Prevalence and risk factors associated with chronic kidney disease in adults over 40 years: a population study from Central China

Ocular findings, surgery details and outcomes in proliferative diabetic retinopathy patients with chronic kidney disease

Purpose

We investigated the influence of impaired renal function on fundus characteristics, pars-plana vitrectomy (PPV) details, and outcomes in patients with proliferative diabetic retinopathy (PDR).

Design

A retrospective cohort study

Methods

We investigated a consecutive series of PDR patients who underwent PPV. The diabetic complications, previous photocoagulation, intravitreal injections before PPV, ocular findings during PPV, surgical details, short-term visual outcome and post-PPV complications were recorded and compared between patients with and without impaired renal function.

Results

149 patients had normal renal function (67.7%), and 71 (32.3%) patients had impaired renal function; 85.4% of patients were identified with chronic kidney disease (CKD) during the preoperative assessment. Impaired renal function was related to hypertension (3.40[1.58–7.29], p = 0.002), incomplete pan-retinal photocoagulation (PRP) (3.18[1.50–6.72], p = 0.002), severe fibrovascular membrane (8.19[3.43–19.54], p<0.001), and extensive retinal vascular closure (3.40[1.54–7.52], p = 0.002). There was a more frequent occurrence of severe intraoperative bleeding (56.3%, 32.2%, p = 0.001) and a higher percentage of intraocular subretinal fluid drainage (45.1%, 22.1%, p = 0.008) in patients with impaired renal function. The percentage of patients whose visual acuity (VA) increased was similar between the two groups (42.3%, 54.4%, p = 0.34).

Conclusions

In PDR patients, screening for CKD was required before PPV. PDR patients with impaired renal function tended to have more severe ischemic retinal conditions. Comparable PPV outcomes could be obtained in patients with and without impaired renal damage.

Prevalence of chronic kidney disease and associated factors among patients visiting renal unit of St. Paul's Hospital Millennium Medical College, Addis Ababa, Ethiopia: A cross-sectional study design

Objective:

This study aimed to assess the magnitude of chronic kidney disease among patients attending the renal unit of St. Paul’s Hospital Millennium Medical College, Addis Ababa, Ethiopia.

Methods:

Institution-based cross-sectional study was conducted among 620 randomly selected patients who visited St. Paul’s Hospital Millennium Medical College renal unit from 1 January to 31 December, 2019. Data on sociodemographic characteristics, clinical conditions, behavioral risk factors, electrolytes, and renal function tests were extracted from patients’ medical records. To enter and analyze data, EpiData 3.1 and SPSS 22 were used, respectively. Bivariable and multivariable logistic regression analyses were conducted to see the association between predictor variables and chronic kidney disease. Adjusted odds ratio at 95% confidence interval was used to describe significant association. A p-value <0.05 was considered to declare an association between chronic kidney disease and independent variables.

Results:

Of 620 patients, 139 (22.4%; 95% confidence interval: 19.2, 25.6) and 61 (9.8%; 95% confidence interval: 7.4, 12.3) had chronic kidney disease using cut-off value of 90 and 60 ml/min/1.73 m², respectively. Having urinary tract obstruction (adjusted odds ratio = 2.32; 95% confidence interval: 1.32, 4.06), hypertension (adjusted odds ratio = 4.06; 95% confidence interval: 2.50, 6.59), diabetes mellitus (adjusted odds ratio = 2.80; 95% confidence interval: 1.62, 4.85), cardiovascular disease (adjusted odds ratio = 2.54; 95% confidence interval: 1.60, 4.01), and age (adjusted odds ratio = 1.83; 95% confidence interval: 1.44, 3.57), family history of chronic kidney disease (adjusted odds ratio = 2.26; 95% confidence interval: 1.36, 3.75) were factors positively associated with having chronic kidney disease.

Conclusion:

Nearly, one out of five and one out of ten patients who visited the renal unit had chronic kidney disease using the two thresholds as a cut value. Patients with concomitant urinary tract obstruction, age, hypertension, diabetes mellitus, cardiovascular disease, and a family history of chronic kidney disease were more likely to develop chronic kidney disease. Regular screening for chronic kidney disease, optimal blood sugar, and blood pressure management should be practiced.

Results of a community-based screening programme for chronic kidney disease and associated risk factors, (obesity, diabetes and hypertension) in a Samoan cohort

OBJECTIVES

In 2019, under the World Kidney Day theme of 'Kidney health for everyone everywhere', the National Kidney Foundation of Samoa undertook an extensive community screening campaign to detect the estimated prevalence of chronic kidney disease (CKD) and its associated risk factors in the community.

SETTING

Fifteen screening sites, with 11 urban and rural sites on the main island of Upolu, and 4 in different rural areas on the island of Savaii.

PARTICIPANTS

All participants were self-referrals to the various screening sites. In total, 1163 Samoans were screened, with similar numbers from both urban and rural areas and similar numbers of female and male.

SCREENING ACTIVITIES

All participants were screened for CKD using point of care serum creatinine determinations, with calculation of estimated glomerular filtration rate using the CKD-EPI formula and dipstix urinalysis. A standardised screening survey was used to capture demographic and medical history with associated risk factors of obesity, diabetes, using point of care determination of HbA1c and hypertension. Logistic regression was used to investigate the association of CKD with risk factors.

RESULTS

In total, 1163 people were screened for CKD within the month of March 2019. The prevalance of CKD (grades 1-5) was 44.5% (95% CI 41.6% to 47.4) with individual grade prevalence CKD 1: 3.7%, CKD 2: 6.1%, CKD 3: 30.7%, CKD 4: 2.9% and CKD 5: 1.0%. The prevalence of obesity (body mass index ≥32), diabetes and hypertension was 66.3%, 30.8% and 54.3%, respectively.

CONCLUSIONS

This is the first paper to report the estimated prevalence of CKD in Samoa or any other Pacific Island nation. It reveals an urgent need for further studies on the epidemiology of CKD in Samoa, to develop country-specific prevention strategies to mitigate this growing burden and prevent subsequent CKD associated complications including development of kidney failure and premature death.

