Serum fetuin-A is correlated with metabolic syndrome in middle-aged and elderly Chinese

OBJECTIVE

Fetuin-A is an important player in the enhancement of insulin resistance. We aimed to investigate the association of serum fetuin-A and metabolic syndrome (MetS) in a community based Chinese population.

METHODS

A total of 5469 subjects aged 40 years or above were recruited from two urban communities in Shanghai. Demographic, anthropometric and biochemical features were collected according to a standard protocol. Serum fetuin-A levels were measured using ELISA and the modified NCEP-ATP III criteria were adopted to diagnose MetS.

RESULTS

A higher level of serum fetuin-A was well associated with a variety of metabolic disorders and an increased prevalence of MetS. The relative risks for MetS were markedly elevated in a dose-dependent manner both before and after extended adjustment in total participants (adjusted odds ratios were 1.00, 1.11, 1.20 and 1.40 for fetuin-A quartiles 1, 2, 3 and 4, respectively; P value for trend = 0.0002). MetS risks were also significantly associated with serum fetuin-A in various subgroups of sex, age, body mass index and glycaemic status. Moreover, an elevated serum fetuin-A was also independently associated with MetS components including central obesity, high blood pressure, high blood glucose and high triglycerides. Stepwise regression analyses revealed fetuin-A as an independent determinant of insulin resistance measured by the index of homeostasis model (HOMA-IR) (β = 0.064; P = 0.009).

CONCLUSION

Serum fetuin-A levels were strongly and independently associated with MetS and its components in community-dwelling Chinese adults.

Polymorphisms in the nonmuscle myosin heavy chain 9 gene (MYH9) are associated with the progression of IgA nephropathy in Chinese

BACKGROUND

IgA nephropathy (IgAN) is the leading cause of end-stage renal disease (ESRD) in China considering different compositions of ESRD causes in different ethnicities. A recent genome-wide association study (GWAS) indicated that the MYH9 gene was significantly associated with non-diabetic ESRD in African-Americans and also influenced kidney function in Europeans. Thus, in the present study, we aim to clarify whether MYH9 confers a shared mechanism among different causes of ESRD and to seek possible further insight into our understanding of IgAN by applying GWAS data from ESRD to IgAN.

METHODS

One thousand one hundred and sixteen Chinese, including 527 patients with renal biopsy-proven IgAN and 589 healthy controls, were enrolled in the present study. Four single neucleotide polymorphisms (SNPs) (rs3752462, rs4821480, rs11089788 and rs2413396) reported to be associated with ESRD with the most significance were genotyped by TaqMan assay or a restriction fragment length polymorphism assay for a further case-control study.

RESULTS

None of the four SNPs was associated with the susceptibility to IgAN or clinical and pathological characters at the time of renal biopsy. However, estimated glomerular filtration rate decline rate was associated with rs11089788 in the dominant model (P = 0.021). Cox regression showed that rs11089788 (hazard ratio, 3.95; 95% confidence interval, 1.23-12.63; P = 2.1 × 10(-2)) was an independent predictive factor for renal survival.

CONCLUSIONS

Based on a large Chinese IgAN cohort, we found an association between rs11089788 and prognosis of IgAN, adding to the mounting evidence of MYH9 as an important gene in IgAN to ESRD.

Chronic kidney disease: a large-scale population-based study of the effects of introducing the CKD-EPI formula for eGFR reporting

Objective To evaluate the effects of introducing the Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) formula for estimated glomerular filtration rate (eGFR) reporting in the adult population in routine clinical practice with clinician-directed testing. Design Retrospective study of all creatinine measurements and calculation of eGFRs using Modification of Diet in Renal Disease (MDRD) and CKD-EPI formulae. Setting General population, Oxfordshire, UK. Participants An unselected population of around 660 000. Interventions Reporting of eGFRs using MDRD or CKD-EPI formulae. Primary and secondary outcome measures Evaluation of the effects of the CKD-EPI formula on the prevalence of different stages of chronic kidney disease (CKD). Results The CKD-EPI formula reduced the prevalence of CKD (stages 2-5) by 16.4% in patients tested in primary care. At the important stage 2-stage 3 cut-off, there was a relative reduction of 7.5% in the prevalence of CKD stages 3-5 from 15.7% to 14.5%. The CKD-EPI formula reduced the prevalence of CKD stages 3-5 in those aged <70 but increased it at ages >70. Above 70 years, the prevalence of stages 3-5 was similar with both equations for women (around 41.2%) but rose in men from 33.3% to 35.5%. CKD stages 4-5 rose by 15% due exclusively to increases in the over 70s, which could increase specialist referral rates. The CKD classification of 18.3% of all individuals who had a creatinine measurement was altered by a change from the MDRD to the CKD-EPI formula. In the UK population, the classification of up to 3 million patients could be altered, the prevalence of CKD could be reduced by up to 1.9 million and the prevalence of CKD stages 3-5 could fall by around 200 000. Conclusions Introduction of the CKD-EPI formula for eGFR reporting will reduce the prevalence of CKD in a primary care setting with current testing practice but will raise the prevalence in the over 70s age group. This has implications for clinical practice, healthcare policy and current prevalence-based funding arrangements.

Analysis of cardiovascular disease in Chinese inpatients with chronic kidney disease

OBJECTIVE

To investigate the prevalence of cardiovascular disease (CVD) in a Chinese patient population with different stages of chronic kidney disease (CKD).

METHODS

Six hundred and two CKD patients who were hospitalized in Ruijin Hospital between Jan. 2004 and Jan. 2006 were selected. Patients' medical histories and the results of laboratory tests were reviewed.

RESULTS

The prevalence of CVD in 602 patients with CKD stages 1 to 5 was 1.28%, 17.24%, 22.86%, 33.33%, 56.2% respectively. The prevalence of CVD in CKD stage 5 patients with dialysis was 78.51%. In all the patients, the prevalence of coronary artery disease (CAD), left ventricular hypertrophy (LVH), and congestive heart failure (CHF) was 8.64% (52/602), 26% (154/602), and 13% (78/602), respectively. Regarding co-morbidities of CVD, 34.52% of patients had 2 or more of the above abnormalities. The prevalence of CAD in patients with CKD stages 1 to 5 respectively was 1.28%, 5.75%, 7.86%, 10.26%, 12.33%;LVH was 0%, 11.49%, 16.43%, 29.49%, 44.75%; and CHF was 0%, 3.45%, 3.57%, 8.97%, 28.77%.

CONCLUSION

The occurrence of CVD started from CKD stage 1 and increased with the progression of CKD. The screening and prevention of CVD should begin at CKD stage 1.

Predictive value of malnutrition markers for mortality in peritoneal dialysis patients

INTRODUCTION

Alterations in nutritional status have been described as important predictors of mortality in patients with chronic kidney disease (CKD). However, the association between multiple markers for nutritional status and the mortality rates of patients with CKD on peritoneal dialysis (PD) has not yet been illustrated in previously published data, particularly by using the new definition of protein energy wasting (PEW).

OBJECTIVE

To evaluate the predictive value of malnutrition markers for mortality rates, on the basis of the PEW definition, of PD patients.

MATERIALS AND METHODS

At the start of PD treatment, the nutritional status of 199 patients (mean age, 56 ± 13.3 years; 53% females) was evaluated. Body mass index (BMI), arm circumference, mid-arm muscle circumference, protein and caloric intake (by using a 3-day food record), and serum albumin were all recorded, as well as a subjective global assessment (SGA) and presence of PEW. Cut-off points were defined on the basis of the consensus of the International Society for Renal Nutrition and Metabolism (albumin, <3.8 g/dL; BMI, <23 kg/m(2); mid-arm muscle circumference, >10% in comparison with the 50th percentile for the reference population; protein intake, <0.8 g/kg/daily; caloric intake, <25 kcal/kg/daily). The data were obtained retrospectively between the years 2001 and 2008 on the basis of routine nutritional evaluation. Patients were monitored for fatal events from all possible causes.

