Organic Anion Transporter Gene Variants Associated With Plasma Exposure and Long-Term Response to Atrasentan in Patients With Diabetic Kidney Disease.

Plasma exposure of the endothelin receptor antagonist atrasentan varies between individuals and is associated with nephroprotective effects and the risk of heart failure. We examined the influence of genetic polymorphisms on atrasentan plasma exposure and pharmacodynamic effects. We performed a substudy of the Study of Diabetic Nephropathy With Atrasentan (SONAR) trial which enrolled adults with type 2 diabetes and chronic kidney disease (estimated glomerular filtration rate: 25-75 mL/min/1.73 m2 , and a urine albumin-to-creatinine ratio of 300-5,000 mg/g). Single nucleotide polymorphisms (SNPs) were determined for prespecified membrane transporters, metabolizing enzymes, and the endothelin-1 peptide. The associations among genotype, atrasentan plasma exposure, and the effect of atrasentan on the prespecified kidney and heart failure hospitalization (HHF) outcomes was assessed with Cox proportional hazards regression models. Of 3,668 patients randomized, 2,329 (63.5%) consented to genotype analysis. Two SNPs in the SLCO1B1 gene (rs4149056 and rs2306283), encoding the hepatic organic anion transporter 1B1 (OATP1B1), showed the strongest association with atrasentan plasma exposure. Based on their SLCO1B1 genotype, patients were classified into normal (atrasentan area under the plasma-concentration time curve from zero to infinity (AUC0-inf ) 41.3 ng·h/mL) or slow (atrasentan AUC0-inf 49.7 ng·h/mL, P < 0.001) OATP1B1 transporter phenotypes. Among patients with a normal OATP1B1 phenotype, the hazard ratio (HR) with atrasentan for the primary kidney and HHF outcomes were 0.61 (95% confidence interval (CI): 0.45-0.81) and 1.35 (95% CI: 0.84-2.13), respectively. In the slow transporter phenotype, HRs for kidney and HHF outcomes were 1.95 (95% CI: 0.95-4.03, P-interaction normal phenotype = 0.004), and 4.18 (95% CI: 1.37-12.7, P-interaction normal phenotype = 0.060), respectively. OATP1B1 gene polymorphisms are associated with significant between-patient variability in atrasentan plasma exposure and long-term efficacy and safety.

Visit-to-visit variability of clinical risk markers in relation to long-term complications in type 1 diabetes.

BACKGROUND: Clinical characteristics such as HbA1c , systolic blood pressure (SBP), albuminuria and estimated glomerular filtration rate (eGFR) are important when treating type 1 diabetes. We investigated the variability in these measures as risk markers for micro- and macrovascular complications. METHODS: This prospective study included 1062 individuals with type 1 diabetes. Visit-to-visit variability of HbA1c , SBP, albuminuria and eGFR was calculated as the SD of the residuals in individual linear regression models using all available measures in a specified period of 3 years (VV). Endpoints included were as follows: cardiovascular events (CVE) defined as myocardial infarction, non-fatal stroke, or coronary or peripheral arterial intervention; end-stage kidney disease (ESKD) defined as eGFR <15 ml/min/1.73 m2 , chronic dialysis or kidney transplantation; eGFR decline ≥30%; and mortality. Adjustment included age, sex, cholesterol, HbA1c , SBP, body mass index, smoking, albuminuria, eGFR, and mean, intercept, slope of respective exposure variables and regression models. RESULTS: SBP VV was significantly associated with CVE (adjusted hazard ratio per 50% increase, (CI 95%); p: 1.21 [1.05-1.39]; p = 0.008), ESKD (1.51 [1.16-1.96]; p = 0.002) and mortality (1.25 [1.09-1.44]; p = 0.002). HbA1c VV was significantly associated with mortality (1.51 [1.30-1.75]; p < 0.001); albuminuria VV with eGFR decline (1.14 [1.08-1.20]; p = 0.024) and ESKD (1.14 [1.02-1.27]; p < 0.001), but neither CVE nor mortality. Adjusted eGFR VV was not associated with endpoints. CONCLUSION: In type 1 diabetes, higher variability of basic clinical risk markers adds important risk stratification information for the development of micro- and macrovascular complications.

Lipoprotein(a)and renal function decline, cardiovascular disease and mortality in type 2 diabetes and microalbuminuria.

