Microalbuminuria precedes the development of NIDDM

Albuminuria in Cardiovascular, Kidney, and Metabolic Disorders: A State-of-the-Art Review

Albuminuria-increased urine albumin excretion-is associated with cardiovascular mortality among patients with diabetes, hypertension, chronic kidney disease, or heart failure, as well as among adults with few cardiovascular risk factors. Many authors have hypothesized that albuminuria reflects widespread endothelial dysfunction, but additional work is needed to uncover whether albuminuria is directly pathologic or causative of cardiovascular disease. Urinary albumin-to-creatinine ratio is an attractive, unifying biomarker of cardiovascular, kidney, and metabolic conditions that may be useful for identifying and monitoring disease trajectory. However, albuminuria may develop through unique mechanisms across these distinct clinical phenotypes. This state-of-the-art review discusses the role of albuminuria in cardiovascular, kidney, and metabolic conditions; identifies potential pathways linking albuminuria to adverse outcomes; and provides practical approaches to screening and managing albuminuria for clinical cardiologists. Future research is needed to determine how broadly and how frequently to screen patients for albuminuria, whether it is cost-effective to treat low-grade albuminuria (10-30 mg/g), and how to equitably offer newer antiproteinuric therapies across the spectrum of cardiovascular-kidney-metabolic diseases.

Association of Albuminuria With Chronic Kidney Disease Progression in Persons With Chronic Kidney Disease and Normoalbuminuria : A Cohort Study

BACKGROUND

Albuminuria is a major risk factor for chronic kidney disease (CKD) progression, especially when categorized as moderate (30 to 300 mg/g) or severe (>300 mg/g). However, there are limited data on the prognostic value of albuminuria within the normoalbuminuric range (<30 mg/g) in persons with CKD.

OBJECTIVE

To estimate the increase in the cumulative incidence of CKD progression with greater baseline levels of albuminuria among persons with CKD who had normoalbuminuria (<30 mg/g).

DESIGN

Multicenter prospective cohort study.

SETTING

7 U.S. clinical centers.

PARTICIPANTS

1629 participants meeting criteria from the CRIC (Chronic Renal Insufficiency Cohort) study with CKD (estimated glomerular filtration rate [eGFR], 20 to 70 mL/min/1.73 m2) and urine albumin-creatinine ratio (UACR) less than 30 mg/g.

MEASUREMENTS

Baseline spot urine albumin divided by spot urine creatinine to calculate UACR as the exposure variable. The 10-year adjusted cumulative incidences of CKD progression (composite of 50% eGFR decline or kidney failure [dialysis or kidney transplantation]) from confounder adjusted survival curves using the G-formula.

RESULTS

Over a median follow-up of 9.8 years, 182 of 1629 participants experienced CKD progression. The 10-year adjusted cumulative incidences of CKD progression were 8.7% (95% CI, 5.9% to 11.6%), 11.5% (CI, 8.8% to 14.3%), and 19.5% (CI, 15.4% to 23.5%) for UACR levels of 0 to less than 5 mg/g, 5 to less than 15 mg/g, and 15 mg/g or more, respectively. Comparing persons with UACR 15 mg/g or more to those with UACR 5 to less than 15 mg/g and 0 to less than 5 mg/g, the absolute risk differences were 7.9% (CI, 3.0% to 12.7%) and 10.7% (CI, 5.8% to 15.6%), respectively. The 10-year adjusted cumulative incidence increased linearly based on baseline UACR levels.

LIMITATION

UACR was measured once.

CONCLUSION

Persons with CKD and normoalbuminuria (<30 mg/g) had excess risk for CKD progression, which increased in a linear fashion with higher levels of albuminuria.

PRIMARY FUNDING SOURCE

None.

Prospective urinary albumin/creatinine ratio for diagnosis, staging, and organ response assessment in renal AL amyloidosis: results from a large cohort of patients

OBJECTIVES

Quantification of 24 h-proteinuria is the gold standard for diagnosing, staging, and monitoring of patients with renal AL amyloidosis. However, 24 h-urine collection is cumbersome and may result in preanalytical error. In this prospective study, we investigated the role of urinary albumin/creatinine ratio (UACR) (cut-off: 300 mg/g) identifying renal involvement, evaluated a UACR-based staging system (UACR cut-off: 3,600 mg/g) and assessed whether UACR response (UACR decrease >30% without worsening in eGFR >25%) predicts renal outcome in 531 patients with newly-diagnosed AL amyloidosis.

METHODS

From October 2013 paired 24 h-proteinuria and UACR (on first morning void) were measured in all newly-diagnosed patients with AL amyloidosis. Correlation between 24 h-proteinuria and UACR at baseline was assessed by Pearson's r test. Impact of UACR response on renal outcome was assessed in randomly created testing (n=354) and validation (n=177) cohorts.

RESULTS

A strong linear correlation was found between 24 h-proteinuria and UACR at baseline (r=0.90; p<0.001). After a median follow-up of 31 months, 57 (11%) patients required dialysis. A UACR-based renal staging system identified three stages with significantly higher dialysis rate at 36 months comparing stage I with stage II and stage II with stage III. Achieving a renal response, according to a UACR-based criterion, resulted in lower dialysis rate in both testing and validation cohorts.

CONCLUSIONS

UACR is a reliable marker for diagnosis, prognosis, and organ response assessment in renal AL amyloidosis and can reliably replace 24 h-proteinuria in clinical trials and individual patients' management.

Risk stratification for mortality in cardiovascular disease survivors: A survival conditional inference tree analysis

BACKGROUND AND AIMS

Efficient analysis strategies for complex network with cardiovascular disease (CVD) risk stratification remain lacking. We sought to identify an optimized model to study CVD prognosis using survival conditional inference tree (SCTREE), a machine-learning method.

METHODS AND RESULTS

We identified 5379 new onset CVD from 2006 (baseline) to May, 2017 in the Kailuan I study including 101,510 participants (the training dataset). The second cohort composing 1,287 CVD survivors was used to validate the algorithm (the Kailuan II study, n = 57,511). All variables (e.g., age, sex, family history of CVD, metabolic risk factors, renal function indexes, heart rate, atrial fibrillation, and high sensitivity C-reactive protein) were measured at baseline and biennially during the follow-up period. Up to December 2017, we documented 1,104 deaths after CVD in the Kailuan I study and 170 deaths in the Kailuan II study. Older age, hyperglycemia and proteinuria were identified by the SCTREE as main predictors of post-CVD mortality. CVD survivors in the high risk group (presence of 2-3 of these top risk factors), had higher mortality risk in the training dataset (hazard ratio (HR): 5.41; 95% confidence Interval (CI): 4.49-6.52) and in the validation dataset (HR: 6.04; 95%CI: 3.59-10.2), than those in the lowest risk group (presence of 0-1 of these factors).

CONCLUSION

Older age, hyperglycemia and proteinuria were the main predictors of post-CVD mortality.

TRIAL REGISTRATION

ChiCTR-TNRC-11001489.

Metabolite Signature of Albuminuria Involves Amino Acid Pathways in 8661 Finnish Men Without Diabetes

OBJECTIVE

To investigate the metabolite signature of albuminuria in individuals without diabetes or chronic kidney disease to identify possible mechanisms that result in increased albuminuria and elevated risk of type 2 diabetes (T2D).

RESEARCH DESIGN AND METHODS

The study cohort was a population-based Metabolic Syndrome In Men (METSIM) study including 8861 middle-aged and elderly Finnish men without diabetes or chronic kidney disease at baseline. A total of 5504 men participated in a 7.5-year follow-up study, and 5181 of them had metabolomics data measured by Metabolon's ultrahigh performance liquid chromatography-tandem mass spectroscopy.

RESULTS

We found 32 metabolites significantly (P < 5.8 × 10-5) and positively associated with the urinary albumin excretion (UAE) rate. These metabolites were especially downstream metabolites in the amino acid metabolism pathways (threonine, phenylalanine, leucine, arginine). In our 7.5-year follow-up study, UAE was significantly associated with a 19% increase (hazard ratio 1.19; 95% confidence interval, 1.13-1.25) in the risk of T2D after the adjustment for confounding factors. Conversion to diabetes was more strongly associated with a decrease in insulin secretion than a decrease in insulin sensitivity.

CONCLUSIONS

Metabolic signature of UAE included multiple metabolites, especially from the amino acid metabolism pathways known to be associated with low-grade inflammation, and accumulation of reactive oxygen species that play an important role in the pathogenesis of UAE. These metabolites were primarily associated with an increase in UAE and were secondarily associated with a decrease in insulin secretion and insulin sensitivity, resulting in an increased risk of incident T2D.

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.