RESULT

The mean BMI for the population was 26.6 ± 5.0 kg/m(2). A median protein intake of 0.94 (0.18 to 4.57) g/kg/daily was reported and 60.3% of the patients reported a protein intake of <0.8 g/kg/daily. With respect to caloric intake, 38.7% of the patients consumed <25 kcal/kg/daily. A median of 3.5 (1.4 to 5.3) g/dL for serum albumin was observed and 29.3% of the patients presented values of <3.8 g/dL. PEW was diagnosed in 17.5% of patients. In the univariate model, being of age >65 years (P = .002), cardiovascular disease (P < .001), diabetes mellitus (P = .02), SGA (P = .02), and albumin (P = .002), were all significant markers for mortality. The presence of patients aged >65 years (P = .02), with diabetes mellitus (P = .057), cardiovascular disease (P = .005), and albumin were considered as independent factors for mortality in this study.

CONCLUSION

SGA, albumin, and PEW were the only nutritional markers found to be associated with mortality in this cohort of PD patients. In the multivariate analysis, after adjusting for classic mortality risk factors, only patients with hypoalbuminemia were found to be at a high risk for mortality at follow-up. These results may be limited by the number of observations and a necessity for confirmation in larger prospective studies.

Clinical features and outcomes of anti-glomerular basement membrane disease in older patients

BACKGROUND

Anti-glomerular basement membrane (GBM) disease is being recognized increasingly in older patients. Disease presentation and outcomes of these patients are unclear.

STUDY DESIGN

Case series.

SETTING & PARTICIPANTS

221 consecutive Chinese patients with anti-GBM disease diagnosed in 1998-2008 in our tertiary referral center. Anti-GBM disease was defined as positive anti-GBM antibodies in circulation and/or linear immunoglobulin G deposition along the GBM on kidney biopsy.

PREDICTOR

Older age, defined as 65 years or older, and antineutrophil cytoplasmic antibody, detected using immunofluorescence and enzyme-linked immunosorbent assay, at presentation.

OUTCOMES

Clinical features, kidney pathologic characteristics, end-stage renal disease (ESRD), and mortality. Multivariate Cox proportional hazard models were used to assess the contribution of age, sex, clinical measures, and treatments to ESRD and mortality.

RESULTS

50 of 221 (22.6%) patients were 65 years or older. Older patients had a male predominance (male/female ratio, 1.9:1). They had a higher proportion of positive antineutrophil cytoplasmic antibody results (46.0% vs 14.6%; P < 0.001), lower prevalence of hemoptysis (26.0% vs 46.2%; P = 0.01), lower urine protein excretion (1.4 ± 1.0 vs 3.9 ± 3.3 g/d; P = 0.001), and higher estimated glomerular filtration rate (eGFR) at presentation (8.4 vs 5.1 mL/min/1.73 m(2); P = 0.007) compared with younger patients. During follow-up, 30 of 37 (81.1%) and 21 of 37 (56.8%) patients developed ESRD and died in the older group compared with 115 of 139 (82.7%) and 35 of 139 (25.2%) in the younger group (P = 0.1 and P = 0.001, respectively). For older patients, multivariate Cox regression analysis showed that higher initial eGFR was an independent predictor for both ESRD (HR, 0.86; 95% CI, 0.78-0.96; P = 0.005) and death (HR, 0.79; 95% CI, 0.66-0.94; P = 0.008).

LIMITATIONS

Not all patients underwent kidney biopsy, especially those with very old age or ESRD at presentation.

CONCLUSIONS

Older patients with anti-GBM disease had milder kidney damage and less pulmonary involvement. Outcomes were predicted by initial eGFR. Thus, early diagnosis was crucial to improve outcomes.

Assessing creatinine clearance from modification of diet in renal disease study equations in the ADEMEX cohort: limitations and potential applications

BACKGROUND AND OBJECTIVES

Twenty-four-hour urine and dialysate collections provide accepted means to assess adequacy in peritoneal dialysis (PD). Recent publications suggest that creatinine clearance (CrCl) estimated from the Modification of Diet in Renal Disease (MDRD) equations (eCrCl) accurately approximates measured CrCl (mCrCl) derived from 24-hour collections of urine and dialysate and might serve as an alternative means to assess small-solute clearance and adequacy in PD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Post hoc analysis of data from patients enrolled in ADEMEX was used to assess agreement between mCrCl and eCrCl derived by four- and six-variable MDRD equations (4V-MDRDE and 6V-MDRDE, respectively). Additionally, associations among mCrCl, eCrCl, and survival were determined.

RESULTS

Acceptable precision was observed between mCrCl and 4V-MDRDE-eCrCl and 6V-MDRDE-eCrCl for the entire cohort. Precision was markedly diminished when analysis was limited to functionally anuric patients with mCrCl < 12 ml/min per 1.73 m². Although there was no association between survival and mCrCl, for every 1-ml/min per 1.73 m² increase in 4V- and 6V-MDRDE-eCrCl, there was a 6% and 4% increase in risk of death, respectively. There was a negative association between MDRDE-eCrCl and creatinine appearance rates, suggesting MDRDE-eCrCl is significantly confounded by individual differences in muscle mass.

CONCLUSIONS

MDRDE-eCrCl provides demographically comparable values to 24-hour urine and dialysate collections across the ADEMEX cohort. However, MDRDEs should not be used to assess small-solute removal or adequacy in individual PD patients or to predict outcome in any cohort of patients over narrow ranges of limited clearance.

Predictive role of polymorphisms in interleukin-5 receptor alpha-subunit, lipoprotein lipase, integrin A2 and nitric oxide synthase genes on ischemic stroke in type 2 diabetes--an 8-year prospective cohort analysis of 1327 Chinese patients

OBJECTIVE

Ischemic stroke is prevalent in type 2 diabetes and may be due to metabolic, vascular and inflammatory factors. Genetic variants implicated in these pathways may have joint effects on stroke risk. In this proof-of-concept study, we examined gene-gene interactions on risk of incident ischemic stroke in an 8-year prospective cohort of Chinese type 2 diabetic patients.

METHODS

Seventy-seven single nucleotide polymorphisms (SNPs) of 53 candidate genes for cardiovascular disease and inflammation were genotyped in 1327 patients with no past history of ischemic stroke. The association of SNPs with stroke was tested using Cox proportional hazard regression analysis. Permutation procedure was performed to control for multiple statistical comparisons.

RESULTS

Genetic variants including A/A of IL5RA (interleukin-5 alpha subunit) -5091G>A, X/X of LPL (lipoprotein lipase) S447X, A/A of ITGA2 (integrin A2) G873A and T/T or G/T of NOS3 (endothelial nitric oxide synthase) G894T showed significant correlations with incident ischemic stroke. The hazard ratios (HR) increased with number of genetic risk factors reaching an adjusted HR (confidence interval) of 3.68 (1.78-7.62, P=4.4×10(-4)) in those with ≥2 genetic risk factors compared to those without.

CONCLUSION

Polymorphisms in IL5RA, LPL, ITGA2 and NOS3 genes were independently associated with ischemic stroke in Chinese diabetic population.

Effect of blood sample type on the measurement of advanced oxidation protein products as a biomarker of inflammation and oxidative stress in hemodialysis patients

Advanced oxidation protein products (AOPP) is widely used as a uremic biomarker, especially for cardiovascular disease. However, it has not been determined whether it is better to measure AOPP in plasma or serum. In this cross-sectional study, which included 102 patients undergoing maintenance hemodialysis, fibrinogen-free serum and defibrinated plasma samples were prepared. AOPP levels from fibrinogen-free samples displayed a stronger correlation with myeloperoxidase activity and levels of C-reactive protein, interleukin-6 and tumor necrosis factor-alpha, as well as prevalent cardiovascular disease, than AOPP levels obtained from plasma samples. These results demonstrated that fibrinogen interferes with the measurement of AOPP.

Renal function and risk factors of moderate to severe chronic kidney disease in Golestan Province, northeast of Iran

INTRODUCTION

The incidence of end-stage renal disease is increasing worldwide. Earlier studies reported high prevalence rates of obesity and hypertension, two major risk factors of chronic kidney disease (CKD), in Golestan Province, Iran. We aimed to investigate prevalence of moderate to severe CKD and its risk factors in the region.

METHODS

Questionnaire data and blood samples were collected from 3591 participants (≥18 years old) from the general population. Based on serum creatinine levels, glomerular filtration rate (GFR) was estimated.