AIMS: Lipoprotein(a)(Lp(a)) has emerged as an independent risk marker for cardiovascular disease (CVD) in the general population and among persons with existing CVD. We investigated associations between serum Lp(a)concentrations and renal function decline, incident CVD and all-cause mortality in individuals with type 2 diabetes (T2D) and microalbuminuria. METHODS: Prospective study including 198 individuals with T2D, microalbuminuria and no CVD. Yearly p-creatinine was measured after baseline in 176 of the participants. The renal endpoint was defined as decline in eGFR of >30% from baseline. CVD events and mortality were tracked from national registries. Cox regression analyses were applied both unadjusted and adjusted for traditional risk factors (sex, age, systolic blood pressure, LDL-cholesterol, smoking, HbA1c, creatinine and urinary albumin creatinine ratio (UAER)). RESULTS: Baseline mean (SD) age was 59 (9)years, eGFR 89 (17) mL/min/1.73 m2, 77% were male, and median [IQR] UAER was 103 [38-242] mg/24-h. Median Lp(a)was 8.04 [3.42-32.3] mg/dL. Median follow-up was 6.1 years; 38 CVD events, 26 deaths and 43 renal events were recorded. For each doubling of baseline Lp(a), the following hazard ratios (95% confidence intervals) were found before and after adjustment respectively: 0.98 (0.84-1.15) and 1.01 (0.87-1.18) for decline in eGFR > 30%, 0.96 (0.81-1.13) and 0.99 (0.82-1.18) for CVD events, 1.04 (0.85-1.27) and 1.06 (0.87-1.30) for all-cause mortality. CONCLUSIONS: In this cohort of individuals with T2D and microalbuminuria, the baseline concentration of Lp(a)was not a risk marker for renal function decline, CVD events or all-cause mortality.

Treatment of Anemia With Darbepoetin Prior to Dialysis Initiation and Clinical Outcomes: Analyses From the Trial to Reduce Cardiovascular Events With Aranesp Therapy (TREAT).

RATIONALE & OBJECTIVE: Evidence from clinical trials to guide patient preparation for maintenance dialysis therapy is limited. Although anemia is associated with mortality and cardiovascular (CV) disease in individuals initiating maintenance dialysis therapy, it is not known if treatment of anemia before dialysis therapy initiation with erythropoiesis-stimulating agents alters outcomes. STUDY DESIGN: Post hoc analysis of a randomized controlled trial. SETTING & PARTICIPANTS: Participants with type 2 diabetes and chronic kidney disease who progressed to dialysis therapy (n=590) in the Trial to Reduce Cardiovascular Events With Aranesp Therapy (TREAT). EXPOSURE: Randomized treatment assignment (darbepoetin vs placebo). OUTCOMES: All-cause mortality, CV mortality, nonfatal myocardial infarction, heart failure, and stroke within the first 180 days of dialysis therapy initiation. ANALYTICAL APPROACH: Proportional hazards regression. RESULTS: Overall, 590 of 4,038 (14.6%) participants initiated dialysis therapy during the trial (n=298 and 292 in the darbepoetin and placebo groups, respectively). Corresponding hemoglobin levels were 11.3±1.6 and 9.5±1.5g/dL (P<0.001). Death from any cause occurred in 31 (10.4%) participants assigned to darbepoetin and 28 (9.6%) assigned to placebo (HR, 1.16; 95% CI, 0.69-1.93), while death from CV causes occurred in 15 (5.0%) and 13 (4.5%) participants, respectively (HR, 1.21; 95% CI, 0.58-1.93). There were no differences in risk for nonfatal myocardial infarction or heart failure. Stroke occurred in 8 (2.8%) participants assigned to darbepoetin and 1 (0.3%) assigned to placebo (HR, 8.6; 95% CI, 1.1-68.7). LIMITATIONS: Post hoc analyses of a subgroup of study participants. CONCLUSIONS: Despite initiating dialysis therapy with a higher hemoglobin level, prior treatment with darbepoetin was not associated with a reduction in mortality, myocardial infarction, or heart failure in the first 180 days, but a higher frequency of stroke was observed. In the absence of more definitive data, this may inform decisions regarding the use of erythropoiesis-stimulating agents to treat mild to moderate anemia in patients with type 2 diabetes and chronic kidney disease nearing dialysis therapy initiation.

Urinary tubular biomarkers as predictors of kidney function decline, cardiovascular events and mortality in microalbuminuric type 2 diabetic patients.

AIMS: Urinary levels of kidney injury molecule 1 (u-KIM-1) and neutrophil gelatinase-associated lipocalin (u-NGAL) reflect proximal tubular pathophysiology and have been proposed as risk markers for development of complications in patients with type 2 diabetes (T2D). We clarify the predictive value of u-KIM-1 and u-NGAL for decline in eGFR, cardiovascular events (CVE) and all-cause mortality in patients with T2D and persistent microalbuminuria without clinical cardiovascular disease. METHODS: This is a prospective study that included 200 patients. u-KIM-1 and u-NGAL were measured at baseline and were available in 192 patients. Endpoints comprised: decline in eGFR > 30%, a composite of fatal and nonfatal CVE consisting of: cardiovascular mortality, myocardial infarction, stroke, ischemic heart disease and heart failure based on national hospital discharge registries, and all-cause mortality. Adjusted Cox models included traditional risk factors, including eGFR. Hazard ratios (HR) are provided per 1 standard deviation (SD) increment of log2-transformed values. Relative integrated discrimination improvement (rIDI) was calculated. RESULTS: During the 6.1 years' follow-up, higher u-KIM-1 was a predictor of eGFR decline (n = 29), CVE (n = 34) and all-cause mortality (n = 29) in adjusted models: HR (95% CI) 1.68 (1.04-2.71), p = 0.034; 2.26 (1.24-4.15), p = 0.008; and 1.52 (1.00-2.31), p = 0.049. u-KIM-1 contributed significantly to risk prediction for all-cause mortality evaluated by rIDI (63.1%, p = 0.001). u-NGAL was not a predictor of any of the outcomes after adjustment. CONCLUSIONS: In patients with T2D and persistent microalbuminuria, u-KIM-1, but not u-NGAL, was an independent risk factor for decline in eGFR, CVE and all-cause mortality, and contributed significant discrimination for all-cause mortality, beyond traditional risk factors.