Risk of Kidney Injury among Construction Workers Exposed to Heat Stress: A Longitudinal Study from Saudi Arabia

Saudi Arabia (SA) is one of the hottest countries in the world. This study was conducted to assess the impact of summer heat stress in Southeastern SA on short-term kidney injury (KI) among building construction workers and to identify relevant risk factors. Measurements of urinary albumin-creatinine ratio (ACR), height, weight, hydration, symptoms, daily work and behavioral factors were collected in June and September of 2016 from a cohort of construction workers (n = 65) in Al-Ahsa Province, SA. KI was defined as ACR ≥ 30 mg/g. Multivariate linear regression analysis was used to assess factors related to cross-summer changes in ACR. A significant increase in ACR occurred among most workers over the study period; incidence of KI was 18%. Risk factors associated with an increased ACR included dehydration, short sleep, and obesity. The findings suggest that exposure to summer heat may lead to the development of KI among construction workers in this region. Adequate hydration and promotion of healthy habits among workers may help reduce the risk of KI. A reduction in work hours may be the most effective intervention because this action can reduce heat exposure and improve sleep quality.

Adverse Outcomes after Major Surgeries in Patients with Diabetes: A Multicenter Matched Study

The impact of diabetes on perioperative outcomes remains incompletely understood. Our purpose is to evaluate post-operative complications and mortality in patients with diabetes. Using the institutional and clinical databases of three university hospitals from 2009⁻2015, we conducted a matched study of 16,539 diabetes patients, aged >20 years, who underwent major surgery. Using a propensity score matching procedure, 16,539 surgical patients without diabetes who underwent surgery were also selected. Logistic regressions were used to calculate the odds ratios (ORs) with 95% confidence intervals (CIs) for post-operative complications and in-hospital mortality associated with diabetes. Patients with diabetes had a higher risk of postoperative septicemia (OR 1.33, 95% CI 1.01⁻1.74), necrotizing fasciitis (OR 3.98, 95% CI 1.12⁻14.2), cellulitis (OR 2.10, 95% CI 1.46⁻3.03), acute pyelonephritis (OR 1.86, 95% CI 1.01⁻3.41), infectious arthritis (OR 3.89, 95% CI 1.19⁻12.7), and in-hospital mortality (OR 1.51, 95% CI 1.07⁻2.13) compared to people without diabetes. Previous admission for diabetes (OR 2.33, 95% CI 1.85⁻2.93), HbA1c >8% (OR 1.96, 95% CI 1.64⁻2.33) and fasting glucose >180 mg/dL (OR 1.90, 95% CI 1.68⁻2.16) were predictors for post-operative adverse events. Diabetes patients who underwent surgery had higher risks of infectious complications and in-hospital mortality compared with patients without diabetes who underwent similar major surgeries.

Circulating microRNAs -192 and -194 are associated with the presence and incidence of diabetes mellitus

We sought to identify circulating microRNAs as biomarkers of prevalent or incident diabetes. In a pilot study of 18 sex- and age-matched patients with metabolic syndrome, nine of whom developed diabetes during 6 years of follow-up, an array of 372 microRNAs discovered significantly elevated serum levels of microRNAs -122, -192, -194, and -215 in patients who developed diabetes mellitus type 2 (T2DM). In two cross-sectional validation studies, one encompassing sex- and age-matched groups of patients with T2DM, impaired fasting glucose (IFG) and euglycemic controls (n = 43 each) and the other 53 patients with type 1 diabetes and 54 age- and BMI-matched euglycemic controls, serum levels of miR-192, miR-194, and mi215 were significantly higher in diabetic subjects than in probands with euglycemia or IFG. In a longitudinal study of 213 initially diabetes-free patients of whom 35 developed diabetes during 6 years of follow-up, elevated serum levels of microRNAs 192 and 194 were associated with incident T2DM, independently of fasting glucose, HbA1c and other risk factors. Serum levels of miR-192 and miR-194 were also elevated in diabetic Akt2 knockout mice compared to wild type mice. In conclusion, circulating microRNAs -192 and -194 are potential biomarkers for risk of diabetes.

Albumin-to-creatinine ratio as a predictor of all-cause mortality and hospitalization of congestive heart failure in Chinese elder hypertensive patients with high cardiovascular risks

Background

Data are limited with regard to the relationship of albuminuria and major adverse cardiovascular events (MACE) in Chinese elder patients with high cardiovascular risk.

Methods

We did a retrospective cohort study using Chinese elder patients with high cardiovascular risks (n = 1474) to identify the association of albumin-to-creatinine ratio (ACR) and the incidence of MACE and all-cause mortality. Individuals were followed up from January, 2002 to November, 2007. The all-cause mortality and MACE, composite outcome of cardiovascular death, myocardial infarction, stroke and hospitalization of congestive heart failure were defined as primary endpoint.

Results

During the median following up of 56 months, 213 patients developed primary endpoint and 117 patients died. Patients with higher baseline urinary ACR (> 30 mg/g) experienced a nearly 2-fold of all-cause mortality and a 3-fold of heart failure hospitalization than those with lower baseline urinary ACR (≤10 mg/g).MACE, cardiovascular death, stoke and myocardial infarction showed no difference in three grades of urinary ACR (> 30 mg/g, 10 mg/g-30 mg/g, ≤10 mg/g) in this cohort. Patients above 65 years with increased ACR tended to experience higher mortality risks, and the association of increased ACR with higher hospitalization of congestive heart failure seemed to be more prominent in patients below 65 years than above 65 years.

Conclusions

In this post hoc analysis of Chinese individuals with high cardiovascular risks, higher urinary ACR was associated with higher all-cause mortality and heart failure hospitalization. Further studies are needed to find out whether there is age-specific ACR cutoff point.

Electronic supplementary material

The online version of this article (10.1186/s40885-018-0095-3) contains supplementary material, which is available to authorized users.

Microalbuminuria as a simple predictor of incident diabetes over 8 years in the Korean Genome and Epidemiology Study (KoGES)

Microalbuminuria (MAU) is a common subclinical disease and related with cardiovascular outcome both in diabetic and non-diabetic patients. However, there is rare data about the effect of MAU on the development of diabetes. Thus, we aimed to investigate whether MAU is associated with the development of incident diabetes. A total of 3385 subjects without diabetes (1503 men and 1882 women; mean age, 53 years) who participated in the Ansung–Ansan cohort study from 2001–2002 (baseline) to 2011–2012 (fifth follow-up visit) were followed for a mean of 8 years. The prevalence of MAU at baseline was 10.8% (365 patients), and the incidence of newly developed diabetes during the follow-up period was 15.3% (56 patients) in subjects with MAU. The hazard ratio (HR) for development of diabetes was 1.43 (95% confidence interval (CI) 1.07–1.91, p-value 0.016), independent of traditional risk factors for diabetes including pre-diabetes, age, obesity, and family history. The impact of MAU on diabetes was also significant in the non-pre-diabetic population (HR 2.08, 95% CI 1.07–4.03, p-value 0.031). In conclusion, our results show that incident MAU is associated with future development of diabetes and could be an early marker for diabetes, even in the non-prediabetic population.

Role of Microalbuminuria in Predicting Cardiovascular Mortality in Individuals With Subclinical Hypothyroidism

PURPOSE

Studies suggest that subclinical hypothyroidism (SCH) is related to cardiovascular mortality (CVM). We explored the role of microalbuminuria (MIA) as a predictor of long-term CVM in population with and without SCH with normal kidney function.

MATERIALS AND METHODS

We examined the National Health and Nutrition Education Survey - III database (n = 6,812). Individuals younger than 40 years, thyroid-stimulating hormone levels ≥20 and ≤0.35mIU/L, estimated glomerular filtration rate <60mL/minute/1.73m² and urine albumin-to-creatinine ratio of >250mg/g in men and >355mg/g in women were excluded. SCH was defined as thyroid-stimulating hormone levels between 5 and 19.99mIU/L and serum T4 levels between 5 and 12µg/dL. MIA was defined as urine albumin-to-creatinine ratio of 17-250mg/g in men and 25-355mg/g in women. Patients were categorized into the following 4 groups: (1) no SCH or MIA, (2) MIA, but no SCH, (3) SCH, but no MIA and (4) both SCH and MIA.

RESULTS

Prevalence of MIA in the subclinical hypothyroid cohort was 21% compared to 16.4% in those without SCH (P = 0.03). SCH was a significant independent predictor of MIA (n = 6,812), after adjusting for traditional risk factors (unadjusted odds ratio = 1.75; 95% CI: 1.24-2.48; P = 0.002 and adjusted odds ratio = 1.83; 95% CI: 1.2-2.79; P = 0.006). MIA was a significant independent predictor of long-term all-cause (adjusted hazard ratio = 1.7, 95% CI: 1.24-2.33) and CVM (adjusted hazard ratio = 1.72, 95% CI: 1.07-2.76) in subclinical hypothyroid individuals.

CONCLUSIONS

In a cohort of subclinical hypothyroid individuals, the presence of MIA predicts increased risk of CVM as compared to nonmicroalbuminurics with SCH. Further randomized trials are needed to assess the benefits of treating microalbuminuric subclinical hypothyroid individuals and impact on CVM.

A Multiethnic Study of Pre-Diabetes and Diabetes in LMIC

BACKGROUND

Diabetes mellitus is one of the leading causes of death and disability worldwide. Approximately three-quarters of people with diabetes live in low- and middle-income countries, and these countries are projected to experience the greatest increase in diabetes burden.

