Risk factors for chronic kidney disease: an update

Notch inhibitor mitigates renal ischemia‑reperfusion injury in diabetic rats

Diabetes mellitus can exacerbate renal ischemia-reperfusion (I/R) injury (RI/RI) in diabetic rats. Previous studies have shown that Notch signaling is involved in renal disorders. The aim of the present study was to evaluate the protective effect of the Notch inhibitor γ-secretase N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT) on RI/RI in a streptozocin (STZ)-induced diabetic rat model. STZ-induced diabetic rats were randomly grouped for different treatments. Cisplatin was used to trigger the Notch signaling pathway and the animals were preconditioned with DAPT to block the signaling pathway. Renal function, oxidative stress and inflammatory factors were examined. DAPT-treated diabetic rats demonstrated mitigated renal injury and function, antioxidative activity was significantly improved and HIF-1a was upregulated. Notch inhibitor DAPT is a potential therapeutic target to improve the outcome of RI/RI in STZ-induced diabetic rats in part via the regulation of anti-oxidation and HIF-1a.

Hypertension Is Predicted by Both Large and Small Artery Disease

Both small and large artery disease might precede the development of hypertension. However, no prospective trial has yet determined the role of small and large artery disease on the rate of new-onset hypertension in a normotensive general population. This study investigated associations between both arterial stiffness and small artery retinopathy and the development of hypertension in adults from Japan. Normotensive individuals who underwent a baseline health checkup from 2005 to 2015 and at least 1 annual follow-up were eligible. The cardio-ankle vascular index (CAVI) was measured, and retinal fundus photography was performed at baseline. Follow-up visits included measurement of clinic blood pressure. The primary end point was new-onset hypertension (blood pressure ≥140/90 mm Hg or initiation of antihypertensive medication with self-reported hypertension). The analysis included 34 649 subjects (mean age, 44.2 years; 46.4% male). Mean follow-up duration was 3.18±2.50 years. The cumulative incidence of new-onset hypertension during the 10-year follow-up period was 40% of patients overall, with rates increasing in parallel with baseline CAVI (quartile [Q]1, 23%; Q2, 33%; Q3, 42%; Q4, 58%; P<0.001), and as the severity of retinopathy increased ( P<0.001). CAVI showed good discriminative ability for detecting new-onset hypertension. In multivariate analysis, both CAVI and small artery retinopathy were independent predictors of hypertension development. There was no interaction between CAVI and small artery retinopathy with respect to incident hypertension. In conclusion, we showed that both large and small artery disease predict future hypertension independently of each other and confounding risk factors in a general normotensive population.

Kidney-based in vitro models for drug-induced toxicity testing

The kidney is frequently involved in adverse effects caused by exposure to foreign compounds, including drugs. An early prediction of those effects is crucial for allowing novel, safe drugs entering the market. Yet, in current pharmacotherapy, drug-induced nephrotoxicity accounts for up to 25% of the reported serious adverse effects, of which one-third is attributed to antimicrobials use. Adverse drug effects can be due to direct toxicity, for instance as a result of kidney-specific determinants, or indirectly by, e.g., vascular effects or crystals deposition. Currently used in vitro assays do not adequately predict in vivo observed effects, predominantly due to an inadequate preservation of the organs' microenvironment in the models applied. The kidney is highly complex, composed of a filter unit and a tubular segment, together containing over 20 different cell types. The tubular epithelium is highly polarized, and the maintenance of this polarity is critical for optimal functioning and response to environmental signals. Cell polarity is dependent on communication between cells, which includes paracrine and autocrine signals, as well as biomechanic and chemotactic processes. These processes all influence kidney cell proliferation, migration, and differentiation. For drug disposition studies, this microenvironment is essential for prediction of toxic responses. This review provides an overview of drug-induced injuries to the kidney, details on relevant and translational biomarkers, and advances in 3D cultures of human renal cells, including organoids and kidney-on-a-chip platforms.

Healthy Dietary Patterns and Incidence of CKD: A Meta-Analysis of Cohort Studies

BACKGROUND AND OBJECTIVES

Whether a healthy dietary pattern may prevent the incidence of developing CKD is unknown. This study evaluated the associations between dietary patterns and the incidence of CKD in adults and children.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This systematic review and meta-analysis identified potential studies through a systematic search of MEDLINE, Embase and references from eligible studies from database inception to February 2019. Eligible studies were prospective and retrospective cohort studies including adults and children without CKD, where the primary exposure was dietary patterns. To be eligible, studies had to report on the primary outcome, incidence of CKD (eGFR<60 ml/min per 1.73 m²). Two authors independently extracted data, assessed risk of bias and evidence certainty using the Newcastle-Ottawa scale and GRADE.

RESULTS

Eighteen prospective cohort studies involving 630,108 adults (no children) with a mean follow-up of 10.4±7.4 years were eligible for analysis. Included studies had an overall low risk of bias. The evidence certainty was moderate for CKD incidence and low for eGFR decline (percentage drop from baseline or reduced by at least 3 ml/min per 1.73 m² per year) and incident albuminuria. Healthy dietary patterns typically encouraged higher intakes of vegetables, fruit, legumes, nuts, whole grains, fish and low-fat dairy, and lower intakes of red and processed meats, sodium, and sugar-sweetened beverages. A healthy dietary pattern was associated with a lower incidence of CKD (odds ratio [OR] 0.70 (95% confidence interval [95% CI], 0.60 to 0.82); I²=51%; eight studies), and incidence of albuminuria (OR 0.77, [95% CI, 0.59 to 0.99]; I²=37%); four studies). There appeared to be no significant association between healthy dietary patterns and eGFR decline (OR 0.70 [95% CI, 0.49 to 1.01], I²=49%; four studies).

CONCLUSIONS

A healthy dietary pattern may prevent CKD and albuminuria.

Nutraceuticals as a potential adjunct therapy toward improving vascular health in CKD

Chronic kidney disease (CKD) is a major public health epidemic and increases risk for developing cardiovascular disease (CVD). Vascular dysfunction is a major independent risk factor toward increased risk for CVD in CKD. Several mechanisms have been postulated to result in vascular dysfunction in CKD, including oxidative stress-mediated inflammation by redox imbalance and reduced nitric oxide (NO) bioavailability and synthesis. Therefore, strategies that decrease oxidative stress and/or increase NO bioactivity may have major clinical implications toward improving vascular health and reducing the burden of CVD in CKD. Nutraceutical therapy in the form of polyphenols, dietary nitrates, or selective mitochondria-targeting therapies has recently been shown to improve vascular function by reducing oxidative stress and/or increasing NO bioavailability and synthesis. This review, therefore, highlights these three emerging nutraceuticals recently implicated in pathophysiological improvement of vascular function in CKD. This review also describes those pathophysiological mechanisms thought to be responsible for the beneficial effects on the vasculature and possible experimental considerations that may exist within human CKD populations. It is clear throughout this review that human-based mechanistic preclinical and health-related clinical studies are lacking regarding whether nutraceuticals do indeed improve vascular function in patients with CKD. As such, a comprehensive, detailed, and fully integrated understanding of nutraceuticals and vasculature function is necessary in patients with CKD. Many opportunities exist for original mechanistic and therapeutic discoveries and investigations on select nutraceuticals and their impact on vascular outcomes in patients with CKD, and these will remain exciting avenues of research in the future.

Chronic Kidney Disease Diagnosis and Management: A Review

Importance

Chronic kidney disease (CKD) is the 16th leading cause of years of life lost worldwide. Appropriate screening, diagnosis, and management by primary care clinicians are necessary to prevent adverse CKD-associated outcomes, including cardiovascular disease, end-stage kidney disease, and death.

Observations

Defined as a persistent abnormality in kidney structure or function (eg, glomerular filtration rate [GFR] <60 mL/min/1.73 m2 or albuminuria ≥30 mg per 24 hours) for more than 3 months, CKD affects 8% to 16% of the population worldwide. In developed countries, CKD is most commonly attributed to diabetes and hypertension. However, less than 5% of patients with early CKD report awareness of their disease. Among individuals diagnosed as having CKD, staging and new risk assessment tools that incorporate GFR and albuminuria can help guide treatment, monitoring, and referral strategies. Optimal management of CKD includes cardiovascular risk reduction (eg, statins and blood pressure management), treatment of albuminuria (eg, angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers), avoidance of potential nephrotoxins (eg, nonsteroidal anti-inflammatory drugs), and adjustments to drug dosing (eg, many antibiotics and oral hypoglycemic agents). Patients also require monitoring for complications of CKD, such as hyperkalemia, metabolic acidosis, hyperphosphatemia, vitamin D deficiency, secondary hyperparathyroidism, and anemia. Those at high risk of CKD progression (eg, estimated GFR <30 mL/min/1.73 m2, albuminuria ≥300 mg per 24 hours, or rapid decline in estimated GFR) should be promptly referred to a nephrologist.

Conclusions and Relevance

Diagnosis, staging, and appropriate referral of CKD by primary care clinicians are important in reducing the burden of CKD worldwide.

Chronic Kidney Disease And Associated Risk Factors Among Cardiovascular Patients

BACKGROUND

Chronic kidney diseases (CKDs) are known in patients with cardiovascular diseases (CVDs) and cause extra morbidity and mortality. There were few related studies in Africa, and no such studies exist in Ethiopia.