Higher Collagen VI Formation Is Associated With All-Cause Mortality in Patients With Type 2 Diabetes and Microalbuminuria.

OBJECTIVE: Type 2 diabetes is a common risk factor for the development of chronic kidney disease (CKD). Enhanced de novo collagen type VI (COL VI) formation has been associated with renal fibrosis and CKD. We investigated the hypothesis that PRO-C6, a product specifically generated during COL VI formation, is prognostic for adverse outcomes in patients with type 2 diabetes and microalbuminuria. RESEARCH DESIGN AND METHODS: In a prospective, observational study, we measured PRO-C6 in the serum (S-PRO-C6) and urine (U-PRO-C6) of 198 patients with type 2 diabetes and microalbuminuria without symptoms of coronary artery disease. Patients were followed for a median of 6.5 years, and end points were a composite of cardiovascular events (n = 38), all-cause mortality (n = 26), and reduction of estimated glomerular filtration rate (eGFR) of >30% (disease progression [n = 42]). Cox models were unadjusted and adjusted for the conventional risk factors of sex, age, BMI, systolic blood pressure, LDL cholesterol, smoking, HbA1c, plasma creatinine, and urinary albumin excretion rate. RESULTS: Doubling of S-PRO-C6 increased hazards for cardiovascular events (hazard ratio 3.06 [95% CI 1.31-7.14]), all-cause mortality (6.91 [2.96-16.11]), and disease progression (4.81 [1.92-12.01]). Addition of S-PRO-C6 to a model containing conventional risk factors improved relative integrated discrimination by 22.5% for cardiovascular events (P = 0.02), 76.8% for all-cause mortality (P = 0.002), and 53.3% for disease progression (P = 0.004). U-PRO-C6 was not significantly associated with any of the outcomes. CONCLUSIONS: S-PRO-C6 generated during COL VI formation predicts cardiovascular events, all-cause mortality, and disease progression in patients with type 2 diabetes and microalbuminuria.

Biomarkers of inflammation and endothelial dysfunction as predictors of pulse pressure and incident hypertension in type 1 diabetes: a 20 year life-course study in an inception cohort.

AIMS/HYPOTHESIS: Vascular inflammation and endothelial dysfunction are thought to contribute to arterial stiffening and hypertension. This study aims to test this hypothesis with longitudinal data in the context of type 1 diabetes. METHODS: We investigated, in an inception cohort of 277 individuals with type 1 diabetes, the course, tracking and temporal inter-relationships of BP, specifically pulse pressure (a marker of arterial stiffening) and hypertension, and the following biomarkers of systemic and vascular inflammation/endothelial dysfunction: C-reactive protein (CRP), soluble intracellular adhesion molecule-1 (sICAM-1), soluble vascular cellular adhesion molecule-1 (sVCAM-1) and soluble E-selectin (sE-selectin). These biomarkers and other risk factors were measured at baseline and repeatedly up to 20 years after the onset of type 1 diabetes. Data were analysed with generalised estimating equations including adjustments for age, sex, smoking status, BMI, HbA1c, serum creatinine, total cholesterol, urinary AER, insulin treatment dose and mean arterial pressure. RESULTS: Increases were noted in all biomarkers except sE-selectin, which decreased over time. Levels differed from baseline at 2-4 years and preceded the increase in pulse pressure, which occurred at 8-10 years after the onset of type 1 diabetes. Higher levels of sICAM-1 and sVCAM-1, but not CRP or sE-selectin, at baseline and throughout the 20 year follow-up, were significantly associated with higher (changes in) pulse pressure at subsequent time points. Higher levels of sVCAM-1 at baseline and during follow-up were also significantly associated with the prevalence (OR 3.60 [95% CI 1.36, 9.53] and OR 2.28 [1.03, 5.25], respectively) and incidence (OR 2.89 [1.08, 7.75] and OR 3.06 [1.01, 9.26], respectively) of hypertension. We also investigated the longitudinal associations between BP or hypertension as determinants of subsequent (changes in) levels of CRP, sICAM-1, sVCAM-1 and sE-selectin, but did not find evidence to support a reverse causality hypothesis. CONCLUSIONS/INTERPRETATION: These findings support the involvement of vascular endothelial dysfunction and inflammation in the development of premature arterial stiffening and hypertension in type 1 diabetes.

Symmetric and asymmetric dimethylarginine as risk markers of cardiovascular disease, all-cause mortality and deterioration in kidney function in persons with type 2 diabetes and microalbuminuria.

