Metabolic Syndrome and the Development of CKD in American Indians: The Strong Heart Study

Metabolic dysfunction, rather than obesity, is a risk factor for chronic kidney disease in Chinese population

BACKGROUND

Metabolic dysfunction and obesity are closely related to chronic kidney disease (CKD). However, studies on the relationship between various metabolic syndrome-body mass index (MetS-BMI) phenotypes and the risk of CKD in the Chinese population have not yet been explored.

MATERIALS AND METHODS

Data from the China Health and Retirement Longitudinal Study (CHARLS) 2015 were analyzed in this study. This study enrolled 12,054 participants. Participants were divided into six distinct groups according to their MetS-BMI status. Across the different MetS-BMI groups, the odd ratios (ORs) for CKD were determined using multivariable logistic regression models.

RESULTS

The prevalence of CKD was higher in metabolically unhealthy groups than in the corresponding healthy groups. Moreover, the fully adjusted model showed that all metabolically unhealthy individuals had an increased risk of developing CKD compared to the metabolically healthy normal weight group (OR = 1.62, p = 0.002 for the metabolically unhealthy normal weight group; OR = 1.55, p < 0.001 for the metabolically unhealthy overweight group; and OR = 1.77, p < 0.001 for the metabolically unhealthy obesity group.

CONCLUSIONS

This study is the first to evaluate the relationship between the MetS-BMI phenotype and renal prognosis in the Chinese population. Individuals with normal weights are at different risk of developing CKD depending on their different metabolic phenotypes.

The sclerotic component of metabolic syndrome: Fibroblast activities may be the central common denominator driving organ function loss and death

Fibrosis is a common feature of more than 50 different diseases and the cause of more than 35% of deaths worldwide, of which liver, kidney, skin, heart and, recently, lungs are receiving the most attention. Tissue changes, resulting in loss of organ function, are both a cause and consequence of disease and outcome. Fibrosis is caused by an excess deposition of extracellular matrix proteins, which over time results in impaired organ function and organ failure, and the pathways leading to increased fibroblast activation are many. This narrative review investigated the common denominator of fibrosis, fibroblasts, and the activation of fibroblasts, in response to excess energy consumption in liver, kidney, heart, skin and lung fibrosis. Fibroblasts are the main drivers of organ function loss in lung, liver, skin, heart and kidney disease. Fibroblast activation in response to excess energy consumption results in the overproduction of a range of collagens, of which types I, III and VI seem to be the essential drivers of disease progression. Fibroblast activation may be quantified in serum, enabling profiling and selection of patients. Activation of fibroblasts results in the overproduction of collagens, which deteriorates organ function. Patient profiling of fibroblast activities in serum, quantified as collagen production, may identify an organ death trajectory, better enabling identification of the right treatment for use in different metabolic interventions. As metabolically activated patients have highly elevated risk of kidney, liver and heart failure, it is essential to identify which organ to treat first and monitor organ status to correct treatment regimes. In direct alignment with this, it is essential to identify the right patients with the right organ deterioration trajectory for enrolment in clinical studies.

Association between pulmonary function and rapid kidney function decline: a longitudinal cohort study from CHARLS

BACKGROUND

Pulmonary function has been reported to be associated with chronic kidney disease. However, the relationship between lung function and rapid kidney function decline remains unclear.

METHODS

Participants aged ≥45 years with complete data from the 2011 and 2015 interviews of the China Health and Retirement Longitudinal Study (CHARLS) were included. Lung function, assessed by peak expiratory flow (PEF), and kidney function, assessed by estimated glomerular filtration rate (eGFR), were tested at the baseline and endpoint surveys. Rapid kidney function decline was defined as a decrease in eGFR ≥3 mL/min/1.73 m²/year, and ΔeGFR represented the difference between baseline and endpoint eGFR. Multivariate logistic regression models and linear regression models were employed to evaluate the association between PEF and the risk of rapid eGFR decline, as well as the correlation between PEF and ΔeGFR.

RESULTS

A total of 6159 participants were included, with 1157 (18.78%) individuals experiencing a rapid decline in eGFR. After adjusting for potential covariates, higher baseline PEF (Quartile 4 vs Quartile 1, OR=0.95, 95% CI 0.92 to 0.98) and elevated PEF % predicted (OR=0.96, 95% CI 0.94 to 0.99) were found to be associated with a lower risk of rapid eGFR decline. ΔeGFR decreased by 0.217 and 0.124 mL/min/1.73 m² for every 1 L/s increase in baseline PEF (β (95% CI): -0.217 (-0.393 to -0.042)) and 10% increase in PEF % predicted (β (95% CI): -0.124 (-0.237 to -0.011)), respectively. During the follow-up period, ΔeGFR decreased as PEF increased over time among participants in Quartile 1 (β per 1 L/s increase in ΔPEF=-0.581, 95% CI -1.003 to -0.158; β per 10% increase in ΔPEF % predicted=-0.279, 95% CI -0.515 to -0.043).

CONCLUSIONS

Higher PEF was associated with a slower longitudinal eGFR decline in middle-aged and older adults.

The association between lipid profile, oxidized LDL and the components of metabolic syndrome with serum mineral status and kidney function in individuals with obesity

BACKGROUND

Metabolic syndrome (MetS) is presented with a cluster of cardio-metabolic risk factors with widespread prevalence. In the present case-control study, we aimed to examine the relationship between several minerals and renal function tests with the components of MetS in individuals with obesity.

METHODS

This study included 127 individuals with obesity of both gender with or without MetS as the case and control, respectively. MetS was characterized based on the Adult Treatment Panel III (ATP III) criteria. Anthropometric variables and blood pressure were recorded. Mineral status including serum magnesium, copper, calcium, phosphorous, and iron were measured using standard colorimetric methods. Also, the serum lipid levels, concentrations of oxidized low-density lipoprotein (Ox-LDL), and renal function tests, including total protein, albumin, urea, creatinine, and uric acid were evaluated using commercial enzyme-linked immunosorbent assay (ELISA) kits.

RESULTS

According to our results, individuals with obesity and MetS had higher levels of waist circumference (WC) and diastolic blood pressure (P < 0.05) compared to individuals with obesity and without MetS. Moreover, individuals with obesity and MetS had higher levels of serum total cholesterol (TC), triglyceride (TG), insulin, and iron (P < 0.05). In individuals with obesity and MetS, iron and albumin showed a positive relationship with LDL cholesterol and TG concentrations, respectively (P < 0.05 for all of them). Also, there was a positive association between serum magnesium and Ox- LDL in individuals with obesity with MetS. While, in individuals with obesity and without MetS, only a positive association between urea and uric acid with WC was observed (P < 0.05).

CONCLUSION

Our results suggest that disturbed serum lipids in obesity-metabolic syndrome is associated with homeostatic changes in the level of minerals or proteins that are involved in their metabolism. Although, further studies are needed to better explain and clarify the underlying mechanism of observed relationships.

Associations of FGF23 with 10-Year Change in eGFR and UACR and with Incident CKD in the CARDIA Cohort

Key Points

FGF23 has a nonlinear positive association with incident CKD among healthy, middle-aged adults. The relationship between FGF23 and incident CKD was only significant among participants with cFGF23 levels in the highest quartile. FGF23 is not associated with 10-year change in eGFR or 10-year change in UACR among healthy, middle-aged adults.

Background

The relationship of fibroblast growth factor 23 (FGF23) with incident CKD has been examined in older but not younger populations.

Methods

Linear regression models were used to examine the associations of c-terminal FGF23 (cFGF23) and intact FGF23 (iFGF23) with 10-year change (1995–96 to 2005–06) in eGFR and urine albumin-to-creatinine ratio (UACR) in the Coronary Artery Risk Development in Young Adults cohort. Cox proportional hazard models were used to assess the association of cFGF23 with incident CKD, defined as eGFR <60 ml/min per 1.73 m2 or UACR ≥30 mg/g. Multivariable models were adjusted for age, sex, race, education, field center, physical activity, body mass index, diabetes, smoking, and systolic BP.

Results

Among 2511 participants, the mean age was 45±3.6 years; mean eGFR was 96.5±14.0 ml/min per 1.73 m2; and median UACR was 4.3 (interquartile range, 3.0–6.7) mg/g. Most (62.6%) participants were nonsmokers; the prevalence of diabetes was low (6.6%); and median values for 10-year changes in eGFR and UACR were modest (−5.50 ml/min per 1.73 m2 and 0.70 mg/g, respectively). No consistent associations between cFGF23 and 10-year change in eGFR and UACR were observed. During a median follow-up of 9.98 years, incident CKD developed in 258 participants. There was a nonlinear association of cFGF23 with incident CKD, and relative to the lowest quartile of cFGF23, a significant relationship was detected only among participants in the highest quartile (hazard ratio, 1.58; 95% confidence interval, 1.09 to 2.27). Similar findings were observed for iFGF23.

Conclusion

Among middle-aged adults in the Coronary Artery Risk Development in Young Adults cohort, median eGFR and UACR changes were modest and cFGF23 and iFGF23 were not consistently associated with 10-year change in eGFR or UACR. A nonlinear relationship was observed between cFGF23 and incident CKD, with individuals with highest cFGF23 levels being at risk of developing CKD.