OBJECTIVE

To determine the magnitude of chronic kidney disease and associated risk factors among cardiovascular (CV) patients.

METHODS

A cross-sectional study was conducted on randomly selected 163 CV patients attending Tikur-Anbessa Specialized Hospital (TASH), Ethiopia. Estimated glomerular filtration rate (GFR) was determined using the Simplified Modification of Diet in Renal Disease (MDRD) equation. Body weight, height, and blood pressure were recorded, and body mass index (BMI) was calculated. Serum urea and creatinine were analyzed using an automatic analyzer (MINDRAY, BE-2000), and blood urea nitrogen (BUN) was calculated.

RESULTS

In this study, CKD, defined as estimated GFR (eGFR) < 60 mL/min/1.73m2 was found in 39 (23.9%) participants using the MDRD equation. Normal serum creatinine (SCr) was observed in 114 (69.9%) participants and proteinuria was found in 41 (25.2%) participants. CKD was significantly associated with systolic blood pressure (COR: -0.240, 95% CI: -0.439 to -0.041, p = 0.018), SCr (COR: -0.679; 95% CI: -0.778 to -0.580; p = 0.001) and BUN (COR: -0.422; 95% CI: -0.550 to -0.295; p = 0.001). In multivariate analysis, only high SCr (AOR = 47.57; 95% CI: 13.72-164.89; p = 0.001) was independently associated with CKD.

CONCLUSION

These findings indicated that the CKD was significantly associated with SBP and increased BUN, while independently associated with increased SCr. Thus, early detection and recognition of CKD in-patient with CVD helps to avoid extra morbidity and mortality. We recommend using the MDRD formula in health facilities for diagnosing of CKD to reduce duplication of laboratory tests (SCr and BUN), as it is the easiest practice and saves patients and the public sector costs.

Distribution and Determinants of Chronic Kidney Disease of Unknown Etiology: A Brief Overview

Globally, 33187000 DALYs and 956000 deaths are attributed to chronic kidney disease (CKD) every year. Diabetes and hypertension are the two most common causes of CKD. Another category of CKD without any known common causes, chronic kidney disease of unknown etiology (CKDu) is also increasingly reported from different regions of the world such as Central America, Sri Lanka, and India. They are predominately observed in agricultural communities where crops such as sugarcane and coconut are commonly cultivated. Young adults and males are at higher risk of developing CKDu. It mainly affects individuals belonging to lower socioeconomic status. Exposure to silica, arsenic, and fluoride might be associated with increased prevalence of CKDu. The role of heat stress in contributing to CKD through dehydration is unclear but cannot be ruled out. Mycotoxins such as aflatoxins and ochratoxins are also found to be associated with CKDu in some settings. Several studies have reported that CKDu has a significant positive association with pesticides used in agriculture such as HCH, Endosulfan, Alachlor, and Pendimethalin. There is also a possible role of infections by Hantavirus and Leptospirosis in acute febrile phase of CKDu. However, there is no conclusive evidence from studies conducted on CKDu regarding its causes and risk factors. Therefore, large-scale studies with better methodology need to be conducted to study the etiology and pathogenesis of CKDu in various settings.

Cross Talk Between TGF-β and JAK Expressions and Nepherotoxicity Induced by Tetrachloromethane: Role of Phytotherapy

The aim of the current study is to assess the effectiveness of milk thistle seeds (Mth) in combination with Taraxacum officinale (Tof) and/or Camellia sinensis (Csin) against tetrachloromethane (Tcm) renotoxicity in rats. Tetrachloromethane was injected in a single dose, followed by 1-month treatments with Mth, Tof, and Csin alone or in combination. Serum urea, uric acid, and creatinine levels were significantly increased matched with the control group. Masson trichrome stain revealed increase in the deposition of fibrous tissue in the interstitium between the tubules and the renal corpuscles. Immunohistochemical analysis of kidney tissues revealed that Tcm induced an increase in the immune response of tumor growth factor β (TGF-β) and Janus kinase (JAK) protein expressions and cysteine–aspartic acid protease 3 (caspase 3), while B-cell lymphoma 2 (Bcl2) was downregulated. Treatment with the antioxidants in question either alone or in combination ameliorated all kidney function parameters and showed mild immune reactivity toward TGF-β and JAK protein expressions in blood vessels and glomeruli in the kidney tissues and downregulated caspase 3 and activated Bcl2 protein expression. The combination regimen of the 3 antioxidants showed the most significant renoprotective effect. This was also confirmed histopathologically. It was concluded that the antioxidant mixture is considered as a promising candidate toward renal dysfunction and immune reactivity induced by Tcm and other toxicants.

Gout and the risk of advanced chronic kidney disease in the UK health system: a national cohort study

OBJECTIVE

Evaluate the association between gout and risk of advanced chronic kidney disease (CKD).

DESIGN

Retrospective matched cohort study.

SETTING

UK Clinical Practice Research Datalink.

PARTICIPANTS

The analysis included data for 68 897 patients with gout and 554 964 matched patients without gout. Patients were aged ≥18 years, registered at UK practices, had ≥12 months of clinical data and had data linked with Hospital Episode Statistics. Patients were excluded for history of advanced CKD, juvenile gout, cancer, HIV, tumour lysis syndrome, Lesch-Nyhan syndrome or familial Mediterranean fever.

PRIMARY AND SECONDARY OUTCOME MEASURES

Advanced CKD was defined as first occurrence of: (1) dialysis, kidney transplant, diagnosis of end-stage kidney disease (ESKD) or stage 5 CKD (diagnostic codes in Read system or International Classification of Diseases, Tenth Revision); (2) estimated glomerular filtration rate (eGFR) <10 mL/min/1.73 m²; (3) doubling of serum creatinine from baseline and (4) death associated with CKD.

RESULTS

Advanced CKD incidence was higher for patients with gout (8.54 per 1000 patient-years; 95% CI 8.26 to 8.83) versus without gout (4.08; 95% CI 4.00 to 4.16). Gout was associated with higher advanced CKD risk in both unadjusted analysis (HR, 2.00; 95% CI 1.92 to 2.07) and after adjustment (HR, 1.29; 95% CI 1.23 to 1.35). Association was strongest for ESKD (HR, 2.13; 95% CI 1.73 to 2.61) and was present for eGFR <10 mL/min/1.73 m² (HR, 1.45; 95% CI 1.30 to 1.61) and serum creatinine doubling (HR, 1.13; 95% CI 1.08 to 1.19) but not CKD-associated death (HR, 1.14; 95% CI 0.99 to 1.31). Association of gout with advanced CKD was replicated in propensity-score matched analysis (HR, 1.23; 95% CI 1.17 to 1.29) and analysis limited to patients with incident gout (HR, 1.28; 95% CI 1.22 to 1.35).

CONCLUSIONS

Gout is associated with elevated risk of CKD progression. Future studies should investigate whether controlling gout is protective and reduces CKD risk.

Proteinuria impacts patient survival differentially based on clinical setting: A retrospective cross-sectional analysis of cohorts from a single health system: Retrospective cohort study

Background

Chronic kidney disease (CKD) staging is improved by adding proteinuria to glomerular filtration rate (GFR). While proteinuria independently predicts CKD progression and mortality, the clinical setting of proteinuria determination has not been well-studied previously. The objective of our study is to determine whether clinical setting differentially impacts survival outcomes.

Methods

Kaplan-Meier and Cox proportional hazards analyses of overall survival were performed retrospectively for cohorts of outpatients (n = 22,918), emergency patients (n = 16,861), and inpatients (n = 12,304) subjected to urinalysis (UA) at a single health system in 2010. GFR (G1-G5) and proteinuria (A1:<30 mg, A2:30–300 mg, A3:>300 mg) were classified under Kidney Disease: Improving Global Outcomes (KDIGO) guidelines.

Results

GFR and proteinuria levels varied more in inpatients than in emergency and outpatients. For each clinical population, survival significantly decreased with increasing proteinuria (A1>A2>A3, p < 0.05 for each comparison). The effect of proteinuria on survival differed by clinical setting, with statistical differences in all categories other than A3 in outpatients and emergency patients (p = 0.98). The strongest predictors of mortality were cancer diagnosis (HR: 3.07, p < 0.0001) and very-high KDIGO classification (HR: 2.01, p < 0.0001). Limitations include the retrospective observational study design and single health system analysis.

Conclusions

The value of UA to screen for proteinuria in each clinical setting is evident, but the impact of A2 and A3 level proteinuria on survival varies depending on the clinical scenario in which the determination was made. The clinical setting of proteinuria measurement should be factored into both patient care and clinical research activities.

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Proteinuria and GFR independently predict survival in inpatients, ED and outpatients.

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The effect of proteinuria on survival differs by clinical setting.

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Hospitalized patients have lower survival rates than emergency and outpatients.

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Clinical setting of proteinuria should be considered in patient care and research.

Prevalence and factors associated with chronic kidney disease among medical inpatients at the Kenyatta National Hospital, Kenya, 2018: a cross-sectional study

INTRODUCTION

The burden of chronic kidney disease (CKD) is increasing worldwide. Few studies in low and low-middle income countries have estimated the prevalence of CKD. We aimed to estimate prevalence and factors associated with CKD among medical inpatients at the largest referral hospital in Kenya.

