Glomerular filtration rate, cardiorenal end points, and all-cause mortality in type 2 diabetic patients

Renal involvement and left ventricular hypertrophy are novel risk factors for morbidity and mortality in diabetes mellitus

Diabetes mellitus and its complications are major causes of morbidity and mortality. Traditionally hypertension and poor diabetic control have been considered to be major risk factors for the development of cardiac involvement. This review will examine two novel risk factors, namely renal involvement and left ventricular hypertrophy. Renal involvement is manifested by increased excretion of protein in the urine and/or decreasing renal function. Several large studies have shown that both these factors are significant risk factors for cardiac involvement and increased mortality both in diabetic and non-diabetic subjects. There is strong evidence to suggest an association between renal and cardiac involvement. Cardiac hypertrophy is an important risk factor for the development of cardiac involvement. It is generally assumed that ventricular hypertrophy is a result of hypertension. However, it has been shown to be associated with metabolic disorders such as central obesity, diabetes mellitus and hypercholesterolemia, even in the absence of hypertension. The prevalence of ventricular hypertrophy is increased in patients with diabetes mellitus, especially in the presence of renal involvement. Diabetic patients with renal involvement and cardiac hypertrophy have also been shown to have an increased risk for developing cardiac complications and having an increased mortality rate. Thus these two risk factors are important in the prognosis of the diabetic patient. Follow-up of the diabetic patient should include careful examination for the presence of proteinuria, reduced renal function and left ventricular hypertrophy in the hope that treatment of these factors may reduce morbidity and mortality.

Estimation of renal function in patients with diabetes

Diabetes is the leading cause of chronic kidney disease (CKD), which makes estimation of renal function crucial. Serum creatinine is not an ideal marker of glomerular filtration rate (GFR), which also depends on digestive absorption, and the production of creatinine in muscle and its tubular secretion. Formulas have been devised to estimate GFR from serum creatinine but, given the wide range of GFR, proteinuria, body mass index and specific influence of glycaemia on GFR, the uncertainty of these estimations is a particular concern for patients with diabetes. The most popular recommended formulas are the simple Cockcroft-Gault equation, which is inaccurate and biased, as it calculates clearance of creatinine in proportion to body weight, and the MDRD equation, which is more accurate, but systematically underestimates normal and high GFR, being established by a statistical analysis of results from renal-insufficient patients. This underestimation explains why the MDRD equation is repeatedly found to give a poor estimation of GFR in patients with recently diagnosed diabetes and is a poor tool for reflecting GFR decline when started from normal, as well as the source of unexpected results when applied to epidemiological studies with a 60mL/min/1.73m(2) threshold as the definition of CKD. The more recent creatinine-based formula, the Mayo Clinic Quadratic (MCQ) equation, and the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) improve such underestimation, as both were derived from populations that included subjects with normal renal function. Determination of cystatin C is also promising, but needs standardisation.

Recognition, pathogenesis, and treatment of different stages of nephropathy in patients with type 2 diabetes mellitus

Nephropathy is a common microvascular complication among patients with type 2 diabetes mellitus and a major cause of kidney failure. It is characterized by albuminuria (≥ 300 mg/d) and a reduced glomerular filtration rate and is often present at the time of diabetes diagnosis after the kidney has been exposed to chronic hyperglycemia during the prediabetic phase. A low glomerular filtration rate (<60 mL/min/1.73 m(2)) is also an independent risk factor for cardiovascular events and death. Detection of diabetic nephropathy during its initial stages provides the opportunity for early therapeutic interventions to prevent or delay the onset of complications and improve outcomes. An intensive and multifactorial management approach is needed that targets all risk determinants simultaneously. The strategy should comprise lifestyle modifications (smoking cessation, weight loss, increased physical activity, and dietary changes) coupled with therapeutic achievement of blood glucose, blood pressure, and lipid goals that are evidence-based. Prescribing decisions should take into account demographic factors, level of kidney impairment, adverse effects, risk of hypoglycemia, tolerability, and effects on other risk factors and comorbidities. Regular and comprehensive follow-up assessments with appropriate adjustment of the therapeutic regimen to maintain risk factor control is a vital component of care, including referral to specialists, when required.

Associations of intra-renal arterial resistance index with chronic kidney disease and carotid intima-media thickness in type 2 diabetes mellitus

Renal dysfunction can be evaluated by increased intra-renal arterial resistance index (RI). We evaluated 113 Chinese men with type 2 diabetes on their RI. Results suggest that RI is associated with chronic kidney disease and subclinical arteriosclerosis. RI may help monitoring the deterioration of intra-renal hemodynamics.

The Complexity of Vascular and Non-Vascular Complications of Diabetes: The Hong Kong Diabetes Registry

Diabetes is a complex disease characterized by chronic hyperglycemia and multiple phenotypes. In 1995, we used a doctor-nurse-clerk team and structured protocol to establish the Hong Kong Diabetes Registry in a quality improvement program. By 2009, we had accrued 2616 clinical events in 9588 Chinese type 2 diabetic patients with a follow-up duration of 6 years. The detailed phenotypes at enrollment and follow-up medications have allowed us to develop a series of risk equations to predict multiple endpoints with high sensitivity and specificity. In this prospective database, we were able to validate findings from clinical trials in real practice, confirm close links between cardiovascular and renal disease, and demonstrate the emerging importance of cancer as a leading cause of death. In addition to serving as a tool for risk stratification and quality assurance, ongoing data analysis of the registry also reveals secular changes in disease patterns and identifies unmet needs.

What can we learn from the recent blood glucose lowering megatrials?

In the past two decades, we have acquired an enormous amount of knowledge regarding the epidemiology, diagnosis, pathophysiology and treatment of type 2 diabetes and its comorbidities. In addition to the earlier landmark blood lipid and blood pressure lowering trials, the latest blood glucose lowering megatrials represent the zenith of this global effort to prevent and control diabetes, and its devastating consequences. Although many of these latter trials have yielded negative results and have shown the narrow risk-benefit ratio of intensive treatment in patients with advanced disease, the exceedingly low event rates in these high-risk patients who were carefully monitored and intensively managed made possible in these clinical trial settings have not been emphasized enough. The heterogeneity of the clinical outcomes in these studies further highlight the complexity of diabetes, which is more than managing a disease, but the multiple needs of a patient with multisystem dysfunction. In the final analysis, what transpires from these megatrials is the need to translate the key components of these studies, namely, protocol, team, documentation and monitoring, into our daily clinical practice to enable the care team to stratify risk, define needs, individualize therapy, monitor progress and reinforce compliance in order to achieve positive outcomes. (J Diabetes Invest, doi: 10.1111/j.2040-1124.2010.00063.x, 2010).

Estimated glomerular filtration rate and albuminuria are independent predictors of cardiovascular events and death in type 2 diabetes mellitus: the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study

AIMS/HYPOTHESIS

We investigated effects of renal function and albuminuria on cardiovascular outcomes in 9,795 low-risk patients with diabetes in the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study.

METHODS

Baseline and year 2 renal status were examined in relation to clinical and biochemical characteristics. Outcomes included total cardiovascular disease (CVD), cardiac and non-cardiac death over 5 years.

RESULTS

Lower estimated GFR (eGFR) vs eGFR ≥90 ml min⁻¹ 1.73 m⁻² was a risk factor for total CVD events: (HR [95% CI] 1.14 [1.01-1.29] for eGFR 60-89 ml min⁻¹ 1.73 m⁻²; 1.59 [1.28-1.98] for eGFR 30-59 ml min⁻¹ 1.73 m⁻²; p < 0.001; adjusted for other characteristics). Albuminuria increased CVD risk, with microalbuminuria and macroalbuminuria increasing total CVD (HR 1.25 [1.01-1.54] and 1.19 [0.76-1.85], respectively; p = 0.001 for trend) when eGFR ≥90 ml min⁻¹ 1.73 m⁻². CVD risk was further modified by renal status changes over the first 2 years. In multivariable analysis, 77% of the effect of eGFR and 81% of the effect of albumin:creatinine ratio were accounted for by other variables, principally low HDL-cholesterol and elevated blood pressure.