OBJECTIVES

We sought to compare the prevalence, awareness, treatment, and control of diabetes in 3 urban and periurban regions: the Southern Cone of Latin America and Peru, South Asia, and South Africa. In addition, we examined the relationship between diabetes and pre-diabetes with known cardiovascular and metabolic risk factors.

METHODS

A total of 26,680 participants (mean age, 47.7 ± 14.0 years; 45.9% male) were enrolled in 4 sites (Southern Cone of Latin America = 7,524; Peru = 3,601; South Asia = 11,907; South Africa = 1,099). Detailed demographic, anthropometric, and biochemical data were collected. Diabetes and pre-diabetes were defined as a fasting plasma glucose ≥126 mg/dl and 100 to 125 mg/dl, respectively. Diabetes control was defined as fasting plasma glucose <130 mg/dl.

RESULTS

The prevalence of diabetes and pre-diabetes was 14.0% (95% confidence interval [CI]: 13.2% to 14.8%) and 17.8% (95% CI: 17.0% to 18.7%) in the Southern Cone of Latin America, 9.8% (95% CI: 8.8% to 10.9%) and 17.1% (95% CI: 15.9% to 18.5%) in Peru, 19.0% (95% CI: 18.4% to 19.8%) and 24.0% (95% CI: 23.2% to 24.7%) in South Asia, and 13.8% (95% CI: 11.9% to 16.0%) and 9.9% (95% CI: 8.3% to 11.8%) in South Africa. The age- and sex-specific prevalence of diabetes and pre-diabetes for all countries increased with age (p < 0.001). In the Southern Cone of Latin America, Peru, and South Africa the prevalence of pre-diabetes rose sharply at 35 to 44 years. In South Asia, the sharpest rise in pre-diabetes prevalence occurred younger at 25 to 34 years. The prevalence of diabetes rose sharply at 45 to 54 years in the Southern Cone of Latin America, Peru, and South Africa, and at 35 to 44 years in South Asia. Diabetes and pre-diabetes prevalence increased with body mass index. South Asians had the highest prevalence of diabetes and pre-diabetes for any body mass index and normal-weight South Asians had a higher prevalence of diabetes and pre-diabetes than overweight and obese individuals from other regions. Across all regions, only 79.8% of persons with diabetes were aware of their diagnosis, of these only 78.2% were receiving treatment, and only 36.6% were able to attain glycemic control.

CONCLUSIONS

The prevalence of diabetes and pre-diabetes is alarmingly high among urban and periurban populations in Latin America, South Asia, and South Africa. Even more alarming is the propensity for South Asians to develop diabetes and pre-diabetes at a younger age and lower body mass index compared with individuals from other low and middle income countries. It is concerning that one-fifth of all people with diabetes were unaware of their diagnosis and that only two-thirds of those under treatment were able to attain glycemic control. Health systems and policy makers must make concerted efforts to improve diabetes prevention, detection, and control to prevent long-term consequences.

Identification of urinary proteins potentially associated with diabetic kidney disease

Diabetic nephropathy (DN) is the most common cause of chronic kidney disease. Although several parameters are used to evaluate renal damage, in many instances, there is no pathological change until damage is already advanced. Mass spectrometry-based proteomics is a novel tool to identify newer diagnostic markers. To identify urinary proteins associated with renal complications in diabetes, we collected urine samples from 10 type 2 diabetes patients each with normoalbuminuria, micro- and macro-albuminuria and compared their urinary proteome with that of 10 healthy individuals. Urinary proteins were concentrated, depleted of albumin and five other abundant plasma proteins and in-gel trypsin digested after prefractionation on sodium dodecyl sulfate polyacrylamide gel electrophoresis. The peptides were analyzed using a nanoflow reverse phase liquid chromatography system coupled to linear trap quadrupole-Orbitrap mass spectrometer. We identified large number of proteins in each group, of which many were exclusively present in individual patient groups. A total of 53 proteins were common in all patients but were absent in the controls. The majority of the proteins were functionally binding, biologically involved in metabolic processes, and showed enrichment of alternative complement and blood coagulation pathways. In addition to identifying reported proteins such as α2-HS-glycoprotein and Vitamin D binding protein, we detected novel proteins such as CD59, extracellular matrix protein 1 (ECM1), factor H, and myoglobin in the urine of macroalbuminuria patients. ECM1 and factor H are known to influence mesangial cell proliferation, and CD59 causes microvascular damage by influencing membrane attack complex deposition, suggestive their biological relevance to DN. Thus, we have developed a proteome database where various proteins exclusively present in the patients may be further investigated for their role as stage-specific markers and possible therapeutic targets.

Treatment with Sildenafil Improves Insulin Sensitivity in Prediabetes: A Randomized, Controlled Trial

CONTEXT

Sildenafil increases insulin sensitivity in mice. In humans, phosphodiesterase 5 inhibition improves disposition index, but the mechanism of this effect has not been elucidated and may depend on duration. In addition, increasing cyclic GMP without increasing nitric oxide could have beneficial effects on fibrinolytic balance.

OBJECTIVE

The objective was to test the hypothesis that chronic phosphodiesterase 5 inhibition with sildenafil improves insulin sensitivity and secretion without diminishing fibrinolytic function.

DESIGN

This was a randomized, double-blind, placebo-controlled study.

SETTING

This trial was conducted at Vanderbilt Clinical Research Center.

PARTICIPANTS

Participants included overweight individuals with prediabetes.

INTERVENTIONS

Subjects were randomized to treatment with sildenafil 25 mg three times a day or matching placebo for 3 months. Subjects underwent a hyperglycemic clamp prior to and at the end of treatment.

MAIN OUTCOME MEASURES

The primary outcomes of the study were insulin sensitivity and glucose-stimulated insulin secretion.

RESULT

Twenty-one subjects completed each treatment arm. After 3 months, the insulin sensitivity index was significantly greater in the sildenafil group compared to the placebo group by 1.84 mg/kg/min per μU/mL*100 (95% confidence interval, 0.01 to 3.67 mg/kg/min per μU/mL*100; P = .049), after adjusting for baseline insulin sensitivity index and body mass index. In contrast, there was no effect of 3-month treatment with sildenafil on acute- or late-phase glucose-stimulated insulin secretion (P > .30). Sildenafil decreased plasminogen activator inhibitor-1 (P = .01), without altering tissue-plasminogen activator. In contrast to placebo, sildenafil also decreased the urine albumin-to-creatinine ratio from 12.67 ± 14.67 to 6.84 ± 4.86 μg/mg Cr. This effect persisted 3 months after sildenafil discontinuation.

CONCLUSIONS

Three-month phosphodiesterase 5 inhibition enhances insulin sensitivity and improves markers of endothelial function.

Urinary albumin excretion within the normal range predicts the development of diabetes in Korean men

AIMS

Urine albumin creatinine ratio (UACR) is a reliable index of urinary albumin excretion. Elevated UACR is known to be associated with increased risk for diabetes complications. However there is only limited information about the predictability of UACR within normal range for diabetes. Therefore, this study was designed to investigate the association between UACR within the normal range and the development of diabetes.

METHODS

The 1410 non-diabetic Korean men with UACR within the normal range were identified in 2005 and followed-up until 2010. All subjects were classified into four categories according to their baseline level of UACR, from the lowest to the highest quartile. Cox proportional hazards analysis was used to evaluate the independent hazard ratios (HRs) for diabetes according to the UACR levels of their quartile group.

RESULTS

During follow-up, diabetes developed in 114 out of 1410 subjects (8.1%), and incidence of diabetes increased in proportion to the level of UACR (quartile 1; 4.5%, quartile 2; 7.9%, quartile 3: 8.8%, quartile 4: 11.1%, p = 0.002). The subjects with incident diabetes had a higher UACR than those without incident diabetes (6.6 ± 5.5 μg/mg v 5.3 ± 4.2 μg/mg, p=0.013). When quartile 1 was considered as the reference, HRs (95% confidential interval) for diabetes was higher in quartile 2 (1.04; 0.45-2.38), quartile 3 (1.09; 0.47-2.52) and quartile 4 (2.16; 1.02-4.57), even after adjusting for other potential confounders.

CONCLUSIONS

Elevated UACR, even within the normal range, could predict the future development of diabetes.

A Family History of Diabetes Modifies the Association between Elevated Urine Albumin Concentration and Hyperglycemia in Nondiabetic Mexican Adolescents

We examined the frequency of elevated urine albumin concentration (UAC) and its association with metabolic syndrome (MetS) and metabolic markers in 515 nondiabetic Mexican adolescents stratified by family history of diabetes (FHD). UAC was measured in a first morning urine sample and considered elevated when excretion was ≥20 mg/mL. MetS was defined using International Diabetes Federation criteria. Fasting insulin, insulin resistance, and lipids were evaluated. Multivariate logistic regression was performed. Elevated UAC was present in 12.4% and MetS was present in 8.9% of the adolescents. No association was found between elevated UAC and MetS. Among adolescents with FHD, 18.4% were overweight and 20.7% were obese, whereas, among those without a FHD, 15.9% were overweight and 7.5% were obese. Hyperglycemia was higher in those with elevated UAC than in those without (44.4% versus 5.1%, p = 0.003). Hyperglycemia (OR = 9.8, 95% CI 1.6-59.4) and number of MetS components (OR = 4.5, 95% CI 1.5-13.3) were independently associated with elevated UAC. Among female participants, abdominal obesity was associated with elevated UAC (OR = 4.5, 95% CI 1.2-16.9). Conclusion. Elevated UAC was associated neither with MetS nor with any metabolic markers in nondiabetic adolescents. However, FHD modified the association of elevated UAC with hyperglycemia and the number of MetS components.