METHODS

We conducted a cross-sectional study among medical inpatients at the Kenyatta National Hospital. We used systematic sampling and collected demographic information, behavioural risk factors, medical history, underlying conditions, laboratory and imaging workup using a structured questionnaire. We estimated glomerular filtration rate (GFR) in ml/min/1.73m2 classified into 5 stages; G1 (≥ 90), G2 (60-89), G3a (45-59), G3b (30-44), G4 (15-29) and G5 (<15, or treated by dialysis/renal transplant). Ethical approval was obtained from Kenyatta National Hospital-University of Nairobi Ethics and Research Committee (KNH-UoN ERC), approval number P510/09/2017. We estimated prevalence of CKD and used logistic regression to determine factors independently associated with CKD diagnosis.

RESULTS

We interviewed 306 inpatients; median age 40.0 years (IQR 24.0), 162 (52.9%) were male, 155 (50.7%) rural residents. CKD prevalence was 118 patients (38.6%, 95% CI 33.3-44.1); median age 42.5 years (IQR 28.0), 74 (62.7%) were male, 64 (54.2%) rural residents. Respondents with CKD were older than those without (difference 4.4 years, 95% CI 3.7-8.4 years, P = 0.032). Fifty-six (47.5%) of the patients had either stage G1 or G2, 17 (14.4%) had end-stage renal disease; 64 (54.2%) had haemoglobin below 10g/dl while 33 (28.0%) had sodium levels below 135 mmol/l. ). History of unexplained anaemia (aOR 1.80, 95% CI 1.02-3.19), proteinuria (aOR 5.16, 95% CI 2.09-12.74), hematuria (aOR 7.68, 95% CI 2.37-24.86); hypertension (aOR 2.71, 95% CI 1.53-4.80) and herbal medications use (aOR 1.97, 95% CI 1.07-3.64) were independently associated with CKD.

CONCLUSION

Burden of CKD was high among this inpatient population. Haematuria and proteinuria can aid CKD diagnosis. Public awareness on health hazards of herbal medication use is necessary.

Kidney Disease in HIV Infection

Antiretroviral therapy (ART) has significantly improved life expectancy of infected subjects, generating a new epidemiological setting of people aging withHuman Immunodeficiency Virus (HIV). People living with HIV (PLWH), having longer life expectancy, now face several age-related conditions as well as side effects of long-term exposure of ART. Chronic kidney disease (CKD) is a common comorbidity in this population. CKD is a relentlessly progressive disease that may evolve toward end-stage renal disease (ESRD) and significantly affect quality of life and risk of death. Herein, we review current understanding of renal involvement in PLWH, mechanisms and risk factors for CKD as well as strategies for early recognition of renal dysfunction and best care of CKD.

The association between plasma selenium and chronic kidney disease related to lead, cadmium and arsenic exposure in a Taiwanese population

This study aimed to determine the interaction of red blood cell cadmium and lead, total urinary arsenic, and plasma selenium in chronic kidney disease (CKD). We recruited 220 CKD patients as well as 438 gender- and age-matched controls, and we defined CKD as <60 mL/min/1.73 m² estimated glomerular filtration rate (eGFR) for three or more consecutive months. Plasma selenium and red blood cell cadmium and lead concentrations were measured by ICP-MS. Urinary arsenic species were determined via HPLC-HG-AAS and were summed to determine the total urinary arsenic concentration. Plasma selenium was positively correlated to eGFR, and subjects with high plasma selenium levels (>243.90 μg/L) had a significantly lower odds ratio (OR) and 95% confidence interval (CI) (0.23, 0.13-0.42) for CKD compared to those with low plasma selenium levels (≤ 196.70 μg/L). High plasma selenium and low red blood cell cadmium or lead concentrations interacted to decrease the OR and 95% CI for CKD (0.12, 0.06-0.26; 0.09, 0.04-0.19). High plasma selenium and low red blood cell lead levels also interacted to increase the eGFR (20.70, 15.56-26.01 mL/min/1.73 m²). This study is the first to suggest that selenium modifies the eGFR and OR in CKD induced by environmental toxicants.

Prevalence of positive chronic kidney Disease screening in professional male long haul drivers at risk of cardiovascular Disease in Lagos, Nigeria: a cross-section study

BACKGROUND

Professional drivers are known to be at high risk for cardiovascular disease (CVD) on account of the higher prevalence co-occurring risk factors they harbour. Chronic kidney disease (CKD) and CVD share similar risk factors. Both impact each other adversely. The renal profile of professional drivers in Nigeria is not well characterised. We decided to study the prevalence of positive CKD screening amongst professional male long distance drivers in Lagos, Southwest Nigeria so as to quantify the burden and its predictors.

METHODS

Two hundred and ninety-three drivers were recruited. Details of their socio-demographic characteristics were obtained. Their anthropometric indices, blood pressure, fasting plasma blood glucose and lipid profile were measured. Serum creatinine was measured and estimated glomerular filtration rate, eGFR, was calculated with Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. Urinary Albumin Creatinine Ratio (UACR) was determined. A 10 year CVD risk of the subjects was calculated with the Framingham Risk Score (FRS).

RESULTS

Mean age of the study population was 44.8 + 9.7 years. The prevalence of alcohol use and smoking were 71.0 and 19.5% respectively. One hundred and twenty-one (62.8%) of the subjects were either overweight or obese while 70(24.1%) had abdominal obesity. The prevalence of hypertension and diabetes were 39.7 and 13.9% respectively. Prevalence of CKD by eGFR< 60 ml/min/1.73m2 or UACR > 30 mg/g was 51.7% (95% CI; 46.0-57.5). The odds for CKD increased with lower HDL-c levels; OR 3.5 (95% CI, 1.1-11.2; p = 0.03) and longer duration of professional driving > 20 years; OR 2.4(95% CI, 1.5-4.0).

CONCLUSION

Professional male long distance drivers in addition to having very high prevalence of clustering of both CVD and CKD risk factors have a significant burden of asymptomatic CKD. UACR appears to be an earlier marker of CKD in this population. Health awareness promotion and aggressive risk factor reduction are advocated as ways to reduce this burden.

Urinary Melamine Levels and Progression of CKD

BACKGROUND AND OBJECTIVES

CKD is a global public health problem. Some cross-sectional studies have associated environmental melamine exposure with kidney diseases, but evidence is limited.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted this prospective cohort study to enroll patients with eGFR≥30 ml/min per 1.73 m² in 2006-2010. Urinary corrected melamine levels (ratio of urinary melamine to urinary creatinine) were measured by liquid chromatography/tandem mass spectrometry at enrollment. Kidney outcomes included doubling of serum creatinine levels, eGFR decline >3 ml/min per 1.73 m² per year, and 30% decline in eGFR in the first 2 years. Subjects were followed until targeted kidney outcomes, cancer, death, last contact, or the end of observation in December 2016.

RESULTS

In a total of 293 subjects, the median urinary corrected melamine level was 0.97 (interquartile range, 0.43-2.08) μg/mmol. Over a median follow-up period of 7.0 years, serum creatinine levels doubled in 80 subjects (27%). Subjects in the highest tertile of urinary melamine level 12.70 μg/mmol) had a 2.30 (95% confidence interval, 1.25 to 4.23; P<0.01) hazard risk for doubling of serum creatinine compared with those in the lowest tertile (0.02-0.58 μg/mmol). Similar significant dose-response results were found in eGFR decline >3 ml/min per 1.73 m² per year and 30% decline in eGFR in the first 2 years.

CONCLUSIONS

Urinary melamine level is significantly associated with kidney function deterioration in patients with early-stage CKD.

The PPARγ agonist pioglitazone prevents TGF-β induced renal fibrosis by repressing EGR-1 and STAT3

Background

It has been proposed that peroxisome proliferator-activated receptor-γ (PPARγ) agonists might reduce renal fibrosis, however, several studies had contradictory results. Moreover, the possible interaction of TGF-β₁, PPARγ, and transcription factors in renal fibrosis have not been investigated. We hypothesized that oral pioglitazone treatment would inhibit TGF-β–driven renal fibrosis and its progression, by modulating profibrotic transcription factors in TGF-β₁ transgenic mice.

Methods

Male C57Bl/6 J mice (control, CTL, n = 14) and TGF-β overexpressing transgenic mice (TGFβ, n = 14, having elevated plasma TGF-β₁ level) were divided in two sets at 10 weeks of age. Mice in the first set were fed with regular rodent chow (CTL and TGFβ, n = 7/group). Mice in the second set were fed with chow containing pioglitazone (at a dose of 20 mg/kg/day, CTL + Pio and TGFβ+Pio, n = 7/group). After 5 weeks of treatment, blood pressure was assessed and urine samples were collected, and the kidneys were analyzed for histology, mRNA and protein expression.

Results

TGF-β₁ induced glomerulosclerosis and tubulointerstitial damage were significantly reduced by pioglitazone. Pioglitazone inhibited renal mRNA expression of all the profibrotic effectors: type-III collagen, TGF-β₁, CTGF and TIMP-1, and alike transcription factors cFos/cJun and protein expression of EGR-1, and STAT3 protein phosphorylation.

Conclusions

Oral administration of PPARγ agonist pioglitazone significantly reduces TGF-β₁-driven renal fibrosis, via the attenuation of EGR-1, STAT3 and AP-1. This implies that PPARγ agonists might be effective in the treatment of chronic kidney disease patients.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1431-x) contains supplementary material, which is available to authorized users.