CONCLUSIONS/INTERPRETATION

Reduced eGFR and albuminuria are independent risk factors for cardiovascular events and mortality rates in a low-risk population of mainly European ancestry. While their independent contributions to CVD risk appear small when other risk factors are considered, they remain excellent surrogate markers in clinical practice because they capture risk related to a number of other characteristics. Therefore, both should be considered when assessing prognosis and treatment strategies in patients with diabetes, and both should be included in risk models.

Association of albuminuria and reduced estimated glomerular filtration rate with incident stroke and coronary artery disease in patients with type 2 diabetes

It is unclear whether albuminuria and reduced glomerular filtration rate (GFR) independently increase the risk of incident stroke and coronary artery disease (CAD) in Japanese patients with diabetes. We investigated the independent effects of albuminuria and estimated GFR (eGFR) on the first occurrence of stroke and CAD in patients with type 2 diabetes mellitus (T2DM). We studied 1002 T2DM patients with eGFR (ml min⁻¹ per 1.73 m²) ≥15 and had no previous cardiovascular disease (CVD) history. GFR was estimated using the modified three-variable equation for the Japanese. Patients were divided into four eGFR categories: ≥90, 60-89, 30-59 and 15-29. The end point was an incident stroke and CAD events. The Cox proportional hazard model was used to calculate hazard ratio and 95% confidence interval. During a mean follow-up period of 5.2±2.1 years, 72 episodes of stroke and 90 of CAD were observed. Multivariate Cox analysis revealed no significant association between the eGFR category and incident stroke. The stroke hazard ratio (95% confidence interval) in reference to patients with an eGFR ≥90 was 0.78 (0.40-1.56) for patients with an eGFR of 60-89, 1.47 (0.70-3.10) for patients with an eGFR of 30-59 and 1.14 (0.39-3.35) for patients with an eGFR of 15-29. Reduced eGFR was a significant risk factor for CAD, with hazard ratios (95% confidence interval) for patients with an eGFRs of 60-89, 30-59 and 15-29 at 1.81 (1.01-3.57), 2.03 (1.04-4.40) and 3.01 (1.13-8.02), respectively. Reduced eGFR is independently associated with incident CAD but not stroke in Japanese patients with T2DM.

A prediction model for the risk of incident chronic kidney disease

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

National Kidney Foundation consensus conference on cardiovascular and kidney diseases and diabetes risk: an integrated therapeutic approach to reduce events

Cardiovascular disease (CVD) is the most common cause of death in industrialized nations. Type 2 diabetes is a CVD risk factor that confers risk similar to a previous myocardial infarction in an individual who does not have diabetes. In addition, the most common cause of chronic kidney disease (CKD) is diabetes. Together, diabetes and hypertension account for more than two-thirds of CVD risk, and other risk factors such as dyslipidemia contribute to the remainder of CVD risk. CKD, particularly with presence of significant albuminuria, should be considered an additional cardiovascular risk factor. There is no consensus on how to assess and stratify risk for patients with kidney disease across subspecialties that commonly treat such patients. This paper summarizes the results of a consensus conference utilizing a patient case to discuss the integrated management of hypertension, kidney disease, dyslipidemia, diabetes, and heart failure across disciplines.

Should targeting albuminuria be part of a cardiovascular risk reduction paradigm?

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in the United States as well as the rest of the world. Chronic kidney disease (CKD) is considered a CVD risk equivalent. The development of albuminuria has been identified as an additional possible risk marker that is almost unique to patients with CKD and a marker for predicting CVD risk. This review focuses on clinical and epidemiologic evidence regarding the role of albuminuria in the context of CVD development. It reviews the association of albuminuria with other comorbidities associated with increased cardiovascular risk and the modalities aimed at the reduction of albuminuria and maximizing of cardiovascular risk reduction.

Silent cerebral infarction is associated with the development and progression of nephropathy in patients with type 2 diabetes

Chronic kidney disease (CKD) is an important risk factor for cardiovascular disease in patients with diabetes. The relationship between renal manifestations of CKD (albuminuria and decreased glomerular filtration rate) and silent cerebral infarction (SCI) has attracted attention; however, most studies examined the effects of components of CKD on prevalence of SCI. We sought to assess the relationship between SCI and the development and progression of nephropathy in type 2 diabetic patients. We studied 366 type 2 diabetic patients with normoalbuminuria (urinary albumin-to-creatinine ratio [ACR] <30 mg g(-1), N=246) or microalbuminuria (ACR=30-299 mg g(-1), N=120). SCI was defined by cranial MRI. The primary end point was progression from normo- to microalbuminuria or from micro- to macroalbuminuria. The cumulative incidence of the primary end point was estimated using the Kaplan-Meier method. Risk estimates for reaching the end point were calculated using Cox proportional hazard model analyses. During a median follow-up period of 3.9 years, 23 normoalbuminuric and 24 microalbuminuric patients reached the primary end point. Patients with SCI (N=171) had a greater incidence of reaching the end point than those without SCI (N=195, P=0.020 by the log-rank test), with a hazard ratio of 2.02 (95% confidence interval=1.09-3.72, P=0.025) in the multivariate Cox regression model. Although the common pathogenesis of SCI and albuminuria in diabetic patients is still unclear, SCI may be a predictor of progression of nephropathy in type 2 diabetic patients.

Development and progression of renal insufficiency with and without albuminuria in adults with type 1 diabetes in the diabetes control and complications trial and the epidemiology of diabetes interventions and complications study

OBJECTIVE

This multicenter study examined the impact of albumin excretion rate (AER) on the course of estimated glomerular filtration rate (eGFR) and the incidence of sustained eGFR <60 ml/min/1.73 m(2) in type 1 diabetes up to year 14 of the Epidemiology of Diabetes Interventions and Complications (EDIC) study (mean duration of 19 years in the Diabetes Control and Complications Trial [DCCT]/EDIC).

RESEARCH DESIGN AND METHODS

Urinary albumin measurements from 4-h urine collections were obtained from participants annually during the DCCT and every other year during the EDIC study, and serum creatinine was measured annually in both the DCCT and EDIC study. GFR was estimated from serum creatinine using the abbreviated Modification of Diet in Renal Disease equation.

RESULTS

A total of 89 of 1,439 subjects developed an eGFR <60 ml/min/1.73 m(2) (stage 3 chronic kidney disease on two or more successive occasions (sustained) during the DCCT/EDIC study (cumulative incidence 11.4%). Of these, 20 (24%) had AER <30 mg/24 h at all prior evaluations, 14 (16%) had developed microalbuminuria (AER 30-300 mg/24 h) before they reached stage 3 chronic kidney disease, and 54 (61%) had macroalbuminuria (AER >300 mg/24 h) before they reached stage 3 chronic kidney disease. Macroalbuminuria is associated with a markedly increased rate of fall in eGFR (5.7%/year vs. 1.2%/year with AER <30 mg/24 h, P < 0.0001) and risk of eGFR <60 ml/min/1.73 m(2) (adjusted hazard ratio 15.3, P < 0.0001), whereas microalbuminuria had weaker and less consistent effects on eGFR.

CONCLUSIONS

Macroalbuminuria was a strong predictor of eGFR loss and risk of developing sustained eGFR <60 ml/min/1.73 m(2). However, screening with AER alone would have missed 24% of cases of sustained impaired eGFR.

Relationship between chronic kidney disease and silent cerebral infarction in patients with Type 2 diabetes

AIMS

Silent cerebral infarction (SCI) is an independent risk factor for future symptomatic stroke. Although the prevalence of SCI is closely related to kidney function in non-diabetic individuals, evidence is lacking whether albuminuria and/or reduced estimated glomerular filtration rate (eGFR) independently increase the risk of SCI in diabetic patients. We therefore examined the relationships between albuminuria, eGFR and SCI in patients with Type 2 diabetes mellitus (T2DM).