RESULTS

High body mass index (BMI) was common: 35.0% of participants were overweight (BMI 25-29.9) and 24.5% were obese (BMI ≥30). Prevalence of CKD stages 3 to 5 (CKD-S3-5), i.e., GFR <60 mL/min/1.73 m(2), was 4.6%. The odds ratio (OR) and 95% confidence interval (95% CI) for the risk of CKD-S3-5 associated with every year increase in age was 1.13 (1.11-1.15). Men were at lower risk of CKD-S3-5 than women (OR = 0.28; 95% CI 0.18-0.45). Obesity (OR = 1.78; 95% CI 1.04-3.05) and self-reported diabetes (OR = 1.70; 95% CI 1.00-2.86), hypertension (OR = 3.16; 95% CI 2.02-4.95), ischemic heart disease (OR = 2.73; 95% CI 1.55-4.81), and myocardial infarction (OR = 2.69; 95% CI 1.14-6.32) were associated with increased risk of CKD-S3-5 in the models adjusted for age and sex. The association persisted for self-reported hypertension even after adjustments for BMI and history of diabetes (OR = 2.85; 95% CI 1.77-4.59).

CONCLUSION

A considerable proportion of inhabitants in Golestan have CKD-S3-5. Screening of individuals with major risk factors of CKD, in order to early detection and treatment of impaired renal function, may be plausible. Further studies on optimal risk prediction of future end-stage renal disease and effectiveness of any screening program are warranted.

ASCI 2010 contrast media guideline for cardiac imaging: a report of the Asian Society of Cardiovascular Imaging cardiac computed tomography and cardiac magnetic resonance imaging guideline working group

The use of contrast media for cardiac imaging becomes increasing as the widespread of cardiac CT and cardiac MR. A radiologist needs to carefully consider the indication and the injection protocol of contrast media to be used as well as the possibility of adverse effect. There are several guidelines for contrast media in western countries. However, these are focusing the adverse effect of contrast media. The Asian Society of Cardiovascular Imaging, the only society dedicated to cardiovascular imaging in Asia, formed a Working Group and created a guideline, which summarizes the integrated knowledge of contrast media for cardiac imaging. In cardiac imaging, coronary artery evaluation is feasible by non-contrast MR angiography, which can be an alternative examination in high risk patients for the use of iodine contrast media. Furthermore, the body habitus of Asian patients is usually smaller than that of their western counterparts. This necessitates modifications in the injection protocol and in the formula for calculation of estimated glomerular filtration rate. This guideline provided fundamental information for the use of contrast media for Asian patients in cardiac imaging.

Use of sulphonylurea and cancer in type 2 diabetes-The Hong Kong Diabetes Registry

BACKGROUND

Hyperglycaemia is a risk factor for cancer and some sulphonylureas have anti-oxidant properties. This study examined associations between use of sulphonylureas and cancer.

METHODS

A consecutive cohort of 6103 Hong Kong Chinese patients with T2DM, free of cancer, was analysed using Cox models. Sulphonylurea usage was defined as use of the drugs at or within 2.5 years before enrolment and/or during follow-up periods. We adjusted for identified risk factors of cancer, use of other drugs, non-linear associations of lipids with cancer and probabilities of use of these drugs at different times and doses where appropriate.

RESULTS

During a median of 4.91 years of follow-up, 271 developed cancer. Glibenclamide, gliclazide and glipizide were ever used in 32.5% (n = 1983), 47.8% (n = 2920) and 13.5% (n = 823). After adjustment for covariates, use of gliclazide and glibenclamide was associated with reduced cancer risk in a dose-dependent manner. In addition, there were interactions between metformin and glibenclamide/glipizide use towards lower adjusted cancer risks.

CONCLUSIONS

In T2DM, use of glibenclamide and gliclazide may be associated with reduced cancer risk.

The relationship of cystatin C, creatinine, estimated GFR, and cardiovascular events

This study examined the predictive value of plasma cystatin C, creatinine and estimated glomerular filtration rate (eGFR) as risk factors for cardiovascular disease in Chinese. Plasma cystatin C and creatinine were measured in 466 coronary heart disease (CHD) patients recruited from 4 hospitals and 349 healthy controls from local communities in Wuhan, China. Cockroft-Gault formula was used to estimate the glomerular filtration rate (GFR) after adjusting for body surface area. With each measure, the study population was divided into quintiles. The results showed that the patients had significantly higher levels of plasma cystatin C, creatinine, and lower level of eGFR than controls. Lower eGFR was associated with a higher risk of cardiovascular events. As compared with the first (highest) quintile, the hazard ratios (and 95% CIs) after multivariate adjustment for CHD were as follows: third quintile, 2.98 (1.54-5.78); fourth quintile, 3.34 (1.58-7.09); fifth quintile, 4.37(1.84-10.35). With higher cystatin C quintiles (≥1.00 mg/L and ≥1.17 mg/L), the hazard ratios for CHD were 2.16 (1.23-3.81) and 2.34 (1.25-4.38), similar to those of creatinine 2.21 (1.21-4.03) and 2.03 (1.07-3.84). However, it was plasma cystatin C not eGFR or creatinine had stronger association with ischemic stroke. The highest quintile had the hazard ratio of 4.51 (1.45-14.08) after multivariate adjustment. It was concluded that plasma cystatin C, associated with renal function, is not an independent risk factor for cardiovascular disease. eGFR is a better risk predictor for CHD than plasma cystatin C and creatinine. But for ischemic stroke, plasma cystatin C is a better risk factor than creatinine and estimated GFR.

Prevalence of hyperuricemia and its association with antihypertensive treatment in hypertensive patients in Taiwan

BACKGROUND

Hyperuricemia is thought to be associated with an increased risk of hypertension, impaired renal function and cardiovascular disease. Our aim is to study the prevalence of hyperuricemia and its association with antihypertensive treatment in Taiwanese hypertensive subjects.

METHODS

We recruited 2145 hypertensive subjects from 19 hospitals in four areas of Taiwan. We assessed the prevalence of hyperuricemia and determined the independent risk factors for raised serum uric acid level by multiple logistic regression analyses.

RESULTS

Compared to the general population, hypertensive subjects in Taiwan had a higher prevalence (mean 35% in males, 43% in females) of hyperuricemia; this prevalence being 1.5- and 1.7-fold higher in males and females respectively. Uric acid levels; gout and prevalence of hyperuricemia were found to be highest in the younger age group (20-39 years) and no regional differences were noted. The most important risk factors for hyperuricemia were impaired renal function and diuretic use. Serum uric acid values correlated significantly with four quintiles of serum creatinine (p<0.0001) independent of diuretic use. Diuretic users had a significantly elevated serum uric acid and serum creatinine values than non-users. Among the patients given diuretics, hyperuricemia occurred in 44% of those given thiazides, in 56% of those given loop diuretics, and in 57% of those given aldosterone receptor blockers.

CONCLUSIONS

Diuretic usage and renal function status have a strong impact on the prevalence of hyperuricemia in Taiwanese hypertensive subjects. It is still unclear, however, whether diuretics induce renal failure through elevating serum uric acid levels.

Prevalence and risk factors associated with chronic kidney disease in a Uygur adult population from Urumqi

Evaluating the prevalence of kidney damage according to population-based studies in different communities has been limited in developing countries. We conducted a population-based screening study in Uygur people of Urumqi, aiming to identify the prevalence and associated risk factors of chronic kidney disease (CKD) in Uygur populations. A total of 2576 residents (>18 years) from four districts of Urumqi were interviewed from June 2007 to January 2009 and tested for haematuria, albuminuria and reduced renal function. Associations between age, gender, smoking, diabetes mellitus, hypertension, hyperuricaemia and kidney damage were examined. There were 2576 subjects enrolled in this study. After age correction, the prevalence of albuminuria, haematuria and reduced estimated glomerular filtration rate (eGFR) was 3.58%, 2.26% and 1.03%, respectively. Approximately 5.65% of the sample population had at least one indicator of kidney damage. Age, diabetes mellitus, hypercholesteremia, hyperuricaemia and hyperlipidaemia were independently associated with CKD. In the general Uygur adult population from Urumqi, 5.65% had either proteinuria, haematuria or reduced eGFR, indicating the presence of kidney damage, with an awareness of only 1.05%. The high prevalence and low awareness of CKD in this population suggest an urgent need for CKD prevention programs in Uygur people.