Association of the combination of weight gain after 20 years of age and current obesity with chronic kidney disease in Japan: a cross-sectional study

OBJECTIVES

Weight gain after 20 years of age is associated with chronic kidney disease (CKD). However, the impact of weight gain on CKD might differ by current obesity status. We investigated the association of the combination of weight gain after 20 years of age and current obesity with CKD among adults in Japan.

DESIGN

A cross-sectional study.

SETTING AND PARTICIPANTS

We analysed data from 94 822 adults aged 40-64 years who had an annual health check-up in Japan from April 2013 to March 2014.

PRIMARY OUTCOME MEASURE

CKD was defined as an estimated glomerular filtration rate <60 mL/min/1.73 m² and/or proteinuria.

RESULTS

Both weight gain ≥10 kg after 20 years of age plus obesity (OR 2.21, 95% CI 2.07 to 2.36) and weight gain of ≥10 kg plus non-obesity (OR 1.31, 95% CI 1.21 to 1.42) significantly increased the OR for CKD when compared with weight gain <10 kg plus non-obesity in men. In women, weight gain ≥10 kg plus obesity (OR 2.04, 95% CI 1.84 to 2.25) and weight gain ≥10 kg plus non-obesity (OR 1.53, 95% CI 1.36 to 1.72) significantly increased the OR for CKD compared with weight gain <10 kg plus non-obesity. These results persisted even after adjustment for age, lifestyle factors, hypertension, dyslipidaemia and diabetes.

CONCLUSIONS

Weight gain ≥10 kg after 20 years of age was significantly associated with CKD in both obese and non-obese subjects. Moreover, the influence of weight gain ≥10 kg plus obesity on CKD was greater than that of weight gain ≥10 kg plus non-obesity on CKD. The present study results suggest that it is important to consider weight gain after maturity in both obese and non-obese subjects to prevent CKD among Japanese middle-aged adults.

Genetic Susceptibility to Chronic Kidney Disease - Some More Pieces for the Heritability Puzzle

Chronic kidney disease (CKD) is a major global health problem with an increasing prevalence partly driven by aging population structure. Both genomic and environmental factors contribute to this complex heterogeneous disease. CKD heritability is estimated to be high (30-75%). Genome-wide association studies (GWAS) and GWAS meta-analyses have identified several genetic loci associated with CKD, including variants in UMOD, SHROOM3, solute carriers, and E3 ubiquitin ligases. However, these genetic markers do not account for all the susceptibility to CKD, and the causal pathways remain incompletely understood; other factors must be contributing to the missing heritability. Less investigated biological factors such as telomere length; mitochondrial proteins, encoded by nuclear genes or specific mitochondrial DNA (mtDNA) encoded genes; structural variants, such as copy number variants (CNVs), insertions, deletions, inversions and translocations are poorly covered and may explain some of the missing heritability. The sex chromosomes, often excluded from GWAS studies, may also help explain gender imbalances in CKD. In this review, we outline recent findings on molecular biomarkers for CKD (telomeres, CNVs, mtDNA variants, sex chromosomes) that typically have received less attention than gene polymorphisms. Shorter telomere length has been associated with renal dysfunction and CKD progression, however, most publications report small numbers of subjects with conflicting findings. CNVs have been linked to congenital anomalies of the kidney and urinary tract, posterior urethral valves, nephronophthisis and immunoglobulin A nephropathy. Information on mtDNA biomarkers for CKD comes primarily from case reports, therefore the data are scarce and diverse. The most consistent finding is the A3243G mutation in the MT-TL1 gene, mainly associated with focal segmental glomerulosclerosis. Only one GWAS has found associations between X-chromosome and renal function (rs12845465 and rs5987107). No loci in the Y-chromosome have reached genome-wide significance. In conclusion, despite the efforts to find the genetic basis of CKD, it remains challenging to explain all of the heritability with currently available methods and datasets. Although additional biomarkers have been investigated in less common suspects such as telomeres, CNVs, mtDNA and sex chromosomes, hidden heritability in CKD remains elusive, and more comprehensive approaches, particularly through the integration of multiple -"omics" data, are needed.

High Dietary Intake of Vegetable Protein Is Associated With Lower Prevalence of Renal Function Impairment: Results of the Dutch DIALECT-1 Cohort

INTRODUCTION

Dietary protein intake may influence development of renal function impairment in diabetes mellitus type 2 (T2DM). We assessed the association between sources of protein and prevalence of renal function impairment.

METHODS

Cross-sectional analyses were performed in baseline data of 420 patients of the DIAbetes and LifEstyle Cohort Twente-1 (DIALECT-1) study. Protein intake was assessed using a Food Frequency Questionnaire, modified for accurate assessment of protein intake, including types and sources of protein. Renal function impairment was defined as estimated glomerular filtration rate (eGFR) <60 ml/min per 1.73 m2 (Chronic Kidney Disease Epidemiology Collaboration formula).

RESULTS

Among 420 patients with T2DM, 99 renal function impairment cases were identified. Multivariate Cox proportional hazard models were used and adjusted for the main lifestyle and dietary factors. The prevalence ratios in the fully adjusted model were 1 (reference), 0.74 (95% confidence interval [CI]: 0.44-1.27; P = 0.28) and 0.47 (95% CI: 0.23-0.98; P = 0.04) according to increasing tertiles of vegetable protein intake. For animal protein intake the prevalence ratios were 1 (reference), 1.10 (95% CI: 0.64-1.88; P = 0.74) and 1.06 (95% CI: 0.56-1.99; P = 0.87) according to increasing tertiles of intake. Theoretical replacement models showed that replacing 3 energy percent from animal protein by vegetable protein lowered the prevalence ratio for the association with renal function impairment to 0.20 (95% CI: 0.06-0.63; P = 0.01).

CONCLUSION

In conclusion, we found that higher intake of vegetable protein was associated with a lower prevalence of renal function impairment, and theoretical replacement of animal protein with vegetable protein was inversely associated with renal function impairment among patients with T2DM.

Association of nonalcoholic fatty liver and chronic kidney disease: An analysis of 37,825 cases from health checkup center in Taiwan

Objective:

Nonalcoholic fatty liver (NAFLD) and chronic kidney disease (CKD) share common pathogenic mechanisms and risk factors. The relationship between in NAFLD and CKD remains controversial. We aim to assess the association between NAFLD and CKD.

Materials and Methods:

A cross-sectional study was based on individuals who received physical checkups at the Taipei Tzu Chi Hospital from September 5, 2005, to December 31, 2016. Demographic and clinical characteristics of the study population were collected. NAFLD was defined by abdominal ultrasonography and excluded other liver disease. CKD was defined as estimated glomerular filtration rate ≤60 mL/min/1.73 m² or the presence of proteinuria. The association between NAFLD and CKD was then analyzed using SAS software by using the multivariable logistic model. A higher prevalence of CKD was shown in individuals with NAFLD compared to those without NAFLD.

Results:

In univariate analysis, individuals with mild NAFLD and moderate-to-severe NAFLD were both significantly associated with CKD (odds ratio [OR], 1.23; 95% confidence interval [CI], 1.13–1.33; OR, 1.66; CI, 1.49–1.85) when compared to individuals without NAFLD. After multivariate adjustment, individuals with moderate-to-severe NAFLD were still significantly more likely to have CKD (OR, 1.17, 95% CI, 1.03–1.33).

Conclusions:

Our finding showed that the presence and severity of NAFLD was positively associated with CKD in unadjusted and adjusted analysis. Further follow-up studies may be needed to validate these associations.

Hypertension in Chronic Kidney Disease: Novel Insights

Management of arterial hypertension in patients with chronic kidney disease (CKD) remains a major challenge due to its high prevalence and associations with cardiovascular disease (CVD) and CKD progression. Several clinical trials and meta-analyses have demonstrated that aggressive treatment of hypertension in patients with and without CKD lowers the risk of CVD and all-cause mortality, nevertheless the effects of blood pressure (BP) lowering in terms of renal protection or harm remain controversial. Both home and ambulatory BP estimation have shown that patients with CKD display abnormal BP patterns outside of the office and further investigation is required, so as to compare the association of ambulatory versus office BP measurements with hard outcomes and adjust treatment strategies accordingly. Although renin-angiotensin system blockade appears to be beneficial in patients with advanced CKD, especially in the setting of proteinuria, discontinuation of renin-angiotensin system inhibition should be considered in the setting of frequent episodes of acute kidney injury or hypotension while awaiting the results of ongoing trials. In light of the new evidence in favor of renal denervation in arterial hypertension, the indications and benefits of its application in individuals with CKD need to be clarified by future studies. Moreover, the clinical utility of the novel players in the pathophysiology of arterial hypertension and CKD, such as microRNAs and the gut microbiota, either as markers of disease or as therapeutic targets, remains a subject of intensive research.

Association between prediabetes (defined by HbA1C, fasting plasma glucose, and impaired glucose tolerance) and the development of chronic kidney disease: a 9-year prospective cohort study

Background

The aim of the present study was to investigate the clinical impact of prediabetes on the development of incident chronic kidney disease (CKD) in a Korean adult population, using data from the Korea Genome and Epidemiology Study.