METHODS

We studied 786 T2DM patients with an eGFR > or = 15 ml/min 1.73/m(2), including 337 women and 449 men [mean (+/- sd), age 65 +/- 11 years]. All patients underwent cranial magnetic resonance imaging (MRI) to detect SCI. GFR was estimated using the modified three-variable equation for Japanese subjects. Albuminuria was defined as a first morning urinary albumin-to-creatinine ratio (ACR) > or = 30 mg/g.

RESULTS

SCI was detected in 415 (52.8%) of the subjects. The prevalence of SCI was significantly associated with both elevated ACR and decreased eGFR in univariate analysis. In multivariate logistic regression analysis, urinary ACR remained independently associated with SCI after adjusting for conventional cardiovascular risk factors [odds ratio (OR) of urinary ACR per logarithmical value: 1.89, 95% confidence interval (CI) = 1.41-2.51, P < 0.001]; however, eGFR was no longer significantly associated with SCI (OR per ml/min 1.73/m(2) = 0.99, 95% CI = 0.98-1.00, P = 0.095).

CONCLUSION

In conclusion, albuminuria but not decreased eGFR may be an independent predictor of prevalent SCI in patients with T2DM.

High prevalence and diversity of kidney dysfunction in patients with type 2 diabetes mellitus and coronary artery disease: the BARI 2D baseline data

BACKGROUND

We describe baseline renal function and albumin excretion rate in patients enrolled in Bypass Angioplasty Revascularization Investigation 2 Diabetes, a randomized clinical trial comparing the impact of revascularization and medical therapy with medical therapy alone and deferred or no revascularization and the impact of glycemic control with either insulin-providing or insulin-sensitizing drugs, on 5-year mortality.

METHODS

Study participants had type 2 diabetes mellitus, documented coronary artery disease, and creatinine <2 mg/dL. Albuminuria status (albumin/creatinine ratio [ACR]) and estimated glomerular filtration rate (eGFR), using the abbreviated Modified Diet in Renal Disease equation, were determined at baseline. Univariate and multivariate relationships between baseline clinical characteristics and the presence of albuminuria and reduced eGFR rate were estimated.

RESULTS

Two thousand one hundred forty-six subjects were included in the analysis. Forty-three percent of the cohort had evidence of kidney dysfunction at baseline: 23% had an eGFR > or =60 mL/min/1.73 m with either microalbuminuria ( >30 ACR; 17%) or macroalbuminuria (>300 ACR; 6%). Twenty-one percent had a reduced eGFR <60 mL/min/1.73 m; 52% with reduced eGFR had no albuminuria; 28% had microalbuminuria, and 20% had macroalbuminuria. Race, smoking status, duration of diabetes, hypertension, hemoglobin A1c, triglycerides, vascular disease, abnormal ejection fraction, and reduced eGFR were associated with greater albuminuria. Age, sex, duration of diabetes, ACR, hemoglobin A1c, high density lipoprotein, and number of hypertensive medications were associated with reduced eGFR.

CONCLUSION

Kidney dysfunction is common in older patients with type 2 diabetes mellitus and coronary artery disease; Albuminuria was present in 33%. Reduced eGFR was present in 21%, and half the patients with reduced eGFR had no evidence of albuminuria.

Renal outcomes with different fixed-dose combination therapies in patients with hypertension at high risk for cardiovascular events (ACCOMPLISH): a prespecified secondary analysis of a randomised controlled trial

BACKGROUND

The Avoiding Cardiovascular Events through Combination Therapy in Patients Living with Systolic Hypertension (ACCOMPLISH) trial showed that initial antihypertensive therapy with benazepril plus amlodipine was superior to benazepril plus hydrochlorothiazide in reducing cardiovascular morbidity and mortality. We assessed the effects of these drug combinations on progression of chronic kidney disease.

METHODS

ACCOMPLISH was a double-blind, randomised trial undertaken in five countries (USA, Sweden, Norway, Denmark, and Finland). 11 506 patients with hypertension who were at high risk for cardiovascular events were randomly assigned via a central, telephone-based interactive voice response system in a 1:1 ratio to receive benazepril (20 mg) plus amlodipine (5 mg; n=5744) or benazepril (20 mg) plus hydrochlorothiazide (12.5 mg; n=5762), orally once daily. Drug doses were force-titrated for patients to attain recommended blood pressure goals. Progression of chronic kidney disease, a prespecified endpoint, was defined as doubling of serum creatinine concentration or end-stage renal disease (estimated glomerular filtration rate <15 mL/min/1.73 m(2) or need for dialysis). Analysis was by intention to treat (ITT). This trial is registered with ClinicalTrials.gov, number NCT00170950.

FINDINGS

The trial was terminated early (mean follow-up 2.9 years [SD 0.4]) because of superior efficacy of benazepril plus amlodipine compared with benazepril plus hydrochlorothiazide. At trial completion, vital status was not known for 143 (1%) patients who were lost to follow-up (benazepril plus amlodipine, n=70; benazepril plus hydrochlorothiazide, n=73). All randomised patients were included in the ITT analysis. There were 113 (2.0%) events of chronic kidney disease progression in the benazepril plus amlodipine group compared with 215 (3.7%) in the benazepril plus hydrochlorothiazide group (HR 0.52, 0.41-0.65, p<0.0001). The most frequent adverse event in patients with chronic kidney disease was peripheral oedema (benazepril plus amlodipine, 189 of 561, 33.7%; benazepril plus hydrochlorothiazide, 85 of 532, 16.0%). In patients with chronic kidney disease, angio-oedema was more frequent in the benazepril plus amlodipine group than in the benazepril plus hydrochlorothiazide group. In patients without chronic kidney disease, dizziness, hypokalaemia, and hypotension were more frequent in the benazepril plus hydrochlorothiazide group than in the benazepril plus amlodipine group.

INTERPRETATION

Initial antihypertensive treatment with benazepril plus amlodipine should be considered in preference to benazepril plus hydrochlorothiazide since it slows progression of nephropathy to a greater extent.

FUNDING

Novartis.

Cardiovascular and renal surrogate markers in the clinical management of hypertension

INTRODUCTION

Surrogate markers represent a significant contribution to early diagnosis, longitudinal prognoses, and outcome prediction in cases of hypertension. They often enable detection of disease and disease potential when the disease is still subclinical and are useful noninvasive tools for designing and evaluating therapeutic programs. Surrogate markers are increasingly employed as predictive endpoints for treatment.

METHODS

Key studies supporting the importance of surrogate markers as diagnostic and prognostic predictors of cardiovascular and renal clinical outcomes in hypertension, as well as what is known about the effects of renin-angiotensin-aldosterone system-blocking agents on these biomarkers were reviewed.

RESULTS

Clinical data supporting the use of surrogate markers for heart failure, such as brain natriuretic peptide (BNP) and N-terminal prohormone BNP; markers for renal function, such as urinary albumin to creatinine ratio (UACR), urinary albumin excretion rates (UAER), and creatinine, reflecting glomerular filtration; and markers of cardiac remodeling, such as left ventricular hypertrophy and calculations of left ventricular mass index (LVMI), were reviewed for their utility in improving prognosis and treatment efficacy. Finally, hypertension treatment with angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and potentially direct renin inhibitors can significantly improve outcomes predicted by surrogate markers.

CONCLUSIONS

BNP, UACR, UAER, and LVMI, among others, have been increasingly established as valid surrogate markers with significant value for hypertension prognosis and therapy. The benefits of using surrogate markers to gauge the effectiveness of hypertension therapy in reducing renal and cardiac complications can be seen in improved morbidity and mortality.