BACKGROUND: To evaluate symmetric dimethylarginine (SDMA) and asymmetric dimethylarginine (ADMA) as risk markers of cardiovascular disease, all-cause mortality and deterioration in renal function in a well characterised type 2 diabetic population with microalbuminuria and without symptoms of coronary artery disease. METHODS: 200 participants followed for 6.1 years. SDMA and ADMA were measured at baseline. Endpoints included (1) composite cardiovascular endpoint (n = 40); (2) all-cause mortality (n = 26); and (3) decline in eGFR of >30% (n = 42). Cox models were unadjusted and adjusted for traditional risk factors (sex, age, systolic blood pressure, LDL-cholesterol, smoking, HbA1c, creatinine and urinary albumin excretion rate). To assess if SDMA or ADMA improved risk prediction beyond traditional risk factors we calculated c statistics and relative integrated discrimination improvement (rIDI). C statistic (area under the curve) quantifies the model's improved ability to discriminate events from non-events. rIDI quantifies the increase in separation of events and non-events on a relative scale. RESULTS: Higher SDMA was associated with increased risk of all three endpoints (unadjusted: p ≤ 0.001; adjusted: p ≤ 0.02). Higher ADMA was associated with all-cause mortality (unadjusted: p = 0.002; adjusted: p = 0.006), but not cardiovascular disease or decline in eGFR (p ≥ 0.29).The c statistic was not significant for any of the endpoints for either SDMA or ADMA (p ≥ 0.10). The rIDI for SDMA was 15.0% (p = 0.081) for the cardiovascular endpoint, 52.5% (p = 0.025) for all-cause mortality and 48.8% (p = 0.007) for decline in eGFR; for ADMA the rIDI was 49.1% (p = 0.017) for all-cause mortality. CONCLUSION: In persons with type 2 diabetes and microalbuminuria higher SDMA was associated with incident cardiovascular disease, all-cause mortality and deterioration in renal function. Higher ADMA was associated with all-cause mortality. SDMA and ADMA significantly improved risk prediction for all-cause mortality, and SDMA for deterioration in renal function beyond traditional risk factors.

Higher Plasma Methylglyoxal Levels Are Associated With Incident Cardiovascular Disease in Individuals With Type 1 Diabetes: A 12-Year Follow-up Study.

Methylglyoxal (MGO), a major precursor for advanced glycation end products, is increased in diabetes. In diabetic rodents, inhibition of MGO prevents cardiovascular disease (CVD). Whether plasma MGO levels are associated with incident CVD in people with type 1 diabetes is unknown. We included 159 individuals with persistent normoalbuminuria and 162 individuals with diabetic nephropathy (DN) from the outpatient clinic at Steno Diabetes Center. We measured MGO at baseline and recorded fatal and nonfatal CVD over a median follow-up of 12.3 years (interquartile range 7.6-12.5 years). Data were analyzed by Cox regression, with adjustment for sex, age, HbA1c, DN, diabetes duration, smoking, systolic blood pressure, antihypertensive medication, and BMI. During follow-up, 73 individuals suffered at least one CVD event (36 fatal and 53 nonfatal). Higher MGO levels were associated with total, fatal, and nonfatal incident CVD (hazard ratios [HRs] 1.47 [95% CI 1.13-1.91], 1.42 [1.01-1.99], and 1.46 [1.08-1.98], respectively). We observed a similar trend for total mortality (HR 1.24 [0.99-1.56]). This study shows for the first time in our knowledge that plasma MGO levels are associated with cardiovascular events in individuals with type 1 diabetes. MGO may explain, at least in part, the increased risk for CVD in type 1 diabetes.

Epicardial, pericardial and total cardiac fat and cardiovascular disease in type 2 diabetic patients with elevated urinary albumin excretion rate.

Background We evaluated the association of cardiac adipose tissue including epicardial adipose tissue and pericardial adipose tissue with incident cardiovascular disease and mortality, coronary artery calcium, carotid intima media thickness and inflammatory markers. Design A prospective study of 200 patients with type 2 diabetes and elevated urinary albumin excretion rate (UAER). Methods Cardiac adipose tissue was measured from baseline echocardiography. The composite endpoint comprised incident cardiovascular disease and all-cause mortality. Coronary artery calcium, carotid intima media thickness and inflammatory markers were measured at baseline. Cardiac adipose tissue was investigated as continuous and binary variable. Analyses were performed unadjusted (model 1), and adjusted for age, sex (model 2), body mass index, low-density lipoprotein cholesterol, smoking, glycated haemoglobin, and systolic blood pressure (model 3). Results Patients were followed-up after 6.1 years for non-fatal cardiovascular disease ( n = 29) or mortality ( n = 23). Cardiac adipose tissue ( p = 0.049) and epicardial adipose tissue ( p = 0.029) were associated with cardiovascular disease and mortality in model 1. When split by the median, patients with high cardiac adipose tissue had a higher risk of cardiovascular disease and mortality than patients with low cardiac adipose tissue in unadjusted (hazard ratio 1.9, confidence interval: 1.1; 3.4, p = 0.027) and adjusted (hazard ratio 2.0, confidence interval: 1.1; 3.7, p = 0.017) models. Cardiac adipose tissue ( p = 0.033) was associated with baseline coronary artery calcium (model 1) and interleukin-8 (models 1-3, all p < 0.039). Conclusions In type 2 diabetes patients without coronary artery disease, high cardiac adipose tissue levels were associated with increased risk of incident cardiovascular disease or all-cause mortality even after accounting for traditional cardiovascular disease risk factors. High cardiac adipose tissue amounts were associated with subclinical atherosclerosis (coronary artery calcium) and with the pro-atherogenic inflammatory marker interleukin-8.