Burden of CKD, proteinuria, and cardiovascular risk among Chinese, Mongolian, and Nepalese participants in the International Society of Nephrology screening programs

BACKGROUND

In 2007, the International Society of Nephrology funded the Kidney Disease Data Center database to house data from sponsored programs aimed at preventing chronic kidney disease and its complications in developing nations. This study compares baseline characteristics and burden of illness among participants from centers in China, Mongolia, and Nepal. An important secondary objective is to show the feasibility of screening for chronic kidney disease and its major risk factors in a diverse group of lower income settings.

STUDY DESIGN

Cross-sectional screening study.

SETTING & PARTICIPANTS

Participants from Nepal (n = 8,398), China (n = 1,999), and Mongolia (n = 997). Screening was open to the public for participants in China and Nepal; referral from a general practitioner was required for participants in Mongolia.

OUTCOMES

Estimated glomerular filtration rate (eGFR), proteinuria, hypertension, diabetes, obesity, cardiovascular risk.

MEASUREMENT

Demographic and clinical data were collected prospectively using a standard format. Blood and urine specimens were provided according to local protocol.

RESULTS

Of 11,394 participants, decreased eGFR (<60 mL/min/1.73 m(2)) was present in 7.3%-14% of participants across centers; proteinuria (≥1+) on dipstick (2.4%-10%), hypertension (26%-36%), diabetes (3%-8%), and obesity (body mass index ≥30 kg/m(2); 2%-20%) were all common. Predicted 5-year cardiovascular risk ≥10% ranged from 20%-89%. Numbers needed to screen to detect a new case of eGFR <60 mL/min/1.73 m(2), hypertension, or diabetes were 2.6 (95% CI, 2.5-2.7), 3.4 (95% CI, 3.1-3.7), and 4.7 (95% CI, 3.3-8.0) for Nepal, China, and Mongolia, respectively.

LIMITATIONS

May not be representative of the general population.

CONCLUSIONS

The acceptable diagnostic yield of abnormalities across these 3 diverse settings suggests that trials of targeted screening and intervention are feasible and warranted in such countries.

Relationship between body mass index and proteinuria in hypertensive nephrosclerosis: results from the African American Study of Kidney Disease and Hypertension (AASK) cohort

BACKGROUND

Few studies have examined the association between obesity and markers of kidney injury in a chronic kidney disease population. We hypothesized that obesity is independently associated with proteinuria, a marker of chronic kidney disease progression.

STUDY DESIGN

Observational cross-sectional analysis.

SETTING & PARTICIPANTS

Post hoc analysis of baseline data for 652 participants in the African American Study of Kidney Disease (AASK).

PREDICTORS

Obesity, determined using body mass index (BMI).

MEASUREMENTS & OUTCOMES

Urine total protein-creatinine ratio and albumin-creatinine ratio measured in 24-hour urine collections.

RESULTS

AASK participants had a mean age of 60.2 ± 10.2 years and serum creatinine level of 2.3 ± 1.5 mg/dL; 61.3% were men. Mean BMI was 31.4 ± 7.0 kg/m(2). Approximately 70% of participants had a daily urine total protein excretion rate <300 mg/d. In linear regression analyses adjusted for sex, each 2-kg/m(2) increase in BMI was associated with a 6.7% (95% CI, 3.2-10.4) and 9.4% (95% CI, 4.9-14.1) increase in urine total protein-creatinine and urine albumin-creatinine ratios, respectively. In multivariable models adjusting for age, sex, systolic blood pressure, serum glucose level, uric acid level, and creatinine level, each 2-kg/m(2) increase in BMI was associated with a 3.5% (95% CI, 0.4-6.7) and 5.6% (95% CI, 1.5-9.9) increase in proteinuria and albuminuria, respectively. The interaction between older age and BMI was statistically significant, indicating that this relationship was driven by younger AASK participants.

LIMITATIONS

May not generalize to other populations; cross-sectional analysis precludes statements regarding causality.

CONCLUSIONS

BMI is associated independently with urine total protein and albumin excretion in African Americans with hypertensive nephrosclerosis, particularly in younger patients.

Ethnic coefficients for glomerular filtration rate estimation by the Modification of Diet in Renal Disease study equations in the Korean population

Race and ethnicity are influential in estimating glomerular filtration rate (GFR). We aimed to find the Korean coefficients for the Modification of Diet in Renal Disease (MDRD) study equations and to obtain novel proper estimation equations. Reference GFR was measured by systemic inulin clearance. Serum creatinine (SCr) values were measured by the alkaline picrate Jaffé kinetic method, then, recalibrated to CX3 analyzer and to isotope dilution mass spectrometry (IDMS). The Korean coefficients for the 4 and 6 variable MDRD and IDMS MDRD study equations based on the SCr recalibrated to CX3 and to IDMS were 0.73989/0.74254 and 0.99096/0.9554, respectively. Coefficients for the 4 and 6 variable MDRD equations based on the SCr measured by Jaffé method were 1.09825 and 1.04334, respectively. The modified equations showed better performances than the original equations. The novel 4 variable equations for Korean based on the SCr measured and recalibrated to IDMS were 107.904×SCr(-1.009)×age(-0.02) (×0.667, if woman) and 87.832×SCr(-0.882)×age(0.01) (×0.653, if woman), respectively. Modified estimations of the MDRD and IDMS MDRD study equations with ethnic coefficients and the novel equations improve the performance of GFR estimation for the overall renal function.

Epidemiology, impact and preventive care of chronic kidney disease in Taiwan

Chronic kidney disease (CKD) has emerged as a global public health burden. Taiwan has the highest incidence and prevalence rates of end-stage renal disease (ESRD) in the world. In this review, the following key issues of CKD in Taiwan are addressed: epidemiological data, underlying diseases patterns, risk factors, public health concerns and a preventive project. Prevalence of CKD are reported to be 6.9% for CKD stage 3-5, 9.83% for clinically recognized CKD and 11.9% for CKD stage 1-5. However, overall awareness of CKD is low, 9.7% for CKD stage 1-3 and 3.5% for stage 1-5. Diabetes mellitus (43.2%), chronic glomerulonephritis (25.1%), hypertension (8.3%) and chronic interstitial nephritis (2.8%) are four major underlying renal diseases of ESRD. Older age, diabetes, hypertension, smoking, obesity, regular use of herbal medicine, family members (both relatives and spouses), chronic lead exposure and hepatitis C are associated with higher risk for CKD. Impact of CKD increases risk of all-cause mortality and cardiovascular diseases, especially in those with overt proteinuria and advanced CKD stages. These impacts lead to increased medical costs. The nationwide CKD Preventive Project with multidisciplinary care program has proved its effectiveness in decreasing dialysis incidence, mortality and medical costs. It is crucially significant from Taiwan experience on CKD survey and preliminary outcome of the preventive project. Provision of a more comprehensive public health strategy and better care plan for CKD should be achieved by future international collaborative efforts and research.

Current status of estimated glomerular filtration rate (eGFR) equations for Asians and an approach to create a common eGFR equation

CKD is now recognized as life-threatening disease and various countermeasures are implemented worldwide. The most important step to overcome CKD is early detection and evaluation. Equation for estimating GFR is the necessary tool for this step. This is also useful to follow-up CKD patients in routine clinical settings. Currently, most commonly used equation is original and re-expressed MDRD formula. For Asians, ethnic co-efficient is needed when applying these formulas. Ethnic co-efficient is different among Asian countries. Recently, different original equations have been developed in several Asian countries. At the present time, it is not clear to develop a single common eGFR equation fit for Asians. There are several factors that affect GFR estimation. These include ethnicity, reference method to measure GFR, method of creatinine measurement and calibration. Towards the future, Asian collaborative study is necessary to validate and standardize eGFR equations.

Chronic kidney disease awareness, screening and prevention: rationale for the design of a public education program

Design principles for a chronic kidney disease (CKD) screening program start with the general population at increased risk of CKD. Simple risk factor analysis demonstrates diabetes, hypertension, cardiovascular disease and older age as significant associated conditions. More comprehensive risk factor analysis shows only diabetes and hypertension as risk factors in people aged less than 50-60 years, and that anyone aged older than 50-60 years is at risk. Assessment of the relationship between CKD stage and cardiovascular risk factors shows early stage CKD to be associated with poor blood pressure control, which should be addressed. Other risk factors should be more completely assessed to determine if participants and their physicians are adequately addressing factors amenable to treatment to reduce high adverse event rates, premature death and progression to end-stage renal disease (ESRD). Such assessment is needed to reduce the high burden of ESRD on national health-care systems, which can only be addressed by early screening and active treatment.