Effects of angiotensin II receptor blockers on diabetic nephropathy

Impaired kidney function increases the risk of cardiovascular morbidity and mortality. Coexistence of hypertension and type 2 diabetes increases the risk of kidney damage, hypertension being an independent risk factor for kidney disease progression. Angiotensin II, through its inflammatory, proliferative, and thrombotic effects, adversely affects renal perfusion and increases oxidative stress, thus playing a pivotal role in kidney disease progression. Angiotensin II receptor blockers (ARBs) and angiotensin-converting enzyme (ACE) inhibitors improve markers of kidney disease and slow kidney disease progression in diabetic and nondiabetic patients; this kidney protection may be in addition to their antihypertensive activity in those with advanced proteinuric nephropathy. Key beneficial effects of ARBs and ACE inhibitors throughout the kidney disease continuum are primarily explained by blood pressure lowering effects and partially by their direct blockade of angiotensin II. Recent studies have shown that telmisartan, an ARB with high lipophilicity and the longest half-life compared with other ARBs, provides benefits on markers of cardiovascular risk, that is, microalbuminuria and slowing of early-stage nephropathy.

Cystatin C, albuminuria, and mortality among older adults with diabetes

OBJECTIVE

Albuminuria and impaired glomerular filtration rate (GFR) are each associated with poor health outcomes among individuals with diabetes. Joint associations of albuminuria and impaired GFR with mortality have not been comprehensively evaluated in this population.

RESEARCH DESIGN AND METHODS

This is a cohort study among Cardiovascular Health Study participants with diabetes, mean age 78 years. GFR was estimated using serum cystatin C and serum creatinine. Albumin-to-creatinine ratio (ACR) was measured in single-voided urine samples.

RESULTS

Of 691 participants, 378 died over 10 years of follow-up. Cystatin C-estimated GFR <60 ml/min per 1.73 m(2), creatinine-based estimated GFR <60 ml/min per 1.73 m(2), and urine ACR > or =30 mg/g were each associated with increased mortality risk with hazard ratios of 1.73 (95% CI 1.37-2.18), 1.54 (1.21-1.97), and 1.73 (1.39-2.17), respectively, adjusting for age, sex, race, diabetes duration, hypoglycemic medications, hypertension, BMI, smoking, cholesterol, lipid-lowering medications, prevalent cardiovascular disease (CVD), and prevalent heart failure. Cystatin C-estimated GFR and urine ACR were additive in terms of mortality risk. Cystatin C-estimated GFR predicted mortality more strongly than creatinine-based estimated GFR.

CONCLUSIONS

Albuminuria and impaired GFR were independent, additive risk factors for mortality among older adults with diabetes. These findings support current recommendations to regularly assess both albuminuria and GFR in the clinical care of patients with diabetes; a focus on interventions to prevent or treat CVD in the presence of albuminuria, impaired GFR, or both; and further consideration of cystatin C use in clinical care.

Integrating albuminuria and GFR in the assessment of diabetic nephropathy

The evaluation of diabetic nephropathy from research and clinical viewpoints depends on the assessment of two continuous variables, albumin excretion rate (AER) and glomerular filtration rate (GFR). These two parameters form the basis of both the European classification of five stages of diabetic nephropathy, assessed according to changes in AER and GFR (hyperfiltration, normoalbuminuria, microalbuminuria, macroalbuminuria and end-stage renal disease), and the National Kidney Foundation classification of five stages of chronic kidney disease based on categories of estimated GFR. Although increases in AER generally precede a decline in GFR, some patients follow a non-albuminuric pathway to renal impairment. In addition, studies indicate that GFR decreases in a linear fashion from normal or above-normal levels. Whether hyperfiltration is part of the pathogenetic process leading to diabetic nephropathy remains unclear. Ideally, both AER and GFR should be assessed at an early stage in patients being evaluated for diabetic nephropathy. New methods such as the use of cystatin-C-based equations for estimating GFR should be considered because current creatinine-based estimates are inaccurate at normal or high GFRs. Serial assessments of both AER and GFR might allow diabetic nephropathy to be diagnosed at early stages of the disease process that are selectively responsive to new interventions. The successful integration of AER categories with the recently defined stages of GFR represents a new challenge in the management of diabetic nephropathy.

Nonalbuminuric renal impairment in type 2 diabetic patients and in the general population (national evaluation of the frequency of renal impairment cO-existing with NIDDM [NEFRON] 11)

OBJECTIVE Most diabetic patients with impaired renal function have a urinary albumin excretion rate in the normal range. In these patients, the etiology of renal impairment is unclear, and it is also unclear whether this nonalbumunuric renal impairment is unique to diabetes. RESEARCH DESIGN AND METHODS In this study, we examined the frequency and predictors of nonalbumunuric renal impairment (estimated glomerular filtration rate [eGFR] <60 ml/min per 1.73 m(2)) in a nationally representative cohort of 3,893 patients with type 2 diabetes and compared our findings with rates observed in the general population from the Australian Diabetes, Obesity and Lifestyle Study (AusDiab) survey (n = 11,247). RESULTS Of the 23.1% of individuals with type 2 diabetes who had eGFR <60 ml/min per 1.73 m(2) (95% CI 21.8-24.5%), more than half (55%) had a urinary albumin excretion rate that was persistently in the normal range. This rate of renal impairment was predictably higher than that observed in the general population (adjusted odds ratio 1.3, 95% CI 1.1-1.5, P < 0.01) but was solely due to chronic kidney disease associated with albuminuria. In contrast, renal impairment in the absence of albuminuria was less common in those with diabetes than in the general population, independent of sex, ethnicity, and duration of diabetes (0.6, 0.5-0.7, P < 0.001). CONCLUSIONS Nonalbuminuric renal impairment is not more common in those with diabetes. However, its impact may be more significant. New studies are required to address the pathogenesis, prevention, and treatment of nonalbuminuric renal disease.

Effects of structured versus usual care on renal endpoint in type 2 diabetes: the SURE study: a randomized multicenter translational study

OBJECTIVE

Multifaceted care has been shown to reduce mortality and complications in type 2 diabetes. We hypothesized that structured care would reduce renal complications in type 2 diabetes.

RESEARCH DESIGN AND METHODS

A total of 205 Chinese type 2 diabetic patients from nine public hospitals who had plasma creatinine levels of 150-350 micromol/l were randomly assigned to receive structured care (n = 104) or usual care (n = 101) for 2 years. The structured care group was managed according to a prespecified protocol with the following treatment goals: blood pressure <130/80 mmHg, A1C <7%, LDL cholesterol <2.6 mmol/l, triglyceride <2 mmol/l, and persistent treatment with renin-angiotensin blockers. The primary end point was death and/or renal end point (creatinine >500 micromol/l or dialysis).

RESULTS

Of these 205 patients (mean +/- SD age 65 +/- 7.2 years; disease duration 14 +/- 7.9 years), the structured care group achieved better control than the usual care group (diastolic blood pressure 68 +/- 12 vs. 71 +/- 12 mmHg, respectively, P = 0.02; A1C 7.3 +/- 1.3 vs. 8.0 +/- 1.6%, P < 0.01). After adjustment for age, sex, and study sites, the structured care (23.1%, n = 24) and usual care (23.8%, n = 24; NS) groups had similar end points, but more patients in the structured care group attained >or=3 treatment goals (61%, n = 63, vs. 28%, n = 28; P < 0.001). Patients who attained >or=3 treatment targets (n = 91) had reduced risk of the primary end point (14 vs. 34; relative risk 0.43 [95% CI 0.21-0.86] compared with that of those who attained <or=2 targets (n = 114).

CONCLUSIONS

Attainment of multiple treatment targets reduced the renal end point and death in type 2 diabetes. In addition to protocol, audits and feedback are needed to improve outcomes.