Methods

This prospective cohort study included 7728 Korean adults without baseline CKD and type 2 diabetes. Prediabetes was defined by impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and HbA1_C level. CKD was defined as estimated glomerular filtration rate < 60 mL/min/1.73 m². We assessed the predictive value of prediabetes for the incidence of CKD, and investigated the incidence of cardiovascular disease including coronary artery disease and stroke.

Results

Over a median follow-up period of 8.7 years, 871 of 7728 (11.3%) subjects developed incident CKD. Patients with prediabetes, as defined by IGT or HbA1_C, developed incident CKD more frequently than the non-prediabetic group did. The risk of CKD development at follow-up was analyzed according to different prediabetes definitions. Compared with the non-prediabetic group, the IGT- (Hazard ratio [HR] = 1.135, 95% confidence interval [CI] = 1.182–1.310, P = 0.043) and HbA1_C-defined prediabetic groups (HR = 1.391, 95% CI = 1.213–1.595, P < 0.001) were significantly associated with incident CKD after adjusting for traditional CKD risk factors; however, IFG was not associated with incident CKD.

Conclusion

IGT- or HbA1_C-defined prediabetes is an independent predictor of incident CKD. The measurement of these parameters might enable early detection of CKD risk, allowing physicians to initiate preventive measures and improve patient outcomes.

eGFR and coronary artery calcification in chronic kidney disease

BACKGROUND

The independent association between eGFR and coronary artery calcification (CAC) is complex and not clear. The aim of this study is to investigate the relationship between eGFR calculated from different equations and CAC in predialysis CKD patients in Korea.

METHODS

In this cross-sectional study, we analyzed 1,533 patients from the KNOW-CKD cohort. eGFR was calculated by a four-variable MDRD equation (eGFR_MDRD ), CKD-EPI creatinine equations (eGFR_{C r} ), CKD-EPI Cystatin C equation (eGFR_{C ys} ), and CKD-EPI Creatinine-Cystatin equation (eGFR_{C rC ys} ). Participants were divided into eGFR categories (< 30, 30-59, 60-89, ≥ 90 ml/min/1.73 m² ). CACS (coronary artery calcium score) was measured using cardiac computed tomography. CAC was defined as CACS > 100.

RESULTS

CAC was found in 334 (21.8%) patients, and was more prevalent in the lower eGFR groups (p < 0.001). In multivariate Tobit regression, CACS increased gradually as eGFR_{C rC ys} decreased (p for trend = 0.034). In multivariate logistic regression, there were gradual associations between lower eGFR and CAC when an eGFR_{C ys} or eGFR_{C rC ys} was used. The adjusted OR for CAC in the group with eGFR < 30 ml/min/1.73m² compared to the group with eGFR ≥ 90 ml/min/1.73m² was 2.64 (95% CI, 1.09-3.60) when eGFR_{C rC ys} was used. Of the four eGFR formulas, only adding eGFR_{C rC ys} significantly improved CAC prediction models without eGFR (p = 0.046).

CONCLUSIONS

There was a gradual and independent association between low eGFR and CAC in a predialysis CKD cohort in Korea. eGFR_{C rC ys} predicted CAC better than other equations in this population. This article is protected by copyright. All rights reserved.

Association of Candidate Gene Polymorphisms With Chronic Kidney Disease: Results of a Case-Control Analysis in the Nefrona Cohort

Chronic kidney disease (CKD) is a major risk factor for end-stage renal disease, cardiovascular disease and premature death. Despite classical clinical risk factors for CKD and some genetic risk factors have been identified, the residual risk observed in prediction models is still high. Therefore, new risk factors need to be identified in order to better predict the risk of CKD in the population. Here, we analyzed the genetic association of 79 SNPs of proteins associated with mineral metabolism disturbances with CKD in a cohort that includes 2,445 CKD cases and 559 controls. Genotyping was performed with matrix assisted laser desorption ionization–time of flight mass spectrometry. We used logistic regression models considering different genetic inheritance models to assess the association of the SNPs with the prevalence of CKD, adjusting for known risk factors. Eight SNPs (rs1126616, rs35068180, rs2238135, rs1800247, rs385564, rs4236, rs2248359, and rs1564858) were associated with CKD even after adjusting by sex, age and race. A model containing five of these SNPs (rs1126616, rs35068180, rs1800247, rs4236, and rs2248359), diabetes and hypertension showed better performance than models considering only clinical risk factors, significantly increasing the area under the curve of the model without polymorphisms. Furthermore, one of the SNPs (the rs2248359) showed an interaction with hypertension, being the risk genotype affecting only hypertensive patients. We conclude that 5 SNPs related to proteins implicated in mineral metabolism disturbances (Osteopontin, osteocalcin, matrix gla protein, matrix metalloprotease 3 and 24 hydroxylase) are associated to an increased risk of suffering CKD.

Diabetes Mellitus: Preoperative Concerns and Evaluation

Diabetes is an important cause of morbidity in the adult population resulting in blindness, renal dysfunction, cardiovascular events, and amputation. Such morbidities may have an impact on perioperative anesthetic care and outcomes. In this review, the authors discuss the preoperative considerations in managing patients with diabetes as well as those without diabetes albeit hyperglycemic. They propose a plan for managing preoperative diabetes pharmacotherapy, including the use of a subcutaneous insulin pump to avoid both hypoglycemia and hyperglycemia. The authors also discuss the decision whether to proceed or cancel surgery for a given hemoglobin A1c percentage or blood glucose concentration.

Predicting outcomes of chronic kidney disease from EMR data based on Random Forest Regression

Chronic kidney disease (CKD) is prevalent across the world, and kidney function is well defined by an estimated glomerular filtration rate (eGFR). The progression of kidney disease can be predicted if the future eGFR can be accurately estimated using predictive analytics. In this study, we developed and validated a prediction model of eGFR by data extracted from a regional health system. This dataset includes demographic, clinical and laboratory information from primary care clinics. The model was built using Random Forest regression and evaluated using Goodness-of-fit statistics and discrimination metrics. After data preprocessing, the patient cohort for model development and validation contained 61,740 patients. The final model included eGFR, age, gender, body mass index (BMI), obesity, hypertension, and diabetes, which achieved a mean coefficient of determination of 0.95. The estimated eGFRs were used to classify patients into CKD stages with high macro-averaged and micro-averaged metrics. In conclusion, a model using real-world electronic medical records (EMR) data can accurately predict future kidney functions and provide clinical decision support.

Effect of Hepatitis C Treatment on Renal Function in Liver Transplant Patients

Background and Aims: Hepatitis C Virus (HCV) is uniformly recurrent after liver transplant (LT) and recurrence is associated with an increased risk of mortality. Immunosuppressive medications increase the risk of chronic kidney disease, and the presence of chronic kidney disease presents a challenge for HCV treatment in LT recipients. The aim of this study was to assess changes in glomerular filtration rates (GFRs) of LT recipients receiving HCV treatment. Methods: This is a retrospective study of LT patients who received HCV treatment between 2015 and 2016 (n = 60). The outcomes of interest were differences in serum creatinine levels and in GFR, measured at treatment initiation and at 24 weeks after treatment. The average age of the patients was 59 years-old, and 17% were cirrhotic and 67% were treatment-experienced. All patients received sofosbuvir/ledipasvir without ribavirin. Results: All patients achieved sustained virologic response at 12 weeks after treatment (SVR12). At baseline, 55% of patients had GFR <60 mL/min per 1.73 m². Among those patients, GFR did not change in 18%, 33% had improved GFR, and 48% had worsened GFR. Up to 45% of the patients had a GFR >60 mL/min per 1.73 m². Among those patients, GFR did not change in 81%, and 19% had worsened GFR. In the entire cohort, 65% of patients had improved or stable GFR and 35% had worsened GFR. The average change in serum creatinine between baseline and 24 weeks was 0.10 (p = 0.18). Conclusions: This study showed improved or unchanged GFR in 65% and worsened GFR in 35% of LT recipients who achieved SVR12. Worsening of GFR was more frequently encountered in those with impaired renal function at baseline. Caution should be used when treating HCV in LT recipients, especially those with baseline status of renal impairment.

Incipient Albuminuria in Persons with Newly Diagnosed Type 2 Diabetes Mellitus: A 5-Year Retrospective Cohort Study

Introduction: This study aimed to determine the 5-year incidence of  albuminuria among Asian persons with newly diagnosed type 2 diabetes mellitus (DM), and to identify the risk factors at diagnosis for progression to albuminuria. Materials and Methods: A retrospective 5-year closed cohort study was conducted among 1016 persons aged ≥18 years old who were diagnosed with type 2 DM between 1 January 2007 and 31 December 2009 at primary care facilities in Singapore. The cumulative incidence of  progression from normoalbuminuria to albuminuria—termed “progression”—was determined. The risk factors associated with progression were evaluated using multiple logistic regression analysis. Results: A total of 541 (53.2%) participants were men. The mean (SD) onset age of type 2 DM was 54 (11) years. From diagnosis of type 2 DM, the 5-year cumulative incidence of  progression was 17.3% and mean (SD) duration to progression was 2.88 (1.23) years. Higher onset age (OR 1.02; 95% CI, 1.00-1.04), history of  hypertension (OR, 1.88; 95% CI, 1.32-2.70) and higher glycated haemoglobin (HbA1c) (OR, 1.17; 95% CI, 1.09-1.26) at diagnosis were associated with progression. In addition, being on angiotensin converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) treatment at baseline modified the effect of hypertension on progression. Conclusion: This study highlighted the importance of early screening and treatment of diabetes as well as prevention of hypertension, which could potentially delay the onset of  microalbuminuria in persons with type 2 DM. Persons on ACEI or ARB treatment should continue to be monitored regularly for progression to albuminuria. Key words: Incidence, New onset, Proteinuria, Risk factors

Association between metabolic parameters and glomerular hyperfiltration in a representative Korean population without chronic kidney disease

Aims

To investigate associations of glomerular hyperfiltration with other metabolic factors in a nationally representative dataset.