Challenging chronic kidney disease: experience from chronic kidney disease prevention programs in Shanghai, Japan, Taiwan and Australia

Chronic kidney disease (CKD) is now a global health problem. One important strategy to prevent and manage CKD is to offer a prevention program which could detect CKD early as well as raise awareness of the disease. In Shanghai, a community-based study demonstrated that the prevalence of CKD was high while awareness was low. The results from Shanghai urged the necessity of a screening and prevention program of CKD. In Japan, the urinalysis screening system was established to early diagnose and prevent CKD. Due to modification of lifestyle and prevalence of diabetes, urine dip-stick test for microalbuminuria might be necessary in adults while screening for proteinuria and haematuria are necessary for students and young adults. In Taiwan, two CKD programs - a CKD care program and diabetic share care program - were initiated. The cost-effectiveness study indicated that both programs could reduce end-stage renal disease (ESRD) burden in Taiwan because integrated pre-ESRD care was important for patients with CKD stage 4 and stage 5 while a diabetic shared care program was cost-effective to prevent nephropathy to patients with diabetic mellitus. In Australia, studies demonstrated that screening of high-risk individuals as well as promoting awareness were cost-effective to early detection of CKD. Furthermore, opportunistic screening with emphasis on early detection was effective in CKD prevention. The studies from those regions share experiences on early prevention and management of CKD.

Prevalence and risk factors of chronic kidney disease: a population study in the Tibetan population

BACKGROUND

The prevalence of chronic kidney disease (CKD) at high altitude is not known. We conducted a population-based survey in Tibet to identify the prevalence and associated risk factors of CKD in subjects living at altitudes of > 3500 m.

METHODS

One thousand two hundred and eighty-nine Tibetans (≥ 18 years) from four districts of Lhasa city (altitude 3658 m) and eight villages of Dangxiong County (altitude 4200 m) were interviewed and tested for haematuria, albuminuria and estimated glomerular filtration rate (eGFR).

RESULTS

The adjusted prevalence of hypertension, albuminuria, haematuria and reduced eGFR were 38.8% (95% CI: 36.2-41.5%), 16.2% (95% CI: 14.1-18.2%), 3.9% (95% CI: 2.8-4.9%) and 2.1% (95% CI: 1.3-2.9%), respectively. Both the presence of hypertension and the presence of albuminuria were strongly and independently associated with hyperuricaemia and elevated haematocrit.

CONCLUSIONS

This is the first population-based epidemiological study of CKD in the Tibetan population. We found a higher prevalence of CKD and associated high prevalence of albuminuria, hypertension, hyperuricaemia and high haematocrit in the Tibetan population. The present study indicates the urgent need to develop comprehensive strategies targeted at reducing the CKD burden in this area and may lead to a better understanding of CKD in high-altitude populations.

Low triglyceride and nonuse of statins is associated with cancer in type 2 diabetes mellitus: the Hong Kong Diabetes Registry

BACKGROUND

Patients with type 2 diabetes mellitus (T2DM) have increased cancer risks. The authors reported nonlinear associations of cancer with triglyceride and other lipids in T2DM. Crosstalk between lipid metabolism and the renin-angiotensin system may increase cancer risk via activation of insulin-like growth factor-1 pathway in T2DM. In this analysis, the authors explored associations of cancer risk with high/low triglyceride in T2DM and possible modifying effects of statins on this risk association, if any.

METHODS

A consecutive cohort of 5166 Chinese patients with T2DM, free of cancer at enrollment and not using statins at or before enrollment, was analyzed using Cox models. Biological interactions were estimated using relative excess risk because of interaction, attributable proportion because of interaction, and synergy index. Relative excess risk because of interaction > 0, attributable proportion because of interaction > 0, or synergy index > 1 indicates biological interaction.

RESULTS

During 5.25 years of follow-up (median), 4.7% (n = 243) patients developed cancer. Triglyceride < 1.70 mmol/L was associated with increased cancer risk in the entire cohort and in statin nonusers, but not in statin users. Patients with triglyceride < 1.70 mmol/L plus nonuse of statins during follow-up had 2.74-fold increased cancer risk compared with their counterparts with either triglyceride ≥ 1.70 mmol/L or use of statins or both. There was significant interaction between triglyceride < 1.70 mmol/L and nonuse of statins (relative excess risk because of interaction, 0.99; 95% confidence interval [CI], 0.07-1.90 and attributable proportion because of interaction, 0.36; 95% CI, 0.02-0.70).

CONCLUSIONS

In Chinese T2DM patients, triglyceride < 1.70 mmol/L might be associated with increased cancer risk, which was attenuated in the presence of use of statins.

Circulating levels of asymmetric dimethylarginine are an independent risk factor for left ventricular hypertrophy and predict cardiovascular events in pre-dialysis patients with chronic kidney disease

BACKGROUND

Several studies have related the circulating level of asymmetric dimethylarginine (ADMA) to cardiac remodeling and cardiovascular (CV) events in end-stage renal disease (ESRD) patients. Studies investigating this relationship in patients with pre-dialysis chronic kidney disease (CKD) are lacking.

METHODS

We enrolled 76 CKD patients (age, 46.7+/-14.3 years, 39 females) and 15 controls (age, 40.1+/-18.5 years, 6 females). Clinical parameters, blood biochemistry and echocardiographic findings were recorded, and plasma ADMA concentrations measured by high-performance liquid chromatography-mass spectrometry (HPLC-MS). Patients were prospectively followed up for a median of 15 (range, 6-24) months.

RESULTS

Plasma ADMA was significantly elevated in CKD patients compared with controls (41.56+/-12.76 microg/mL vs 17.12+/-7.09 microg/mL, P<0.001), and correlated with the left ventricular mass index (LVMI) (r=0.597, P<0.001). During follow-up, 25 patients experienced new CV events and their plasma ADMA level was significantly elevated (48.27+/-13.70 vs 34.91+/-6.38 in CV event-free patients, P<0.001). Cox regression analysis further confirmed that ADMA was an independent risk factor for CVD (HR=1.175, 95%CI[1.070-1.290], P=0.001).

CONCLUSION

Similar to findings in ESRD patients, elevated circulating levels of ADMA may increase the risk of LVH and CV events in pre-dialysis CKD patients.

Epidemiology of hypertension and chronic kidney disease in China

PURPOSE OF REVIEW

Hypertension and chronic kidney disease have become major public health challenges in China.

RECENT FINDINGS

It is estimated that approximately 153 million Chinese adults had hypertension in 2002. It is also estimated that 2.33 million total cardiovascular deaths and 1.27 million premature cardiovascular deaths were attributable to increased blood pressure in 2005 in China. Approximately 39% of Chinese adult populations are highly sensitive to dietary sodium intake, a risk factor for hypertension and cardiovascular disease. The prevalence of chronic kidney disease varied greatly among studies due to differences in study populations and definitions of chronic kidney disease. A large prospective cohort study estimates that incidence and mortality of end-stage renal disease was 30.7 and 20.9 per 100,000 person-years among Chinese adults aged 40 years and older. Hypertension and the metabolic syndrome have been documented as risk factors for chronic kidney disease. In addition, a J-shaped association between body weight and incidence of end-stage renal disease and an inverse association between alcohol consumption and risk of end-stage renal disease were documented.

SUMMARY

These results underscore the urgent need to develop national strategies for the prevention, detection, and treatment of hypertension and chronic kidney disease.