Effect of interactions between C peptide levels and insulin treatment on clinical outcomes among patients with type 2 diabetes mellitus

BACKGROUND

A recently halted clinical trial showed that intensive treatment of type 2 diabetes mellitus was associated with increased mortality. Given the phenotypic heterogeneity of diabetes, therapy targeted at insulin status may maximize benefits and minimize harm.

METHODS

In this longitudinal cohort study, we followed 503 patients with type 2 diabetes who were free of cardiovascular disease from 1996 until data on mortality and cardiovascular outcomes were censored in 2005. Phenotype-targeted therapy was defined as use of insulin therapy in patients with a fasting plasma C peptide level of 0.2 nmol/L or less and no insulin therapy in patients with higher C peptide levels.

RESULTS

The mean age of the cohort was 54.4 (standard deviation 13.1) years, and 56% were women. The mean duration of diabetes was 4.6 years (range 0-35.9 years). Of the 503 patients, 110 (21.9%) had a low C peptide level and 111 (22.1%) were given insulin. Based on their C peptide status, 338 patients (67.2%) received phenotype-targeted therapy (non-insulin-treated, high C peptide level [n = 310] or insulin-treated, low C peptide level [n = 28]), and 165 patients (32.8%) received non-phenotype-targeted therapy (non-insulin-treated, low C peptide level [n = 82] or insulin-treated, high C peptide level [n = 83]). Compared with the insulin-treated, low-C-peptide referent group, the insulin-treated, high-C-peptide group was at a significantly higher risk of cardiovascular events (hazard ratio [HR] 2.85, p = 0.049) and death (HR 3.43, p = 0.043); the risk was not significantly higher in the other 2 groups. These differences were no longer significant after adjusting for age, sex and diabetes duration.

INTERPRETATION

Patients with low C peptide levels who received insulin had the best clinical outcomes. Patients with normal to high C peptide levels who received insulin had the worst clinical outcomes. The results suggest that phenotype-targeted insulin therapy may be important in treating diabetes.

The kidney, hypertension, and remaining challenges

There is an epidemic of chronic kidney disease in the Western world, with hypertension being the second most common cause. Blood pressure control rates, while improving, are still below 50% for the United States population. The following three challenges remain for the treatment of hypertension and associated prevention of end-stage kidney disease. First, a better understanding by the general medical community of how and in whom to use renin angiotensin aldosterone system blockers is needed. Second, the appropriate initiation of fixed-dose combination therapy to achieve blood-pressure goals needs to be clarified. Finally, the subgroup of patients with kidney disease needs more aggressive blood pressure lowering.

Is a reduced estimated glomerular filtration rate a risk factor for stroke in patients with type 2 diabetes?

Although chronic kidney disease is a risk factor for cardiovascular disease it is unclear whether diabetic patients with a reduced glomerular filtration rate (GFR), independent of (micro)albuminuria, carry an increased risk of stroke. We therefore investigated the independent effect of estimated GFR (eGFR) on stroke events in patients with type 2 diabetes mellitus (T2DM). We studied T2DM patients with an eGFR >or=15 ml min(-1) per 1.73 m(2), who had no history of stroke. Patients were divided into four categories by the eGFR at baseline for comparison: >or=90, 60-89, 30-59 and 15-29 ml min(-1) per 1.73 m(2). The end point was an incident stroke event. The Cox proportional hazard model was used to calculate the hazard ratio (HR) and 95% confidence interval (CI). The study included a total of 1300 T2DM patients (546 women and 754 men) with a mean (+/-s.d.) age of 63+/-13 years. During a mean follow-up period of 3.7+/-1.4 years, 91 patients experienced an incident stroke event. Although a lower eGFR was associated with an increased stroke risk using a univariate model, statistical significance disappeared after adjusting for other risk factors including albuminuria. The HR (95% CI) was 0.75 (0.40-1.41, P=0.373), 0.99 (0.50-1.95, P=0.964) and 0.91 (0.36-2.28, P=0.844) for patients with eGFRs of 60-89, 30-59 and 15-29 ml min(-1) per 1.73 m(2), respectively, compared with patients with an eGFR >or=90. Clinical albuminuria remained a significant risk factor for stroke, and the adjusted HR compared with normoalbuminuria was 2.40 (1.46-3.95, P=0.001). In conclusion, the association between reduced GFR and stroke events in patients with T2DM is likely to be mediated by albuminuria.

Poor glycemic control in diabetes and the risk of incident chronic kidney disease even in the absence of albuminuria and retinopathy: Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND

Diabetic nephropathy is the leading cause of kidney failure in the United States. The extent to which an elevated glycated hemoglobin (HbA(1c)) concentration is associated with increased risk of chronic kidney disease (CKD) in the absence of albuminuria and retinopathy, the hallmarks of diabetic nephropathy, is uncertain.

METHODS

Glycated hemoglobin concentration was measured in 1871 adults with diabetes mellitus followed up for 11 years in the Atherosclerosis Risk in Communities (ARIC) Study. Incident CKD was defined as an estimated glomerular filtration rate less than 60 mL/min/1.73 m(2) after 6 years of follow-up or a kidney disease-related hospitalization. We categorized HbA(1c) concentrations into 4 clinically relevant categories. Albuminuria and retinopathy were measured midway through follow-up.

RESULTS

Higher HbA(1c) concentrations were strongly associated with risk of CKD in models adjusted for demographic data, baseline glomerular filtration rate, and cardiovascular risk factors. Compared with HbA(1c) concentrations less than 6%, HbA(1c) concentrations of 6% to 7%, 7% to 8%, and greater than 8% were associated with adjusted relative hazard ratios (95% confidence intervals) of 1.4 (0.97-1.91), 2.5 (1.70-3.66), and 3.7 (2.76-4.90), respectively. Risk of CKD was higher in individuals with albuminuria and retinopathy, and the association between HbA(1c) concentration and incident CKD was observed even in participants without either abnormality: adjusted relative hazards, 1.46 (95% confidence intervals, 0.80-2.65), 1.17 (0.43-3.19), and 3.51 (1.67-7.40), respectively; P(trend) = .004.

CONCLUSIONS

We observed a positive association between HbA(1c) concentration and incident CKD that was strong, graded, independent of traditional risk factors, and present even in the absence of albuminuria and retinopathy. Hyperglycemia is an important indicator of risk of both diabetic nephropathy with albuminuria or retinopathy and of less specific forms of CKD.

ASH position paper: treatment of hypertension in patients with diabetes-an update

This report updates concepts on hypertension management in patients with diabetes. It focuses on clinical outcomes literature published within the last 3 years and incorporates these observations into modifications of established guidelines. While the fundamentals of treatment and goal blood pressures remain unchanged, approaches to specific patient-related issues has changed. This update focuses on questions such as what to do when a patient has an elevated potassium level when therapy is initiated and whether combinations of agents that block the renin-angiotensin system still be used. In addition, there are updates from trials, just published and in press, that focus on related management issues influencing cardiovascular outcomes in persons with diabetes. Last, an updated algorithm is provided that incorporates many of the new findings and is suggested as a starting point to achieve blood pressure goals.

Reduced GFR and microalbuminuria are independently associated with prevalent cardiovascular disease in Type 2 diabetes: JDDM study 16

AIMS

We investigated whether a reduced estimated glomerular filtration rate (eGFR) was associated with cardiovascular disease (CVD) prevalence, independent of the effect of microalbuminuria in patients with diabetes.

METHODS

In a multicentre, large-scale cohort including 3002 Japanese patients with Type 2 diabetes without macroalbuminuria, the relationship of a reduced eGFR and microalbuminuria with CVD was investigated.