Longitudinal Studies 5: Development of Risk Prediction Models for Patients with Chronic Disease

Chronic diseases are now the major cause of ill health in both developed and developing countries. Chronic diseases evolve, over decades, from an early reversible phase, to a late stage of irreversible organ damage. Importantly, the trajectory of individual patients with a chronic disease is highly variable. This uncertainty causes substantial stress and difficulty for patients, care providers, and health systems. Clinical risk prediction models address this uncertainty by incorporating multiple variables to more precisely estimate the risk of adverse events for an individual patient. In the current chapter, we describe the general approach to developing a risk prediction model. We then illustrate how these methods are applied in the development and validation of the kidney failure risk equation (KFRE), which accurately predicts the risk of kidney failure in patients with chronic kidney disease stages 3-5.

The role of uric acid in inflammasome-mediated kidney injury

PURPOSE OF REVIEW

Uric acid is produced after purine nucleotide degradation, upon xanthine oxidase catalytic action. In the evolutionary process, humans lost uricase, an enzyme that converts uric acid into allantoin, resulting in increased serum uric acid levels that may vary according to dietary ingestion, pathological conditions, and other factors. Despite the controversy over the inflammatory role of uric acid in its soluble form, crystals of uric acid are able to activate the NLRP3 inflammasome in different tissues. Uric acid, therefore, triggers hyperuricemic-related disease such as gout, metabolic syndrome, and kidney injuries. The present review provides an overview on the role of uric acid in the inflammasome-mediated kidney damage.

RECENT FINDINGS

Hyperuricemia is present in 20-35% of patients with chronic kidney disease. However, whether this increased circulating uric acid is a risk factor or just a biomarker of renal and cardiovascular injuries has become a topic of intense discussion. Despite these conflicting views, several studies support the idea that hyperuricemia is indeed a cause of progression of kidney disease, with a putative role for soluble uric acid in activating renal NLRP3 inflammasome, in reprograming renal and immune cell metabolism and, therefore, in promoting kidney inflammation/injury.

SUMMARY

Therapies aiming to decrease uric acid levels prevent renal NLRP3 inflammasome activation and exert renoprotective effects in experimental kidney diseases. However, further clinical studies are needed to investigate whether reduced circulating uric acid can also inhibit the inflammasome and be beneficial in human conditions.

Association of exposure to phthalates and environmental phenolics with markers of kidney function: Korean National Environmental Health Survey (KoNEHS) 2015-2017

Increasing number of consumer chemicals have been associated with chronic kidney disease (CKD) in human populations. However, many studies that investigated estimated glomerular filtration rate (eGRF) as an outcome reported inconsistent associations. In the present study, we employed a subset (n = 1292) of a nationally representative adult population participating in Korean National Environmental Health Survey (KoNEHS) 2015-2017, and assessed associations of major phthalates, bisphenol A (BPA), and parabens with both eGRF and albuminuria. In order to address a potential collider issue, a covariate-adjusted standardization method was applied, in addition to the conventional creatinine-correction, for adjusting urine dilution. Regardless of adjustment method, urinary DEHP metabolites showed significant positive associations with albumin to creatinine ratio (ACR). In addition, urinary metabolites of other heavy molecular weight phthalates such as MCOP and MCNP showed significant positive associations with ACR in the female population, but only following the covariate-adjusted standardization. For eGFR, conventional creatinine-correction resulted in positive associations with most of measured phthalate metabolites. However, with the covariate-adjusted standardization, most of positive associations with eGFR disappeared, and instead, significant negative associations were observed for MnBP, BPA, and EtP. Secondary analysis following stratification by CKD status, as well as principal component analysis (PCA), generally supported the observed associations. The present observations highlight the importance of urine dilution adjustment method for association studies on eGFR, and suggest potential effects of several consumer chemicals on adverse kidney function among humans.

Prevalence and risk factors of chronic kidney disease and diabetic kidney disease in a central Chinese urban population: a cross-sectional survey

Background

This study was conducted to evaluate and update the current prevalence of and risk factors for chronic kidney disease (CKD) and diabetic kidney disease (DKD) in a central Chinese urban population.

Methods

From December 2017 to June 2018, a total of 5231 subjects were randomly enrolled from 3 communities in 3 districts of Zhengzhou. CKD was defined as estimated glomerular filtration rate (eGFR) < 60 mL/min.1.73m² or urinary albumin to creatinine ratio ≥ 30 mg/g (albuminuria). Diabetic subjects with systolic blood pressure > 140 mmHg, albuminuria or an eGFR less than 60 mL/min/1.73 m² were classified as having DKD. Participants completed a questionnaire assessing lifestyle and relevant medical history, and blood and urine specimens were taken. Serum creatinine, uric acid, total cholesterol, triglycerides, low-density lipoprotein, high-density lipoprotein and urinary albumin were assessed. The age- and sex-adjusted prevalences of CKD and DKD were calculated, and risk factors associated with the presence of reduced eGFR, albuminuria, DKD, severity of albuminuria and progression of reduced renal function were analyzed by binary and ordinal logistic regression.

Results

The overall adjusted prevalence of CKD was 16.8% (15.8–17.8%) and that of DKD was 3.5% (3.0–4.0%). Decreased renal function was detected in 132 participants (2.9, 95% confidence interval [CI]: 2.5–3.2%), whereas albuminuria was found in 858 participants (14.9, 95% CI: 13.9–15.9%). In all participants with diabetes, the prevalence of reduced eGFR was 6.3% (95% CI = 3.9–8.6%) and that of albuminuria was 45.3% (95% CI = 40.4–50.1%). The overall prevalence of CKD in participants with diabetes was 48.0% (95% CI = 43.1–52.9%). The results of the binary and ordinal logistic regression indicated that the factors independently associated with a higher risk of reduced eGFR and albuminuria were older age, sex, smoking, alcohol consumption, overweight, obesity, diabetes, hypertension, dyslipidemia and hyperuricemia.

Conclusions

Our study shows the current prevalence of CKD and DKD in residents of Central China. The high prevalence suggests an urgent need to implement interventions to relieve the high burden of CKD and DKD in China.