Plasma lipidomic profile of depressive symptoms: a longitudinal study in a large sample of community-dwelling American Indians in the strong heart study

Dyslipidemia has been associated with depression, but individual lipid species associated with depression remain largely unknown. The temporal relationship between lipid metabolism and the development of depression also remains to be determined. We studied 3721 fasting plasma samples from 1978 American Indians attending two exams (2001-2003, 2006-2009, mean ~5.5 years apart) in the Strong Heart Family Study. Plasma lipids were repeatedly measured by untargeted liquid chromatography-mass spectrometry (LC-MS). Depressive symptoms were assessed using the 20-item Center for Epidemiologic Studies for Depression (CES-D). Participants at risk for depression were defined as total CES-D score ≥16. Generalized estimating equation (GEE) was used to examine the associations of lipid species with incident or prevalent depression, adjusting for covariates. The associations between changes in lipids and changes in depressive symptoms were additionally adjusted for baseline lipids. We found that lower levels of sphingomyelins and glycerophospholipids and higher level of lysophospholipids were significantly associated with incident and/or prevalent depression. Changes in sphingomyelins, glycerophospholipids, acylcarnitines, fatty acids and triacylglycerols were associated with changes in depressive symptoms and other psychosomatic traits. We also identified differential lipid networks associated with risk of depression. The observed alterations in lipid metabolism may affect depression through increasing the activities of acid sphingomyelinase and phospholipase A2, disturbing neurotransmitters and membrane signaling, enhancing inflammation, oxidative stress, and lipid peroxidation, and/or affecting energy storage in lipid droplets or membrane formation. These findings illuminate the mechanisms through which dyslipidemia may contribute to depression and provide initial evidence for targeting lipid metabolism in developing preventive and therapeutic interventions for depression.

The Effect of Metabolic Syndrome and Its Individual Components on Renal Function: A Meta-Analysis

BACKGROUND

Observational studies have reported inconsistent findings in the relationship between metabolic syndrome (MetS), its components, and loss of renal function, mainly including eGFR decline, new-onset CKD, and ESRD. This meta-analysis was performed to investigate their potential associations.

METHODS

PubMed and EMBASE were systematically searched from their inception to 21 July 2022. Observational cohort studies in English assessing the risk of renal dysfunction in individuals with MetS were identified. Risk estimates and their 95% confidence intervals (CIs) were extracted and pooled using the random-effects approach.

RESULTS

A total of 32 studies with 413,621 participants were included in the meta-analysis. MetS contributed to higher risks of renal dysfunction (RR = 1.50, 95% CI = 1.39-1.61) and, specifically, rapid decline in eGFR (RR 1.31, 95% CI 1.13-1.51), new-onset CKD (RR 1.47, 95% CI 1.37-1.58), as well as ESRD (RR 1.55, 95% CI 1.08-2.22). Moreover, all individual components of MetS were significantly associated with renal dysfunction, while elevated BP conveyed the highest risk (RR = 1.37, 95% CI = 1.29-1.46), impaired fasting glucose with the lowest and diabetic-dependent risk (RR = 1.20, 95% CI = 1.09-1.33).

CONCLUSIONS

Individuals with MetS and its components are at higher risk of renal dysfunction.

High risk of renal outcome of metabolic syndrome independent of diabetes in patients with CKD stage 1-4: The ICKD database

AIMS

To investigate whether metabolic syndrome (MetS) could predict renal outcome in patients with established chronic kidney disease (CKD).

MATERIALS AND METHODS

We enroled 2500 patients with CKD stage 1-4 from the Integrated CKD care programme, Kaohsiung for delaying Dialysis (ICKD) prospective observational study. 66.9% and 49.2% patients had MetS and diabetes (DM), respectively. We accessed three clinical outcomes, including all-cause mortality, RRT, and 50% decline in estimated glomerular filtration rate events.

RESULTS

The MetS score was positively associated with proteinuria, inflammation, and nutrition markers. In fully adjusted Cox regression, the hazard ratio (HR) (95% confidence interval) of MetS for composite renal outcome (renal replacement therapy, and 50% decline of renal function) in the DM and non-DM subgroups was 1.56 (1.15-2.12) and 1.31 (1.02-1.70), respectively, while that for all-cause mortality was 1.00 (0.71-1.40) and 1.27 (0.92-1.74). Blood pressure is the most important component of MetS for renal outcomes. In the 2 by 2 matrix, compared with the non-DM/non-MetS group, the DM/MetS group (HR: 1.62 (1.31-2.02)) and the non-DM/MetS group (HR: 1.33 (1.05-1.69)) had higher risks for composite renal outcome, whereas the DM/MetS group had higher risk for all-cause mortality (HR: 1.43 (1.09-1.88)).

CONCLUSIONS

MetS could predict renal outcome in patients with CKD stage 1-4 independent of DM.

Metabolic Syndrome-Related Kidney Injury: A Review and Update

Metabolic syndrome (MetS) includes visceral obesity, hyperglycemia, dyslipidemia, and hypertension. The prevalence of MetS is 20-25%, which is an important risk factor for chronic kidney disease (CKD). MetS causes effects on renal pathophysiology, including glomerular hyperfiltration, RAAS, microalbuminuria, profibrotic factors and podocyte injury. This review compares several criteria of MetS and analyzes their differences. MetS and the pathogenesis of CKD includes insulin resistance, obesity, dyslipidemia, inflammation, oxidative stress, and endothelial dysfunction. The intervention of MetS-related renal damage is the focus of this article and includes controlling body weight, hypertension, hyperglycemia, and hyperlipidemia, requiring all components to meet the criteria. In addition, interventions such as endoplasmic reticulum stress, oxidative stress, gut microbiota, body metabolism, appetite inhibition, podocyte apoptosis, and mesenchymal stem cells are reviewed.

Metabolic syndrome severity score and the progression of CKD

BACKGROUND

Metabolic syndrome severity, expressed by the continuous metabolic syndrome risk score (MetS score), has been demonstrated to be able to predict future health conditions. However, little is known about the association between MetS score and renal function.

METHODS

A total of 22,719 participants with normal renal function abstracted from the Kailuan Study were followed from 2006 to 2016. The new onset of chronic kidney disease (CKD) was defined as eGFR <60 ml/min per 1.73 m² and/or proteinuria >300 mg/dl. Progressive decline in renal function was defined as an annual change rate of eGFR below the 10th percentile of the whole population.

RESULTS

In the multivariate-adjusted model, we found that the risk of progressive decline in renal function increased consistently with the MetS score, with an odds ratio of 1.49 (95% CI, 1.28, 1.73) for those subjects>75th percentile compared with those <25th percentile. Additionally, a high MetS score was found to be associated with an increased risk of CKD, with a hazard ratio of 1.53 (95% CI, 1.33, 1.78) for subjects >75th percentile compared with those <25th percentile.

CONCLUSIONS

Our findings suggested that the MetS score was associated with an increased risk of a progressive decline in renal function and was also a strong and independent risk factor for the development of CKD. These findings provide evidence of the potential clinical utility of the MetS score for assessing metabolic syndrome severity to detect the risk of decreased renal function and CKD.

Impact of Obesity in Kidney Diseases

The clinical consequences of obesity on the kidneys, with or without metabolic abnormalities, involve both renal function and structures. The mechanisms linking obesity and renal damage are well understood, including several effector mechanisms with interconnected pathways. Higher prevalence of urinary albumin excretion, sub-nephrotic syndrome, nephrolithiasis, increased risk of developing CKD, and progression to ESKD have been identified as being associated with obesity and having a relevant clinical impact. Moreover, renal replacement therapy and kidney transplantation are also influenced by obesity. Losing weight is key in limiting the impact that obesity produces on the kidneys by reducing albuminuria/proteinuria, declining rate of eGFR deterioration, delaying the development of CKD and ESKD, and improving the outcome of a renal transplant. Weight reduction may also contribute to appropriate control of cardiometabolic risk factors such as hypertension, metabolic syndrome, diabetes, and dyslipidemia which may be protective not only in renal damage but also cardiovascular disease. Lifestyle changes, some drugs, and bariatric surgery have demonstrated the benefits.

Prediabetes is associated with proteinuria development but not with glomerular filtration rate decline: A longitudinal observational study

AIMS

Diabetes is recognized as the leading cause of chronic kidney disease (CKD); however, the association of prediabetes with CKD remains unclear, in particular, the independent effect of prediabetes on proteinuria or estimated glomerular filtration rate (eGFR) has not been evaluated. This study aimed to investigate the associations of prediabetes with the proteinuria development and with eGFR decline separately in the Japanese general population without CKD.

METHODS

Participants who underwent health check-ups in 2014 and had adequate data after 2 years were retrospectively analysed. A total of 405,487 participants without CKD (eGFR, ≥60 ml min^-1  1.73 m^-2 , with negative or trace urinary protein) at baseline were categorized according to fasting plasma glucose as having diabetes (≥126 mg/dl [7.0 mmol/l]), prediabetes (100-125 mg/dl [5.6-6.9 mmol/l]) or normal glucose level (˂100 mg/dl [5.6 mmol/l]). Logistic regression analysis was used to analyse the effects of prediabetes (vs. normal glucose level) on the proteinuria development (urinary protein of ≥1+) and eGFR decline (˂60 ml min^-1  1.73 m^-2 ) after 2 years.

RESULTS

After 2 years, 7037 participants (1.7%) developed proteinuria alone, 19,015 (4.7%) presented eGFR decline alone and 636 (0.2%) showed both proteinuria and eGFR decline. Compared to normal glucose level and adjusting for prognostic factors, prediabetes was independently associated with the proteinuria development (odds ratio [OR] 1.233; 95% confidence interval [CI] 1.170-1.301], whereas prediabetes was not associated with eGFR decline (OR 0.981; 95% CI 0.947-1.017).

