uncertain. The purpose of this meta-analysis was to examine whether shorter DAPT in patients with drug-eluting stents and CKD is associated with lower mortality or major adverse cardiovascular event rates compared with longer DAPT.

A Medline literature research was conducted to identify randomized trials in patients with drug-eluting stents comparing different DAPT duration strategies. Inclusion of patients with CKD was also required. The primary outcome was a composite of all-cause mortality, myocardial infarction, stroke, or stent thrombosis (definite or probable). Major bleeding was the secondary outcome. The risk ratio (RR) was estimated using a random-effects model.

Five randomized trials were included (1902 patients with CKD). Short DAPT (≤6 months) was associated with a similar incidence of the primary outcome, compared with 12-month DAPT among patients with CKD (48 versus 50 events; RR, 0.93; 95% confidence interval [95% CI], 0.64 to 1.36; P=0.72). Twelve-month DAPT was also associated with a similar incidence of the primary outcome compared with extended DAPT (≥30 months) in the CKD subgroup (35 versus 35 events; RR, 1.04; 95% CI, 0.67 to 1.62; P=0.87). Numerically lower major bleeding event rates were detected with shorter versus 12-month DAPT (9 versus 13 events; RR, 0.69; 95% CI, 0.30 to 1.60; P=0.39) and 12-month versus extended DAPT (9 versus 12 events; RR, 0.83; 95% CI, 0.35 to 1.93; P=0.66) in patients with CKD.

Short DAPT does not appear to be inferior to longer DAPT in patients with CKD and drug-eluting stents. Because of imprecision in estimates (few events and wide confidence intervals), no definite conclusions can be drawn with respect to stent thrombosis.

Serum and Urine Albumin and Response to Loop Diuretics in Heart Failure.

Clinical Journal of the American

Diuretic resistance can limit successful decongestion of patients with heart failure. Because loop diuretics tightly bind albumin, low serum albumin and high urine albumin can theoretically limit diuretic delivery to the site of action. However, it is unknown if this represents a clinically relevant mechanism of diuretic resistance in human heart failure.

In total, 208 outpatients with heart failure at the Yale Transitional Care Center undergoing diuretic treatment were studied. Blood and urine chemistries were collected at baseline and 1.5 hours postdiuretic administration. Urine diuretic levels were normalized to urine creatinine and adjusted for diuretic dose administered, and diuretic efficiency was calculated as sodium output per doubling of the loop diuretic dose. Findings were validated in an inpatient heart failure cohort (n=60).

Serum albumin levels in the outpatient cohort ranged from 2.4 to 4.9 g/dl, with a median of 3.7 g/dl (interquartile range, 3.5-4.1). Serum albumin had no association with urinary diuretic delivery (r=-0.05; P=0.52), but higher levels weakly correlated with better diuretic efficiency (r=0.17; P=0.02). However, serum albumin inversely correlated with systemic inflammation as assessed by plasma IL-6 (r=-0.35; P<0.001), and controlling for IL-6 eliminated the diuretic efficiency-serum albumin association (r=0.12; P=0.12). In the inpatient cohort, there was no association between serum albumin and urinary diuretic excretion (r=0.15; P=0.32) or diuretic efficiency (r=-0.16; P=0.25). In the outpatient cohort, 39% of patients had microalbuminuria, and 18% had macroalbuminuria. There was no correlation between albuminuria and diuretic efficiency after adjusting for kidney function (r=-0.02; P=0.89). Results were similar in the inpatient cohort.

Serum albumin levels were not associated with urinary diuretic excretion, and urinary albumin levels were not associated with diuretic efficiency.