Prediabetes is not independently associated with microalbuminuria in Korean general population: the Korea National Health and Nutrition Examination Survey 2011-2012 (KNHANES V-2,3)

We investigated the association between microalbuminuria and prediabetes in Korean population using data from the KNHANES 2011-2012. Prevalence of microalbuminuria was significantly increased in prediabetes group. However, the odds ratio became insignificant after adjustment for blood pressure, and the prevalence of microalbuminuria was not increased in prediabetic subjects without hypertension.

A disease modification effect of APOE E4 on the association between urinary albumin excretion and cognition in Korean adults

Background. No previous study examined a disease modifying effect of APOE E4 status on the association between the urinary albumin-to-creatinine ratio (UACR) and cognition. This study aimed to investigate whether APOE E4 modified the association in Korean adults. Methods. We performed a cross-sectional study in adults aged 45 to 74 who were living in Namwon City, Republic of Korea. Cognitive function was measured with the Korean version of modified Mini-Mental State Examination (K-mMMSE) and cognitive impairment was defined as scores falling below the 25th percentile of the K-mMMSE according to age, sex, and educational attainments. Results. A total of 10,190 participants (4006 men and 6184 women) were analyzed in the present study. Of these, 1698 subjects (16.7%) were APOE E4 carriers. The UACR values were negatively associated with the K-mMMSE scores, even after adjusting for potential confounders including age, sex, education, and vascular risk factors. APOE E4 modified the association significantly, resulting in a steeper decline of cognitive function with the increase in UACR in E4 carriers (P for interaction = 0.021). Conclusion. Higher UACR values were significantly associated with cognitive dysfunction in the general Korean population, with cognition in APOE E4 carriers being more severely affected by increased UACR.

Urine albumin-creatinine ratio in women with gestational diabetes: its link with glycaemic status

BACKGROUND

Micro-albuminuria has been established as a marker for micro-vascular disease. Spot urine albumin-to-creatinine ratio (UACR), even in the high normal range, predicts future cardiovascular events. The value of UACR in women with gestational diabetes mellitus (GDM) during pregnancy is uncertain.

AIM

The objectives of this study were to assess the associations between UACR (performed at the time of GDM diagnosis) and various maternal parameters and to evaluate its correlation with pregnancy outcomes.

MATERIALS AND METHODS

We conducted a retrospective review of women with GDM who attended antenatal clinics at a single centre between March 2010 and September 2013.

RESULTS

Among 1015 women included in this study, high UACR levels were associated with advancing maternal age, maternal obesity, gestational hypertension, elevated glycosylated haemoglobin (HbA1c) and high fasting glucose level. After adjustments for various maternal factors, only advancing age, HbA1c and fasting glucose level were associated with UACR. In terms of pregnancy outcomes, elevated UACR was not associated with adverse events, but was a predictor for pre-eclampsia.

CONCLUSIONS

The finding that UACR was associated with glycaemic status in women with GDM suggests early micro-vascular disease may be present in women who had greater degree of hyperglycaemia. This raises the question of whether women with GDM and elevated UACR may be at higher risk of developing cardiovascular disease in the future. Long-term follow-up of this subgroup of women would be worthwhile.

Urinary albumin : creatinine ratio predicts prediabetes progression to diabetes and reversal to normoglycemia: role of associated insulin resistance, inflammatory cytokines and low vitamin D

BACKGROUND

The relationship between albumin : creatinine ratio (ACR), insulin resistance (IR), cytokines, dyslipidemia, and 25-hydroxy vitamin D (25-OHD) in individuals with prediabetes (IPD) was investigated to evaluate their role in predicting future risk of progression to diabetes.

METHODS

The aforementioned parameters were evaluated in 147 IPD with persistent impaired fasting glucose and/or impaired glucose tolerance over two oral glucose tolerance tests, who were then followed up at 3-monthly intervals for progression to diabetes or reversal to normoglycemia.

RESULTS

Data were analyzed for 137 IPD with at least 1-year follow-up. Forty-three IPD reversed to normoglycemia (Group I), 69 continued with prediabetes (Group II), and 25 progressed to diabetes (Group III) over a mean follow-up period of 28.36 ± 8.19 months. Baseline fasting blood glucose levels (BGLs), 2-h post-glucose BGLs, and ACR were lowest in Group I and highest in Group III. Of the 137 IPD, 54.75% (n = 75) had microalbuminuria. The IPD in the lowest ACR quartile had the highest reversal to normoglycemia. Cox regression revealed that baseline IL-6 was predictive of progression to diabetes (P = 0.03) and ACR was an independent predictor of reversal to normoglycemia (P = 0.007). Kaplan-Meier analysis showed higher reversal to normoglycemia in IPD without microalbuminuria (P < 0.001).

CONCLUSION

An increased ACR is associated with higher creatinine, IR, and cytokine levels and lower 25-OHD levels in IPD. Microalbuminuria is associated with decreased reversal to normoglycemia and increased progression to diabetes. Low 25-OHD may be associated with increased progression to diabetes, perhaps via modulation of the ACR.

Novel Therapies of Diabetic Nephropathy

Diabetic nephropathy is currently the most common cause of end stage renal disease not only in the Western hemisphere but also in the developing nations. While the available therapeutic options remain not very effective, there is a strong ongoing effort to understand the pathogenesis better and develop more useful biomarkers. As the pathogenic mediators and signaling pathways get better defined, the scope of novel pharmaceutical agents to address such mediating factors as therapeutic targets is advancing. This review provides, in addition to a brief synopsis of currently used strategies, a comprehensive review of potential therapies that have been evolving in the past decade with a specific focus on the promising agents.

Subclinical hypothyroidism is independently associated with microalbuminuria in a cohort of prediabetic egyptian adults

BACKGROUND

Recent evidence has suggested an association between subclinical hypothyroidism (SCH) and microalbuminuria in patients with type 2 diabetes. However, whether SCH is related to microalbuminuria among subjects with prediabetes has not been studied. Thus, we evaluated the association between SCH and microalbuminuria in a cohort of prediabetic Egyptian adults.

METHODS

A total of 147 prediabetic subjects and 150 healthy controls matched for age and sex were enrolled in this study. Anthropometric measurements, plasma glucose, lipid profile, homeostasis model assessment of insulin resistance (HOMA-IR), thyroid stimulating hormone (TSH), free thyroxine, triiodothyronine levels, and urinary albumin-creatinine ratio (UACR) were assessed.

RESULTS

The prevalence of SCH and microalbuminuria in the prediabetic subjects was higher than that in the healthy controls (16.3% vs. 4%, P<0.001; and 12.9% vs. 5.3%, P=0.02, respectively). Prediabetic subjects with SCH were characterized by significantly higher HOMA-IR, TSH levels, UACR, and prevalence of microalbuminuria than those with euthyroidism. TSH level was associated with total cholesterol (P=0.05), fasting insulin (P=0.01), HOMA-IR (P=0.01), and UACR (P=0.005). UACR was associated with waist circumference (P=0.01), fasting insulin (P=0.05), and HOMA-IR (P=0.02). With multiple logistic regression analysis, SCH was associated with microalbuminuria independent of confounding variables (β=2.59; P=0.01).

CONCLUSION

Our findings suggest that prediabetic subjects with SCH demonstrate higher prevalence of microalbuminuria than their non-SCH counterparts. SCH is also independently associated with microalbuminuria in prediabetic subjects. Screening and treatment for SCH may be warranted in those patients.

High-normal albuminuria predicts metabolic syndrome in middle-aged Korean men: a prospective cohort study

OBJECTIVE

High-normal albuminuria has recently been associated with an elevated risk of cardiovascular disease. However, it is uncertain whether high-normal albuminuria is associated with metabolic syndrome (MetS). The objective of this prospective cohort study was to investigate whether a temporal relationship exists between a high-normal urine albumin-to-creatinine ratio (UACR) and the development of MetS.

STUDY DESIGN

A total of 4338 healthy Korean men who had their UACRs and MetS components assessed in 2005 were enrolled in the study. A MetS-free cohort of 1364 individuals, who did not have any conditions that would have excluded them from the study, was followed up until 2010.

MAIN OUTCOME MEASURE

MetS was defined according to the joint interim statement of the International Diabetes Federation Task Force on Epidemiology and Prevention.