High prevalence of kidney disease in two rural communities in Kosovo and Metohia

A systematic survey was carried out in an enclave in Kosovo and Metohia, with the aim of assessing the prevalence of kidney diseases. The survey involved 423 (180 males) adult inhabitants from two small settlements, Velika Hoca and Orahovac, and included an interview, medical documentation, physical, ultrasound, and laboratory examinations. Persons with any detected disorder indicating kidney disease were invited for additional examination of kidney function. Using urine dipstick test, proteinuria was detected in 19.1% and hemoglobinuria in 4.5% of the examined subjects. Glomerular filtration rate (Modification of Diet in Renal Disease (MDRD) formula) below 60 mL/min/1.73 m(2) was found in 5.2% of subjects. Kidney ultrasound examination detected reduced length of right and left kidneys in 38 and 24 persons, respectively. Cysts were also a frequent finding, but polycystic kidney, hydronephrosis, and kidney stones were found in about 2% each. The analysis of data obtained by the present examination and available medical documentation revealed kidney and urinary tract diseases in 98 persons: 52 patients with already known disease and 46 patients detected in the survey. Out of them in 22 patients diagnosis of kidney disease could not be established during the survey but laboratory analyses indicated that they might suffer from tubulointerstitial disease: 14 had tubular dysfunctions, 8 of them low-grade proteinuria, and 12 had a positive family history for kidney disease. In the enclave of Velika Hoca and Orahovac the prevalence of kidney disease was 7.0% indicating that these communities might be placed among those with a high prevalence of kidney disease in Serbia.

Normoalbuminaemia is associated with IgA nephropathy in primary glomerulopathy with nephrotic-range proteinuria in Chinese patients

BACKGROUND

Massive proteinuria is often associated with hypoalbuminaemia in glomerulopathy. However, patients may have normal levels of serum albumin despite heavy proteinuria in many circumstances. This study analysed factors affecting serum levels of albumin in primary glomerulopathy patients with nephrotic-range proteinuria.

METHODS

The renal histopathological data of 780 consecutive adult patients (age ≥ 18 years old) with primary glomerulopathy and nephrotic-range proteinuria, who received native renal biopsies in Peking University First Hospital from 1998 to 2007, were retrospectively analysed.

RESULTS

Compared with patients with hypoalbuminaemia (serum albumin < 30 g/L), patients without hypoalbuminaemia were significantly younger (P < 0.001) and had significantly lower levels of proteinuria (P < 0.001). Patients without hypoalbuminaemia had a significantly higher proportion of IgA nephropathy (66.0% vs. 17.2%, P < 0.001). The independent predictors of hypoalbuminaemia in nephrotic-range proteinuria patients included age, gender, interval between onset of the disease and renal biopsy, proteinuria level, and pathological type of glomerulopathy. A serum level of albumin ≥ 35 g/L could predict IgA nephropathy with a specificity of 95.8%, and specificity increased with age.

CONCLUSIONS

Among patients with primary glomerulopathy and nephrotic-range proteinuria, normoalbuminaemia is associated with IgA nephropathy.

Prevalence of CKD in northeastern Italy: results of the INCIPE study and comparison with NHANES

BACKGROUND AND OBJECTIVES

Sufficiently powered studies to investigate the CKD prevalence are few and do not cover southern Europe.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

For the INCIPE study, 6200 Caucasian patients ≥40 years old were randomly selected in northeastern Italy in 2006. Laboratory determinations were centralized. The albumin to creatinine ratio in urine and estimated GFR from calibrated creatinine (SCr) were determined. A comparison with 2001 through 2006 NHANES surveys was performed.

RESULTS

Prevalence of CKD was 13.2% in northeastern (NE) Italy (age and gender standardized to the U.S. 2007 Caucasian population). Prevalence of CKD in U.S. Caucasians is higher (20.3%), the major difference being in CKD 3. Risk factors for CKD are more prevalent in the United States than in Italy. With use of CKD 3a and 3b stages, CKD prevalence decreased in NE Italy (8.5%) and in the United States (12.8%).

CONCLUSIONS

The prevalence of CKD is high in NE Italy, but lower than that in the United States. A large part of the difference in CKD prevalence in NE Italy versus that in the United States is due to the different prevalence of CKD 3. The higher prevalence of a number of renal risk factors in persons from the United States explains in part the different dimensions of the CKD problem in the two populations.

A prediction model for the risk of incident chronic kidney disease

BACKGROUND

Chronic kidney disease is a health burden for the general population. We designed a cohort study to construct prediction models for chronic kidney disease in the Chinese population.

METHODS

A total of 5168 participants were followed up during a median of 2.2 (interquartile range, 1.5-2.9) years, and 190 individuals (3.7%) developed chronic kidney disease, defined by a glomerular filtration rate of less than 60 mL/min/1.73 m(2).

RESULTS

We developed a point system to estimate chronic kidney disease risk at 4 years using the following variables: age (8 points), body mass index (2 points), diastolic blood pressure (2 points), and history of type 2 diabetes (1 point) and stroke (4 points) for the clinical model, with the addition of uric acid (2 points), postprandial glucose (1 point), hemoglobin A1c (1 point), and proteinuria 100 mg/dL or greater (6 points) for the biochemical model. Similar discrimination measures were found between the clinical model (area under the receiver operating characteristic curve, 0.768; 95% confidence interval (CI), 0.738-0.798) and the biochemical model (area under the receiver operating characteristic curve, 0.765; 95% CI, 0.734-0.796). The area under the receiver operating characteristic curve of the clinical model was 0.667 (95% CI, 0.631-0.703) for the external validation data from community-based cohort participants. The optimal cutoff value for the clinical model was set as 7, with a sensitivity of 0.76 and a specificity of 0.66.

CONCLUSION

We constructed a clinical point-based model to predict the 4-year incidence of chronic kidney disease. This prediction tool may help to target Chinese subjects at risk of developing chronic kidney disease.

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

AIM

Chronic kidney disease (CKD) poses a serious public health problem worldwide. Population-based studies determining the prevalence of this disease in China have been limited in several large developed cities. In the present study, a population-based screening study in Henan, a representative province in Central China, was conducted in order to quantify the prevalence of CKD and identify the associated risk factors for this disease in a population of developing areas of China.

METHODS

Residents (n = 4156) over 40 years old in four major cities of Henan Province were interviewed and their albuminuria, reduced renal function, haematuria and blood pressure were measured. Associations between age, components of metabolism syndrome and indicators of CKD were examined.

RESULTS

Among these subjects, the prevalence rates of albuminuria, haematuria and reduced renal function were 4.51%, 6.28% and 1.53%, respectively. Approximately 10.49% of the subjects had at least one indicator of kidney damage. The awareness rate of this disease in subjects with CKD was only 9.50%. Hypertension, diabetes and hyperuricaemia were three independent risk factors for CKD.

CONCLUSION

The high prevalence and low awareness of CKD in the studied population suggest that CKD is a severe public health problem in Central China. Effectively preventive and therapeutic interventions are needed.

A challenge to chronic kidney disease in Asia: The report of the second Asian Forum of Chronic Kidney Disease Initiative

BACKGROUND

The Asian Forum of Chronic Kidney Disease Initiative started in 2007 in Hamamatsu, Japan when delegates from 16 countries joined together to facilitate collaboration in studying chronic kidney disease (CKD) in the Asia-Pacific region. Based on the outcome of the first meeting, the second meeting was organized as a consensus conference to frame the most relevant issues, and develop research recommendations and action plan.

PROCEEDINGS

The meeting was held on 4 May 2008 as a pre-conference meeting to the 11th Asian Pacific Congress of Nephrology in Kuala Lumpur. This meeting consisted of three sessions: Session I was dedicated to the estimation of glomerular filtration rate and the standardization of serum creatinine measurements. Session II discussed specific considerations in the aetiology of and risk factors for end-stage renal disease in Asia. We concluded that there were regional specific problems that might lead to a very high prevalence of end-stage renal disease. Session III discussed the issue of facilitation of coordination and integration of the CKD initiative between developed and developing countries in the Asia-Pacific region.

CONCLUSION

The following action plans were formulated: (i) validating the existing global estimated glomerular filtration rate equation or creating a new one using serum creatinine standardized by a central laboratory; (ii) establishing a pan-Asian CKD registry to facilitate risk analysis of CKD and its comorbidities; (iii) adapting existing clinical practice guidelines for CKD detection and management to address specific problems in this region; and (iv) working closely with other international professional organizations to promote manpower development and education in different aspects of CKD in developing countries.

Gender differences in age-related decline in glomerular filtration rates in healthy people and chronic kidney disease patients

BACKGROUND

Since men with chronic kidney disease (CKD) progress faster than women, an accurate assessment of CKD progression rates should be based on gender differences in age-related decline of glomerular filtration rate (GFR) in healthy individuals.