CONCLUSIONS

Prediabetes is associated with the proteinuria development but not with eGFR decline in the general population.

Reported sources of health inequities in Indigenous Peoples with chronic kidney disease: a systematic review of quantitative studies

BACKGROUND

To summarise the evidentiary basis related to causes of inequities in chronic kidney disease among Indigenous Peoples.

METHODS

We conducted a Kaupapa Māori meta-synthesis evaluating the epidemiology of chronic kidney diseases in Indigenous Peoples. Systematic searching of MEDLINE, Google Scholar, OVID Nursing, CENTRAL and Embase was conducted to 31 December 2019. Eligible studies were quantitative analyses (case series, case-control, cross-sectional or cohort study) including the following Indigenous Peoples: Māori, Aboriginal and Torres Strait Islander, Métis, First Nations Peoples of Canada, First Nations Peoples of the United States of America, Native Hawaiian and Indigenous Peoples of Taiwan. In the first cycle of coding, a descriptive synthesis of the study research aims, methods and outcomes was used to categorise findings inductively based on similarity in meaning using the David R Williams framework headings and subheadings. In the second cycle of analysis, the numbers of studies contributing to each category were summarised by frequency analysis. Completeness of reporting related to health research involving Indigenous Peoples was evaluated using the CONSIDER checklist.

RESULTS

Four thousand three hundred seventy-two unique study reports were screened and 180 studies proved eligible. The key finding was that epidemiological investigators most frequently reported biological processes of chronic kidney disease, particularly type 2 diabetes and cardiovascular disease as the principal causes of inequities in the burden of chronic kidney disease for colonised Indigenous Peoples. Social and basic causes of unequal health including the influences of economic, political and legal structures on chronic kidney disease burden were infrequently reported or absent in existing literature.

CONCLUSIONS

In this systematic review with meta-synthesis, a Kaupapa Māori methodology and the David R Williams framework was used to evaluate reported causes of health differences in chronic kidney disease in Indigenous Peoples. Current epidemiological practice is focussed on biological processes and surface causes of inequity, with limited reporting of the basic and social causes of disparities such as racism, economic and political/legal structures and socioeconomic status as sources of inequities.

The determinants of complication trajectories in American Indians with type 2 diabetes

BACKGROUNDWe aimed to determine whether metabolic syndrome (MetS) affects longitudinal trajectories of diabetic complications, including neuropathy, cardiovascular autonomic neuropathy (CAN), and kidney disease in American Indians with type 2 diabetes.METHODSWe performed a prospective study where participants underwent annual metabolic phenotyping and outcome measurements. The updated National Cholesterol Education Program criteria were used to define MetS and its individual components, using BMI instead of waist circumference. Neuropathy was defined using the Michigan Neuropathy Screening Instrument index, CAN with the expiration/inspiration ratio, and kidney disease with glomerular filtration rate. Mixed-effects models were used to evaluate associations between MetS and these outcomes.RESULTSWe enrolled 141 participants: 73.1% female, a mean (±SD) age of 49.8 (12.3), and a diabetes duration of 19.6 years (9.7 years) who were followed for a mean of 3.1 years (1.7 years). MetS components were stable during follow-up except for declining obesity and cholesterol. Neuropathy (point estimate [PE]: 0.30, 95% CI: 0.24, 0.35) and kidney disease (PE: -14.2, 95% CI: -16.8, -11.4) worsened over time, but CAN did not (PE: -0.002, 95% CI: -0.006, 0.002). We found a significant interaction between the number of MetS components and time for neuropathy (PE: 0.05, 95% CI: 0.01-0.10) but not CAN (PE: -0.003, 95% CI: -0.007, 0.001) or kidney disease (PE: -0.69, 95% CI: -3.16, 1.76). Systolic blood pressure (SBP, unit = 10 mmHg) was associated with each complication: neuropathy (PE: 0.23, 95% CI: 0.07, 0.39), CAN (PE: -0.02, 95% CI: -0.03, -0.02), and kidney disease (PE: -10.2, 95% CI: -15.4, -5.1).CONCLUSIONIn participants with longstanding diabetes, neuropathy and kidney disease worsened during follow-up, despite stable to improving MetS components, suggesting that early metabolic intervention is necessary to prevent complications in such patients. Additionally, the number of MetS components was associated with an increased rate of neuropathy progression, and SBP was associated with each complication.FUNDINGThe following are funding sources: NIH T32NS0007222, NIH R24DK082841, NIH R21NS102924, NIH R01DK115687, the Intramural Program of the NIDDK, the NeuroNetwork for Emerging Therapies, the Robert and Katherine Jacobs Environmental Health Initiative, the Robert E. Nederlander Sr. Program for Alzheimer's Research, and the Sinai Medical Staff Foundation.TRIAL REGISTRATIONClinicalTrials.gov, NCT00340678.

Patient and allograft outcomes after kidney transplant for the Indigenous patients in the United States

Background

The objective is to assess cardiovascular (CV), malignancy, infectious, graft outcomes and tacrolimus levels for the Indigenous patients compared to Whites after kidney transplant (KTx).

Methods

165 Indigenous and 165 White patients matched for the KTx year at Mayo Clinic Arizona from 2007–2015 were studied over a median follow-up of 3 years. Propensity score was calculated to account for baseline differences.

Results

Compared to Whites, Indigenous patients had the following characteristics: younger age, more obesity, diabetes, hypertension, and required dialysis prior to KTx (p<0.01). Indigenous patients had longer hospital stay for KTx, shorter follow-up and lived further from the transplant center (p<0.05). 210 (63.6%) received deceased donor KTx and more Whites received a living donor KTx compared to Indigenous patients (55.2% vs 17.6%, p<0.0001). Post-KTx, there was no difference in the CV event rates. The cumulative incidence of infectious complications was higher among the Indigenous patients (HR 1.81, p = 0.0005, 48.5% vs 38.2%, p = 0.013), with urinary causes as the most common. Malignancy rates were increased among Whites (13.3% vs 3.0%, p = 0.001) with skin cancer being the most common. There was a significant increase in the dose normalized tacrolimus level for the Indigenous patients compared to Whites at 1 months, 3 months, and 1 year post-KTx. After adjustment for the propensity score, there was no statistical difference in infectious or graft outcomes between the two groups but the mean number of emergency room visits and hospitalizations after KTx was significantly higher for Whites compared to Indigenous patients.

Conclusions

Compared to Whites, Indigenous patients have similar CV events, graft outcomes and infectious complications after accounting for baseline differences.

Combined Effects of Dyslipidemia and High Adiposity on the Estimated Glomerular Filtration Rate in a Middle-Aged Chinese Population

BACKGROUND

Some studies have reported that chronic kidney disease (CKD) or the estimated glomerular filtration rate (eGFR) is significantly associated with metabolic abnormalities.

METHODS

Six hundred forty-six community residents aged 45-60 years without overt renal dysfunction were recruited in this cross-sectional study. eGFR was estimated by serum creatinine measurement. The visceral fat area (VFA) and subcutaneous fat area (SFA) were assessed by magnetic resonance imaging (MRI). The body mass index (BMI) and waist-hip ratio (WHR) were also evaluated. Additionally, we tested the subjects' blood lipid levels to diagnose dyslipidemia.

RESULTS

Compared with the subjects with neither dyslipidemia nor obesity, men with both dyslipidemia and high obesity indices, such as BMI, WHR and VFA, showed a significantly lower mean eGFR; women with dyslipidemia with high WHR, VFA or SFA also showed a significantly lower mean eGFR. Although an independent association between the metabolic variables and eGFR was not found except for BMI, some of the combined effects of each variable were related to eGFR decline. Comorbidity of dyslipidemia and high WHR was significant risk factor for eGFR reduction (β -8.805, SD 4.116, p < 0.05). Additionally, comorbidity of dyslipidemia and high obesity indices such as BMI (β -12.942, SD 5.268, p < 0.05) and VFA (β -7.069, SD 3.394, p < 0.05) were significant risk factors for eGFR reduction in men.

CONCLUSION

The combined effect of dyslipidemia and high obesity indices is significantly related to the decline in eGFR. The association is more profound in men.

Association between Dietary Patterns and Kidney Function Parameters in Adults with Metabolic Syndrome: A Cross-Sectional Study

This study explored the association between dietary patterns and kidney function parameters in adults with metabolic syndrome in Taiwan. This cross-sectional study was undertaken in 56,476 adults from the health screening centers in Taiwan from 2001 to 2010. Dietary intake and dietary patterns were assessed using a food frequency questionnaire and principal component analysis, respectively. Blood urea nitrogen (BUN), creatinine, estimated glomerular filtration rate (eGFR), and uric acid were measured as clinical parameters of kidney function. Multivariate linear regression was conducted to explore the relationship between dietary patterns and kidney function parameters. After adjusting for confounders, the highest tertiles of the processed food–sweets dietary pattern and the meat–seafood–eggs dietary pattern were associated with increased BUN, creatinine, and uric acid but decreased eGFR (all adjusted p < 0.05). Meanwhile, the highest tertiles of the veggie–fruit–grains dietary pattern and the milk–dairy dietary pattern were associated with decreased BUN, creatinine, and uric acid but increased eGFR (all adjusted p < 0.05). A processed food–sweets dietary pattern or a meat–seafood–eggs dietary pattern is associated with worse kidney function parameters in adults with metabolic syndrome. In contrast, a veggie–fruit–grains dietary pattern or a milk–dairy dietary pattern is associated with better kidney function parameters.