High osteoprotegerin is associated with development of foot ulcer in type 1 diabetes.

BACKGROUND AND AIM: The bone-related peptide osteoprotegerin has been linked to vascular calcification and peripheral vascular disease. We investigated the association between osteoprotegerin and development of foot complications in persons with type 1 diabetes. MATERIALS AND METHODS: Prospective observational study of 573 persons with type 1 diabetes, 225 women; age [mean±SD] 42.3±10.3years. Plasma osteoprotegerin was measured by ELISA. RESULTS: Median (IQR) osteoprotegerin was 2.80(2.35-3.63)µg/L and follow-up time (median (range)) was 12.7(0.1-15.6)years. Endpoints included: new foot ulceration (n=153), Charcot foot (n=14), vascular surgery/amputation (n=53), loss of foot pulse (n=57), and peripheral neuropathy (n=99). In unadjusted analyses, higher osteoprotegerin was associated with development of all endpoints (p≤0.026). Higher osteoprotegerin remained associated with development of foot ulcer, and the combination of vascular surgery/amputation, loss of foot pulse and neuropathy (p≤0.001) in a sex and age adjusted model. After further adjustment (nephropathy status, smoking, HbA1c, systolic blood pressure, serum cholesterol, high sensitivity C-reactive protein, eGFR, and presence of neuropathy and/or claudication and/or foot ulcer at baseline), higher osteoprotegerin remained associated with development of foot ulcer (HR (95% CI) per doubling: 1.75 (1.04-2.97); p=0.037). CONCLUSION: Higher osteoprotegerin levels were associated with development of foot ulcer, even after comprehensive adjustment.

Urinary biomarkers are associated with incident cardiovascular disease, all-cause mortality and deterioration of kidney function in type 2 diabetic patients with microalbuminuria.

AIMS/HYPOTHESIS: We evaluated two urinary biomarkers reflecting different aspects of renal pathophysiology as potential determinants of incident cardiovascular disease (CVD), all-cause mortality and a reduced estimated GFR (eGFR) in patients with type 2 diabetes and microalbuminuria but without clinical features of coronary artery disease. METHODS: In a prospective study of 200 patients, all received multifactorial treatment. Baseline measurements of urinary hepatocyte growth factor (HGF) and adiponectin were available for 191 patients. Cox models were adjusted for sex, age, LDL-cholesterol, smoking, HbA1c, plasma creatinine, systolic BP and urinary AER (UAER). The pre-defined endpoint of chronic kidney disease progression was a decline in the eGFR of >30% during follow-up. HRs per 1 SD increment of log-transformed values are presented. RESULTS: Patients had a mean ± SD age of 59 ± 9 years with a median (interquartile range) UAER of 103 (39-230) mg/24 h. During a median 6.1 years of follow-up, there were 40 incident CVD events, 26 deaths and 42 patients reached the pre-defined chronic kidney disease progression endpoint after 4.9 years (median). Higher urinary HGF was a determinant of CVD in unadjusted (HR 1.9 [95% CI 1.3, 2.8], p = 0.001) and adjusted (HR 2.0 [95% CI 1.2, 3.2], p = 0.004) models, and of all-cause mortality in unadjusted (HR 2.3 [95% CI 1.3, 3.9], p = 0.003) and adjusted (HR 2.5 [95% CI 1.3, 4.8], p = 0.005) models. A higher adiponectin level was associated with CVD in unadjusted (HR 1.4 [95% CI 1.0, 1.9], p = 0.04) and adjusted (HR 1.4 [95% CI 1.1, 2.3], p = 0.013) models, and with a decline in the eGFR of >30% in unadjusted (HR 1.6 [95% CI 1.2, 2.2], p = 0.008) and adjusted (HR 1.5 [95% CI 1.1, 2.2], p = 0.007) models. CONCLUSIONS/INTERPRETATION: In patients with type 2 diabetes and microalbuminuria receiving multifactorial treatment, higher urinary HGF was associated with incident CVD and all-cause mortality, and higher adiponectin was associated with CVD and deterioration in renal function.

Improved prognosis of diabetic nephropathy in type 1 diabetes.