RESULTS

Of those patients, 4.8% had a reduced eGFR and microalbuminuria, 12.7% had a reduced eGFR without microalbuminuria and 18.7% had microalbuminuria but normal eGFR. A reduced eGFR and microalbuminuria were each associated with a doubling of the prevalence of CVD. Compared with patients with no microalbuminuria/normal eGFR [odds ratio (OR) 1.0], the OR for CVD was significantly higher in those with a reduced eGFR without microalbuminuria (OR 1.97) and similarly higher in those with microalbuminuria without a reduced eGFR (OR 1.85). The OR was highest in those with both a reduced eGFR and microalbuminuria (OR 3.97, 95% confidence interval 2.55-6.20). The OR for CVD remained significant after adjustments for age, sex, hypertension, dyslipidaemia, smoking, body mass index, glycated haemoglobin and the duration of diabetes, and remained significant if the cut-off point for microalbuminuria was set at the median albumin : creatinine ratio (13.7 mg/g creatinine). In patients without microalbuminuria, a reduced eGFR was associated with CVD only in the older and male groups.

CONCLUSION

A reduced eGFR and the presence of microalbuminuria were each associated with a near doubling of the prevalence of CVD, independently of traditional CVD risk factors and glycaemic control in patients with Type 2 diabetes.

Metabolic syndrome predicts new onset of chronic kidney disease in 5,829 patients with type 2 diabetes: a 5-year prospective analysis of the Hong Kong Diabetes Registry

OBJECTIVE

Type 2 diabetes is the leading cause of end-stage renal disease worldwide. Aside from hyperglycemia and hypertension, other metabolic factors may determine renal outcome. We examined risk associations of metabolic syndrome with new onset of chronic kidney disease (CKD) in 5,829 Chinese patients with type 2 diabetes enrolled between 1995 and 2005.

RESEARCH DESIGN AND METHODS

Metabolic syndrome was defined by National Cholesterol Education Program Adult Treatment Panel III criteria with the Asian definition of obesity. Estimated glomerular filtration rate (eGFR) was calculated using the abbreviated Modification of Diet in Renal Disease formula modified for the Chinese population. New onset of CKD was defined as eGFR <60 ml/min per 1.73 m(2) at the time of censor. Subjects with CKD at baseline were excluded from the analysis.

RESULTS

After a median follow-up duration of 4.6 years (interquartile range: 1.9-7.3 years), 741 patients developed CKD. The multivariable-adjusted hazard ratio (HR) of CKD was 1.31 (95% CI 1.12-1.54, P = 0.001) for subjects with metabolic syndrome compared with those without metabolic syndrome. Relative to subjects with no other components of metabolic syndrome except for diabetes, those with two, three, four, and five metabolic syndrome components had HRs of an increased risk of CKD of 1.15 (0.83-1.60, P = 0.407) 1.32 (0.94-1.86, P = 0.112), 1.64 (1.17-2.32, P = 0.004), and 2.34 (1.54-3.54, P < 0.001), respectively. The metabolic syndrome traits of central obesity, hypertriglyceridemia, hypertension, and low BMI were independent predictors for CKD.

CONCLUSIONS

The presence of metabolic syndrome independently predicts the development of CKD in subjects with type 2 diabetes.

Diabetic nephropathy--what are the unmet needs?

In this pandemic of diabetes and obesity, Asia will have the highest number of affected people with the greatest increase in the young-to-middle aged group. Asian patients have increased risk for diabetic kidney disease which may be compounded by low grade infection, obesity and genetic factors. In these subjects, the onset of albuminuria and diabetic kidney disease causes further perturbation of metabolic milieu with increased oxidative stress, anaemia and vascular calcification which interact to markedly increase the risk of cardiovascular disease. Despite receiving optimal care to control blood pressure and metabolic risk factors as well as inhibition of the renin-angiotensin system in a clinical trial setting, there is a considerable residual risk for cardio-renal complications in patients with diabetic kidney disease. Control of obesity and low grade inflammation as well as correction of anaemia may represent areas where novel strategies can be developed and tested to curb this rising global burden of cardio-renal complications.

Aldose reductase genotypes and cardiorenal complications: an 8-year prospective analysis of 1,074 type 2 diabetic patients

OBJECTIVE

We report the independent risk association of type 2 diabetic nephropathy with the z-2 allele of the 5'-(CA)(n) microsatellite and C-106T promoter polymorphisms of the aldose reductase gene (ALR2) using a case-control design. In this expanded cohort, we examined their predictive roles on new onset of cardiorenal complications using a prospective design.

RESEARCH DESIGN AND METHODS

In this 8-year prospective cohort of 1,074 type 2 diabetic patients (59% male, median age 61 years; disease duration 7 years) with an observation period of 8,592 person-years, none had clinical evidence of coronary heart disease (CHD) or chronic kidney disease at recruitment. The renal end point was defined as new onset of estimated glomerular filtration rate <60 ml/min per 1.72 m(2) or hospitalizations with dialysis or death due to renal disease, and CHD was defined as hospitalizations with myocardial infarction, ischemic heart disease, or related deaths.

RESULTS

After controlling for baseline risk factors and use of medications, we found that the ALR2 z-2 allele of (CA)(n) microsatellite carriers had increased risk of renal (hazard ratio 1.53 [95% CI 1.14-2.05], P = 0.005) or combined cardiorenal (1.31 [1.01-1.72], P = 0.047) end points. Carriers of the ALR2 C-106T polymorphism also had increased risk of renal (1.54 [1.15-2.07], P = 0.004) and cardiorenal (1.49 [1.14-1.95], P = 0.004) end points. Compared with noncarriers, patients with two risk-conferring genotypes had a twofold increased risk of renal (2.41 [1.57-3.70], P < 0.001) and cardiorenal (1.94 [1.29-2.91], P = 0.002) end points.

CONCLUSIONS

In Chinese type 2 diabetic patients, genetic polymorphisms of ALR2 independently predicted new onset of renal and cardiorenal end points, with the latter being largely mediated through renal disease.

Coronary artery calcification, arterial stiffness and renal insufficiency associate with serum levels of tumor necrosis factor-alpha in Japanese type 2 diabetic patients

Although the kidneys are the major source of proinflammatory cytokines, association of tumor necrosis factor-alpha (TNF-alpha) with severity of atherosclerosis or kidney function in diabetic patients is unclear. Two hundred type 2 diabetic patients and 30 age-matched nondiabetic subjects consecutively admitted to our hospital were enrolled. The Agatston coronary artery calcium score (CACS), a quantitative marker of coronary atherosclerosis, was obtained using multidetector-row computed tomography. Arterial stiffness was assessed by brachial-ankle pulse wave velocity (baPWV). Diabetic patients had higher log(CACS+1) (p=0.0089), baPWV (p=0.0293), frequency of elevated urinary albumin excretion (UAE) (p<0.0001) and TNF-alpha (p=0.0029) and similar estimated glomerular filtration rate (eGFR) compared to nondiabetic subjects. When diabetic patients were grouped into four subgroups with or without elevated UAE and renal insufficiency (UAE of >/=30 or <30mg/24h and eGFR of <60 or >/=60ml/min per 1.73m(2)), patients with micro- and macroalbuminuric renal insufficiency showed the highest log(CACS+1) (p<0.0001), baPWV (p=0.0068) and TNF-alpha (p<0.0001) of these groups. Log(CACS+1) (p=0.0008) and baPWV (p=0.0006) positively and eGFR (p<0.0001) negatively correlated with TNF-alpha in diabetic patients. We find that coronary artery calcification, arterial stiffness, and renal insufficiency associate with circulating levels of TNF-alpha in type 2 diabetic patients.

Analysis of traditional and nontraditional risk factors for peripheral arterial disease in elderly type 2 diabetic patients in Taiwan

AIMS

Diagnosing peripheral arterial disease (PAD) and recognizing its associated risk factors in diabetes is important due to high cardiovascular disease and limb loss risk. However, both traditional and nontraditional risk factors have seldom been analyzed in the same diabetic cohort. The aim of this study was to examine the traditional and nontraditional risk factors for PAD in elderly type 2 diabetic patients.