Association of microalbuminuria and high-normal 24-hour urinary albumin excretion with metabolic syndrome and its components in the general Chinese population: cross-sectional study

OBJECTIVE

Microalbuminuria (MAU) has been described as a risk factor for metabolic syndrome (MetS). However, the association between MetS components with MAU and 24-hour urinary albumin excretion (UAE) has not been clearly explained in the general Chinese population. We aimed to analyse the associations between MAU and high-normal 24-hour UAE with MetS and its components.

DESIGN

Cross-sectional observational study.

SETTING

Four selected counties/districts in China's Shandong and Jiangsu Provinces.

PARTICIPANTS

A total of 2261 participants aged 18-69 years were included in this study. Participants with missing physical examination data or incomplete urine collection were not included in the analysis.

RESULTS

The prevalence of MAU was 9%, and the mean 24-hour UAE was 18 mg/d. The prevalence of MAU was significantly higher for the MetS, high blood pressure (BP), high triglyceride (TG) levels, low high-density lipoprotein cholesterol (HDL-C) and hyperglycaemia groups but not for the central obesity group. Both MAU and mean 24-hour UAE were significantly increased in association with a number of MetS components. The adjusted prevalence OR (POR) for MetS with MAU was 2.95 (95% CI 2.15 to 4.04) compared with those without MAU. MAU was significantly associated with three components of MetS: high BP (POR=1.86, 95% CI 1.31 to 2.64), high TG levels (POR=1.80, 95% CI 1.31 to 2.46) and hyperglycaemia (POR=1.84, 95% CI 1.34 to 2.53). No significant association between MAU and central obesity or low HDL-C was found. The presence of MetS gradually increased according to the normal-range 24-hour UAE quartiles: POR=1.00, POR=1.22, POR=1.14 and POR=2.02, respectively. Hyperglycaemia also increased significantly according to the normal-range 24-hour UAE quartiles.

CONCLUSIONS

MAU and elevated 24-hour UAE within the normal range were closely associated with MetS in the Chinese population, which may provide a basis for the development of early interventions to decrease the effects of MetS.

Inflammation in Renal Diseases: New and Old Players

Inflammation, a process intimately linked to renal disease, can be defined as a complex network of interactions between renal parenchymal cells and resident immune cells, such as macrophages and dendritic cells, coupled with recruitment of circulating monocytes, lymphocytes, and neutrophils. Once stimulated, these cells activate specialized structures such as Toll-like receptor and Nod-like receptor (NLR). By detecting danger-associated molecules, these receptors can set in motion major innate immunity pathways such as nuclear factor ĸB (NF-ĸB) and NLRP3 inflammasome, causing metabolic reprogramming and phenotype changes of immune and parenchymal cells and triggering the secretion of a number of inflammatory mediators that can cause irreversible tissue damage and functional loss. Growing evidence suggests that this response can be deeply impacted by the crosstalk between the kidneys and other organs, such as the gut. Changes in the composition and/or metabolite production of the gut microbiota can influence inflammation, oxidative stress, and fibrosis, thus offering opportunities to positively manipulate the composition and/or functionality of gut microbiota and, consequentially, ameliorate deleterious consequences of renal diseases. In this review, we summarize the most recent evidence that renal inflammation can be ameliorated by interfering with the gut microbiota through the administration of probiotics, prebiotics, and postbiotics. In addition to these innovative approaches, we address the recent discovery of new targets for drugs long in use in clinical practice. Angiotensin II receptor antagonists, NF-ĸB inhibitors, thiazide diuretics, and antimetabolic drugs can reduce renal macrophage infiltration and slow down the progression of renal disease by mechanisms independent of those usually attributed to these compounds. Allopurinol, an inhibitor of uric acid production, has been shown to decrease renal inflammation by limiting activation of the NLRP3 inflammasome. So far, these protective effects have been shown in experimental studies only. Clinical studies will establish whether these novel strategies can be incorporated into the arsenal of treatments intended to prevent the progression of human disease.

Prevalence and risk factors of chronic kidney disease and diabetic kidney disease in Chinese rural residents: a cross-sectional survey

We conducted a cross-sectional survey including 23869 participants and aimed to measure the prevalences of and risk factors for chronic kidney disease (CKD) and diabetic kidney disease (DKD) in a Chinese rural population. CKD and DKD status was defined according to the combination of estimated glomerular filtration rate (eGFR) and presence of albuminuria Participant completed a questionnaire involving life-style and relevant medical history, and the blood and urinary specimen were taken. The age- and gender- adjusted prevalences of CKD and DKD were calculated and risk factors associated with the presence of CKD and DKD were analyzed by logistic regression. The overall prevalence of CKD was 16.4% (15.9–16.8%) and of DKD was 2.9% (2.7–3.1%). In participants with diabetes, the overall prevalence of CKD was 35.5% (95% CI = 33.7–37.3%). Factors independently associated with renal damage were age, gender, education, personal income, alcohol consumption, overweight, obesity, diabetes, hypertension and dyslipidemia. Our study shows current prevalences of CKD and DKD in Chinese rural residents. Further researches could identify potential factors explaining the observed differences and implement the interventions to relieve the high burden of CKD and DKD in rural population.

Bone marrow mesenchymal stem cells attenuate the progression of focal segmental glomerulosclerosis in rat models

Background

Focal segmental glomerulosclerosis (FSGS) is the most common glomerular etiology of end-stage kidney disease (ESKD). Increasing evidence has indicated the reparative potential of mesenchymal stem cells (MSCs) in damaged diseased kidneys. However, the effect of bone marrow mesenchymal stem cells (BMSCs) on the FSGS progression remains unclear. This study aimed to investigate the protective effects of BMSCs on FSGS progression.

Methods

A rat model of FSGS was generated via unilateral nephrectomy plus adriamycin injection. Rat BMSCs were isolated and characterized on the basis of their differentiative potential towards adipocytes and osteoblasts and via flow cytometry analysis. Thereafter, rat BMSCs were transplanted into FSGS recipients through the caudal vein. After 8 weeks, 24-h proteinuria, serum creatinine, and urea nitrogen levels were determined. Renal morphology was assessed using a light and transmission electron microscope. MMP9 and TIMP-1 positive cells were detected via immunohistochemical analysis. Expression levels of proinflammatory cytokines IL-6 and TNF-α were examined via RT-PCR.