RESULTS

Cox proportional hazards models were used to estimate the hazard ratio (HR) associated with normal UACR values stratified into following tertiles: <3.12 μg/mg, ≥3.12, <4.87 μg/mg, and ≥4.87 μg/mg. The UACR was categorised into the following tertiles. During 4470.6 person-years of follow-up, 247 incident cases of MetS developed between 2006 and 2010. The third UACR tertile was associated with the development of MetS after adjusting for multiple baseline covariates (HR 1.57; 95% confidence interval: 1.14-2.18).

CONCLUSIONS

On the basis of our 5-year follow-up study, a high-normal UACR predicts the development of MetS in Korean men.

Predictors of progression in albuminuria in the general population: results from the PREVEND cohort

Background

Urinary albumin excretion is known to be independently associated with progression of renal and cardiovascular disease. The aim of this study was to identify predictors for progression in albuminuria in the general population.

Methods

Data were used of the first 4 screening rounds of a community-based prospective cohort study (PREVEND). Included were 5,825 subjects that at baseline had no known renal disease or macroalbuminuria. Subjects were defined as having progressive albuminuria when they belonged to the quintile of subjects with highest absolute increase in urinary albumin excretion per year and a urinary albumin excretion during the last screening in which they participated of ≥150 mg/24 h. Change in urinary albumin excretion per year was calculated as last available urinary albumin excretion minus baseline UAE divided by follow-up time.

Results

During 9.3 years follow-up 132 subjects had progressive albuminuria. These subjects were significantly older, more often of male gender and had a worse cardiovascular risk profile. In a multivariable model, testing baseline values, significant predictors of progressive albuminuria were male gender (OR 2.23; p<0.001), age (OR 1.03; p<0.001), BMI (OR 1.06; p = 0.02) and baseline albuminuria (OR 5.71; p<0.001). Based on these findings a risk score was made to estimate a subject's risk for progressive albuminuria.

Conclusion

A high baseline albuminuria is by far the most important predictor of progressive albuminuria. Thus, screening for baseline albuminuria will be more important than screening for cardiovascular risk factors in order to identify subjects at risk for progressive albuminuria.

Microvascular dysfunction is associated with a higher incidence of type 2 diabetes mellitus: a systematic review and meta-analysis

OBJECTIVE

Recent data support the hypothesis that microvascular dysfunction may be a potential mechanism in the development of insulin resistance. We examined the association of microvascular dysfunction with incident type 2 diabetes mellitus (T2DM) and impaired glucose metabolism by reviewing the literature and conducting a meta-analysis of longitudinal studies on this topic.

METHODS AND RESULTS

We searched Medline and Embase for articles published up to October 2011. Prospective cohort studies that focused on microvascular measurements in participants free of T2DM at baseline were included. Pooled relative risks were calculated using random effects models. Thirteen studies met the inclusion criteria for this meta-analysis. These studies focused on T2DM or impaired fasting glucose, not on impaired glucose tolerance. The pooled relative risks for incident T2DM (3846 cases) was 1.25 (95% confidence interval, 1.15; 1.36) per 1 SD greater microvascular dysfunction when all estimates of microvascular dysfunction were combined. In analyses of single estimates of microvascular dysfunction, the pooled relative risks for incident T2DM was 1.49 (1.36; 1.64) per 1 SD higher plasma soluble E-selectin levels; 1.21(1.11; 1.31) per 1 SD higher plasma soluble intercellular adhesion molecule-1 levels; 1.48 (1.03; 2.12) per 1 SD lower response to acetylcholine-mediated peripheral vascular reactivity; 1.18 (1.08; 1.29) per 1 SD lower retinal arteriole-to-venule ratio; and 1.43 (1.33; 1.54) per 1 logarithmically transformed unit higher albumin-to-creatinine ratio. In addition, the pooled relative risks for incident impaired fasting glucose (409 cases) was 1.15 (1.01-1.31) per 1 SD greater retinal venular diameters.

CONCLUSIONS

These data indicate that various estimates of microvascular dysfunction were associated with incident T2DM and, possibly, impaired fasting glucose, suggesting a role for the microcirculation in the pathogenesis of T2DM.

Racial and ethnic differences in cardio-metabolic risk in individuals with undiagnosed diabetes: National Health and Nutrition Examination Survey 1999-2008

BACKGROUND

Although early recognition and treatment of diabetes may be essential to prevent complications, roughly one-fifth of diabetes remains undiagnosed.

OBJECTIVE

Examine cardio-metabolic risk factors and their control in non-Hispanic white (NHW), non-Hispanic black (NHB) and Mexican American (MA) individuals with undiagnosed diabetes.

DESIGN

Nationally representative cross-sectional study of participants in the National Health and Nutrition Examination Survey (NHANES) continuous cycles conducted 1999 through 2008.

PARTICIPANTS

Of 22,621 non-pregnant individuals aged ≥20 years, 2521 had diagnosed diabetes. Of the remaining 20,100 individuals, 17,963 had HbA1c measured, 551 of whom were classified as having undiagnosed diabetes and comprise the study population.

MAIN MEASURES

Undiagnosed diabetes was defined as HbA1c ≥ 6.5% without a self-report of physician diagnosed diabetes. Cardio-metabolic risk factor control was examined using regression methods for complex survey data.

KEY RESULTS

Among individuals with undiagnosed diabetes, mean HbA1c level was 7.7% (95% CI: 7.5, 7.9), 19.3% (95% CI: 14.2, 24.3) smoked, 59.7% (95% CI: 54.5, 64.8%) had hypertension and 96.5% (95% CI: 94.6, 98.4%) had dyslipidemia. Lipid profiles were remarkably different across racial-ethnic groups: NHB had the highest LDL- and HDL-cholesterol, but the lowest triglycerides, while MA had the highest triglycerides and the lowest LDL-cholesterol. After adjusting for age, sex, NHANES examination cycle and use of either blood pressure or lipid medication, the odds of having blood pressure ≥130/80 mmHg was higher in NHB [1.92 (95% CI: 1.09, 3.55)] than NHW, while the odds of having LDL-cholesterol >100 mg/dl was higher in NHW[2.93 (95% CI: 1.37, 6.24)] and NHB[3.34 (95% CI: 1.08, 10.3)] than MA.

CONCLUSIONS

In a nationally representative sample of individuals with undiagnosed diabetes, cardio-metabolic risk factor levels were high across all racial/ethnic groups, but NHB and MA had poorer control compared to NHW. Interventions that target identification of diabetes and treatment of cardio-metabolic risk factors are needed.

Prevalence, risk factors and awareness of albuminuria on a Canadian First Nation: a community-based screening study

BACKGROUND

Both diabetic and non-diabetic end stage renal disease (ESRD) are more common among Canadian First Nations people than among the general Canadian population. The purpose of this research was to determine the prevalence of and risk factors for albuminuria in a Canadian First Nation population at high risk for ESRD and dialysis.

METHODS

Data from a community-based screening study of 483 residents of a Plains Ojibway First Nation in Manitoba was used. Participants provided random urine samples. Proteinuria was defined as any dipstick positive for protein (≥1 g/L) or those with ACR in the macroalbuminuric range (≥30 mg/mmol) on at least one sample. Microalbuminuria was defined as ACR ≥2 mg/mmol for males and ≥2.8 mg/mmol for females. Other measures included fasting glucose, haemoglobin A1c, triglycerides, cholesterol, blood pressure, height, weight and waist and hip circumferences.

RESULTS

Twenty percent of study participants had albuminuria, (5% proteinuria and 15% microalbuminuria). Of participants with diabetes, 42% (56/132) had albuminuria compared to 26% (7/27) among those with impaired fasting glucose and 10% (30/303) among those with normal glucose tolerance. Only 5.3% of those with albuminuria were aware of any degree of renal disease. In a multivariate logistic regression, independent associations with albuminuria were male gender [p = 0.002], increasing fasting glucose [p <0.0001], years diagnosed with diabetes [p = 0.03], increasing systolic blood pressure [p = 0.009], and increasing body mass index (BMI) [p = 0.04].

CONCLUSIONS

The independent association between BMI and albuminuria has not been previously reported among indigenous populations. There is a high prevalence of albuminuria in this Canadian First Nation population; the high proportion of patients with diabetes and undiagnosed kidney disease demonstrates the need for screening, education and intervention to halt the progression and development of albuminuria and ultimately ESRD and CVD.

Do albuminuria and hs-CRP add to the International Diabetes Federation definition of the metabolic syndrome in predicting outcome?

BACKGROUND

To investigate the added value of elevated urinary albumin excretion (UAE) and high high-sensitive C-reactive protein (hs-CRP) in predicting new-onset type 2 diabetes mellitus (T2DM), cardiovascular disease (CVD) and chronic kidney disease (CKD) in addition to the present metabolic syndrome (MetS) defining criteria.

METHODS

The PREVEND Study is a prospective population-based cohort study in the Netherlands, including 8592 participants. The MetS was defined according to the 2004 International Diabetes Federation criteria, elevated UAE as albuminuria ≥ 30 mg/24 h and high hs-CRP as ≥ 3 mg/L.