Chronic Microvascular Complications in Prediabetic States-An Overview

A prediabetic state is a major risk factor for the development of diabetes, and, because of an identical pathophysiological background of both conditions, their prevalence increases parallelly and equally fast. Long-term hyperglycemia is the main cause inducing chronic complications of diabetes, yet the range of glucose levels at which they start has not been yet unequivocally determined. The current data show that chronic microvascular complications of diabetes can be observed in patients with abnormal glucose metabolism in whom glycaemia is higher than optimal but below diagnostic criteria for diabetes. Prediabetes is a heterogenous nosological unit in which particular types are differently characterized and show different correlations with particular kinds of complications. Analysis of the latest research results shows the need to continue studies in a larger population and can imply the need to verify the currently employed criteria of diagnosing diabetes and chronic complications of diabetes in people with prediabetes.

The effect of linagliptin on renal progression in type-2 diabetes mellitus patients with chronic kidney disease: A prospective randomized controlled study

BACKGROUND

Linagliptin does not require dose adjustment in diabetes mellitus patients with chronic kidney disease (CKD). But, renal effects of linagliptin are not clear. Our aim was to examine the effect of linagliptin on renal disease progression in only insulin dependent type 2 diabetes mellitus (DM) patients with CKD.

METHODS

Stage 3-4 CKD patients were randomized into 2 groups in this prospective randomized controlled study. In the first group, linagliptin 5mg was added in addition to the background insulin therapy. In the second group, patients continued their insulin therapy. Patients were followed up at 3-month intervals for one year.

RESULTS

The study population consisted of 164 patients (90 patients in linagliptin group, 74 patients in other group) with a mean age of 67.5±8.8 years. eGFR significantly increased in linagliptin group (p=0.033), but decreased in other group (p=0.003). No significant change was observed in total insulin dose in linagliptin group (p=0.111), but in other group, total insulin dose significantly increased (p<0.001). Proteinuria levels decreased in both groups, but there was no significant change. In the multiple logistic regression analysis, male gender and proteinuria emerged as variables that showed significant association with increased risk and the use of linagliptin emerged as variable that showed significant association with decreased risk for CKD progression.

CONCLUSION

Linagliptin in DM patients with CKD was able to improve renal progression without significant effect on proteinuria and glucose control. With regard to treating diabetic nephropathy, linagliptin may offer a new therapeutic approach.

Association between microalbuminuria and outcome of non-diabetic population aged 40 years and over: The reaction study

AIMS

The goal of this study was to analyze the association between microalbuminuria (MAU) and the outcome of non-diabetic populations among Chinese people.

METHODS

A cohort of 2042 Chinese individuals without diabetes, aged 40 years or older were included. We identified people with impaired fasting glucose and/or impaired glucose tolerance by conducting an oral glucose tolerance test, and then followed them up after 3years. We defined MAU as a urinary albumin-to-creatinine ratio (ACR) exceeding the normal range of 2.5-25mg/mmol (males) or 3.5-35mg/mmol (females).

RESULTS

Among 2042 adults aged 40 years or older in an urban fringe area of Luzhou city (1984 cases were followed up), 262 (12.8%) developed diabetes over 3years. MAU was significantly associated with age, fasting plasma glucose, 2-h glucose, hemoglobin A1c, and triglycerides (P<0.05). Follow-up FBG, 2hPG, TG, and HbA1c levels in the IGR+MAU group were higher than those in other groups (P<0.05). If the relative risk of the isolated normal glucose tolerance (NGT) group progressing to diabetes was set to 1, the risk of progression to diabetes in the NGT+MAU, isolated impaired glucose regulation (IGR), and IGR+MAU groups increased 1.1, 3.9, and 7.5 times, respectively.

CONCLUSIONS

Our study found that MAU is associated with increased risk of diabetes in NGT and IGR populations, especially in the IGR populations, MAU may predict adulthood at very high risk for diabetes.

Metabolic syndrome and concomitant diabetes mellitus are associated with higher risk of cardiovascular comorbidity in patients with primary glomerular diseases: A retrospective observational study

BACKGROUND

Metabolic syndrome (MS) and diabetes mellitus (DM) are risk factors for cardiovascular diseases in general population. However, there was a paucity of studies investigating their impact in primary glomerular diseases (PGD).

HYPOTHESIS

MS and concomitant DM are associated with higher risk of cardiovascular comorbidity in PGD.

METHODS

In a retrospective observational design, we analyzed 3622 hospitalized adult PGD patients and compared the prevalence of cardiovascular comorbidity in non-MS, MS with and without DM. Risk factors for cardiovascular comorbidity were identified using univariate and multivariate logistic regression.

RESULTS

Among 3622 PGD patients, 308 (8.5%) cases accompanied with MS, including 180 (5.0%) patients with DM and 128 (3.5%) without DM. One hundred and sixty four (4.5%) cases coexisted with cardiovascular comorbidity. Patients with MS and concomitant DM exhibited a higher prevalence of cardiovascular comorbidity than those without MS stratified by estimated glomerular filtration rate and pathological types. Logistic regression showed that MS and concomitant DM (OR: 2.496, 95% CI: 1.600-3.894, P < .001), older age (OR: 1.060, 95% CI: 1.047-1.074, P < .001), male (OR: 1.536, 95% CI: 1.072-2.200, P = .019), higher level of serum ti (OR: 1.002, 95% CI: 1.001-1.003, P < .001), hyperuricemia (OR: 1.901, 95% CI: 1.327-2.725, P < .001), idiopathic membranous nephropathy (OR: 2.874, 95% CI: 1.244-6.640, P < .001) and focal segmental glomerulosclerosis (OR: 2.906, 95% CI: 1.147-7.358, P < .001) were independently associated with a higher risk for cardiovascular comorbidity.

CONCLUSIONS

In PGD patients, MS and concomitant DM are associated with an increased risk for cardiovascular comorbidity. More evidence for the causal link between MS/DM and cardiovascular outcomes is needed to be clarified.

Impaired fasting glucose and development of chronic kidney disease in non-diabetic population: a Mendelian randomization study

INTRODUCTION

Diabetes mellitus is a risk factor of chronic kidney disease (CKD); however, the relationship between fasting glucose and CKD remains controversial in non-diabetic population. This study aimed to assess causal relationship between genetically predicted fasting glucose and incident CKD.

RESEARCH DESIGN AND METHODS

This study included 5909 participants without diabetes and CKD from the Korean Genome Epidemiology Study. The genetic risk score (GRS₉) was calculated using nine genetic variants associated with fasting glucose in previous genome-wide association studies. Incident CKD was defined as estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m² and/or proteinuria (≥1+). The causal relationship between fasting glucose and CKD was evaluated using the Mendelian randomization (MR) approach.

RESULTS

The GRS₉ was strongly associated with fasting glucose (β, 1.01; p<0.001). During a median follow-up of 11.6 years, 490 (8.3%) CKD events occurred. However, GRS₉ was not significantly different between participants with CKD events and those without. After adjusting for confounding factors, fasting glucose was not associated with incident CKD (OR 0.990; 95% CI 0.977 to 1.002; p=0.098). In the MR analysis, GRS₉ was not associated with CKD development (OR per 1 SD increase, 1.179; 95% CI 0.819 to 1.696; p=0.376). Further evaluation using various other MR methods and strict CKD criteria (decrease in the eGFR of ≥30% to a value of <60 mL/min/1.73 m²) found no significant relationship between GRS₉ and incident CKD.

CONCLUSIONS

Fasting glucose was not causally associated with CKD development in non-diabetic population.

Risk of chronic kidney disease defined by decreased estimated glomerular filtration rate in individuals with different prediabetic phenotypes: results from a prospective cohort study in China

OBJECTIVE

We aimed to investigate the effects of prediabetes and its phenotypes of impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and elevated glycated hemoglobin A₁c (EHbA_1c) on chronic kidney disease (CKD) occurrence, and define the cut-off point of each glycemic index that significantly increases the risk of CKD.

RESEARCH DESIGN AND METHODS

In this prospective cohort study, 6446 non-diabetic subjects aged 40 years and over were followed over a period of 3 years to track the new onset of CKD. Cox regression was used to assess the association of prediabetes and its phenotypes with CKD. Receiver operating characteristic curves were used to define the cut-off point of each glycemic index that significantly increases the occurrence of CKD. Population attributable risk percent was calculated to estimate the contribution of prediabetes to CKD.

RESULTS

Compared to subjects with normal glucose tolerance, patients with prediabetes significantly increased the risk of development of CKD (HR=2.33 (1.19-4.55)). Specifically, this increased risk of CKD development was observed in patients with IFG, IGT and EHbA_1c. The cut-off points shown to significantly increase the risk of CKD are fasting plasma glucose of 5.63 mmol/L, 2-hour plasma glucose of 6.80 mmol/L and HbA_1c of 5.6%. The contribution of prediabetes to CKD occurrence in the study population was 60.6%.

CONCLUSIONS

This result suggests that the stricter criteria might be needed to define normal plasma glucose level in China that would not be predisposed to diabetic complications, particularly CKD.