Results

The isolated adherent cells from the bone marrow of rats were phenotypically and functionally equivalent to typical MSCs. Clinical examination revealed that BMSC transplantation reduced the 24-h urinary protein excretion, and serum creatinine and urea nitrogen levels. Renal morphology was ameliorated in BMSCs-transplanted rats. Mechanistically, BMSC transplantation significantly downregulated TIMP-1 and upregulated MMP9, thereby increasing the renal MMP9/TIMP-1 ratio. Moreover, BMSC transplantation also downregulated IL-6 and TNF-α.

Conclusions

BMSC transplantation can attenuate FSGS progression in a rat model of FSGS, thereby providing a theoretical foundation for the application of autologous BMSCs in clinical FSGS therapy.

Walking, But Not Other Physical Activity at a Higher Intensity, Is Associated With Improved Kidney Function: A Cross-Sectional Health Survey of General Adult Population

BACKGROUND

Chronic kidney disease is common and brings significant health burden. The purpose of this study was to investigate the relationship between physical activity and kidney function.

METHODS

This was a cross-sectional study set in the Nanjing Community Cardiovascular Risk Survey, using random cluster sampling. Questionnaires were completed, wherever possible, through face-to-face interviews. Data on age, sex, body mass index, weekly physical activity, and kidney function were collected. Physical activity was measured by the metabolic equivalent of task-minutes per week and grouped into "walking," "moderate," and "vigorous" according to intensity. Kidney function was measured by the estimated glomerular filtration rate (eGFR, in mL/min/1.73 m²). Regression modeling was used to investigate the proposed relationship with adjustment for other confounding factors.

RESULTS

A total of 5824 participants were included, with an average age of 52; 44% were male. The eGFR in average was 76 mL/min/1.73 m², with 19% ≥ 90, 67% between 60 and 89, and 14% < 60. In average, the total physical activity during a week was 3644 MET-minutes per week. Moderate activity contributed 64% of the total activity, followed by walking (23%) and vigorous activity (13%). Overall, the total activity was weakly associated with eGFR (P = .039). However, in stratified analysis, only walking-related activity was associated with eGFR (P < .0001) after confounding adjustment.

CONCLUSIONS

Walking is associated with improved kidney function.

Hematuria as a risk factor for progression of chronic kidney disease and death: findings from the Chronic Renal Insufficiency Cohort (CRIC) Study

BACKGROUND

Hematuria is associated with chronic kidney disease (CKD), but has rarely been examined as a risk factor for CKD progression. We explored whether individuals with hematuria had worse outcomes compared to those without hematuria in the CRIC Study.

METHODS

Participants were a racially and ethnically diverse group of adults (21 to 74 years), with moderate CKD. Presence of hematuria (positive dipstick) from a single urine sample was the primary predictor. Outcomes included a 50% or greater reduction in eGFR from baseline, ESRD, and death, over a median follow-up of 7.3 years, analyzed using Cox Proportional Hazards models. Net reclassification indices (NRI) and C statistics were calculated to evaluate their predictive performance.

RESULTS

Hematuria was observed in 1145 (29%) of a total of 3272 participants at baseline. Individuals with hematuria were more likely to be Hispanic (22% vs. 9.5%, respectively), have diabetes (56% vs. 48%), lower mean eGFR (40.2 vs. 45.3 ml/min/1.73 m2), and higher levels of urinary albumin > 1.0 g/day (36% vs. 10%). In multivariable-adjusted analysis, individuals with hematuria had a greater risk for all outcomes during the first 2 years of follow-up: Halving of eGFR or ESRD (HR Year 1: 1.68, Year 2: 1.36), ESRD (Year 1: 1.71, Year 2: 1.39) and death (Year 1:1.92, Year 2: 1.77), and these associations were attenuated, thereafter. Based on NRIs and C-statistics, no clear improvement in the ability to improve prediction of study outcomes was observed when hematuria was included in multivariable models.

CONCLUSION

In a large adult cohort with CKD, hematuria was associated with a significantly higher risk of CKD progression and death in the first 2 years of follow-up but did not improve risk prediction.

The association between urbanization and reduced renal function: findings from the China Health and Nutrition Survey

BACKGROUND

While chronic kidney disease (CKD) is a growing public health concern in low- and middle-income countries, such as China, few studies have investigated the association between urbanization and the occurrence of CKD in those countries.

METHODS

We investigated the association between urbanization and estimated glomerular filtration rate (eGFR), an important CKD risk marker. Data came from the China Health and Nutrition Survey wave 2009, in which we collected fasting serum, individual and household data along with community level urbanization data, which was used to derive a study-specific urbanization measure, in 218 communities across nine provinces. A total of 3644 men and 4154 women participants aged 18 years or older were included in the analysis. Reduced renal function was defined as eGFR of less than 60 mL/min/1.73 m2 measured using serum creatinine concentration (mg/dL).

RESULTS

After adjusting for socio-demographic (e.g., age, education and household income), a sex-stratified multilevel logistic model revealed that living in a more urbanized community was associated with higher odds of reduced eGFR (odds ratio [OR] = 1.38 per one-standard deviation [SD] increase in the CHNS specific urbanization index, 95% confidence interval [CI] = 1.11-1.73 for men; OR = 1.35, 95% CI = 1.11-1.62 for women). After adjusting for behavioral variables (i.e., alcohol consumption, smoking, physical activity and diet), as well as obesity and cardiometabolic risk factors, the association was attenuated in men (OR = 1.25, 95% CI = 0.98-1.59), but remained statistically significant in women (OR = 1.24, 95% CI = 1.01-1.52).

CONCLUSION

Our findings suggest that living in an urban environment is linked with higher odds of reduced renal function independently of behavioral and cardiometabolic risk factors, which have been shown to increase along with urbanization.