METHODS

A Chinese sample population from a stratified, multistage, and clustered CKD screening study was classified into healthy, at-risk, and CKD groups. The gender differences in estimated GFR (eGFR) and age-related eGFR decline were calculated for each group after controlling for blood pressure, fasting glucose levels, serum lipids levels, education level, and smoking status. After referencing to the healthy group, gender-specific multivariate-adjusted rates of decline in eGFR and differences in the rates of decline were calculated for both CKD and at-risk groups.

RESULTS

The healthy, at-risk, and CKD groups consisted of 4569, 7434, and 1573 people, respectively. In all the 3 groups, the multivariate-adjusted eGFRs in men were lower than the corresponding eGFRs in women. In addition, in the healthy and at-risk groups, the rates of decline in eGFR in men were lower than the corresponding rates of decline in women (healthy group: 0.51 mLxmin-1x1.73 m-2·yr-1 vs. 0.74 mLxmin-1x1.73 m-2xyr-1 and at-risk group: 0.60 mLxmin-1x1.73 m-2xyr-1 vs. 0.73 mLxmin-1x1.73 m-2xyr-1). However, in the CKD group, the rates of decline in eGFR in men were similar to those in women (0.96 mLxmin-1x1.73 m-2xyr-1 vs. 0.91 mLxmin-1x1.73 m-2xyr-1). However, after referencing to the healthy group, the rates of decline in eGFR in men in the at-risk and CKD groups were greater faster than the corresponding rates in women (at-risk group: 0.10 mLxmin-1x1.73 m-2·yr-1 vs. -0.03 mLxmin-1x1.73 m-2xyr-1 and CKD group: 0.44 mLxmin-1x1.73 m-2·yr-1 vs. 0.15 mLxmin-1x1.73 m-2xyr-1).

CONCLUSION

To accurately assess gender differences in CKD progression rates, gender differences in age-related decline in GFR should be considered.

Combination of urinary kidney injury molecule-1 and interleukin-18 as early biomarker for the diagnosis and progressive assessment of acute kidney injury following cardiopulmonary bypass surgery: a prospective nested case-control study

The aim of this nested case-control study was to assess the combined use of urinary kidney injury molecule (KIM)-1 and interleukin (IL)-18 for acute kidney injury (AKI) after cardiopulmonary bypass surgery (CPB). From a cohort of 122 subjects who underwent CPB, serial urinary KIM-1 and IL-18 concentrations were determined in 30 AKI and 92 non-AKI patients. An increased level of urinary KIM-1 was associated with the occurrence of AKI, whereas an increased level of IL-18 was related to progressive AKI. The combination of these two biomarkers facilitates the early diagnosis and assessment of the likely progression of AKI after CPB.

Worsening renal function defined as an absolute increase in serum creatinine is a biased metric for the study of cardio-renal interactions

OBJECTIVES

Worsening renal function (WRF) during the treatment of decompensated heart failure, frequently defined as an absolute increase in serum creatinine >or=0.3 mg/dl, has been reported as a strong adverse prognostic factor in several studies. We hypothesized that this definition of WRF is biased by baseline renal function secondary to the exponential relationship between creatinine and renal function.

METHODS

We reviewed consecutive admissions with a discharge diagnosis of heart failure. An increase in creatinine >or=0.3 mg/dl (WRF(CREAT)) was compared to a decrease in GFR >or=20% (WRF(GFR)).

RESULTS

Overall, 993 admissions met eligibility. WRF(CREAT) occurred in 31.5% and WRF(GFR) in 32.7%. WRF(CREAT) and WRF(GFR) had opposing relationships with baseline renal function (OR = 1.9 vs. OR = 0.51, respectively, p < 0.001). Both definitions had similar unadjusted associations with death at 30 days [WRF(GFR) OR = 2.3 (95% CI 1.1-4.8), p = 0.026; WRF(CREAT) OR = 2.1 (95% CI 1.0-4.4), p = 0.047]. Controlling for baseline renal insufficiency, WRF(GFR) added incrementally in the prediction of mortality (p = 0.009); however, WRF(CREAT) did not (p = 0.11).

CONCLUSIONS

WRF, defined as an absolute change in serum creatinine, is heavily biased by baseline renal function. An alternative definition of WRF should be considered for future studies of cardio-renal interactions.

Imprecision of urinary iothalamate clearance as a gold-standard measure of GFR decreases the diagnostic accuracy of kidney function estimating equations

BACKGROUND

Evaluating the accuracy of estimated glomerular filtration rate (eGFR) derived from serum creatinine (SCr) and serum cystatin C (SCysC) equations requires gold-standard measures of GFR. However, the influence of imprecise measured GFRs (mGFRs) on estimates of equation error is unknown.

STUDY DESIGN

Diagnostic test study.

SETTING & PARTICIPANTS

1,995 participants from the Modification of Diet in Renal Disease (MDRD) Study and African American Study of Kidney Disease and Hypertension (AASK) with at least 2 baseline mGFRs from iodine 125-iothalamate urinary clearances, 1 standardized SCr value, and 1 SCysC value.

INDEX TESTS

eGFRs calculated using the 4-variable isotope-dilution mass spectrometry (IDMS)-traceable MDRD Study equation, the Chronic Kidney Disease (CKD) Epidemiology Collaboration (CKD-EPI) SCysC equation, the CKD-EPI SCr-SCysC equation, and mGFRs collected from another prerandomization visit.

REFERENCE TESTS

A single reference mGFR, average of 2, and average of 3 mGFRs; additional analysis limited to consistent mGFRs (difference <or=25% from reference mGFR).

RESULTS

We found that mGFRs had stable mean values, but substantial variability across visits. Of all mGFRs collected a mean of 62 days apart from the reference visit, 8.0% were outside 30% of the single reference mGFR (1 - P(30)). Estimation equations were less accurate because 12.1%, 17.1%, and 8.3% of eGFRs from the MDRD Study, CKD-EPI SCysC, and CKD-EPI SCr-SCysC equations were outside 30% of the same gold standard (1 - P(30)). However, improving the precision of the reference test from a single mGFR to the average of 3 consistent mGFRs decreased these error estimates (1 - P(30)) to 8.0%, 12.5%, and 3.9%, respectively.

LIMITATIONS

Study population limited to those with CKD.

CONCLUSIONS

Imprecision in gold-standard measures of GFR contribute to an appreciable proportion of the cases in which eGFR and mGFR differ by >30%. Reducing and quantifying errors in gold-standard measurements of GFR is critical to fully estimating the accuracy of GFR estimates.

Prevalence of and risk factors for chronic kidney disease in rural Nicaragua

BACKGROUND

Mostly anecdotal reports describe a high prevalence of chronic kidney disease in northwestern Nicaragua, predominantly among younger men, resulting in substantial morbidity and mortality. The true prevalence, nature and aetiology of kidney disease in this region remain unknown.

METHODS

We performed a population-based prevalence study in Quezalguaque, Nicaragua to assess the frequency of estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m(2), and compared the prevalence of reduced eGFR in Quezalguaque with the USA using the NHANES 1999-2006 data. We also conducted an embedded case-control study in a subset of participants to assess kidney disease risk factors.

RESULTS

From 1882 eligible households, 771 individuals from 300 households participated in the prevalence study, 98 (13%) of whom had reduced eGFR. Reduced eGFR was more common among older participants, men and participants living at lower altitudes. Among 18-29-year-old participants, 2.6% had reduced eGFR, and among 30-41-year-old participants, 7.4% had reduced eGFR; this compares with 0.2% and 0.8%, respectively, in NHANES. No individuals in these age groups were diabetic. Among cases, only 27% had dipstick proteinuria of 1+ or greater, compared with 7% of controls. Haematuria did not significantly differ between cases and controls (24% versus 18%). In age- and sex-adjusted models, hypertension and residence at lower altitude were independently associated with reduced eGFR, while occupational history was not associated with reduced eGFR.

CONCLUSIONS

Kidney disease appears common in residents of Quezalguaque, Nicaragua, particularly in younger men, with features most consistent with tubulointerstitial disease. Further research is needed to elucidate the causes of kidney disease in this region.