Association between Prediabetes and Renal Dysfunction from a Community-based Prospective Study

Objective: Our study aimed to evaluate the association between prediabetes and renal dysfunction, and further assess which of glycemic indices of fasting plasma glucose (FPG), postprandial plasma glucose (PPG) and hemoglobin A1c (HbA1c) has a higher risk of renal dysfunction. Methods: This was a community-based prospective cohort study, which included 7015 participants from Beijing and Taian between May and October in 2015. The outcome was the renal dysfunction defined as estimated glomerular filtration rate (eGFR)<60 mL/min/1.73 m². Univariate and multivariate logistic regression model was performed, and calculated the odds ratio (OR) and 95% confidence interval (95%CI) of renal dysfunction. Receiver operating curve (ROC) analysis was used to predict renal dysfunction for glycemic indices. Results: 121 renal dysfunction cases were identified. We found that the adjusted ORs (95%CI) of renal dysfunction were 1.72 (1.11-2.38), 1.48 (1.09-1.93), 1.97 (1.27-2.89) and 1.35 (1.07-2.13), respectively, for those with prediabetes, impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and elevated HbA1c, compared with individuals with normal glucose tolerance. And IGT presented a higher risk of renal dysfunction than other glycemic indices. The similar results were obtained by performing the subgroup analysis. ROC analysis revealed the PPG had a higher predictive value for renal dysfunction. Conclusion: We found prediabetes was positively associated with the risk of renal dysfunction and PPG had a higher risk and predictive value of renal dysfunction than other glycemic indices of FPG and HbA1c.

Association between dietary inflammatory index and components of metabolic syndrome

Introduction: Limited data are available on the association of Dietary Inflammatory Index (DII) with metabolic syndrome (MetS) and its components. The present study was conducted to investigate the association of DII with MetS and its components among Iranian adults.

Methods: A total of 404 subjects, aged 18 years or older, were included in the current cross-sectional study. We used a validated and reliable 147-item food frequency questionnaire (FFQ) to assess dietary intakes. Fasting blood sample was obtained to quantify glycemic indicators and lipid profile. MetS was defined based on the guidelines of the National Cholesterol Education Program Adult Treatment Panel III (ATP III).

Results: Mean age of study participants was 38.20 ± 9.55 years. No significant association was found between DII and odds of MetS (odds ratio [OR]: 0.92, 95% CI: 0.48-1.76). In terms of MetS components, a significant positive association was seen between DII scores and reduced levels of high-density lipoprotein cholesterol (HDL-C) (OR: 2.29, 95% CI: 1.32-3.97); such that after controlling for energy intake, demographic variables and BMI, participants in the highest category of DII had 2.71 times greater odds for having reduced levels of HDL-C (OR: 2.71, 95% CIs: 1.34, 5.47). There was no other significant association between other components of MetS and DII scores either before or after adjusting for confounding variables.

Conclusion: We observed no significant association between DII and odds of MetS. However, higher score of DII was associated with lower levels of HDL.

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

Background

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

Methods

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

Results

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

Conclusion

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

Metabolic syndrome and its components are related to a higher risk for albuminuria and proteinuria: Evidence from a meta-analysis on 10,603,067 subjects from 57 studies

BACKGROUND & AIM

Previous studies have explored the relation of metabolic syndrome (MetS), its components and the risk of albuminuria/proteinuria but their results are inconsistent. Then, we aimed to conduct a meta-analysis in order to resolve these controversies.

METHOD

PubMed and Scopus were systematically searched from their inception to 1 march 2018. Risk estimates and their 95% confidence intervals were extracted and pooled using the random-effects approach.

RESULT

A total of 57 studies, 44 studies on albuminuria and 13 studies on proteinuria, with a total sample size of 10,603,067 participants, were included in this meta-analysis. Overall, MetS was contributed to higher risks of proteinuria (OR = 2.08, 95%CI = 1.85-2.34) and albuminuria (OR = 1.92, 95%CI = 1.71-2.15), independent of diabetes status; although, this relationship was more noticeable in studies that used the WHO definition of MetS and in non-East Asian populations. Also, the relationship between MetS and proteinuria was sex independent, while, for albuminuria was significant only in men. MetS components such as obesity, impaired fasting glucose, elevated blood pressure and hypertriglyceridemia were associated with significant increases in proteinuria and albuminuria risk, while lower HDL-Cholesterol was only linked to greater risk of proteinuria. Moreover, the total impact of MetS on proteinuria was more remarkable than each component of the syndrome and an escalating dose-response association was found between the number of MetS components and albuminuria risk.

CONCLUSION

MetS and its components are potential risk factors for albuminuria and proteinuria.

Metabolic syndrome and its components are associated with increased chronic kidney disease risk: Evidence from a meta-analysis on 11 109 003 participants from 66 studies

BACKGROUND & AIMS

Observational studies examining the relationship between metabolic syndrome and the risk of chronic kidney disease (CKD) have reported inconclusive results. This meta-analysis was performed to resolve these controversies.

METHODS

The MEDLINE, EMBASE, and PubMed databases were systematically searched from their inception until March 2016 to identify all relevant studies. Risk estimates and their corresponding 95% confidence intervals (CIs) for the associations of MetS and its components with CKD risk were extracted and pooled using a random-effects model.

RESULTS

A total of 66 studies, including 18 prospective cohorts and 48 cross-sectional studies, with 699 065 CKD patients and 11 109 003 participants were included in the meta-analysis. When all definitions were pooled, the presence of MetS was associated with a significant 50% increase of CKD risk (OR = 1.50, 95% CI = 1.43-1.56), with evidence of moderate heterogeneity (I2  = 72.3%, P < .001). The risk of CKD associated with MetS was higher in studies using the American Heart Association/National Heart, Lung, and Blood Institute criteria (OR = 1.68, 95% CI = 1.25-2.10) compared with those using the Adult Treatment Panel III (OR = 1.49, 95% CI = 1.42-1.56) and the International Diabetes Federation (OR = 1.32, 95% CI = 1.22-1.41) definitions. This relationship was independent of diabetes status. Moreover, all individual components of the MetS were significantly associated with CKD, and their coexistence resulted in an escalating dose-response relationship. The sensitivity and subgroup analyses established the stability of the findings.

CONCLUSIONS

This meta-analysis strongly suggests that the metabolic syndrome and its components are independently associated with the increased risk of CKD.

Is decreased lung function associated with chronic kidney disease? A retrospective cohort study in Korea

OBJECTIVE

There is some evidence that lung function and chronic kidney disease (CKD) may be related. We evaluated the impact of lung function on the development of CKD in a large-scale longitudinal study.

METHOD

Retrospective longitudinal analyses were conducted among subjects who participated in comprehensive health check-ups at least four times during 7 years (between 2006 and 2012). We investigated the development of CKD during the follow-up period according to lung function status.

RESULTS

Ten thousand one hundred and twenty-eight individuals (mean age =51.2 years) without CKD at baseline were enrolled. During the mean follow-up of 5 years (58.5±14.4 months), 167 of the 10 128 subjects (1.6%) developed CKD. Multivariable Cox proportional hazards analyses adjusting for age, sex, body mass index, systolic blood pressure, fasting glucose, estimated glomerular filtration rate, uric acid, triglycerides, serum albumin, and the presence of diabetes and hypertension revealed that a decrease of 10% in the forced expiratory volume in 1s (FEV₁)/forced vital capacity (FVC) ratio was associated with a 35% increase in the development of CKD during the follow-up. The incidence of CKD was higher in those with an FEV₁/FVC ratio <0.8 compared with those with FEV₁/FVC ratio ≥0.8 (HR=1.454; 95% CI 1.042 to 2.028, p=0.028).

CONCLUSIONS

Limited airflow as measured by the FEV₁/FVC ratio was associated with an increased risk of CKD.

Metabolic Syndrome Severity and Risk of CKD and Worsened GFR: The Jackson Heart Study

BACKGROUND/AIMS

The metabolic syndrome (MetS), as assessed using dichotomous criteria, is associated with increased risk of future chronic kidney disease (CKD), though this relationship is unclear among African Americans, who have lower risk for MetS but higher risk for CKD.

METHODS

We performed logistic regression using a sex- and race-specific MetS-severity z-score to assess risk of incident CKD among 2,627 African-American participants of the Jackson Heart Study, assessed at baseline and 8 years later. Based on quartile of baseline MetS severity, we further assessed prevalence of being in the lowest quartile of baseline GFR, the lowest quartile of relative GFR at follow-up, microalbuminuria and incident CKD.

RESULTS

Higher MetS-severity was associated with higher prevalence of GFR in the lowest quartile at baseline among males and females. Among African-American females but not males, higher baseline MetS-severity was associated with a higher prevalence of baseline elevations in microabuminuria (p<0.01), steep decline in GFR (p<0.001) and a higher incidence of CKD (p<0.0001). Women in increasing quartiles of baseline MetS-severity exhibited a linear trend toward higher odds of future CKD (p<0.05), with those in the 4th quartile of MetS-severity (compared to the 1st) having an odds ratio of 2.47 (95% confidence interval 1.13, 5.37); no such relationship was seen among men (p value for trend 0.49).

CONCLUSION

MetS-severity exhibited sex-based interactions regarding risk for future GFR deterioration and CKD, with increasing risk in women but not men. These data may have implications for triggering CKD screening among African-American women with higher degrees of MetS-severity.

Prediabetes is associated with microalbuminuria, reduced kidney function and chronic kidney disease in the general population: The KORA (Cooperative Health Research in the Augsburg Region) F4-Study

BACKGROUND AND AIMS

We investigated the associations of serum fasting (FG) and 2-h postload (2HG) glucose from an oral glucose tolerance test (OGTT), glycated hemoglobin (HbA1c), fasting insulin and the homeostasis model assessment-insulin resistance index (HOMA-IR) with urinary albumin-to-creatinine ratio (ACR) and estimated glomerular filtration rate (eGFR).