Soluble Urokinase-type Plasminogen Activator Receptor (suPAR) and Impaired Kidney Function in the Population-based Malmö Diet and Cancer Study

Introduction

The soluble urokinase-type plasminogen activator receptor (suPAR) has recently been associated with a decline in kidney function and incidence of chronic kidney disease in patients with cardiovascular disease undergoing cardiac catheterization, yet little is known whether suPAR is associated with deterioration of kidney function in the general population.

Methods

In the population-based Malmö Diet and Cancer Study cohort, plasma levels of suPAR were quantified in 5381 participants at baseline (1991–1994), and creatinine was measured and used to calculate estimated glomerulus filtration rate (eGFR) at baseline and follow-up (2007–2012). Incident chronic kidney disease was defined as eGFR < 60 ml/min per 1.73 m² at follow-up.

Results

Participants within the highest quartile of suPAR had a significantly lower mean eGFR at follow-up than those within the lowest quartile (mean 68 vs. 74 ml/min per 1.73 m²; P-trend = 4.3 × 10^–7). In multivariate regression analysis, suPAR (per 1 SD increment of log-transformed suPAR) was associated with a decline in eGFR (P = 3.3 × 10^–9) and incident chronic kidney disease (561 events, odds ratio = 1.25; 95% confidence interval, 1.10–1.41). Furthermore, we identified 110 cases of hospitalization due to impaired kidney function via linkage to national registers of inpatient and outpatient hospital diagnoses. During a mean follow-up time of 19 years, suPAR was associated with risk for hospitalization due to impaired kidney function (hazard ratio = 1.49; 95% confidence interval, 1.27–1.74) in multivariate Cox proportional hazard analysis.

Discussion

The increased suPAR level at baseline was associated with a significantly higher longitudinal decline in eGFR, higher incidence of chronic kidney disease, and hospitalization due to impaired kidney function in a cohort of healthy middle-aged participants.

Global Prevalence of Chronic Kidney Disease - A Systematic Review and Meta-Analysis

Chronic kidney disease (CKD) is a global health burden with a high economic cost to health systems and is an independent risk factor for cardiovascular disease (CVD). All stages of CKD are associated with increased risks of cardiovascular morbidity, premature mortality, and/or decreased quality of life. CKD is usually asymptomatic until later stages and accurate prevalence data are lacking. Thus we sought to determine the prevalence of CKD globally, by stage, geographical location, gender and age. A systematic review and meta-analysis of observational studies estimating CKD prevalence in general populations was conducted through literature searches in 8 databases. We assessed pooled data using a random effects model. Of 5,842 potential articles, 100 studies of diverse quality were included, comprising 6,908,440 patients. Global mean(95%CI) CKD prevalence of 5 stages 13·4%(11·7-15·1%), and stages 3-5 was 10·6%(9·2-12·2%). Weighting by study quality did not affect prevalence estimates. CKD prevalence by stage was Stage-1 (eGFR>90+ACR>30): 3·5% (2·8-4·2%); Stage-2 (eGFR 60-89+ACR>30): 3·9% (2·7-5·3%); Stage-3 (eGFR 30-59): 7·6% (6·4-8·9%); Stage-4 = (eGFR 29-15): 0·4% (0·3-0·5%); and Stage-5 (eGFR<15): 0·1% (0·1-0·1%). CKD has a high global prevalence with a consistent estimated global CKD prevalence of between 11 to 13% with the majority stage 3. Future research should evaluate intervention strategies deliverable at scale to delay the progression of CKD and improve CVD outcomes.

High prevalence of chronic kidney disease in a semi-urban population of Western India

BACKGROUND

Globally there is an increase in incidence of chronic kidney diseases (CKDs). Diabetes mellitus (DM), hypertension and stone diseases are the major risk factors for CKD. We organized kidney disease screening camps in a semi-urban population of Gujarat, India on the occasion of World Kidney Day (WKD).

METHODS

Voluntary participants from six towns were screened. Estimated glomerular filtration rate (eGFR) was calculated by the Modification of Diet in Renal Disease formula and CKD was defined as an eGFR <60 mL/min/1.73 m(2) or albuminuria ≥1+. Urogenital ultrasonography was performed with emphasis on stone burden. Participants with known diabetes, stone diseases, hypertension, kidney/liver/cardiac disease, hepatitis, HIV, transplant recipients, pregnant women and those <18 years were excluded from the study.

RESULTS

Of the 2350 participants (1438 men), CKD was found in 20.93% and eGFR <60 mL/min/1.73 m(2) was noted in 8.29% of participants. The prevalence of CKD peaked after the seventh decade of life in both genders. There was no significant difference in the prevalence of CKD between coastal and non-coastal regions, however, obesity, hypertension and diabetes were more common in the coastal belt, whereas stone burden was greater in the non-coastal region.

CONCLUSIONS

The prevalence of CKD in a semi-urban apparently healthy Indian population was higher than the reported prevalence in developed countries. Significant differences between regions point to the need to evaluate and correctregion-specific risk factors.

Anthropometric measurements and markers of renal function in adults and older adults

Objective: To determine whether anthropometric indicators are associated with markers of renal function in adults and older adults. Methods: This cross-sectional study included 279 adults and older adults attending eight primary healthcare units in eastern Goiânia, Góias. Sociodemographic, lifestyle, and clinical data were collected using a standard questionnaire. Body mass index was categorized as overweight (≥25 kg/m²) or non-overweight. Waist circumference was classified as normal or high; chronic kidney disease was defined as a glomerular filtration rate below 60 mL/minutes/1.73 m²; micro/macroalbuminuria was defined as an albumin/creatinine ratio above 30 mg/g. The association between anthropometric indicators and renal function markers was assessed by multiple linear regression analysis. Results: Chronic kidney disease was present in 8.9% and micro/macroalbuminuria in 34.8% of the sample. The prevalence of overweight was 57.0%. Waist circumference and body mass index were positively associated with glomerular filtration rate, characterized as glomerular hyperfiltration. Microalbuminuria was positively associated with body mass index in women. Conclusion: The prevalences of chronic kidney disease and overweight were high in the study population. Overweight was positively associated with glomerular filtration rate.