Methods

We analyzed cross-sectional data from 15,918 subjects with estimated glomerular filtration rate (eGFR) >60 ml/min/1.73 m² and urine albumin creation ratio (ACR) <30 mg/g, who participated in the 5th and 6th Korea National Health and Nutrition Examination Surveys. Hyperfiltration was defined as eGFR (CKD-EPI equation) exceeding the age- and sex-specific 95th percentile for healthy control subjects.

Results

Prevalence of hyperfiltration was 5.2% and that among normal, prediabetic, and diabetic subjects was 4.9%, 5.6%, and 7.3%, respectively, after adjusting for age, sex, and body weight (p for trend = 0.008). In a multiple logistic regression analysis, hyperfiltration was associated with a body mass index ≥30 kg/m² [odds ratio (OR) = 3.461, p<0.001], waist circumference 85 cm (men) or 80 cm (women) (OR = 1.425, p = 0.015), systolic blood pressure 120–129 mmHg (OR = 1.644, p = 0.022), fasting plasma glucose 140 mg/dL (OR = 1.695, p = 0.033) and t serum triglyceride level 500 mg/dL (OR = 2.988, p = 0.001), and was independently associated with the ACR (B = 0.053, p<0.001).

Conclusions

In a general Korean population, both hyperfiltration and ACR were associated with similar metabolic parameters, and hyperfiltration correlated independently with a high ACR. Longitudinal studies are needed to further explore risks of hyperfiltration and microalbuminuria.

Cadmium affects blood pressure and negatively interacts with obesity: Findings from NHANES 1999-2014

Inconsistencies are noted regarding the association between cadmium exposure and blood pressure/hypertension and the interaction between cadmium and body mass index (BMI). This study aims to clarify these inconsistencies in a large sample (n = 32,791) of adults age ≥20 years from eight cycles of the US National Health Examination and Nutrition Survey (NHANES, 1999-2014). The cadmium levels in blood (BCd) and urine (UCd) were used as exposure biomarker. Multiple-linear/logistic regression models were built and stratified by sex, ethnicity and BMI category. The interaction between BCd and BMI was assessed on additive and multiplicative scales. A twofold increase in BCd was associated with 0.54 mm Hg (95% CI: 0.49, 0.58) and 0.05 mm Hg (95% CI: 0.04, 0.06) increases in the systolic blood pressure (SBP) and diastolic blood pressure (DBP), respectively, in black women. The SBP and DBP increased by 0.92 mm Hg (95% CI: 0.73, 1.11) and 0.85 mm Hg (95% CI: 0.65, 1.05), respectively, in Mexican-Am women. Significant associations were found between BCd and hypertension in them (systolic risk per twofold BCd, OR = 1.31; 95% CI: 1.07, 1.61; and diastolic risk per twofold BCd, OR = 1.55; 95% CI: 1.17, 2.05). UCd was significantly associated with hypertension in all individuals (OR = 1.14 per twofold; 95% CI: 1.07, 1.21). The associations between cadmium exposure and blood pressure/hypertension showed some discrepancies across BMI categories. A negative interaction was observed between BCd and obesity with regard to their effects on systolic hypertension (RERI = -0.30; 95% CI: -0.56, -0.03; ratio of ORs = 0.55; 95% CI: 0.35, 0.89). Our findings provided evidence for the effect of cadmium on blood pressure and the prevalence of hypertension in American adults. The associations showed discrepancies by sex and ethnicity. The negative interaction between cadmium exposure and obesity influenced systolic hypertension risk.

Increased end-stage renal disease risk in patients with inflammatory bowel disease: A nationwide population-based study

AIM

To estimate the risk of end-stage renal disease (ESRD) in patients with inflammatory bowel disease (IBD).

METHODS

From January 2010 to December 2013, patients with Crohn’s disease (CD) and ulcerative colitis (UC) were identified, based on both the International Classification of Diseases, 10^th revision (ICD-10) and the rare, intractable disease registration program codes from the National Health Insurance (NHI) database in South Korea. We compared 38812 patients with IBD to age- and sex-matched non-IBD controls with a ratio of 1:3. Patients newly diagnosed with ESRD were identified with the ICD-10 code.

RESULTS

During a mean follow-up of 4.9 years, ESRD was detected in 79 (0.2%) patients with IBD and 166 (0.1%) controls. The incidence of ESRD in patients with IBD was 0.42 per 1000 person-years. Patients with IBD had a significantly higher risk of ESRD than controls [adjusted hazard ratio (HR) = 3.03; 95% confidence interval (CI): 1.77-5.20; P < 0.001]. The incidences (per 1000 person-years) of ESRD were 0.51 in patients with CD and 0.13 in controls, respectively (adjusted HR = 6.33; 95%CI: 2.75-14.56; P < 0.001). In contrast, the incidence of ESRD was similar between the UC and control groups (0.37 vs 0.37 per 1000 person-years; adjusted HR = 2.01; 95%CI: 0.90-4.51; P = 0.089).

CONCLUSION

The risk of ESRD was elevated in patients with CD, but not UC. Patients with CD should be monitored carefully for signs of renal insufficiency.

Kidney Damage Biomarkers and Incident Chronic Kidney Disease During Blood Pressure Reduction: A Case-Control Study

BACKGROUND

Whether the increased incidence of chronic kidney disease (CKD) during intensive systolic blood pressure (SBP) lowering is accompanied by intrinsic kidney injury is unknown.

OBJECTIVE

To compare changes in kidney damage biomarkers between incident CKD case participants and matched control participants as well as between case participants in the intensive (<120 mm Hg) versus the standard (<140 mm Hg) SBP management groups of SPRINT (Systolic Blood Pressure Intervention Trial).

DESIGN

Nested case-control study within SPRINT.

SETTING

Adults with hypertension without baseline kidney disease.

PARTICIPANTS

Case participants (n = 162), who developed incident CKD during trial follow-up (128 in the intensive and 34 in the standard group), and control participants (n = 162) without incident CKD, who were matched on age, sex, race, baseline estimated glomerular filtration rate, and randomization group.

MEASUREMENTS

9 urinary biomarkers of kidney damage were measured at baseline and at 1 year. Linear mixed-effects models were used to estimate 1-year biomarker changes.

RESULTS

Higher concentrations of urinary albumin, kidney injury molecule-1, and monocyte chemoattractant protein-1 at baseline were significantly associated with greater odds of incident CKD (adjusted odds ratio per doubling: 1.50 [95% CI, 1.14 to 1.98], 1.51 [CI, 1.05 to 2.17], and 1.70 [CI, 1.13 to 2.56], respectively). After 1 year of blood pressure intervention, incident CKD case participants in the intensive group had significantly greater decreases in albumin-creatinine ratio (ACR), interleukin-18, anti-chitinase-3-like protein 1 (YKL-40), and uromodulin than the matched control participants. Compared with case participants in the standard group, those in the intensive group had significantly greater decreases in ACR, β2-microglobulin, α1-microglobulin, YKL-40, and uromodulin.

LIMITATION

Biomarker measurements were available only at baseline and 1 year.

CONCLUSION

Incident CKD in the setting of intensive SBP lowering was accompanied by decreases, rather than elevations, in levels of kidney damage biomarkers and thus may reflect benign changes in renal blood flow rather than intrinsic injury.

PRIMARY FUNDING SOURCE

National Institute for Diabetes and Digestive and Kidney Diseases.

Changes in Kidney Function Do Not Differ between Healthy Adults Consuming Higher- Compared with Lower- or Normal-Protein Diets: A Systematic Review and Meta-Analysis

Background

Higher-protein (HP) diets are advocated for several reasons, including mitigation of sarcopenia, but their effects on kidney function are unclear.

Objective

This meta-analysis was conducted to determine the effect of HP intakes on kidney function in healthy adults.

Methods

We conducted a systematic review and meta-analysis of trials comparing HP (≥1.5 g/kg body weight or ≥20% energy intake or ≥100 g protein/d) with normal- or lower-protein (NLP; ≥5% less energy intake from protein/d compared with HP group) intakes on kidney function. Medline and EMBASE databases were searched. Randomized controlled trials comparing the effects of HP with NLP (>4 d duration) intakes on glomerular filtration rate (GFR) in adults without kidney disease were included.

Results

A total of 2144 abstracts were reviewed, with 40 articles selected for full-text review; 28 of these were analyzed and included data from 1358 participants. Data were analyzed using random-effects meta-analysis (RevMan 5; The Cochrane Collaboration), meta-regression (STATA; StataCorp), and dose-response analysis (Prism; GraphPad). Analyses were conducted using postintervention (post) GFR and the change in GFR from preintervention to post. The post-only comparison showed a trivial effect for GFR to be higher after HP intakes [standardized mean difference (SMD): 0.19; 95% CI: 0.07, 0.31; P = 0.002]. The change in GFR did not differ between interventions (SMD: 0.11; 95% CI: -0.05, 0.27; P = 0.16). There was a linear relation between protein intake and GFR in the post-only comparison (r = 0.332, P = 0.03), but not between protein intake and the change in GFR (r = 0.184, P = 0.33). The main limitation of the current analysis is the unclear risk of selection bias of the included trials.