METHODS AND RESULTS

We performed cross-sectional analyses of 2713 subjects (1429 women; 52.7%) without known type 2 diabetes, aged 31-82 years, from the KORA (Cooperative Health Research in the Augsburg Region) F4-Study. FG, 2HG, HbA1c, fasting insulin, HOMA-IR and glucose tolerance categories were analyzed for association with ACR and eGFR in multivariable adjusted linear and median regression models, and with isolated microalbuminuria (i-MA), isolated reduced kidney function (i-RKF) and chronic kidney disease (CKD, defined as MA and/or RKF) in multivariable adjusted logistic regression models. Among the 2713 study participants, 28% revealed prediabetes (isolated impaired fasting glucose [i-IFG], isolated glucose tolerance [i-IGT] or both by American Diabetes Association definition), 4.2% had unknown type 2 diabetes, 6.5% had i-MA, 3.1% i-RKF and 10.9% CKD. In multivariable adjusted analysis, all continuous variables (FG, 2HG, HbA1c, fasting insulin and HOMA-IR) were associated with i-MA, i-RKF and CKD. The odds ratios (ORs) for i-MA and CKD were 1.54 (95% confidence interval: 1.02-2.33) and 1.58 (1.10-2.25) for individuals with i-IFG. Moreover, the OR for i-RKF was 2.57 (1.31-5.06) for individuals with IFG + IGT.

CONCLUSION

Our findings suggest that prediabetes might have harmful effects on the kidney.

Application of survival tree analysis for exploration of potential interactions between predictors of incident chronic kidney disease: a 15-year follow-up study

Background

Chronic kidney disease (CKD) is a growing public health challenges worldwide. Various studies have investigated risk factors of incident CKD; however, a very few studies examined interaction between these risk factors. In an attempt to clarify the potential interactions between risk factors of CKD, we performed survival tree analysis.

Methods

A total of 8238 participants (46.1% men) aged > 20 years without CKD at baseline [(1999–2001) and (2002–2005)], were followed until 2014. The first occurrence of CKD, defined as the estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m², was set as the main outcome. Multivariable Cox proportional hazard (Cox PH) regression was used to identify significant independent predictors of CKD; moreover, survival tree analysis was performed to gain further insight into the potential interactions between predictors.

Results

The crude incidence rates of CKD were 20.2 and 35.2 per 1000 person-years in men and women, respectively. The Cox PH identified the main effect of significant predictors of CKD incidence in men and women. In addition, using a limited number of predictors, survival trees identified 12 and 10 subgroups among men and women, respectively, with different survival probability. Accordingly, a group of men with eGFR > 74 ml/min/1.73 m², age ≤ 46 years, low level of physical activity, waist circumference ≤ 100 cm and FPG ≤ 4.7 mmol/l had the lowest risk of CKD incidence; while men with eGFR ≤ 63.4 ml/min/1.73 m², age > 50 years had the highest risk for CKD compared to men in the lowest risk group [hazard ratio (HR), 70.68 (34.57–144.52)]. Also, a group of women aged ≤ 45 years and eGFR > 83.5 ml/min/1.73 m² had the lowest risk; while women with age > 48 years and eGFR ≤ 69 ml/min/1.73 m² had the highest risk compared to low risk group [HR 27.25 (19.88–37.34)].

Conclusion

In this post hoc analysis, we found the independent predictors of CKD using Cox PH; furthermore, by applying survival tree analysis we identified several numbers of homogeneous subgroups with different risk for incidence of CKD. Our study suggests that two methods can be used simultaneously to provide new insights for intervention programs and improve clinical decision making.

Historical perspectives of the metabolic syndrome

The metabolic syndrome (MetS) or insulin resistance syndrome is a constellation of obesity-related metabolic derangements predisposing to type 2 diabetes and cardiovascular disease. In 1998, WHO defined the first criteria of MetS. Three years later, the user-friendly National Cholesterol Education Program criteria of MetS were proposed. Different criteria were issued by the International Diabetes Federation in 2005, making abdominal obesity a necessary component. Several international societies, including The International Diabetes Federation, jointly adopted the revised National Cholesterol Education Program criteria as harmonizing criteria of MetS in 2009. WHO warned the next year that MetS has limited practical utility as a management tool. Adipose tissue inflammation has been shown to be a fundamental mechanism of metabolic derangements, associated with ectopic lipid deposit and mitochondrial dysfunction in skeletal muscle and the liver.

Glycemic status and chronic kidney disease in Chinese adults: Findings from the REACTION study

BACKGROUND

Diagnosed diabetes has been associated with chronic kidney disease (CKD). However, the association between non-diabetic hyperglycemia and CKD remained uncertain. The aim of the present study was to investigate the association between different glycemic status and CKD in Chinese adults and to assess the prevalence and control of diabetes among individuals with CKD.

METHODS

In all, 250 752 adults aged ≥40 years were selected from the baseline cohort of the Risk Evaluation of cAncers in Chinese diabeTic Individuals: a lONgitudinal (REACTION) study. Plasma glucose concentrations and biochemical and other clinical data were collected; CKD was defined as an estimated glomerular filtration rate (eGFR) <60 mL/min per 1.73 m² .

RESULTS

The prevalence of CKD increased gradually with deterioration of glucose metabolic status in both men and women ( P _trend  < 0.001 for both). Compared with individuals with normal glucose regulation, men with prediabetes and diabetes had higher risks of prevalent CKD (prediabetes odds ratio [OR] 1.15, 95% confidence interval [CI] 1.02-1.32; newly diagnosed diabetes OR 1.27, 95% CI 1.08-1.49; previously diagnosed diabetes OR 2.05, 95% CI 1.78-2.35). Similar results were observed in women, but not among those with prediabetes. In male CKD patients with diabetes, 52.1% received antidiabetic treatment and 41.8% of those treated had effective glycemic control, higher than values for females.

CONCLUSIONS

Prediabetes and diabetes were associated with an increased risk of CKD in Chinese men. Control of diabetes among Chinese CKD patients is far from optimal.

Metabolic syndrome, serum uric acid and renal risk in patients with T2D

Background and aims

Metabolic Syndrome (Mets) and increased serum uric acid (SUA), are well known renal risk predictors and often coexist in patients with type 2 diabetes (T2D). Whether they independently contribute to the onset of CKD is at present unclear.

Methods and results

Within the AMD Annals database we identified patients with T2D and normal renal function and urine albumin excretion at baseline and regular follow-up visits during a 4-year period. Blood pressure, BMI, HDL, triglycerides, and SUA were available in 14,267 patients. The association between Mets and/or hyperuricemia (HU, top fifth gender specific quintile) and the occurrence of renal outcomes were evaluated.

Results

At baseline 59% of patients (n = 8,408) showed Mets and 18% (n = 2,584) HU. Over the 4-year follow-up, 14% (n = 1,990) developed low eGFR (i.e. below 60 mL/min/1.73 m²), and 26% (n = 3,740) albuminuria. After adjustment for confounders, BP≥130/85, low HDL, triglycerides ≥150 and HU were independently related to the development of low eGFR (1.57, P<0.001; 1.13, P = 0.056; 1.18, P = 0.008; 1.26, P = 0.001) and of albuminuria (1.35, P<0.001; 1.18, P = 0.001; 1.15, P = 0.002; 1.24, P = 0.001), respectively.

The incidence of low eGFR was higher in patients with HU independent of the presence or absence of Mets (21%, OR 1.30, p = 0.009 and 20%, 1.57, p<0.000 respectively), while albuminuria occurred more frequently in those with Mets and HU (32%, OR 1.25, p = 0.005) as compared to the reference group.

Conclusions

HU and Mets are independent predictors of CKD and its individual components in patients with T2D.

Association between prediabetes and risk of chronic kidney disease: a systematic review and meta-analysis

AIMS

To assess the effect of prediabetes (impaired fasting glucose and/or impaired glucose tolerance) on the incidence of chronic kidney disease.

METHODS

PubMed and EMBASE were searched (for studies published up to March 2015). Effects estimated from cohort studies reporting the relationship of prediabetes to incident chronic kidney disease [kidney damage (microalbuminuria, albuminuria or proteinuria) and/or decreased glomerular filtration rate] were pooled using a random-effects model meta-analysis.

RESULTS

Nine cohort studies with a total of 185 452, mainly Asian and white, participants were followed for a total of 835 146 person-years. In eight cohort studies defining impaired fasting glucose as fasting glucose 6.1-6.9 mmol/l, the summary relative risk of chronic kidney disease after adjustment for established risk factors was 1.11 (95% CI 1.02-1.21). When a study defining impaired fasting glucose as fasting glucose 5.6-6.9 mmol/dl was added, the overall relative risk of chronic kidney disease was 1.12 (95% CI 1.02-1.21). Exclusion of the only study with information on impaired glucose tolerance did not change the relative risk (1.12; 95% CI 1.02-1.21). There was no evidence of publication bias (P value for Egger test = 0.12).

CONCLUSION

Prediabetes is modestly associated with an increase in chronic kidney disease risk, but this remains to be robustly confirmed. Chronic kidney disease screening among people with prediabetes, and aggressive management of prediabetes in those with chronic kidney disease may be warranted.

Cardiovascular metabolic risk factors and glomerular filtration rate: a rural Chinese population study

METHODS

A total of 2426 study subjects from rural China aged 35 years and above (934 men and 1492 women) were enrolled in a cross-sectional survey. The eGFR calculation was based on the Modification of Diet in Renal Disease (MDRD) equation. The strength of the association between cardiovascular metabolic risk factors and eGFR was analyzed using a linear regression model.