Influence of changes in serum uric acid levels on renal function in elderly patients with hypertension: a retrospective cohort study with 3.5-year follow-up

Background

Hyperuricemia is closely related to renal diseases. Therefore, the aim of this study was to explore the relationship between the longitudinal changes in serum uric acid and the estimated glomerular filtration rate (eGFR) in a cohort of elderly hypertensive patients.

Methods

Eighty hundred and thirty-seven re-hospitalized patients with hypertension were included in this retrospective cohort study. Multiple regression analysis was used to investigate the relationship between changes in serum uric acid and renal function after 3.5 years follow-up.

Results

The average age at baseline was 69.0+/-10.0 years, and the average follow-up duration was 3.5 years. Multiple linear regression analysis showed that the baseline uric acid levels had a linearly negative correlation with baseline eGFR (P < 0.01), after adjustment for age, gender, blood pressure, and body mass index, et al. An increase of 100 μmol/L baseline uric acid level resulted in a decrease of 5.684 ml/min/1.73 m² in eGFR [95 % confidence interval (CI): 7.735-3.633]. Patients with increased uric acid levels had higher risk of renal function decline over the follow-up period, with an adjusted odds ratio of 1.639 (95 % CI: 1.129-2.378, P = 0.009) , whereas eGFR was remained unchanged in patients with hyperuricemia at baseline and with normal uric acid level 3.5-year later.

Conclusions

Longitudinal changes in uric acid levels were independently associated with the renal function decline in elderly patients with hypertension. Uric acid level should be considered in hypertension management in the elderly.

Prevalence and risk factors associated with chronic kidney disease in a Zhuang ethnic minority area in China

AIM

Numerous studies have examined and reported a high prevalence of chronic kidney disease (CKD) in the general population in various countries including China. However, the situation may be different in undeveloped rural minority regions in China because of China's economic diversity. The aim of the present study was to estimate the prevalence of CKD and to analyze its associated factors in a Zhuang ethnic minority area in Southwest China.

METHODS

A cross-sectional survey of a rural minority area populated by people of Zhuang ethnicity in Southwest China using multistage, cluster random sampling methods was performed. The prevalence of indicators of kidney damage and CKD were calculated and risk factors associated with the presence of CKD were analyzed.

RESULTS

In total, 7588 people participated in the study. After adjustment for age and gender, the prevalence of albuminuria, haematuria and reduced estimated glomerular filtration rate were 2.7%, 3.7%, and 2.2%, respectively. After adjustment for age and gender, the prevalence of CKD was 8.3%, while recognition of the disease was 3.6%. Independent risk factors associated with CKD were age, gender, and hypertension. Risk factors independently associated with kidney damage were age, gender, hyperuricaemia, and hypertension.

CONCLUSION

Our data exhibited a lower prevalence and awareness of CKD in undeveloped rural minority regions, especially exhibited a low prevalence of albuminuria. This result attributed to the low prevalence of metabolic disorders in the local region. Risk factors associated with CKD in our study is similar to surveys in other regions of China.

Longitudinal studies 5: Development of risk prediction models for patients with chronic disease

Chronic diseases are now the major cause of ill health in both developed and developing countries. Chronic diseases evolve, over decades, from an early reversible phase, to a late stage of irreversible organ damage. Importantly, the trajectory of individual patients with a chronic disease is highly variable. This uncertainty causes substantial stress and difficulty for patients, care providers and health systems. Clinical risk prediction models address this uncertainty by incorporating multiple variables to more precisely estimate the risk of adverse events for an individual patient. In the current chapter, we describe the general approach to developing a risk prediction model. We then illustrate how these methods were applied in the development and validation of the Kidney Failure Risk Equation (KFRE), which accurately predicts the risk of kidney failure in patients with Chronic Kidney Disease Stages 3-5.

Urinary albumin excretion and prevalence of microalbuminuria in a general Chinese population: a cross-sectional study

BACKGROUND

Microalbuminuria has been shown to be a risk factor for cardiovascular and renal disease in patients with hypertension and diabetes as well as in the general population. Urinary albumin excretion over 24 h is considered a 'gold standard' to detect microalbuminuria. Few studies have used 24-h urinary albumin excretion to analyze the prevalence of and related factors for microalbuminuira in a general Chinese population.

METHODS

This study included 1980 adults aged 18-69 years from the Shandong-Ministry of Health Action on Salt and Hypertension (SMASH) Project 2011 survey. Blood pressure, height, weight and waist circumference were measured, and a venous blood and timed 24-h urine samples were collected from each participant. Linear and logistic regression analyses were used to test associations between established cardiovascular risk factors and microalbuminuria.

RESULTS

The median (25th-75th percentile) of 24-h urinary albumin excretion was 6.1 mg/d (4.5-8.7 mg/d) for all adults, 6.0 mg/d (4.4-8.5 mg/d) for men and 6.2 mg/d (4.6-8.9 mg/d) for women. The overall prevalence of microalbuminuria was 4.1% (95% confidence interval [CI]: 3.2-5.0%), 3.7% (95% CI: 2.9-4.5%) for men and 4.6% (95% CI: 3.7-5.5%) for women. Microalbuminuria was present in 8.1% (95% CI: 6.9-9.3%) of individuals with hypertension, 11.4% (95% CI: 10.0-12.8%) of those with diabetes and 15.6% (95% CI: 14.0-17.2%) of those with both. Multiple logistic regression analysis indicated that systolic blood pressure (odds ratio [OR] 1.02; 95% CI: 1.01-1.03) and fasting blood glucose (OR 1.19; 95% CI: 1.05-1.35) were the independent risk factors for microalbuminuria.

CONCLUSIONS

Adults in the general population of Shandong Province have a moderate prevalence of microalbuminuria. Those with hypertension and diabetes are at high risk of having microalbuminuria, suggesting the need for screening and early intervention for microalbuminuria among these individuals.

An estimation of the prevalence and progression of chronic kidney disease in a rural diabetic cambodian population

BACKGROUND

To date, there are no known estimates of the prevalence of chronic kidney disease within Cambodia, the vast majority of whose citizens live in rural areas with limited access to renal replacement therapy.