RESULTS

At follow-up, subjects without MetS when compared to subjects with MetS had a lower incidence of T2DM, CVD as well as CKD (2.5 versus 15.5; 4.1 versus 10.3 and 5.8 versus 11.2%, all P < 0.001). In subjects with MetS, the incidence of all three outcomes was higher among subjects with elevated albuminuria versus subjects with normoalbuminuria (all P < 0.01). The incidence of all outcomes was also higher among subjects with high hs-CRP versus subjects without elevated hs-CRP but only significant for CKD (P = 0.002). Multivariate analysis including elevated UAE, hs-CRP and the variables defining the MetS showed that elevated albuminuria was independently associated with the risk for new-onset T2DM, CVD and CKD, whereas high hs-CRP was only independently associated with new-onset CVD and CKD.

CONCLUSION

Our data show that elevated UAE has added value to the present MetS defining variables in predicting new-onset T2DM, CVD and CKD, whereas hs-CRP adds to predicting new-onset CVD and CKD, but not T2DM.

HISS, not insulin, causes vasodilation in response to administered insulin

Meal-induced sensitization to the dynamic actions of insulin results from the peripheral actions of a hormone released by the liver (hepatic insulin sensitizing substance or HISS). Absence of meal-induced insulin sensitization results in the pathologies associated with cardiometabolic risk. Using three protocols that have previously demonstrated HISS metabolic action, we tested the hypothesis that HISS accounts for the vasodilation that has been associated with insulin. The dynamic metabolic actions of insulin and HISS were determined using a euglycemic clamp in response to a bolus of 100 mU/kg insulin in pentobarbital-anesthetized Sprague-Dawley rats. Hindlimb blood flow was measured with an ultrasound flow probe on the aorta above the bifurcation of the iliac arteries. Fed rats showed tightly coupled metabolic and vascular responses, which were completed by 35 min after insulin administration. Blocking HISS release, with the use of atropine or hepatic surgical denervation, eliminated the HISS-dependent metabolic and vascular responses to insulin administration. Physiological suppression of HISS release occurs with fasting. In 24-h fasted rats, HISS metabolic and vascular actions were absent, and atropine had no effect on either action. Fed rats with liver denervation did not release HISS, but intraportal venous infusion of acetylcholine, to mimic the permissive parasympathetic nerve signal, restored the ability of insulin to cause HISS release and restored both the metabolic and vascular actions. These studies report vascular actions of HISS for the first time and demonstrate that HISS, not insulin action, results in the peripheral vasodilation generally attributed to insulin.

Early microvascular complications of prediabetes in mice with impaired glucose tolerance and dyslipidemia

Microvascular complications are an important cause of morbidity in diabetic patients and can be detected in a significant number of patients at the time of diabetes diagnosis. However, little is known about the alterations in the microvasculature previous to the clinical manifestation of diabetes mellitus type 2. To obtain more insights into the early microvascular deterioration resulting from prediabetes, morphological and functional microvascular parameters were monitored using intravital fluorescence microscopy through a dorsal skin-fold chamber preparation in the uncoupling promotor-driven diphtheria toxin A chain (UCP1/DTA) mice. At the age of 12 weeks, the UCP1/DTA-mice were characterized by impaired glucose tolerance with concurrent unchanged fasting glucose, as well as dyslipidemia, hyperinsulinemia, hypertension and obesity. Prediabetic mice displayed combined hypertriglyceridemia and hypercholesterinemia. Associated with these prediabetic metabolic alterations, we demonstrate that microvascular density showed a dramatic decrease due to a reduction in perfused small vessels. A reduction in vascular density combined with unaltered blood flow in single vessels resulted in impaired tissue perfusion. Endothelial dysfunction with subsequently increased microvascular permeability and leukocyte-endothelium interactions were found. Our results of profound microvascular alterations at stages of normal fasting glucose underline the importance of early screening for prediabetes and associated microvascular complications.

Prediabetes: the importance of early identification and intervention

Prediabetes is a state of abnormal glucose homeostasis characterized by the presence of impaired fasting glucose, impaired glucose tolerance, or both. Individuals with prediabetes are at increased risk for type 2 diabetes, compared with individuals with normal glucose values (normal fasting plasma glucose, < 100 mg/dL [5.6 mmol/L]). The increased risk for cardiovascular disease in prediabetes is multifactorial, with etiologies including insulin resistance, hyperglycemia, dyslipidemia, hypertension, systemic inflammation, and oxidative stress. The preferred treatment is intensive lifestyle management and aggressive pharmacologic therapies directed toward individual coronary heart disease risk factors. The use of antihyperglycemic agents in this setting is a topic of intense debate. This review discusses the pathophysiology of prediabetes and its clinical implications, highlighting the importance of early identification and intervention.

Incidence rates and predictors of diabetes in those with prediabetes: the Strong Heart Study

BACKGROUND

The association between prediabetes as currently defined and incident diabetes in populations with widespread obesity, insulin resistance syndrome, and diabetes is not well defined. In this article, diabetes risk factors and incidence rates in American Indians (AI) with prediabetes are examined.

METHODS

A total of 1677 AI who were nondiabetic at baseline was examined during a median 7.8-year follow-up as part of the Strong Heart Study (SHS). Risk factors for incident diabetes were measured. Prediabetes was defined according to American Diabetes Association 2003 criteria as having impaired glucose tolerance (IGT) (2-h plasma glucose [2-h PG] >or= 140 mg/dL but < 200 mg/dL) and/or impaired fasting glucose (IFG) (fasting plasma glucose [FPG] >or= 100 mg/dL but < 126 mg/dL).

RESULTS

Prediabetes was identified by FPG alone in 87.5%. Diabetes incidence in those with baseline prediabetes was 66.1/1000 person-years, with a hazard ratio (HR) of 2.35 (95% conference interval: 1.84-3.01), compared with participants with normal glucose tolerance (NGT) at baseline. Elevated A(1c), 2-h PG, and fasting insulin (FI); albuminuria; and obesity were significantly associated with conversion from prediabetes to diabetes. Younger age, elevated FI (or body mass index [BMI] in models without FI), and less physical activity were significantly associated with conversion from NGT.

CONCLUSIONS

Prediabetes is an independent predictor of conversion to type 2 diabetes in AI, and most can be identified through a fasting glucose measure. Measures of obesity, A(1c), FPG, 2-h PG, FI, albuminuria, and insulin resistance (IR) help predict this conversion. Obesity is a modifiable risk factor. Strategies to reduce obesity should be emphasized in individuals with prediabetes.

Low serum creatinine is associated with type 2 diabetes in morbidly obese women and men: a cross-sectional study

BACKGROUND

Low skeletal muscle mass is associated with insulin resistance and metabolic syndrome. Serum creatinine may serve as a surrogate marker of muscle mass, and a possible relationship between low serum creatinine and type 2 diabetes has recently been demonstrated. We aimed to validate this finding in a population of Caucasian morbidly obese subjects.

METHODS

Cross-sectional study of 1,017 consecutive morbidly obese patients with an estimated glomerular filtration rate >60 ml/min/1.73 m2. Logistic regression (univariate and multiple) was used to assess the association between serum creatinine and prevalent type 2 diabetes, including statistically testing for the possibility of non-linearity in the relationship by implementation of Generalized Additive Models (GAM) and piecewise linear regression. Possible confounding variables such as age, family history of diabetes, waist-to-hip ratio, hypertension, current smoking, serum magnesium, albuminuria and insulin resistance (log HOMA-IR) were adjusted for in three separate multiple logistic regression models.

RESULTS

The unadjusted GAM analysis suggested a piecewise linear relationship between serum creatinine and diabetes. Each 1 mumol/l increase in serum creatinine was associated with 6% (95% CI; 3%-8%) and 7% (95% CI; 2%-13%) lower odds of diabetes below serum creatinine levels of 69 and 72 mumol/l in women and men, respectively. Above these breakpoints the serum creatinine concentrations did not reduce the odds further. Adjustments for non-modifiable and modifiable risk factors left the piecewise effect for both women and men largely unchanged. In the fully adjusted model, which includes serum magnesium, albuminuria and log HOMA-IR, the piecewise effect for men was statistically non-significant, but it remained present for women. Patients with creatinine levels below median had approximately 50% (women) and 75% (men) increased odds of diabetes.

CONCLUSIONS

Low serum creatinine is a predictor of type 2 diabetes in Caucasian morbidly obese patients, independent of age, gender, family history of diabetes, anthropometric measures, hypertension, and current smoking. Longitudinal studies of both obese and non-obese populations are needed to investigate whether serum creatinine may be causally linked with type 2 diabetes, and if so, precisely how they are linked.

Overproduction of phosphoprotein enriched in diabetes (PED) induces mesangial expansion and upregulates protein kinase C-beta activity and TGF-beta1 expression

AIMS/HYPOTHESIS

Overproduction of phosphoprotein enriched in diabetes (PED, also known as phosphoprotein enriched in astrocytes-15 [PEA-15]) is a common feature of type 2 diabetes and impairs insulin action in cultured cells and in mice. Nevertheless, the potential role of PED in diabetic complications is still unknown.