Conclusions

Postintervention GFR comparisons indicate that HP diets result in higher GFRs; however, when changes in GFR were compared, dietary protein had no effect. Our analysis indicates that HP intakes do not adversely influence kidney function on GFR in healthy adults.

Risk of chronic kidney disease in patients with gout and the impact of urate lowering therapy: a population-based cohort study

Background

An association between gout and renal disease is well-recognised but few studies have examined whether gout is a risk factor for subsequent chronic kidney disease (CKD). Additionally, the impact of urate-lowering therapy (ULT) on development of CKD in gout is unclear. The objective of this study was to quantify the risk of CKD stage ≥ 3 in people with gout and the impact of ULT.

Methods

This was a retrospective cohort study using data from the Clinical Practice Research Datalink (CPRD). Patients with incident gout were identified from general practice medical records between 1998 and 2016 and randomly matched 1:1 to patients without a diagnosis of gout based on age, gender, available follow-up time and practice. Primary outcome was development of CKD stage ≥ 3 based on estimated glomerular filtration rate (eGFR) or recorded diagnosis. Absolute rates (ARs) and adjusted hazard ratios (HRs) were calculated using Cox regression models. Risk of developing CKD was assessed among those prescribed ULT within 1 and 3 years of gout diagnosis.

Results

Patients with incident gout (n = 41,446) were matched to patients without gout. Development of CKD stage ≥ 3 was greater in the exposed group than in the unexposed group (AR 28.6 versus 15.8 per 10,000 person-years). Gout was associated with an increased risk of incident CKD (adjusted HR 1.78 95% CI 1.70 to 1.85). Those exposed to ULT had a greater risk of incident CKD, but following adjustment this was attenuated to non-significance in all analyses (except on 3-year analysis of women (adjusted HR 1.31 95% CI 1.09 to 1.59)).

Conclusions

This study has demonstrated gout to be a risk factor for incident CKD stage ≥ 3. Further research examining the mechanisms by which gout may increase risk of CKD and whether optimal use of ULT can reduce the risk or progression of CKD in gout is suggested.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1746-1) contains supplementary material, which is available to authorized users.

Sleep duration and risk of end-stage renal disease: the Singapore Chinese Health Study

OBJECTIVES

Although epidemiological evidence suggests that short sleep duration may affect renal function, the influence of long sleep and risk of end-stage renal disease (ESRD) is unclear. We examined the association between sleep duration and risk of ESRD.

METHODS

We investigated sleep duration and ESRD risk in the Singapore Chinese Health Study, a prospective population-based cohort of 63,257 Chinese in Singapore, who were aged 45-74 years at recruitment (1993-1998). Information on daily sleep duration (including naps), diet, medical history and other lifestyle factors was collected at recruitment from in-person interviews. ESRD cases were identified via linkage with the nationwide Singapore Renal Registry through year 2014. We used the Cox proportional hazards regression method to estimate hazard ratio (HR) and 95% confidence interval (CI) of ESRD in relation to sleep duration.

RESULTS

After an average 16.8 years of follow-up, 1143 (1.81%) ESRD cases were documented. Sleep duration had a U-shaped association with risk of ESRD (P for quadratic trend < 0.001). Compared with participants with 7 h/day of sleep, the multivariable adjusted HR (95% CI) of ESRD was 1.43 (1.18-1.74) for short sleep (≤5 h/day) and 1.28 (1.03-1.60) for long sleep duration (≥9 h/day). The increased risk was stronger in participants with more than 10 years of follow-up compared to those with shorter follow-up time, especially for long sleep (P for interaction = 0.003).

CONCLUSIONS

Our findings demonstrated that both short and long sleep durations were associated with a higher risk of ESRD in this Asian population.

Impact of bariatric surgery on cardiovascular and renal complications of diabetes: a focus on clinical outcomes and putative mechanisms

INTRODUCTION

Cardiovascular and renal disease accounts for a substantial proportion of the morbidity and mortality associated with obesity and type 2 diabetes mellitus (T2DM). Bariatric surgery is associated with improved long-term cardiovascular and renal outcomes.

AREAS COVERED

All major case-control, cohort, and randomized controlled trial studies of bariatric surgery in adults with T2DM were screened and data on prespecified cardiovascular and renal outcomes collated. Bariatric surgery reduces all-cause mortality and risk of cardiovascular disease, albuminuria and progressive chronic kidney disease. Patients with poorer glycemic control and established microvascular disease preoperatively may stand to benefit the most from the surgical approach. Reduced sympathetic drive, remission of glomerular hypertension, enhanced natriuresis, gut microbiota shifts, reduced systemic and renal inflammation, improved lipoprotein profiles, and reductions in chronic cardiac remodeling may all be implicated.

EXPERT COMMENTARY

Ongoing RCTs of bariatric surgery selectively recruiting patients with class 1 obesity and established microvascular complications of diabetes will help to better characterize which subgroups of patients benefit most from this effective therapy.

Lenalidomide and dexamethasone in patients with relapsed multiple myeloma and impaired renal function: PrE1003, a PrECOG study

Renal insufficiency is common in patients with relapsed multiple myeloma and can often limit choice of therapy. Lenalidomide, a critical agent in the treatment of relapsed multiple myeloma, is renally cleared., This phase I/II trial evaluated the efficacy and safety of lenalidomide with dexamethasone in patients with relapsed multiple myeloma and renal insufficiency. Three groups were treated, with creatinine clearance 30–60 cc/hr (group A), CrCl < 30 not on dialysis (group B), and patients on dialysis (group C) at escalating doses of lenalidomide. A total of 63 patients were treated and no DLTs were observed in phase I. All three groups were able to escalate to full dose lenalidomide 25 mg daily 21/28 days, although due to reduced accrual the phase II component was not entirely completed for groups B and C. Adverse events were as expected, including anemia, diarrhea and fatigue. Ten patients experienced grade 3–4 pneumonia. Overall response rate was 54% across all groups. PFS was 7.5 months and OS was 19.7 months. Lenalidomide can be given at full dose 25 mg daily 21/28 in patients with a CrCl > 30, and can be given daily to those with CrCl < 30, even when on dialysis, at doses of at least 15 mg daily.

Progression to chronic kidney disease in patients undergoing nephrectomy for small renal masses: a price to pay for a therapeutic success?

Nephrectomy, which constitutes a gold-standard procedure for the treatment of renal-cell carcinoma (RCC), has been widely discussed in the past decade as a significant risk factor of the development of chronic kidney disease (CKD). RCC is the third most common genitourinary cancer in the United States, with an estimated more than 65,000 new cases and 14,970 deaths. The aim of this review was to precisely and comprehensively summarize the status of current knowledge in CKD risk factors after nephrectomy, the advantages of minimally invasive vs. radical nephrectomy, post-nephrectomy biomarkers of CKD, ways of post-operative CKD prevention and, therefore, better understand why various aspects of CKD after nephrectomy. The majority of current studies indicated a better long-term kidney function preservation in patients undergoing partial nephrectomy in comparison to those after radical nephrectomy. Furthermore, a nephron-sparing surgery should be a preferred first-line procedure among young patients with small renal masses. As partial nephrectomy is followed by a greater risk of adverse outcomes relative to radical nephrectomy, a potential survival benefit should always be considered especially in the elderly or patients with comorbidities.

Sociodemographic associations with abnormal estimated glomerular filtration rate (eGFR) in a large Canadian city: a cross-sectional observation study

BACKGROUND

Chronic kidney disease (CKD) is often asymptomatic in its early stages but is indicated and is diagnosed with an estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73m2. Certain sociodemographic groups are known to be at risk for CKD, but it is unclear if there are strong associations between these at risk groups with abnormal eGFR test results in Canada. Using only secondary laboratory and Census data, geospatial variation and sociodemographic associations with abnormal eGFR result rate were investigated in Calgary, Alberta.

METHODS

Secondary laboratory data from all adult community patients who received an eGFR test result were collected from Calgary Laboratory Service's Laboratory Information System, which is the sole supplier of laboratory services for the large metropolitan city. Group-level sociodemographic variables were inferred by combining laboratory data with the 2011 Canadian Census data. Poisson regression and relative risk (RR) were used to calculate associations between sociodemographic variables with abnormal eGFR. Geographical distribution of abnormal eGFR result rates were analyzed by geospatial analysis using ArcGIS.

RESULTS

Of the 346,663 adult community patients who received an eGFR test result, 28,091 were abnormal (8.1%; eGFR < 60 ml/min/1.73m2). Geospatial analysis revealed distinct geographical variation in abnormal eGFR result rates in Calgary. Women (RR = 1.11, P < 0.0001), and the elderly (age ≥ 70 years; P < 0.0001) were significantly associated with an increased risk for CKD, while visible minority Chinese (RR = 0.73, P = 0.0011), South Asians (RR = 0.67, P < 0.0001) and those with a high median household income (RR = 0.88, P < 0.0001) had a significantly reduced risk for CKD.