METHODS

Observational analysis of patients from the Takeo province in Cambodia who presented to MoPoTsyo, a non-governmental organization, for screening and management of diabetes mellitus between 2010 and 2012 (n = 402; 75% females). Estimated glomerular filtration rate (eGFR) was calculated using the CKD-Epi equation.

RESULTS

On average, women were younger, with a higher percentage of hypercholesterolemia but also high-density lipoprotein level. Men had a higher serum creatinine level (1.31 mg/dl) than that of women (1.13 mg/dl) at 95% CI. More than half of all screened patients had a reduced eGFR; 60% (95% CI 55%, 65%) had an eGFR<60 ml/min/1.73 m(2); 54% (49%, 59%) had an eGFR 30-60 ml/min/1.73 m(2), and 5.7% (3.4%, 8.0%) with eGFR 15-30 ml/min/1.73 m(2). Women had a greater prevalence of stage 3 CKD (57% women vs. 47% men) and stage 4 CKD (7.0% vs. 2.0%). The adjusted odds ratio for females compared to males having an eGFR <60 ml/min/1.73 m(2) was 3.19 (95% CI 1.78, 5.43; p value<0.001). Thirty-two percent of patients lost ≥ 5 ml/min/1.73 m2 eGFR during median follow-up time of 433 days (IQR 462 days) days.

CONCLUSIONS

Over one-half of Cambodians with diabetes mellitus had reduced eGFR, implying a point-prevalence of chronic kidney disease of 1.2% in among adult Cambodians within the country. This high burden of kidney disease in a society that lacks universal access to renal replacement therapy underscores the importance of early diagnosis - a largely unmet need in Cambodia.

Diabetes and its comorbidities--where East meets West

Fetal programming associated with in utero exposure to maternal stress is thought to alter gene expression, resulting in phenotypes that promote survival in a pathogen-rich and nutrient-poor environment but substantially increase the risk of cardiovascular, metabolic and renal disorders (such as diabetes mellitus) in adults with obesity. These (epi)genetic phenomena are modified by environmental and socioeconomic factors, resulting in multiple subphenotypes and clinical consequences. In individuals from areas undergoing rapid economic development, which is associated with a transition from communicable to noncommunicable diseases, an efficient innate immune response can exaggerate obesity-associated inflammation. By contrast, in individuals with a genetic predisposition to autoimmune or monogenic diabetes mellitus, obesity can lead to atypical presentation of diabetes mellitus, termed 'double diabetes mellitus'. The increasingly young age at diagnosis of diabetes mellitus in developing countries results in prolonged exposure to glucolipotoxicity, low-grade inflammation and increased oxidative stress, which put enormous strain on pancreatic β cells and renal function. These conditions create a metabolic milieu conducive to cancer growth. This Review discusses how rapid changes in technology and human behaviour have brought on the global epidemic of metabolic diseases, and suggests that solutions will be based on using system change, technology and behavioural strategies to combat this societal-turned-medical problem.

Cohort profile: Canadian study of prediction of death, dialysis and interim cardiovascular events (CanPREDDICT)

Background

The Canadian Study of Prediction of Death, Dialysis and Interim Cardiovascular Events (CanPREDDICT) is a large, prospective, pan-Canadian, cohort study designed to improve our understanding of determinants of renal and cardiovascular (CV) disease progression in patients with chronic kidney disease (CKD). The primary objective is to clarify the associations between traditional and newer biomarkers in the prediction of specific renal and CV events, and of death in patients with CKD managed by nephrologists. This information could then be used to better understand biological variation in outcomes, to develop clinical prediction models and to inform enrolment into interventional studies which may lead to novel treatments.

Methods/Designs

Commenced in 2008, 2546 patients have been enrolled with eGFR between 15 and 45 ml/min 1.73m2 from a representative sample in 25 rural, urban, academic and non academic centres across Canada. Patients are to be followed for an initial 3 years at 6 monthly intervals, and subsequently annually. Traditional biomarkers include eGFR, urine albumin creatinine ratio (uACR), hemoglobin (Hgb), phosphate and albumin. Newer biomarkers of interest were selected on the basis of biological relevance to important processes, commercial availability and assay reproducibility. They include asymmetric dimethylarginine (ADMA), N-terminal pro-brain natriuretic peptide (NT-pro-BNP), troponin I, cystatin C, high sensitivity C-reactive protein (hsCRP), interleukin-6 (IL6) and transforming growth factor beta 1 (TGFβ1). Blood and urine samples are collected at baseline, and every 6 monthly, and stored at −80°C. Outcomes of interest include renal replacement therapy, CV events and death, the latter two of which are adjudicated by an independent panel.

Discussion

The baseline distribution of newer biomarkers does not appear to track to markers of kidney function and therefore may offer some discriminatory value in predicting future outcomes. The granularity of the data presented at baseline may foster additional questions.

The value of the cohort as a unique resource to understand outcomes of patients under the care of nephrologists in a single payer healthcare system cannot be overstated. Systematic collection of demographic, laboratory and event data should lead to new insights.

The mean age of the cohort was 68 years, 90% were Caucasian, 62% were male, and 48% had diabetes. Forty percent of the cohort had eGFR between 30–45 mL/min/1.73m², 22% had eGFR values below 20 mL/min/1.73m²; 61% had uACR < 30. Serum albumin, hemoglobin, calcium and 25-hydroxyvitamin D (25(OH)D) levels were progressively lower in the lower eGFR strata, while parathyroid hormone (PTH) levels increased. Cystatin C, ADMA, NT-proBNP, hsCRP, troponin I and IL-6 were significantly higher in the lower GFR strata, whereas 25(OH)D and TGFβ1 values were lower at lower GFR. These distributions of each of the newer biomarkers by eGFR and uACR categories were variable.

Biomarkers in native and transplant kidneys: opportunities to improve prediction of outcomes in chronic kidney disease

PURPOSE OF REVIEW

Predicting the outcomes of patients with chronic kidney disease (CKD) is important from both patient and healthcare system perspectives. This review examines the current state of conventional and nonconventional biomarkers as noninvasive tools to improve risk-stratification and outcome prediction in CKD.