METHODS

Five hundred and eighty type 2 diabetic subjects aged >or=60 years were cross-sectionally studied. Diagnosis of PAD was by ankle-brachial index (ABI) <0.90 on either leg. The association between traditional and nontraditional risk factors of PAD was analyzed.

RESULTS

Among the confounders, age, diabetes duration, HDL cholesterol, albuminuria, CKD (chronic kidney disease), hsCRP and insulin use differed between patients with and without PAD. Multiple logistic regression revealed that only CKD, insulin use, albuminuria, elevated hsCRP level (>3mg/l) and low HDL cholesterol were independent risk factors.

CONCLUSIONS

The findings of this study highlight the importance of monitoring nontraditional risk factors of PAD in diabetes. Implementing effective interventions to improve management of these risk factors may lower the risk for PAD.

Impaired peripheral circulation in lower-leg arteries caused by higher arterial stiffness and greater vascular resistance associates with nephropathy in type 2 diabetic patients with normal ankle-brachial indices

Diabetic nephropathy is a major cause of lower-limb amputation. We enrolled 250 type 2 diabetic patients without apparent occlusive peripheral arterial disease (ankle-brachial indices >0.9) and 40 age-matched nondiabetic subjects consecutively admitted to our hospital. Flow volume and resistive index (RI), an index of vascular resistance, at the popliteal artery were evaluated using gated two-dimensional cine-mode phase-contrast magnetic resonance imaging. Brachial-ankle pulse wave velocity (baPWV) was measured as an index of arterial distensibility. Flow volume was negatively correlated with both baPWV (p=0.0009) and RI (p<0.0001) among the patients. When the patients were grouped into four subgroups with or without albuminuria and renal insufficiency according to the levels of urinary albumin excretion rate (>or=20 or <20microg/min) and estimated glomerular filtration rate (eGFR) (<60 or >or=60ml/min/1.73m(2)), albuminuric patients with renal insufficiency (n=30) showed the lowest flow volume (p=0.0078) and the highest baPWV (p=0.0006) and RI (p=0.0274) among the groups. Simple linear regression analyses demonstrated that eGFR correlated positively with flow volume (p=0.0020) and negatively with baPWV (p=0.0258) and RI (p=0.0029) in patients with albuminuria (n=92), but not with normoalbuminuria (n=158). Impaired peripheral circulation in lower-leg arteries associates with nephropathy in diabetic patients even though they have normal ankle-brachial indices.

Association between intrarenal arterial resistance and diastolic dysfunction in type 2 diabetes

Background

In comparison to the well established changes in compliance that occur at the large vessel level in diabetes, much less is known about the changes in compliance of the cardiovascular system at the end-organ level. The aim of this study was therefore to examine whether there was a correlation between resistance of the intrarenal arteries of the kidney and compliance of the left ventricle, as estimated by measurements of diastolic function, in subjects with type 2 diabetes.

Methods

We studied 167 unselected clinic patients with type 2 diabetes with a kidney duplex scan to estimate intrarenal vascular resistance, i.e. the resistance index (RI = peak systolic velocity-minimum diastolic velocity/peak systolic velocity) and a transthoracic echocardiogram (TTE) employing tissue doppler studies to document diastolic and systolic ventricular function.

Results

Renal RI was significantly higher in subjects with diastolic dysfunction (0.72 ± 0.05) when compared with those who had a normal TTE examination (0.66 ± 0.06, p < 0.01). Renal RI values were correlated with markers of diastolic dysfunction including the E/Vp ratio (r = 0.41, p < 0.001), left atrial area (r = 0.36, p < 0.001), the E/A ratio (r = 0.36, p < 0.001) and the E/E' ratio (r = 0.31, p < 0.001). These associations were independent of systolic function, hypertension, the presence and severity of chronic kidney disease, the use of renin-angiotensin inhibitors and other potentially confounding variables.

Conclusion

Increasing vascular resistance of the intrarenal arteries was associated with markers of diastolic dysfunction in subjects with type 2 diabetes. These findings are consistent with the hypothesis that vascular and cardiac stiffening in diabetes are manifestations of common pathophysiological mechanisms.

Development and validation of a total coronary heart disease risk score in type 2 diabetes mellitus

There are no validated risk scores for predicting coronary heart disease (CHD) in Chinese patients with type 2 diabetes mellitus. This study aimed to validate the UKPDS risk engine and, if indicated, develop CHD risk scores. A total of 7,067 patients without CHD at baseline were analyzed. Data were randomly assigned to a training data set and a test data set. Cox models were used to develop risk scores to predict total CHD in the training data set. Calibration was assessed using the Hosmer-Lemeshow test, and discrimination was examined using the area under the receiver-operating characteristic curve in the test data set. During a median follow-up of 5.40 years, 4.97% of patients (n = 351) developed incident CHD. The UKPDS CHD risk engine overestimated the risk of CHD with suboptimal discrimination, and a new total CHD risk score was developed. The developed total CHD risk score was 0.0267 x age (years) - 0.3536 x sex (1 if female) + 0.4373 x current smoking status (1 if yes) + 0.0403 x duration of diabetes (years) - 0.4808 x Log(10) (estimated glomerular filtration rate [ml/min/1.73 m(2)]) + 0.1232 x Log(10) (1 + spot urinary albumin-creatinine ratio [mg/mmol]) + 0.2644 x non-high-density lipoprotein cholesterol (mmol/L). The 5-year probability of CHD = 1 - 0.9616(EXP(0.9440 x [RISK SCORE - 0.7082])). Predicted CHD probability was not significantly different from observed total CHD probability, and the adjusted area under the receiver-operating characteristic curve was 0.74 during 5 years of follow-up. In conclusion, the UKPDS CHD risk engine overestimated the risk of Chinese patients with type 2 diabetes mellitus and the newly developed total CHD risk score performed well in the test data set. External validations are required in other Chinese populations.

Risk factors in V-shaped risk associations with all-cause mortality in type 2 diabetes-The Hong Kong Diabetes Registry

BACKGROUND

Body mass index (BMI) is associated with death in a V-shaped manner in general populations but it is unknown whether BMI or other risk factors also exhibit V-shaped relationships with death in type 2 diabetic patients.

METHODS

A prospective cohort of 7534 Chinese, type 2 diabetic patients enrolled since 1995 were censored on 30 July 2005. Spline Cox regression analysis with a stepwise algorithm (p < 0.05) was used to select predictors. Hazard ratio (HR) curves were used to explore the relationships, which were confirmed by standard Cox models.

RESULTS

763 patients died during the 5.5 years of follow-up. BMI, high-density lipoprotein cholesterol (HDL-C) and white blood cell (WBC) count were related to all-cause mortality in a V-shaped manner. The nadirs of the risk curves were at 26 kg/m(2) for BMI, 1.15 mmol/L for HDL-C and 6.25 x 10(9) counts/L for WBC. The multivariate hazard ratio of BMI away from 26.0 kg/m(2) was 1.08; HDL-C, 1.06 per mmol/L for values less than the nadir and 6.97 per mmol/L for greater than the nadir; and WBC, 1.16 per 10(9) count/L for less than 6.25 x 10(9) and 1.47 for greater than the nadir. Respiratory and neoplastic deaths were the major contributors to the increased death in patients with low or high BMI. Neoplastic death was the major contributor to the increased death in those with low WBC. Genitourinary death was the major contributor to the increased death in those with low and high HDL-C.

CONCLUSION

BMI, HDL-C and WBC are associated with death in a V-shaped manner in type 2 diabetic patients.

Relationship between lipid profiles and kidney function in patients with type 1 diabetes

AIMS/HYPOTHESIS

We studied the relationship between the lipid profile, estimated GFR (eGFR) and AER in patients with type 1 diabetes. We also assessed the association between the lipid profile and glycaemic control, obesity and hypertension in an environment free of manifest renal disease, as well as exploring how well the patients would have achieved the targets set in international guidelines.