RESULTS

Cardiovascular metabolic risk factors, including age, body weight, waist circumference, fasting plasma glucose (FPG), creatinine (Cr), high-density lipoprotein-cholesterol (HDL-C), total cholesterol (TC), triglyceride (TG), systolic pressure, and diastolic pressure, were associated with eGFR. Additionally, the eGFR level gradually decreased and showed a linear trend with the increase in metabolic syndrome risk factors.

CONCLUSION

Metabolic risk factors are correlated with a reduction in renal function and CKD.

Prediabetes and Risk of Glomerular Hyperfiltration and Albuminuria in the General Nondiabetic Population: A Prospective Cohort Study

BACKGROUND

The role of prediabetes as a risk factor for hyperfiltration and albuminuria in persons who do not develop diabetes is unclear. The lack of evidence is mainly due to the difficulty of accurately assessing the glomerular filtration rate (GFR) in the near-normal range of GFR. We investigated whether prediabetes is an independent risk factor for glomerular hyperfiltration and high-normal urinary albumin-creatinine ratio (ACR) using measured GFR (mGFR) rather than estimated GFR.

STUDY DESIGN

Prospective cohort study based on the Renal Iohexol Clearance Survey in Tromsø 6 (RENIS-T6) and the RENIS Follow-Up Study. Median observation time was 5.6 years.

SETTING & PARTICIPANTS

A representative sample of 1,261 persons without diabetes mellitus (DM) from the general population aged 50 to 62 years.

PREDICTOR

Prediabetes defined by fasting glucose and hemoglobin A1c according to levels suggested by the American Diabetes Association (preDMADA) and the International Expert Committee of 2009 (preDMIEC).

OUTCOMES

Change in mGFR; hyperfiltration defined as mGFR>90th percentile adjusted for age, sex, weight, and height; and high-normal ACR (>10mg/g) at follow-up.

MEASUREMENTS

GFR was measured with iohexol clearance.

RESULTS

Baseline fasting glucose, hemoglobin A1c, and both definitions of prediabetes were predictors of higher mGFR at follow-up and lower annual mGFR decline in multivariable-adjusted regression analyses. Participants with preDMIEC had an OR for hyperfiltration of 1.95 (95% CI, 1.20-3.17) and for high-normal ACR of 1.83 (95% CI, 1.04-3.22) at follow-up. We adjusted for cardiovascular risk factors including ambulatory blood pressure at baseline and change in use of antihypertensive medication between baseline and follow-up.

LIMITATIONS

Only middle-aged white patients participated. There is no consensus on how to define glomerular hyperfiltration.

CONCLUSIONS

Our findings imply an independent role of prediabetes in the development of glomerular hyperfiltration and albuminuria. Prediabetes might be a target for early treatment to prevent chronic kidney disease in chronic hyperglycemia.

Metabolic Syndrome and Smoking Are Associated with Future Development of Advanced Chronic Kidney Disease in Older Adults

INTRODUCTION

Metabolic syndrome (MetS) and smoking have been identified as risk factors for chronic kidney disease (CKD) in cross-sectional studies in various age groups, but longitudinal data on progression of CKD in older adults are limited. Our objectives were to examine whether MetS and its components and smoking predict the onset of CKD stage 3b (CKD-3b) in older adults.

METHODS

A subset of participants of the Einstein Aging Study who were free of diabetes, dementia, and CKD-3b at enrollment were included in this analysis. CKD-3b was defined as an estimated glomerular filtration rate <45 ml/min/1.73 m(2). Cox proportional hazards models were used in these analyses.

RESULTS

In total, 413 ≥70-year-old individuals were eligible for this study. 65.4% were female and 26.6% were black. 22.3% of the participants had MetS at baseline, 4.4% were active smokers, and 6.1% developed CKD-3b over a mean of 4 years of follow-up. MetS and smoking independently predicted incident CKD in our fully adjusted model (hazard ratio 3.65, 95% CI 1.20-10.60, p = 0.022; hazard ratio 29.69, 95% CI 4.47-197.23, p = 0.000).

CONCLUSION

MetS and smoking are associated with an increased incidence of CKD-3b. These risk factors are modifiable, easily identified and prevented through better health care practice and early diagnosis.

Metabolic syndrome and its components associated with chronic kidney disease

Background:

There is limited information on the relationship between metabolic syndrome (MetS) and chronic kidney disease (CKD) in the Iranian population, a group that has a high prevalence of CKD and obesity. The aim of present study was to determine the relationship between MetS and CKD in West of Iran.

Materials and Methods:

A total of 800 subjects aged more than 35 years admitted from 2011 to 2013 were enrolled in the study. MetS was defined based on the Adult Treatment Panel III criteria, and CKD was defined from the Kidney Disease Outcomes Quality Initiative practice guidelines. Waist circumference and body mass index were calculated, as well, blood samples were taken and lipid profile, plasma glucose levels, and serum creatinine were measured. Data were analyzed with SPSS version 17 (SPSS Inc., Chicago, IL, USA).

Results:

CKD was seen in 14.8% patients with MetS and 8.3% individuals without MetS. MetS was associated with an increased odds ratio (OR) for a glomerular filtration rate <60 ml/min/1.73 m² (OR: 1.91; 95% confidence interval [CI]: 1.22-2.99; P = 0.004). Individuals with 2, 3, 4, and 5 components of the MetS had an increased OR for CKD: 2.19 (95% CI: 0.95-3.62), 2.65 (95% CI: 1.03-4.71), 2.86 (95% CI: 1.08-5.53), and 5.03 (95% CI: 1.80-8.57), respectively, compared with individuals with none of the components.

Conclusion:

We found a high prevalence of CKD in patients with MetS compared with the subject without MetS. Our observations raised major clinical and public health concerns in Iran, where both the MetS and kidney diseases are becoming common.

Chronic Kidney Disease in Non-Diabetic Older Adults: Associated Roles of the Metabolic Syndrome, Inflammation, and Insulin Resistance

BACKGROUND

The aims of the study were to examine the association between CKD and the metabolic syndrome (MetS) and its components in older adults. We also explored two possible pathways linking the metabolic syndrome with CKD: inflammation as measured by high sensitivity C-Reactive Protein (hsCRP) and insulin resistance as measured by HOMA-IR.

METHODS

Community-dwelling non-diabetic 70+ adults from the Einstein Aging Study participated in the study. We defined CKD as eGFR below 60mL/min/1.73m2. MetS was defined according to recent guidelines from the National Cholesterol Education Program. Binary logistic regressions were used to assess the association between the metabolic syndrome, its components and CKD with adjustments for demographics, HOMA-IR and hsCRP.

RESULTS

Of 616 participants (mean age = 79.3 years, 65.5% female), 25% had MetS and 26.5% had CKD. Participants with CKD had a significantly higher prevalence of the MetS than individuals without CKD (34.4% vs. 24.3%). Binary logistic regression models showed that CKD was associated with MetS (OR = 1.72, 95%CI = 1.13-2.61). The association was unaltered by adjustment for hsCRP but altered by adjustment for HOMA-IR. As the number of MetS components increased the relative odds of CKD also increased. None of the individual components was independently associated with CKD.

CONCLUSION

MetS is associated with CKD in non-diabetic older adults. Results showed that as the number of MetS components increased so did the odds for CKD. HOMA-IR seems to be in the casual pathway linking MetS to CKD.

Metabolic Syndrome without Diabetes or Hypertension Still Necessitates Early Screening for Chronic Kidney Disease: Information from a Chinese National Cross-Sectional Study

Metabolic syndrome (MS) is prevalent, with an increasing contribution to the incidence of chronic kidney disease (CKD). The study of the relationship between them is important. The CKD survey, a national cross-sectional study, provided a large database to accomplish this study. The study population were 41 131 adults from this survey between 2008 and 2009. CKD was defined as estimate glomerular filtration rate (eGFR) less than 60 mL/min per 1.73 m2 or the presence of albuminuria. MS was diagnosed by National Cholesterol Education Program-Adult Treatment Panel III (ATPIII), ATPIII-modified or International Diabetes Federation (IDF) criteria. Logistic regression model was applied to study the impact of MS or its components on CKD or its components. The age and sex standardized prevalence of MS by ATPIII, ATPIII-modified and IDF criteria was 11.77% (11.13%-12.40%), 21.51% (20.69%-22.34%) and 16.67% (15.92-17.42)% respectively. Multivariate logistic regression models showed that MS and its components were associated with higher CKD prevalence. The risk for CKD and its components increased with the number of MS components. After adjusting for hypertension and diabetes, the odds ratios of MS for CKD decreased, but remained significantly more than 1 between 1.16(95%CI 1.07-1.26) and 1.37 (95% CI 1.25-1.50) across the different models. Similar results were found with albuminuria, while for decreased eGFR, after adjusting for hypertension and diabetes, the odds ratios of MS and MS components (except elevated TG) became insignificant. In conclusion, MS is prevalent and associated with a higher prevalence of CKD. Different MS components are associated with different risks for CKD, even after adjusting for hypertension and diabetes, which may mainly be contributed more by the increased risk for albuminuria than that for decreased eGFR. More attention must be paid to the population with MS, including those with elevated blood pressure and serum glucose.

Oxidized LDL and Fructosamine Associated with Severity of Coronary Artery Atherosclerosis in Insulin Resistant Pigs Fed a High Fat/High NaCl Diet

Background

Insulin-resistant subjects develop more severe and diffuse coronary artery atherosclerosis than insulin-sensitive controls but the mechanisms that mediate this atherosclerosis phenotype are unknown.

Research Objective

To determine the metabolic parameters that associate with the severity of coronary atherosclerosis in insulin resistant pigs fed a high fat/high NaCl diet.