The natural history of diabetic nephropathy offered an average survival of only 5-7 years. During the past decades, multiple changes in therapy and lifestyle have occurred. The prognosis of diabetic nephropathy after implementing stricter control of blood pressure (including increased use of long-term renin-angiotensin system inhibition), lipids, and glycemia, along with less smoking and other lifestyle and treatment advancements, is inadequately analyzed. To clarify this, we studied 497 patients with type 1 diabetes and diabetic nephropathy at the Steno Diabetes Center and compared them with previous data, obtained using identical criteria at our hospital. The glomerular filtration rate, measured yearly by 51Cr-EDTA plasma clearance, was a mean of 71 ml/min per 1.73 m2 at baseline. The mean glomerular filtration rate decline was significantly reduced by 19% (95% confidence interval 5-34) from previously 4.0 to 3.3 ml/min per 1.73 m2/year. During a median follow-up of 9.1 years, 29% of participants doubled their plasma creatinine or developed end-stage renal disease. Mortality risk was similar to our prior study (hazard ratio 1.05 (0.76-1.43). However, after age adjustment, as both diabetes and nephropathy onset occurred later in life, mortality was reduced by 30%. Risk factors for decline in glomerular filtration rate, death, and other renal end points were generally in agreement with prior studies. Thus, with current treatment of nephropathy in type 1 diabetes, the prognosis and loss of renal function has improved along with better control of modifiable risk factors.

Association of the pattern recognition molecule H-ficolin with incident microalbuminuria in an inception cohort of newly diagnosed type 1 diabetic patients: an 18 year follow-up study.

AIMS/HYPOTHESIS: Increasing evidence links complement activation through the lectin pathway to diabetic nephropathy. Adverse complement recognition of proteins modified by glycation has been suggested to trigger complement auto-attack in diabetes. H-ficolin (also known as ficolin-3) is a pattern recognition molecule that activates the complement cascade on binding to glycated surfaces, but the role of H-ficolin in diabetic nephropathy is unknown. We aimed to investigate the association between circulating H-ficolin levels and the incidence of microalbuminuria in type 1 diabetes. METHODS: We measured baseline H-ficolin levels and tracked the development of persistent micro- and macroalbuminuria in a prospective 18 year observational follow-up study of an inception cohort of 270 patients with newly diagnosed type 1 diabetes. RESULTS: Patients were followed for a median of 18 years (range 1-22 years). During follow-up, 75 patients developed microalbuminuria, defined as a persistent urinary albumin excretion rate (UAER) above 30 mg/24 h. When H-ficolin levels were divided into quartile groups an unadjusted Cox proportional hazards regression model showed a significant association with risk of incident microalbuminuria during follow-up (HR, fourth vs first quartile, 2.45; 95% CI 1.24, 4.85) (p = 0.01). This remained significant after adjusting for HbA1c, systolic blood pressure, smoking and baseline UAER (HR 2.09; 95% CI 1.03, 4.25) (p = 0.04). CONCLUSIONS/INTERPRETATION: Our data suggest that high levels of the complement activating molecule H-ficolin are associated with an increased risk of future progression to microalbuminuria in patients with newly diagnosed type 1 diabetes.

New susceptibility loci associated with kidney disease in type 1 diabetes.

Diabetic kidney disease, or diabetic nephropathy (DN), is a major complication of diabetes and the leading cause of end-stage renal disease (ESRD) that requires dialysis treatment or kidney transplantation. In addition to the decrease in the quality of life, DN accounts for a large proportion of the excess mortality associated with type 1 diabetes (T1D). Whereas the degree of glycemia plays a pivotal role in DN, a subset of individuals with poorly controlled T1D do not develop DN. Furthermore, strong familial aggregation supports genetic susceptibility to DN. However, the genes and the molecular mechanisms behind the disease remain poorly understood, and current therapeutic strategies rarely result in reversal of DN. In the GEnetics of Nephropathy: an International Effort (GENIE) consortium, we have undertaken a meta-analysis of genome-wide association studies (GWAS) of T1D DN comprising ~2.4 million single nucleotide polymorphisms (SNPs) imputed in 6,691 individuals. After additional genotyping of 41 top ranked SNPs representing 24 independent signals in 5,873 individuals, combined meta-analysis revealed association of two SNPs with ESRD: rs7583877 in the AFF3 gene (P = 1.2 × 10(-8)) and an intergenic SNP on chromosome 15q26 between the genes RGMA and MCTP2, rs12437854 (P = 2.0 × 10(-9)). Functional data suggest that AFF3 influences renal tubule fibrosis via the transforming growth factor-beta (TGF-ß1) pathway. The strongest association with DN as a primary phenotype was seen for an intronic SNP in the ERBB4 gene (rs7588550, P = 2.1 × 10(-7)), a gene with type 2 diabetes DN differential expression and in the same intron as a variant with cis-eQTL expression of ERBB4. All these detected associations represent new signals in the pathogenesis of DN.

The effect of RAAS blockade on markers of renal tubular damage in diabetic nephropathy: u-NGAL, u-KIM1 and u-LFABP.