METHODS

A total of 2,927 adult patients who had type 1 diabetes and for whom lipid profiles were available were included from people participating in the nationwide, multicentre Finnish Diabetic Nephropathy Study (FinnDiane). eGFR was determined using the Cockcroft-Gault formula adjusted for body surface area.

RESULTS

Patients with impaired renal function (eGFR <60 ml min(-1) 1.73 m(-2)) had higher total cholesterol, triacylglycerol and apolipoprotein B, and lower HDL-cholesterol concentrations than patients with normal renal function (eGFR >90 ml min(-1) 1.73 m(-2)) or mildly impaired renal function (eGFR 60-90 ml min(-1) 1.73 m(-2)) (p < 0.001 for all associations). In type 1 diabetic patients without manifest renal disease, similar adverse lipid profiles could be observed in those who were overweight or obese and in those who had intermediate or poor glycaemic control or hypertension. In all the different patient groups 14 to 43% would have achieved the recommended target of <2.6 mmol/l for LDL-cholesterol.

CONCLUSIONS/INTERPRETATION

Multiple lipid abnormalities are not only present in type 1 diabetic patients with an abnormal AER, but also in those with impaired renal function. In patients without manifest renal disease, obesity, glycaemic control or hypertension were associated with an adverse lipid profile. A substantial number of patients studied would have exceeded the targets set by international guidelines, particularly the targets for LDL-cholesterol.

Impacts of chronic kidney disease and albuminuria on associations between coronary heart disease and its traditional risk factors in type 2 diabetic patients - the Hong Kong diabetes registry

Background

Glycated haemoglobin (HbA_1c), blood pressure and body mass index (BMI) are risk factors for albuminuria, the latter in turn can lead to hyperlipidaemia. We used novel statistical analyses to examine how albuminuria and chronic kidney disease (CKD) may influence the effects of other risk factors on coronary heart disease (CHD).

Methods

A prospective cohort of 7067 Chinese type 2 diabetic patients without history of CHD enrolled since 1995 were censored on July 30^th, 2005. Cox proportional hazard regression with restricted cubic spline was used to auto-select predictors. Hazard ratio plots were used to examine the risk of CHD. Based on these plots, non-linear risk factors were categorised and the categorised variables were refitted into various Cox models in a stepwise manner to confirm the findings.

Results

Age, male gender, duration of diabetes, spot urinary albumin: creatinine ratio, estimated glomerular filtration rate, total cholesterol (TC), high density lipoprotein cholesterol (HDL-C) and current smoking status were risk factors of CHD. Linear association between TC and CHD was observed only in patients with albuminuria. Although in general, increased HDL-C was associated with decreased risk of CHD, full-range HDL-C was associated with CHD in an A-shaped manner with a zenith at 1.1 mmol/L. Albuminuria and CKD were the main contributors for the paradoxically positive association between HDL-C and CHD for HDL-C values less than 1.1 mmol/L.

Conclusion

In type 2 diabetes, albuminuria plays a linking role between conventional risk factors and CHD. The onset of CKD changes risk associations between lipids and CHD.

Chronic kidney disease as a risk factor for coronary artery disease in Chinese with type 2 diabetes

BACKGROUND

Chronic kidney disease (CKD) is associated with cardiovascular disease (CVD) in the general population. We investigated the effects of renal function on coronary artery disease (CAD) in Chinese with type 2 diabetes who have a high risk of developing diabetic nephropathy but who may have a low risk of developing CAD.

METHODS

We recruited a total of 2,434 Chinese with type 2 diabetes (1,078 men and 1,356 women) and diagnosed CAD by history or with an abnormal electrocardiogram (coronary probable or possible by Minnesota codes). Renal function was evaluated by serum creatinine (SCr) levels, estimated glomerular filtration rate (eGFR) (calculated by the abbreviated Modification of Diet in Renal Disease Study Croup formula) and urinary albumin/creatinine ratio (ACR).

RESULTS

We found that patients with CAD were older, had higher SCr levels and body mass index (BMI), and had lower serum high-density lipoprotein cholesterol (HDL-c) levels. After adjusting for age, BMI, blood pressure, glycosylated hemoglobin, cholesterol, LDL-c, HDL-c, and triglycerides, we found that SCr levels >1.5 mg/dl, eGFR <60 ml/min, and urinary ACR >30 mg/g were independent risk factors for CAD in diabetic men, and that SCr levels >1.4 mg/dl and eGFR <60 ml/min were independently associated with CAD in women.

CONCLUSION

Our findings indicate that Chinese with type 2 diabetes and CKD are likely to have had CAD previously and CKD is 'CVD risk state' in diabetic Chinese.

Are differences in calcium antagonists relevant across all stages of nephropathy or only proteinuric nephropathy?

PURPOSE OF REVIEW

The main effects of classic calcium antagonists are mediated by the inhibition of L-type calcium channels broadly distributed within the renal vascular bed. Calcium antagonists act predominantly on the afferent arterioles, and dihydropyridines can favour the increase in glomerular hypertension and progression of kidney diseases, in particular when systemic blood pressure remains uncontrolled.

RECENT FINDINGS

Calcium antagonists have been widely used in clinical practice because of their antihypertensive capacity. The prevention of renal damage is a very important aim of antihypertensive therapy. This is particularly so taking into account the high prevalence of chronic kidney disease in the general population. Non-dihydropyridines such as verapamil have been shown to possess an antiproteinuric effect that could be particularly relevant.

SUMMARY

Recent data from clinical trials have confirmed that, in hypertensive patients with preserved renal function or with chronic kidney disease, calcium antagonists are effective antihypertensive drugs to be considered alone or in combination with an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. In those patients presenting with proteinuric kidney disease, non-dihydropyridines could reduce proteinuria to a greater degree than dihydropyridines.

Normoalbuminuric renal-insufficient diabetic patients: a lower-risk group

OBJECTIVE

About 20% of diabetic patients with chronic kidney disease (CKD) detected from the new American Diabetes Association recommendations (albumin excretion rate >30 mg/24 h or estimated glomerular filtration rate [GFR] <60 ml/min per 1.73 m2) may be normoalbuminuric. Do the characteristics and outcome differ for subjects with and without albuminuria?

RESEARCH DESIGN AND METHODS

A total of 89 patients with diabetes and a modification of diet in renal disease (MDRD) estimated GFR (e-GFR) <60 ml/min per 1.73 m2 underwent a 51Cr-EDTA B-isotopic GFR determination and were followed up for 38 +/- 11 months.

RESULTS

The mean MDRD e-GFR (41.3 +/- 13.1 ml/min per 1.73 m2) did not significantly differ from the i-GFR (45.6 +/- 29.7). Of the subjects, 15 (17%) were normoalbuminuric. Their i-GFR did not differ from the albuminuric rate and from their MDRD e-GFR, although their serum creatinine was lower (122 +/- 27 vs. 160 +/- 71 micromol/l, P < 0.05): 71% would not have been detected by measuring serum creatinine (sCr) alone. They were less affected by diabetic retinopathy, and their HDL cholesterol and hemoglobin were higher (P < 0.05 vs. albuminuric). None of the CKD normoalbuminuric subjects started dialysis (microalbuminuric: 2/36, macroalbuminuric: 10/38) or died (microalbuminuric: 3/36, macroalbuminuric: 7/38) during the follow-up period (log-rank test: P < 0.005 for death or dialysis), and their albumin excretion rate and sCr values were stable after 38 months, whereas the AER increased in the microalbuminuric patients (P < 0.05), and the sCr increased in the macroalbuminuric patients (P < 0.01).

CONCLUSIONS

Although their sCr is usually normal, most of the normoalbuminuric diabetic subjects with CKD according to an MDRD e-GFR below 60 ml/min per 1.73 m2 do really have a GFR below 60 ml/min per 1.73 m2. However, as expected, because of normoalbuminuria and other favorable characteristics, their risk for CKD progression or death is lower.