RECENT FINDINGS

Conventional biomarkers (serum creatinine, urine albumin, and clinical variables such as sex, age, and diabetes) have been the cornerstone of most prediction models for CKD progression to end-stage renal disease (ESRD), and adverse cardiovascular outcomes including death. With better understanding of the pathophysiology of CKD and the evolution of molecular diagnostics, numerous novel or nonconventional markers have emerged. They have been examined individually and in combination to predict specific outcomes. We highlight these markers and studies, conducted primarily in patients with native kidneys. In those with transplant kidneys, markers of both acute and chronic kidney dysfunction have been examined, although to a lesser extent. Similarities and differences in knowledge derived from these two populations are highlighted.

SUMMARY

Improving prediction of outcomes in CKD patients with either native or transplant kidneys remains an important goal. Increasingly sophisticated biomarkers may potentially identify targets for clinical research, improve the nature and timing of therapeutic interventions, and guide resource allocation.

Oxidative stress, anti-oxidant therapies and chronic kidney disease

Chronic kidney disease (CKD) is a common and serious problem that adversely affects human health, limits longevity and increases costs to health-care systems worldwide. Its increasing incidence cannot be fully explained by traditional risk factors. Oxidative stress is prevalent in CKD patients and is considered to be an important pathogenic mechanism. Oxidative stress develops from an imbalance between free radical production often increased through dysfunctional mitochondria formed with increasing age, type 2 diabetes mellitus, inflammation, and reduced anti-oxidant defences. Perturbations in cellular oxidant handling influence downstream cellular signalling and, in the kidney, promote renal cell apoptosis and senescence, decreased regenerative ability of cells, and fibrosis. These factors have a stochastic deleterious effect on kidney function. The majority of studies investigating anti-oxidant treatments in CKD patients show a reduction in oxidative stress and many show improved renal function. Despite heterogeneity in the oxidative stress levels in the CKD population, there has been little effort to measure patient oxidative stress levels before the use of any anti-oxidants therapies to optimize outcome. This review describes the development of oxidative stress, how it can be measured, the involvement of mitochondrial dysfunction and the molecular pathways that are altered, the role of oxidative stress in CKD pathogenesis and an update on the amelioration of CKD using anti-oxidant therapies.

Clinical research promotes development of nephrology in China: an analysis of 20 years of scientific publications

BACKGROUND

To study the trend of clinical and basic research output in the field of nephrology in China during the past 20 years.

METHODS

The journals listed in the "Urology and Nephrology" category of Science Citation Index Expanded (SCIE) subject categories were selected. The papers were retrieved by searching the PubMed database. Mainland China (ML), Hong Kong (HK), and Taiwan (TW) were chosen as investigative regions compared with other developed countries. Geographical difference in publications in ML was analyzed. The change between clinical and basic research papers was compared. The accumulated or average impact factor (IF) and the number of papers published in the 10 most impacted journals were calculated to determine the quality of papers.

RESULTS

The research output in the field of nephrology in ML developed markedly in the last 7 years (an average annual increase of 54% from 2004); ML exceeded TW and HK since 2008. The research output born in ML was mainly from five cities, for example, Beijing, Shanghai, Nanjing, Guangzhou, and Hangzhou, which accounted for 72% of the total. Since 2001, clinical research papers increased yearly by 11.55, and the basic research papers increased by 4.55. However, clinical trials were still limited. In 2010, ML had the highest accumulated IF and the lowest average IF. ML had the second highest number of publications in the 10 top-ranking nephrology journals among the three regions.

CONCLUSIONS

China has made a remarkable progress in the field of nephrology. Clinical researches have promoted the development of nephrology. The quality of research papers in China needs further improvement.

Biomarkers in chronic kidney disease: a review

Chronic kidney disease (CKD) is a major public health problem. The classification of CKD by KDOQI and KDIGO and the routine eGFR reporting have resulted in increased identification of CKD. It is important to be able to identify those at high risk of CKD progression and its associated cardiovascular disease (CVD). Proteinuria is the most sensitive marker of CKD progression in clinical practice, especially when combined with eGFR, but these have limitations. Hence, early, more sensitive, biomarkers are required. Recently, promising biomarkers have been identified for CKD progression and its associated CVD morbidity and mortality. These may be more sensitive biomarkers of kidney function, the underlying pathophysiological processes, and/or cardiovascular risk. Although there are some common pathways to CKD progression, there are many primary causes, each with its own specific pathophysiological mechanism. Hence, a panel measuring multiple biomarkers including disease-specific biomarkers may be required. Large, longitudinal observational studies are needed to validate candidate biomarkers in a broad range of populations prior to implementation into routine CKD management. Recent renal biomarkers discovered include neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, and liver-type fatty acid-binding protein. Although none are ready for use in clinical practice, it is timely to review the role of such biomarkers in predicting CKD progression and/or CVD risk in CKD.

Chronic kidney disease: a public health priority and harbinger of premature cardiovascular disease

The epidemics of cardiovascular disease, obesity, diabetes, HIV and cancer have all received much attention from the public, media and policymakers. By contrast, chronic kidney disease (CKD) has remained largely a 'silent' epidemic. This is unfortunate because early diagnosis of renal disease based on proteinuria and/or reduced estimated glomerular filtration rate could enable early intervention to reduce the high risks of cardiovascular events, end-stage renal disease (ESRD) and death that are associated with CKD. Given the global increase in the incidence of the leading causes of CKD--hypertension, obesity and diabetes mellitus--better disease management and prevention planning are needed, as effective strategies are available to slow the progression of CKD and reduce cardiovascular risk. CKD may be regarded as a clinical model of accelerated vascular disease and premature ageing, and the risk-factor profile changes during the progression from mild/moderate CKD to ESRD. Although many randomized controlled trials in patients with mild to moderate CKD have shown beneficial effects of interventions aimed at preventing the progression of CKD, most trials have been unable to demonstrate a beneficial effect of interventions aimed at improving outcome in ESRD. Thus, novel treatment strategies are needed in this high-risk patient group.