Naturally occurring human urinary peptides for use in diagnosis of chronic kidney disease

Because of its availability, ease of collection, and correlation with physiology and pathology, urine is an attractive source for clinical proteomics/peptidomics. However, the lack of comparable data sets from large cohorts has greatly hindered the development of clinical proteomics. Here, we report the establishment of a reproducible, high resolution method for peptidome analysis of naturally occurring human urinary peptides and proteins, ranging from 800 to 17,000 Da, using samples from 3,600 individuals analyzed by capillary electrophoresis coupled to MS. All processed data were deposited in an Structured Query Language (SQL) database. This database currently contains 5,010 relevant unique urinary peptides that serve as a pool of potential classifiers for diagnosis and monitoring of various diseases. As an example, by using this source of information, we were able to define urinary peptide biomarkers for chronic kidney diseases, allowing diagnosis of these diseases with high accuracy. Application of the chronic kidney disease-specific biomarker set to an independent test cohort in the subsequent replication phase resulted in 85.5% sensitivity and 100% specificity. These results indicate the potential usefulness of capillary electrophoresis coupled to MS for clinical applications in the analysis of naturally occurring urinary peptides.

Chronic kidney disease and end-stage renal disease in the elderly population: current prevalence, future projections, and clinical significance

The world's population is aging, with the number of older adults projected to increase dramatically over the next 2 decades. This trend poses major challenges to health care systems, reflecting the greater health care use and more comorbid conditions among elderly adults. Chronic kidney disease (CKD) is a substantial concern in the elderly population, with both an increasing incidence of treated kidney failure with dialysis as well as a high prevalence of earlier stages of CKD. Given the high burden of risk factors for CKD, the high prevalence of CKD in the elderly population is not surprising, with the rise in obesity, diabetes, and hypertension in middle-aged adults likely foreshadowing further increases in CKD prevalence among the elderly population. It is now commonly agreed that the presence of CKD identifies a higher risk state in the elderly population, with increased risk for multiple adverse outcomes, including kidney failure, cardiovascular disease, cognitive impairment, and death. Accordingly, CKD in older adults is worthy of attention by both health care providers and patients, with the presence of a reduced glomerular filtration rate or albuminuria in the elderly potentially informing therapeutic and diagnostic decisions for these individuals.

Gout and risk of non-alcoholic fatty liver disease

OBJECTIVES

To investigate the association between gout and non-alcoholic fatty liver disease (NAFLD).

METHODS

The study subjects were participants in a health-screening programme at Chang Gung Memorial Hospital from 2000 to 2006. Subjects were classified into eight groups based on serum urate (SU) level and gout status (≤ 4.9, 5.0-6.9, 7.0-8.9, and ≥ 9.0 mg/dL, without and with gout). The association between gout and NAFLD was assessed by multiple logistic regression.

RESULTS

Among a total of 54 325 subjects, 1930 (3.6%) had gout and 6169 (11.3%) had NAFLD. The prevalence of NAFLD was significantly higher in subjects with gout (23.1%, n = 445) than in those without gout (10.9%, n = 5724, p < 0.001). Among subjects with NAFLD, the severity of NAFLD was higher in gout patients. Gout was associated with an increased risk for NAFLD [odds ratio (OR) 1.42, 95% confidence interval (CI) 1.25-1.60, p < 0.001], after adjustment for age, sex, presence of metabolic syndrome, and low estimated glomerular filtration rate (eGFR). With SU ≤ 4.9 mg/dL in the absence of gout as reference, the ORs (95% CI) for NAFLD, after adjustment for age, sex, presence of metabolic syndrome, and low eGFR, were, respectively, 2.16 (1.94-2.41), 3.98 (3.55-4.46), and 5.99 (5.19-6.90) for SU levels 2-4 in those without gout and 2.61 (1.39-4.91), 2.87 (2.04-4.04), 4.53 (3.70-5.56), and 6.31 (5.12-7.77) for SU levels 1-4 in those with gout.

CONCLUSIONS

There was an independent association between gout and the risk for NAFLD. In addition, there was a dose-response relationship between SU and NAFLD in subjects with and without gout.

Urinary neutrophil gelatinase-associated lipocalin: A potential biomarker for predicting rapid progression of drug-induced chronic tubulointerstitial nephritis

INTRODUCTION

The role of urinary biomarkers of kidney injury in the prediction of adverse clinical outcomes in drug-induced chronic tubulointerstitial nephritis (D-CTIN) has not been well described.

METHODS

A total of 36 patients with D-CTIN were enrolled in the study. The baseline urinary excretion of neutrophil gelatinase-associated lipocalin (NGAL), alpha1-microglobin (alpha1-MG), albumin (mAlb) and total protein were measured, and estimated glomerular filtration rate change rates within a period of 6 to 33 (mean: 24 months) follow-up months were recorded.

RESULTS

Areas under the receiver-operator characteristic curve of urinary NGAL, alpha1-MG, mAlb and total protein for predicting deterioration of estimated glomerular filtration rate were 0.707, 0.631, 0.685 and 0.678, respectively. The cutoff points that maximized the combined sensitivity and specificity for NGAL, alpha1-MG, mAlb and total protein were 37.71 ng/mL, 33.20 microg/mL, 6.91 mg/L and 60.00 mg/L, respectively. At these thresholds, the sensitivity and specificity was 64.7% and 78.9% for NGAL, 66.7% and 50.0% for alpha1-MG, 80.0% and 50.0% for mAlb and 70.6% and 63.2% for total protein, respectively. The median renal survival time (years) of patients with urinary NGAL level exceeding 37.705 ng/mL was shorter than that of patients with urinary NGAL level below 37.705 ng/mL (1.59 +/- 0.79 versus 2.09 +/- 0.63, P = 0.040, chi(2) = 4.218).

CONCLUSIONS

Increase of baseline urinary NGAL was better than alpha1-MG, mAlb and total protein in predicting renal function deterioration in patients with D-CTIN. This noninvasive approach has potential to serve as a practical tool in D-CTIN prognosis.

Association of estimated glomerular filtration rate and albuminuria with all-cause and cardiovascular mortality in general population cohorts: a collaborative meta-analysis

BACKGROUND

Substantial controversy surrounds the use of estimated glomerular filtration rate (eGFR) and albuminuria to define chronic kidney disease and assign its stages. We undertook a meta-analysis to assess the independent and combined associations of eGFR and albuminuria with mortality.

METHODS

In this collaborative meta-analysis of general population cohorts, we pooled standardised data for all-cause and cardiovascular mortality from studies containing at least 1000 participants and baseline information about eGFR and urine albumin concentrations. Cox proportional hazards models were used to estimate hazard ratios (HRs) for all-cause and cardiovascular mortality associated with eGFR and albuminuria, adjusted for potential confounders.

FINDINGS

The analysis included 105,872 participants (730,577 person-years) from 14 studies with urine albumin-to-creatinine ratio (ACR) measurements and 1,128,310 participants (4,732,110 person-years) from seven studies with urine protein dipstick measurements. In studies with ACR measurements, risk of mortality was unrelated to eGFR between 75 mL/min/1.73 m(2) and 105 mL/min/1.73 m(2) and increased at lower eGFRs. Compared with eGFR 95 mL/min/1.73 m(2), adjusted HRs for all-cause mortality were 1.18 (95% CI 1.05-1.32) for eGFR 60 mL/min/1.73 m(2), 1.57 (1.39-1.78) for 45 mL/min/1.73 m(2), and 3.14 (2.39-4.13) for 15 mL/min/1.73 m(2). ACR was associated with risk of mortality linearly on the log-log scale without threshold effects. Compared with ACR 0.6 mg/mmol, adjusted HRs for all-cause mortality were 1.20 (1.15-1.26) for ACR 1.1 mg/mmol, 1.63 (1.50-1.77) for 3.4 mg/mmol, and 2.22 (1.97-2.51) for 33.9 mg/mmol. eGFR and ACR were multiplicatively associated with risk of mortality without evidence of interaction. Similar findings were recorded for cardiovascular mortality and in studies with dipstick measurements.

INTERPRETATION

eGFR less than 60 mL/min/1.73 m(2) and ACR 1.1 mg/mmol (10 mg/g) or more are independent predictors of mortality risk in the general population. This study provides quantitative data for use of both kidney measures for risk assessment and definition and staging of chronic kidney disease.

FUNDING

Kidney Disease: Improving Global Outcomes (KDIGO), US National Kidney Foundation, and Dutch Kidney Foundation.