METHODS

We studied the effect of PED overproduction and depletion on kidney function in animal and cellular models.

RESULTS

Transgenic mice overexpressing PED (PEDTg) featured age-dependent increases of plasma creatinine levels and urinary volume, accompanied by expansion of the mesangial area, compared with wild-type littermates. Serum and kidney levels of TGF-beta1 were also higher in 6- and 9-month-old PEDTg. Overexpression of PED in human kidney 2 cells significantly increased TGF-beta1 levels, SMAD family members (SMAD)2/3 phosphorylation and fibronectin production. Opposite results were obtained following genetic silencing of PED in human kidney 2 cells by antisense oligonucleotides. Inhibition of phospholipase D and protein kinase C-beta by 2-butanol and LY373196 respectively reduced TGF-beta1, SMAD2/3 phosphorylation and fibronectin production. Moreover, inhibition of TGF-beta1 receptor activity and SMAD2/3 production by SB431542 and antisense oligonucleotides respectively reduced fibronectin secretion by about 50%. TGF-beta1 circulating levels were significantly reduced in Ped knockout mice and positively correlated with PED content in peripheral blood leucocytes of type 2 diabetic patients.

CONCLUSIONS/INTERPRETATION

These data indicate that PED regulates fibronectin production via phospholipase D/protein kinase C-beta and TGF-beta1/SMAD pathways in kidney cells. Raised PED levels may therefore contribute to the abnormal accumulation of extracellular matrix and renal dysfunction in diabetes.

A1C predicts type 2 diabetes and impaired glucose tolerance in a population at risk: the community diabetes prevention project

AIMS

In a population at risk for type 2 diabetes (T2DM), we assessed early physical and metabolic markers that predict progression from normal to impaired glucose tolerance (IGT) and T2DM.

METHODS

A total of 388 individuals (22% male, age 46 + 11 years) at risk for T2DM were randomized to Standard (n = 182) or Intervention (n = 206) care and evaluated at baseline and 5 annual follow-up visits, including blood pressure, BMI, A1C, lipids, urine albumin/creatinine ratio, VO2max, fasting glucose, insulin and C-peptide. The Standard group received results of annual lab tests and quarterly newsletters, while the Intervention group received quarterly newsletters and detailed discussions of lab results, routine self-directed activities, semi-annual group meetings and monthly telephone calls for ongoing support.

RESULTS

Overall, 359 (93%) returned for at least one follow-up visit and 272 (70%) completed the final 5-year assessment. Return rates, changes in measures and incidence of IGT/T2DM were similar between groups. Low cardiorespiratory fitness (VO2max) was the most prevalent baseline abnormality. A1C and BMI were significant predictors of IGT/T2DM after controlling for other factors. The risk of IGT/T2DM within 5 years was 17.16 (95% CL: 6.169, 47.736) times greater for those with baseline A1C>=5.8% as compared to those <5.8% (p < 0.0001).

CONCLUSION

Baseline A1C>=5.8% was a significant predictor of IGT/T2DM within 5 years in a population at high risk for T2DM. A1C is routinely performed among patients with diabetes, however these data and other evidence suggest that it may also be a useful tool for risk assessment and screening.

Relationship between glycated haemoglobin and microvascular complications: is there a natural cut-off point for the diagnosis of diabetes?

AIMS/HYPOTHESIS

This study was designed to determine whether the relationship of glycated haemoglobin to diabetic microvascular complications shows any natural thresholds that could be useful in diagnosing diabetes.

METHODS

We examined a population-based sample of 3,190 Malay adults aged 40-80 years in Singapore. The microvascular outcomes of interest were: (1) any retinopathy, defined from fundus photographs; (2) mild retinopathy, defined as in (1); (3) moderate retinopathy, defined as in (1); (4) chronic kidney disease, defined from estimated glomerular filtration rate; (5) micro- or macroalbuminuria, defined from urinary albumin to creatinine ratio; and (6) peripheral neuropathy, defined from neurothesiometer or monofilament sensory testing.

RESULTS

Increasing HbA(1c) was associated with all microvascular complications. The optimal cut-off points for detecting mild and moderate retinopathy were 6.6% (87.0% sensitivity, 77.1% specificity and area under the receiver operating characteristics [ROC] curve 0.899) and 7.0% (82.9% sensitivity, 82.3% specificity and area under ROC curve 0.904). The prevalences of mild and moderate retinopathy were <1% below the optimal cut-off points. For other complications, the association with HbA(1c) was linear without evidence of a distinct threshold. Although ROC analysis for these other complications also suggested optimal cut-off points between 6.6% and 7.0%, the sensitivity at these cut-off points was considerably lower than for mild and moderate retinopathy, ranging from 31.8% to 66.5%.

CONCLUSIONS/INTERPRETATION

Higher levels of HbA(1c) were associated with microvascular complications. Our data support use of an HbA(1c) cut-off point of between 6.6 and 7.0% in diagnosing diabetes. Cut-off points in this range were best for the identification of individuals with mild and moderate retinopathy. Any retinopathy, chronic kidney disease, albuminuria and peripheral neuropathy are less well detected at these cut-off points.

Risk of type 2 diabetes among individuals with high and low glomerular filtration rates

AIMS/HYPOTHESIS

Metabolic abnormalities frequently develop prior to the diagnosis of type 2 diabetes and chronic kidney disease. However, it is not known whether GFR predicts the onset of type 2 diabetes.

METHODS

Incident diabetes was ascertained in the Insulin Resistance Atherosclerosis Study (IRAS) (n = 864; age 40-69 years; median follow-up 5.2 years [4.5-6.6 years]; 141 incident cases of diabetes). GFR was estimated by the Modification of Diet in Renal Disease equation. We assessed the relationship between GFR and incident diabetes by logistic regression analysis. Results were adjusted for age, sex, ethnicity, clinic location, BMI, systolic blood pressure, antihypertensive treatment, family history of diabetes, insulin sensitivity and secretion, albumin to creatinine ratio, and levels of triacylglycerols, HDL-cholesterol, plasminogen activator inhibitor-1, and fasting and 2 h glucose.

RESULTS

The relationship between GFR and incident diabetes was not linear. This relationship was statistically significant (p = 0.039) using a restricted cubic polynomial spline for GFR as a regression modelling strategy. Participants were stratified by GFR quintiles. Mean values for GFR from the first to the fifth quintile were 60.8, 71.6, 79.8, 88.2 and 109.0 ml min(-1) 1.73 m(-2). Relative to the fourth quintile, the odds ratios of incident diabetes for the first, second, third and fifth quintiles were 2.32 (95% CI 1.06-5.05), 1.76 (95% CI 0.80-3.88), 1.26 (95% CI 0.56-2.84) and 2.59 (95% CI 1.18-5.65), respectively.

CONCLUSIONS/INTERPRETATION

Individuals in the upper and lower ranges of GFR are at increased risk of future diabetes. GFR and type 2 diabetes may share common pathogenic mechanisms.

Value of urinary albumin-to-creatinine ratio as a predictor of type 2 diabetes in pre-diabetic individuals

OBJECTIVE

The albumin-to-creatinine ratio (ACR) reflects urinary albumin excretion and is increasingly being accepted as an important clinical outcome predictor. Because of the great public health need for a simple and inexpensive test to identify individuals at high risk for developing type 2 diabetes, it has been suggested that the ACR might serve this purpose. We therefore determined whether the ACR could predict incident diabetes in a well-characterized cohort of pre-diabetic Americans.

RESEARCH DESIGN AND METHODS

A total of 3,188 Diabetes Prevention Program (DPP) participants with a mean BMI of 34 kg/m(2) and elevated fasting glucose, impaired glucose tolerance, and baseline urinary albumin excretion measurements were followed for incident diabetes over a mean of 3.2 years.

RESULTS

Of the participants, 94% manifested ACR levels below the microalbuminuria range and 21% ultimately developed diabetes during follow-up. Quartiles of ACR (median [range] within quartiles: 1, 3.0 [0.7-3.7]; 2, 4.6 [3.7-5.5]; 3, 7.1 [5.5-9.7]; and 4, 16.5 [9.7-1,578]) were positively associated with age, markers of adiposity and insulin secretion and resistance, blood pressure, and use of antihypertensive agents with antiproteinuric effects and inversely related to male sex and serum creatinine. An elevated hazard rate for developing diabetes with doubling of ACR disappeared after adjustment for covariates. Within the DPP intervention groups (placebo, lifestyle, and metformin), we found no consistent trend in incident diabetes by quartile or decile of ACR.

CONCLUSIONS

An ACR at levels below the microalbuminuria range does not independently predict incident diabetes in adults at high risk of developing type 2 diabetes.