AIM: Blockade of the renin-angiotensin-aldosterone system (RAAS) affects both the glomerulus and tubules. We aimed to investigate the effect of irbesartan on the tubular markers: urinary (u) neutrophil gelatinase associated protein (NGAL), Kidney injury molecule 1 (KIM1) and liver-fatty acid-binding protein (LFABP). METHODS: A substudy of a double-masked, randomized, cross-over study including 52 patients with type 2 diabetes, hypertension and microalbuminuria. After 2 months washout of all antihypertensive medication except bendroflumethiazid, patients were treated in random order with irbesartan 300, 600 and 900 mg for 2 months. END POINTS: Urinary tubular markers at baseline and after each treatment period (ELISA), 24-h blood pressure, glomerular filtration rate (GFR, (51)CrEDTA) and 24-h urine albumin excretion (UAER). RESULTS: Fifty-two patients completed the study (41 male). Age (mean (SD)): 58(10) years and diabetes duration 13(8) years. Baseline GFR was 101(24) and UAER (geometric mean [95%CI]) 133 (103-172) mg/24 h. With increasing doses of irbesartan (300, 600, 900 mg) u-KIM1 was reduced with 15%, 10% and 15% (p = 0.07 between 300 mg vs. baseline and no difference between doses). Patients with high u-KIM1 at baseline (above median) had a 32% reduction in u-KIM1 during treatment (p = 0.01). No significant decline in U-NGAL compared to baseline. U-LFABP increased during treatment (p < 0.01). CONCLUSIONS: Irbesartan treatment reduced levels of the tubular marker u-KIM1 in patients with type 2 diabetes and microalbuminuria. u-NGAL changed insignificantly and u-LFABP increased. More studies with longer follow up are needed to determine the role of tubular markers in monitoring treatment effect and prediction of prognosis in diabetic nephropathy.

Vitamin D levels and asymptomatic coronary artery disease in type 2 diabetic patients with elevated urinary albumin excretion rate.

OBJECTIVE: Coronary artery disease (CAD) is the major cause of morbidity and mortality in type 2 diabetic patients. Severe vitamin D deficiency has been shown to predict cardiovascular mortality in type 2 diabetic patients. RESEARCH DESIGN AND METHODS: We investigated the association among severe vitamin D deficiency, coronary calcium score (CCS), and asymptomatic CAD in type 2 diabetic patients with elevated urinary albumin excretion rate (UAER) >30 mg/24 h. This was a cross-sectional study including 200 type 2 diabetic patients without a history of CAD. Severe vitamin D deficiency was defined as plasma 25-hydroxyvitamin D (p-25[OH]D3) <12.5 nmol/L. Patients with plasma N-terminal pro-brain natriuretic peptide >45.2 ng/L or CCS ≥400 were stratified as being high risk for CAD (n= 133). High-risk patients were examined by myocardial perfusion imaging (MPI; n = 109), computed tomography angiography (n = 20), or coronary angiography (CAG; n = 86). Patients' p-25(OH)D3 levels were determined by high-performance liquid chromatography/tandem mass spectrometry. RESULTS: The median (range) vitamin D level was 36.9 (3.8-118.6) nmol/L. The prevalence of severe vitamin D deficiency was 9.5% (19/200). MPI or CAG demonstrated significant CAD in 70 patients (35%). The prevalence of CCS ≥400 was 34% (68/200). Severe vitamin D deficiency was associated with CCS ≥400 (odds ratio [OR] 4.3, 95% CI [1.5-12.1], P = 0.005). This association persisted after adjusting for risk factors (4.6, 1.5-13.9, P = 0.007). Furthermore, severe vitamin D deficiency was associated with asymptomatic CAD (adjusted OR 2.9, 1.02-7.66, P = 0.047). CONCLUSIONS: In high-risk type 2 diabetic patients with elevated UAER, low levels of vitamin D are associated with asymptomatic CAD.

Stroke in patients with type 2 diabetes mellitus, chronic kidney disease, and anemia treated with Darbepoetin Alfa: the trial to reduce cardiovascular events with Aranesp therapy (TREAT) experience.

BACKGROUND: More strokes were observed in the Trial to Reduce Cardiovascular Events With Aranesp Therapy (TREAT) among patients assigned to darbepoetin alfa. We sought to identify baseline characteristics and postrandomization factors that might explain this association. METHODS AND RESULTS: A multivariate logistic regression model was used to identify baseline predictors of stroke in 4038 patients with diabetes mellitus, chronic kidney disease, and anemia randomized to receive darbepoetin alfa or placebo. To determine whether postrandomization blood pressure, hemoglobin level, platelet count, or treatment dose were responsible for the increased risk related to darbepoetin alfa, we performed a nested case-control analysis (1:10 matching) identifying nonstroke controls with propensity matching. The risk of stroke was doubled with darbepoetin alfa. Overall, 154 patients had a stroke, 101/2012 (5.0%) in the darbepoetin alfa arm and 53/2026 (2.6%) in the placebo arm (hazard ratio 1.9; 95% confidence interval, 1.4-2.7). Independent predictors of stroke included assignment to darbepoetin alfa (odds ratio 2.1; 95% confidence interval, 1.5-2.9), history of stroke (odds ratio 2.0; 95% confidence interval, 1.4-2.9), more proteinuria, and known cardiovascular disease. In patients assigned to darbepoetin alfa, postrandomization systolic and diastolic blood pressure, hemoglobin level, platelet count, and darbepoetin alfa dose did not differ between those with and without stroke. Additional sensitivity analyses using maximal values, latest values, or changes over varying periods of exposure yielded similar results. CONCLUSIONS: The 2-fold increase in stroke with darbepoetin alfa in TREAT could not be attributed to any baseline characteristic or to postrandomization blood pressure, hemoglobin, platelet count, or dose of treatment. These readily identifiable factors could not be used to mitigate the risk of darbepoetin alfa-related stroke. CLINICAL TRIAL REGISTRATION: http://www.clinicaltrials.gov. Unique identifier: NCT00093015.