Key Methods

The primary endpoint was severity of coronary atherosclerosis in adult pigs (Sus scrofa, n = 37) fed a high fat diet that also contained high NaCl (56% above recommended levels) for 1 year.

Principal Findings

Twenty pigs developed severe and diffuse distal coronary artery atherosclerosis (i.e., severe = intimal area as a percent medial area > 200% in at least 2 coronary artery cross sections and diffuse distal = intimal area as a percent medial area ≥ 150% over 3 sections separated by 2 cm in the distal half of the coronary artery). The other 17 pigs had substantially less coronary artery atherosclerosis. All 37 pigs had blood pressure in a range that would be considered hypertensive in humans and developed elevations in total and LDL and HDL cholesterol, weight gain, increased backfat, and increased insulin resistance (Bergman Si) without overt diabetes. Insulin resistance was not associated with atherosclerosis severity. Five additional pigs fed regular pig chow also developed increased insulin resistance but essentially no change in the other variables and little to no detectible coronary atherosclerosis. Most importantly, the 20 high fat/high NaCl diet -fed pigs with severe and diffuse distal coronary artery atherosclerosis had substantially greater increases (p< 0.05) in oxidized LDL (oxLDL) and fructosamine consistent with increased protein glycation.

Conclusion

In pigs fed a high fat/high NaCl diet, glycated proteins are induced in the absence of overt diabetes and this degree of increase is associated with the development of severe and diffuse distal coronary artery atherosclerosis.

Haematuria increases progression of advanced proteinuric kidney disease

Background

Haematuria has been traditionally considered as a benign hallmark of some glomerular diseases; however new studies show that haematuria may decrease renal function.

Objective

To determine the influence of haematuria on the rate of chronic kidney disease (CKD) progression in 71 proteinuric patients with advanced CKD (baseline eGFR <30 mL/min) during 12 months of follow-up.

Results

The mean rate of decline in eGFR was higher in patients with both haematuria and proteinuria (haemoproteinuria, HP, n=31) than in patients with proteinuria alone (P patients, n=40) (-3.8±8.9 vs 0.9±9.5 mL/min/1.73m2/year, p<0.05, respectively). The deleterious effect of haematuria on rate of decline in eGFR was observed in patients <65 years (-6.8±9.9 (HP) vs. 0.1±11.7 (P) mL/min/1.73m2/year, p<0.05), but not in patients >65 years (-1.2±6.8 (HP) vs. 1.5±7.7 (P) mL/min/1.73m2/year). Furthermore, the harmful effect of haematuria on eGFR slope was found patients with proteinuria >0.5 g/24 h (-5.8±6.4 (HP) vs. -1.37± 7.9 (P) mL/min/1.73m2/year, p<0.05), whereas no significant differences were found in patients with proteinuria < 0.5 g/24 h (-0.62±7.4 (HP) vs. 3.4±11.1 (P) mL/min/1.73m2/year). Multivariate analysis reported that presence of haematuria was significantly and independently associated with eGFR deterioration after adjusting for traditional risk factors, including age, serum phosphate, mean proteinuria and mean serum PTH (β=-4.316, p=0.025).

Conclusions

The presence of haematuria is closely associated with a faster decrease in renal function in advanced proteinuric CKD patients, especially in younger CKD patients with high proteinuria levels; therefore this high risk subgroup of patients would benefit of intensive medical surveillance and treatment.

Association between Metabolic Syndrome and Microalbuminuria in Korean Adults

Background

We conducted a population-based cross-sectional study of Korean adults to evaluate the association between metabolic syndrome and microalbuminuria as a marker for early-stage chronic kidney disease.

Methods

A total of 8,497 adults (3,625 men and 4,872 women) who participated in the Korea National Health and Nutrition Examination Survey between 2011 and 2012 were included. Metabolic syndrome was defined according to recommendation from a joint interim statement of international organizations published in 2009. Microalbuminuria was defined as a urinary albumin-to-creatinine ratio of 30 to 300 mg/g. The association between metabolic syndrome and microalbuminuria was evaluated using logistic regression analysis with adjustment for covariates while considering sampling weights and the complex survey design.

Results

The prevalence of microalbuminuriain subjects with metabolic syndrome was 11% for men and 14.4% for women, whereas the prevalence in subjects without metabolic syndrome was 3.1% for men and 6.7% for women. Metabolic syndrome was significantly associated with an increased risk of microalbuminuriain both women (odds ratio, 2.79; 95% confidence interval, 2.01 to 3.88) and men (odds ratio, 3.00; 95% confidence interval, 2.11 to 4.27). All components of the metabolic syndrome were associated with a significantly increased risk of microalbuminuria with the strongest association for high blood pressure. The risk of microalbuminuria increased in a dose-dependent manner (P-value for trend < 0.001) with the number of metabolic syndrome components observed for both sexes.

Conclusion

These findings suggest that metabolic syndrome is a risk factor for chronic kidney disease from an early stage.

Increased prevalence of albuminuria in individuals with higher range of impaired fasting glucose: the 2011 Korea National Health and Nutrition Examination Survey

AIMS

We investigated the prevalence of albuminuria across a range of fasting plasma glucose (FPG), including normal fasting glucose (NFG), impaired fasting glucose (IFG), and diabetes.

METHODS

A total of 5202 subjects who participated in the fifth Korea National Health and Nutrition Examination Survey were enrolled. Spot urine samples were taken and the albumin-creatinine ratio was calculated for each patient. Subjects were divided into five groups according to FPG levels: <5.0 (NFG1, n=1,905), 5.0-5.5 (NFG2, n=1,784), 5.6-6.0 (IFG1, n=727), 6.1-6.9 (IFG2, n=268), and ≥7.0 (diabetes, n=518) mmol/L. Analysis of covariance tests and logistic regression were used.

RESULTS

The rates of albuminuria were 4.1%, 6.0%, 7.6%, 12.3%, and 23.4% in the NFG1, NFG2, IFG1, IFG2 and diabetes groups, respectively (P<0.01 for the trend). The rate of albuminuria in the IFG2 group was significantly higher than in the IFG1 group, even after adjustment for age, gender, hypertension, and obesity. The odds ratio for the presence of albuminuria in the IFG2 group was 1.87 (95% CI, 1.19-2.94), using the NFG1 group as a control in logistic regression analyses.

CONCLUSIONS

Albuminuria is more prevalent in subjects in the higher range of IFG. Therefore, strategies to reduce albuminuria should be emphasized especially in these subjects.

Risk of chronic kidney disease in non-obese individuals with clustering of metabolic factors: a longitudinal study

OBJECTIVE

The impact of the clustering of metabolic factors on chronic kidney disease (CKD) in non-obese individuals remains unclear.

METHODS

We conducted a follow-up study of 23,894 Japanese adults (age, 18-69 years) who continuously received annual health examinations between 2000 and 2011. Obesity, high blood pressure, high triglycerides, low high-density lipoprotein (HDL) cholesterol and high fasting blood sugar were defined as metabolic factors, and CKD was defined as renal dysfunction (estimated glomerular filtration rate: <60 mL/min/1.73 m(2)) or proteinuria (dipstick test: ≥1+). The association between the clustering of metabolic factors and CKD was assessed based on the presence or absence of obesity using a Cox proportional hazard model.

RESULTS

Of 2,867 subjects with ≥3 metabolic factors, 650 (22.7%) were non-obese. These individuals were older and had higher metabolic risks than their obese counterparts at baseline. Among the entire cohort of 23,894 subjects, 1,764 developed renal dysfunction and 904 developed proteinuria during an average follow-up period of 7.8 years. The cumulative incidence of renal dysfunction was higher (22.1% vs. 16.1%), whereas that of proteinuria was lower (10.5% vs. 14.4%), among the non-obese subjects with ≥3 metabolic factors than the obese subjects with ≥3 metabolic factors after 11 years. The adjusted relative risk (RR) (95% confidence interval) of renal dysfunction was 1.54 (1.34-1.77) and 1.67 (1.35-2.07) for the obese and non-obese subjects with ≥3 metabolic factors, respectively.

CONCLUSION

Non-obese subjects with ≥3 metabolic factors, who are missed based on the essential criterion of obesity for metabolic syndrome, may have an equal or slightly higher risk of renal dysfunction than obese subjects with ≥3 metabolic factors.

Metabolic syndrome and chronic kidney disease: Current status and future directions

Metabolic syndrome (MetS) is a term used to denote a combination of selected, widely prevalent cardiovascular disease (CVD)-related risk factors. Despite the ambiguous definition of MetS, it has been clearly associated with chronic kidney disease markers including reduced glomerular filtration rate, proteinuria and/or microalbuminuria, and histopathological markers such as tubular atrophy and interstitial fibrosis. However, the etiological role of MetS in chronic kidney disease (CKD) is less clear. The relationship between MetS and CKD is complex and bidirectional, and so is best understood when CKD is viewed as a common progressive illness along the course of which MetS, another common disease, may intervene and contribute. Possible mechanisms of renal injury include insulin resistance and oxidative stress, increased proinflammatory cytokine production, increased connective tissue growth and profibrotic factor production, increased microvascular injury, and renal ischemia. MetS also portends a higher CVD risk at all stages of CKD from early renal insufficiency to end-stage renal disease. Clinical interventions for MetS in the presence of CKD should include a combination of weight reduction, appropriate dietary modification and increase physical activity, plus targeting of individual CVD-related risk factors such as dysglycemia, hypertension, and dyslipidemia while conforming to relevant national societal guidelines.

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.