Prevention of heart failure: a scientific statement from the American Heart Association Councils on Epidemiology and Prevention, Clinical Cardiology, Cardiovascular Nursing, and High Blood Pressure Research; Quality of Care and Outcomes Research Interdisciplinary Working Group; and Functional Genomics and Translational Biology Interdisciplinary Working Group

The increase in heart failure (HF) rates throughout the developed and developing regions of the world poses enormous challenges for caregivers, researchers, and policymakers. Therefore, prevention of this global scourge deserves high priority. Identifying and preventing the well-recognized illnesses that lead to HF, including hypertension and coronary heart disease, should be paramount among the approaches to prevent HF. Aggressive implementation of evidence-based management of risk factors for coronary heart disease should be at the core of HF prevention strategies. Questions currently in need of attention include how to identify and treat patients with asymptomatic left ventricular systolic dysfunction (Stage B HF) and how to prevent its development. The relationship of chronic kidney disease to HF and control of chronic kidney disease in prevention of HF need further investigation. Currently, we have limited understanding of the pathophysiological basis of HF in patients with preserved left ventricular systolic function and management techniques to prevent it. New developments in the field of biomarker identification have opened possibilities for the early detection of individuals at risk for developing HF (Stage A HF). Patient groups meriting special interest include the elderly, women, and ethnic/racial minorities. Future research ought to focus on obtaining a much better knowledge of genetics and HF, especially both genetic risk factors for development of HF and genetic markers as tools to guide prevention. Lastly, a national awareness campaign should be created and implemented to increase public awareness of HF and the importance of its prevention. Heightened public awareness will provide a platform for advocacy to create national research programs and healthcare policies dedicated to the prevention of HF.

Prevalence and determinants of microalbuminuria among diabetic patients in the United Arab Emirates

BACKGROUND

Microalbuminuria (MA) represents the earliest clinical evidence of diabetic nephropathy and is a predictor of increased cardiovascular morbidity and mortality. The aim of this study was to determine the prevalence of MA among diabetic patients in the Al-Ain district of the United Arab Emirates (UAE).

METHODS

The study was part of a general cross-sectional survey carried out to assess the prevalence of diabetes mellitus (DM) complications in Al-Ain district, UAE and was the first to assess the prevalence of MA among diabetic patients. A sample of 513 diabetic patients with a mean age of 53 years (SD: +/- 13) was randomly selected during 2003/2004. All patients completed an interviewer-administered questionnaire and underwent medical assessment. First morning urine collections were obtained and were tested for clinical proteinuria using urine dipsticks and for MA using the single Micral-Test II strips.

RESULTS

MA was found in 61% (95% CI: 56.7-65.7) of the sample and the rate was significantly higher among males, positively related to body mass index (BMI), type 2 DM and presence of other DM complications such as diabetic retinopathy and neuropathy. Of the total sample population, 12.5% (95% CI: 8.1-14.1) had clinical proteinuria.

CONCLUSION

The prevalence rate of MA was considerably high ( 61%) among diabetic patients in the UAE. Therefore, regular screening for MA is recommended for all diabetic patients, as early treatment is critical for reducing cardiovascular risks and slowing the progression to late stages of diabetic nephropathy (overt proteinuria and end-stage renal disease).

Being overweight modifies the association between cardiovascular risk factors and microalbuminuria in adolescents

OBJECTIVE

The goal was to determine the association between cardiovascular risk factors and microalbuminuria in a nationally representative sample of adolescents and to determine whether being overweight modifies this association.

METHODS

We analyzed cross-sectional data from the National Health and Nutrition Examination Survey (1999-2004) for 2515 adolescents 12 to 19 years of age. Cardiovascular risk factors included abdominal obesity, impaired fasting glucose, diabetes mellitus, insulin resistance, high triglyceride levels, low high-density lipoprotein cholesterol levels, hypertension, smoking, and the metabolic syndrome. Microalbuminuria was defined as a urinary albumin/creatinine ratio of 30 to 299 mg/g in a random morning sample. Overweight was defined as BMI of > or = 95th percentile, according to the Centers for Disease Control and Prevention 2000 growth charts.

RESULTS

Microalbuminuria was present in 8.9% of adolescents. The prevalence of microalbuminuria was higher among nonoverweight adolescents than among overweight adolescents. The median albumin/creatinine ratio decreased with increasing BMI z scores. The association of microalbuminuria with cardiovascular risk factors differed according to BMI category. Among nonoverweight adolescents, microalbuminuria was not associated with any cardiovascular disease risk factor except for overt diabetes mellitus. Among overweight adolescents, however, microalbuminuria was associated with impaired fasting glucose, insulin resistance, hypertension, and smoking, as well as diabetes mellitus.

CONCLUSION

For the majority of adolescents, microalbuminuria is not associated with cardiovascular risk factors. Among overweight adolescents, however, microalbuminuria is associated with cardiovascular risk factors. The prognostic importance of microalbuminuria in overweight and nonoverweight adolescents with regard to future cardiovascular and renal disease needs to be defined in prospective studies conducted specifically in children.

An association of a variety of cardiovascular risk factors with low grade albuminuria in Korean men

BACKGROUND

Recent studies have challenged the original definition of microalbuminuria when used to assess the risk of coronary heart disease or death. However, no large study has been conducted on Asian subjects regarding this topic to date. Therefore, we investigated the relationship between albuminuria below 17 microg/mg and other cardiovascular risk factors in apparently healthy Korean men.

METHODS

We enrolled 2474 men with albuminuria below 17 microg/mg to participate in this study. We evaluated a variety of cardiovascular risk factors as well as the urine albumin creatinine ratio (UACR). The subjects were stratified into five groups by their UACR values and comparisons were made among the five groups.

RESULTS

The comparisons showed that the UACR was progressively higher in subjects with a larger waist circumference and BMI as well as higher values for: serum triglyceride, glucose, hsCRP, and the systolic BP, in addition to a higher prevalence of diabetes and metabolic syndrome. When we excluded subjects with hypertension and diabetes, the results were similar.

CONCLUSIONS

Our findings suggest that low grade albuminuria in Korean men was associated with a variety of cardiovascular risk factors, and this finding was unchanged when we excluded subjects with diabetes and hypertension. Further studies are warranted to evaluate the clinical implications of our findings.

Change in prevalence and 6-year incidence of diabetes and impaired fasting glucose in Korean subjects living in a rural area

AIMS

To determine the change in prevalence, incidence and risk factors associated with diabetes and impaired fasting glucose (IFG) in a rural Korean area.

METHODS

Initially a total of 1119 subjects (424 men and 695 women) aged 31-99 years were recruited in 1997. Baseline clinical data and various laboratory values were obtained. Six years later, we visited the same area and measured similar parameters in 814 subjects (316 men and 498 women) of which 558 were original participants and 256 subjects were new. Incidence and risk factors of diabetes were analyzed in 518 subjects. Diabetes and IFG were defined according to American Diabetes Association criteria.

RESULTS

Age- and sex-adjusted prevalence of diabetes in 1997 was 6.9%, increasing to 11.7% in 2003. The prevalence of IFG increased alarmingly from 21.9% in 1997 to 38.8% in 2003. The age- and sex-adjusted incidence rate of diabetes was 16.3 per 1000 person-years. Baseline fasting plasma glucose, 2h post-load glucose, abdominal circumference and urinary albumin excretion rate (UAER) acted as independent risk factors for diabetes in a multivariate logistic regression analysis.

CONCLUSIONS

The prevalence of diabetes and IFG increased markedly from 1997 to 2003, indicating the need for urgent preventive measures. Fasting and 2h post-load glucose, abdominal circumference and UAER independently predicted the development of diabetes in this rural Korean population.

Characterization of Diabetic Nephropathy by Urinary Proteomic Analysis: Identification of a Processed Ubiquitin Form as a Differentially Excreted Protein in Diabetic Nephropathy Patients

Background: Identification of markers for prediction of the clinical course of diabetic nephropathy remains a major challenge in disease management. We established a proteomics approach for identification of diabetic nephropathy-related biomarkers in urine.

Methods: We used SELDI-TOF mass spectrometry and SAX2 protein arrays to compare protein profiles from urine of 4 defined patient groups. Samples from patients with type 2 diabetes (DM; n = 45) without nephropathy and without microalbuminuria (DM-WNP), patients with DM with macro- or microalbuminuria (DM-NP; n = 38), patients with proteinuria due to nondiabetic renal disease (n = 34), and healthy controls (n = 45) were analyzed. Anionic exchange, reversed-phase fractionation, gel electrophoresis, and mass spectrometry were used to isolate and identify proteins with high discriminatory power.

Results: A protein with m/z 6188 (P &lt;0.0000004) was strongly released in the urine of healthy controls, patients with proteinuria due to nondiabetic disease, and DM-WNP in contrast to DM-NP patients. An m/z 14 766 protein (P &lt;0.00008) was selectively excreted in the urine of DM-NP patients, whereas the protein with m/z 11 774 (P &lt;0.000004) was significantly excreted by patients with proteinuria and DM-NP. The m/z 11 774 and m/z 14 766 mass peaks were identified as β2-microglobulin and UbA52, a ubiquitin ribosomal fusion protein, respectively. The protein with m/z 6188 was identified as a processed form of ubiquitin.

Conclusion: The release of high amounts of UbA52 in urine of DM-NP patients could serve as a diagnostic marker, whereas the lack of the short form of ubiquitin raises interesting questions about the pathophysiology.