CONCLUSIONS

Presented here are significant sociodemographic risk associations, and geospatial clustering of abnormal eGFR result rates in a large metropolitan Canadian city. Using solely publically available secondary laboratory and Census data, the results from this study aligns with known sociodemographic risk factors for CKD, as certain sociodemographic variables were at a higher risk for having an abnormal eGFR test result, while others were protective in this analysis.

Intracellular lipids are an independent cause of liver injury and chronic kidney disease in non alcoholic fatty liver disease-like context

Objective

Ectopic lipid accumulation in the liver and kidneys is a hallmark of metabolic diseases leading to non-alcoholic fatty liver disease (NAFLD) and chronic kidney disease (CKD). Moreover, recent data have highlighted a strong correlation between NAFLD and CKD incidences. In this study, we use two mouse models of hepatic steatosis or CKD, each initiated independently of the other upon the suppression of glucose production specifically in the liver or kidneys, to elucidate the mechanisms underlying the development of CKD in the context of NAFLD-like pathology.

Methods

Mice with a deletion of G6pc, encoding glucose-6 phosphatase catalytic subunit, specifically in the liver (L.G6pc^−/− mice) or the kidneys (K.G6pc^−/− mice), were fed with either a standard diet or a high fat/high sucrose (HF/HS) diet during 9 months. These mice represent two original models of a rare metabolic disease named Glycogen Storage Disease Type Ia (GSDIa) that is characterized by both NAFLD-like pathology and CKD. Two other groups of L.G6pc^−/− and K.G6pc^−/− mice were fed a standard diet for 6 months and then treated with fenofibrate for 3 months. Lipid and glucose metabolisms were characterized, and NAFLD-like and CKD damages were evaluated.

Results

Lipid depot exacerbation upon high-calorie diet strongly accelerated hepatic and renal pathologies induced by the G6pc-deficiency. In L.G6pc^−/− mice, HF/HS diet increased liver injuries, characterized by higher levels of plasmatic transaminases and increased hepatic tumor incidence. In K.G6pc^−/− mice, HF/HS diet increased urinary albumin and lipocalin 2 excretion and aggravated renal fibrosis. In both cases, the worsening of NAFLD-like injuries and CKD was independent of glycogen content. Furthermore, fenofibrate, via the activation of lipid oxidation significantly decreased the hepatic or renal lipid accumulations and prevented liver or kidney damages in L.G6pc^−/− and K.G6pc^−/− mice, respectively. Finally, we show that L.G6pc^−/− mice and K.G6pc^−/− mice developed NAFLD-like pathology and CKD independently.

Conclusions

This study highlights the crucial role that lipids play in the independent development of both NAFLD and CKD and demonstrates the importance of lipid-lowering treatments in various metabolic diseases featured by lipid load, from the “rare” GSDIa to the “epidemic” morbid obesity or type 2 diabetes.

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Exacerbating lipid accumulation aggravates liver/kidney injury in GSDI.

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Fenofibrate-mediated PPARα activation induces hepatic and renal lipid turnover.

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Increased lipid turnover prevents glycogen synthesis and accumulation.

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PPARα–mediated metabolic reprograming prevents hepatic and renal GSDI complications.

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NAFLD and CKD develop independently.

Epithelial Cell Cycle Behaviour in the Injured Kidney

Acute kidney injury (AKI), commonly caused by ischemia-reperfusion injury, has far-reaching health consequences. Despite the significant regenerative capacity of proximal tubular epithelium cells (PTCs), repair frequently fails, leading to the development of chronic kidney disease (CKD). In the last decade, it has been repeatedly demonstrated that dysregulation of the cell cycle can cause injured kidneys to progress to CKD. More precisely, severe AKI causes PTCs to arrest in the G1/S or G2/M phase of the cell cycle, leading to maladaptive repair and a fibrotic outcome. The mechanisms causing these arrests are far from known. The arrest might, at least partially, be attributed to DNA damage since activation of the DNA-damage response pathway leads to cell cycle arrest. Alternatively, cytokine signalling via nuclear factor kappa beta (NF-κβ) and p38-mitogen-activated protein kinase (p38-MAPK) pathways, and reactive oxygen species (ROS) can play a role independent of DNA damage. In addition, only a handful of cell cycle regulators (e.g., p53, p21) have been thoroughly studied during renal repair. Still, why and how PTCs decide to arrest their cell cycle and how this arrest can efficiently be overcome remain open and challenging questions. In this review we will discuss the evidence for cell cycle involvement during AKI and development of CKD together with putative therapeutic approaches.

Dairy products and chronic kidney disease: protective or harmful? asystematic review of prospective cohort studies

OBJECTIVE

Evidence on the relationship between food sources of protein and progressive decline in renal function in the general population is still controversial. Among the protein-rich foods, dairy products have gained a lot of attention in research on the prevention of metabolic disorders. This systemic review attempted to summarize the findings of prospective cohort studies on the relationship between dairy foods and incident chronic kidney disease (CKD) in the general population.

METHODS

The PubMed, Embase, Scopus, and Web of Science databases were searched from inception up to January 2018 with no restriction on the language of publication. Studies conducted in the general population with consumption of dairy foods as the exposure of interest and with incident CKD and/or decline in renal function as the study outcome were eligible for inclusion in the review.

RESULTS

Of the 391 articles that were extracted through database searching, 7 were included in the review. Of the seven studies, five reported a protective association for dairy consumption, particularly low-fat dairy, against incident CKD or rapid decline in renal function; however, two studies did not find such an association.

CONCLUSION

Despite the limited studies on this topic, findings from the available reports are generally in favor of a positive association between dairy and renal health in the general population. However, further studies are needed to replicate this finding and to determine whether this relationship could be influenced by the fat content and/or the dairy subtypes.

Chronic kidney disease in patients at high risk of cardiovascular disease in the United Arab Emirates: A population-based study

Chronic kidney disease has become an increasingly significant clinical and public health issue, accounting for 1.1 million deaths worldwide. Information on the epidemiology of chronic kidney disease and associated risk factors is limited in the United Arab Emirates. Therefore, this study aimed to evaluate the incidence and causes of chronic kidney disease stages 3-5 in adult United Arab Emirates nationals with or at high risk of cardiovascular disease. This retrospective study included 491 adults with or at high risk of cardiovascular disease (diabetes mellitus or associated clinical disease) who attended outpatient clinics at a tertiary care hospital in Al-Ain, United Arab Emirates. Estimated glomerular filtration rate was assessed every 3 months from baseline to June 30, 2017. Chronic kidney disease stages 3-5 were defined as an estimated glomerular filtration rate < 60 mL/min/1.73 m2 for ≥ 3 months. Multivariable Cox's proportional hazards analysis was used to determine the independent risk factors associated with developing chronic kidney disease stages 3-5. The cumulative incidence of chronic kidney disease stages 3-5 over a 9-year period was 11.4% (95% confidence interval 8.6, 14.0). The incidence rate of these disease stages was 164.8 (95% confidence interval 121.6, 207.9) per 10,000 person-years. The independent risk factors for developing chronic kidney disease stages 3-5 were older age, history of coronary heart disease, history of diabetes mellitus, and history of smoking. These data may be useful to develop effective strategies to prevent chronic kidney disease development in high-risk United Arab Emirates nationals.

Decline of kidney function during the pre-dialysis period in chronic kidney disease patients: a systematic review and meta-analysis

Purpose

Substantial heterogeneity exists in reported kidney function decline in pre-dialysis chronic kidney disease (CKD). By design, kidney function decline can be studied in CKD 3–5 cohorts or dialysis-based studies. In the latter, patients are selected based on the fact that they initiated dialysis, possibly leading to an overestimation of the true underlying kidney function decline in the pre-dialysis period. We performed a systematic review and meta-analysis to compare the kidney function decline during pre-dialysis in CKD stage 3–5 patients, in these two different study types.

Patients and methods

We searched PubMed, EMBASE, Web of Science and Cochrane to identify eligible studies reporting an estimated glomerular filtration rate (eGFR) decline (mL/min/1.73 m²) in adult pre-dialysis CKD patients. Random-effects meta-analysis was performed to obtain weighted mean annual eGFR decline.

Results

We included 60 studies (43 CKD 3–5 cohorts and 17 dialysis-based studies). The meta-analysis yielded a weighted annual mean (95% CI) eGFR decline during pre-dialysis of 2.4 (95% CI: 2.2, 2.6) mL/min/1.73 m² in CKD 3–5 cohorts compared to 8.5 (95% CI: 6.8, 10.1) in dialysis-based studies (difference 6.0 [95% CI: 4.8, 7.2]).

Conclusion

To conclude, dialysis-based studies report faster mean annual eGFR decline during pre-dialysis than CKD 3–5 cohorts. Thus, eGFR decline data from CKD 3–5 cohorts should be used to guide clinical decision making in CKD patients and for power calculations in randomized controlled trials with CKD progression during pre-dialysis as the outcome.

Exploratory Cluster Analysis to Identify Patterns of Chronic Kidney Disease in the 500 Cities Project

Chronic kidney disease is a leading cause of death in the United States. We used cluster analysis to explore patterns of chronic kidney disease in 500 of the largest US cities. After adjusting for socio-demographic characteristics, we found that unhealthy behaviors, prevention measures, and health outcomes related to chronic kidney disease differ between cities in Utah and those in the rest of the United States. Cluster analysis can be useful for identifying geographic regions that may have important policy implications for preventing chronic kidney disease.