Predictors of fatal and nonfatal cardiovascular events in patients with type 2 diabetes mellitus, chronic kidney disease, and anemia: an analysis of the Trial to Reduce cardiovascular Events with Aranesp (darbepoetin-alfa) Therapy (TREAT).

AIMS: This study aims to examine predictors of cardiovascular mortality and morbidity in patients with chronic kidney disease (CKD). Individuals with the triad of diabetes, CKD, and anemia represent a significant proportion of patients with cardiovascular disease and are at particularly high risk for adverse outcomes. METHODS AND RESULTS: Using Cox proportional hazards models, we identified independent predictors of the composite of cardiovascular death, myocardial infarction, stroke, hospitalization for myocardial ischemia, or heart failure (HF) in 3,847 patients in the TREAT, 961 (25%) of whom experienced this outcome. The predictors (ranked by χ(2) value) were prior HF (hazard ratio [HR] 1.74, 95% CI 1.51-2.01), age (HR 1.03, 95% CI 1.02-1.04 per year), log urine protein/creatinine ratio (HR 1.19, 95% CI 1.13-1.26 per log unit ), C-reactive protein ≥6.6 mg/L (HR 1.44, 95% CI 1.23-1.69, compared with C-reactive protein ≤3.0 mg/L), and abnormal electrocardiogram (HR 1.42, 95% CI 1.21-1.66 ), all P < .0001. Addition of cardiac-derived biomarkers (subset of first 1,000 patients enrolled) significantly enhanced risk estimation, with N-terminal pro B-type natriuretic peptide becoming the highest ranked predictor of outcome (HR 1.30, 95% CI 1.15-1.46 per log unit, P < .001) and troponin T providing additional predictive information. These biomarkers improved risk classification in 17.8% (9.4%-26.2%) of patients. CONCLUSION: In patients with diabetes, CKD, and anemia, cardiovascular risk is most strongly predicted by age, history of HF, C-reactive protein, urinary protein/creatinine ratio, abnormal electrocardiogram, and 2 specific cardiac biomarkers, serum N-terminal pro B-type natriuretic peptide and troponin T, which are elevated in many. These findings suggest ways to improve cardiovascular risk stratification of patients with predialysis CKD, support the concept of cardiorenal syndrome, and may help target therapy.

Fibulin-1 is a marker for arterial extracellular matrix alterations in type 2 diabetes.

BACKGROUND: Extracellular matrix alterations are important elements in the arterial changes seen in diabetes, being associated with increased vascular stiffness and the development of cardiovascular diseases. However, no biomarkers for diabetes-related arterial changes have been defined. METHODS: Mammary artery specimens from 17 men with type 2 diabetes and 18 nondiabetic individuals were used for microarray expression profiling, quantitative real-time PCR, immunoassay, and immunohistochemical analyses. A derived candidate marker, fibulin-1, which is an elastin-associated matrix molecule, was measured immunochemically in plasma from (a) 70 patients scheduled for vascular surgery, (b) 305 patients with type 2 diabetes examined with carotid ultrasonography and echocardiography, and (c) 308 patients with type 2 diabetes, followed for 15 years. RESULTS: The most upregulated transcript in nonatherosclerotic arterial tissue from patients with type 2 diabetes encoded the extracellular matrix protein, fibulin-1. Higher concentrations of fibulin-1-protein were present in artery extracts from patients with diabetes than extracts from individuals without diabetes, and increased fibulin-1 immunostaining was apparent around the external elastic lamina of diabetic arteries. Patients with diabetes displayed increased plasma concentrations of fibulin-1 (P = 0.006). Plasma fibulin-1 concentrations correlated with hemoglobin A(1c) (P < 0.001), arterial stiffness indices including pulse pressure (P < 0.001), and carotid compliance (P = 0.004), as well as plasma N-terminal pro-B-type natriuretic peptide concentrations (P < 0.001) and were predictive of 15-year mortality (P = 0.013). CONCLUSIONS: Fibulin-1 accumulates in the arterial wall and in plasma of patients with type 2 diabetes, and appears to be a factor associated with arterial extracellular matrix changes in type 2 diabetes.