Reproducibility of albuminuria in type 2 diabetic subjects. Findings from the Renal Insufficiency And Cardiovascular Events (RIACE) study

Association between age at diagnosis and all-cause mortality in type 2 diabetes: the Renal Insufficiency and Cardiovascular Events (RIACE) Italian Multicenter Study

AIMS

It is unclear whether type 2 diabetes diagnosed in young adulthood is associated with increased severity than that occurring later in life beyond longer lifetime exposure to hyperglycemia. This study aimed at assessing the independent association of age at type 2 diabetes diagnosis with all-cause mortality.

METHODS

This prospective cohort study enrolled 15,773 Caucasian patients with type 2 diabetes in 19 Italian centers in 2006-2008. Cardiometabolic risk profile and presence of complications and comorbidities were assessed at baseline and participants were stratified by quartiles of age at diabetes diagnosis. All-cause mortality was verified on 31 October 2015.

RESULTS

Valid information on vital status was retrieved for 15,656 participants (99.3%). Patients in the lowest quartile had the longest diabetes duration, the worst glycemic control and the highest prevalence of insulin treatment, obesity, atherogenic dyslipidemia, and smoking habits. All complications were inversely associated with age at diabetes diagnosis after adjustment for age and sex, but not after further adjustment for diabetes duration. Percentages of death, Kaplan-Meier estimates, and unadjusted hazard ratios and mortality rates increased from the lowest to the highest quartile. In contrast, when adjusting for age and sex, participants falling in the lowest quartile, showed the highest mortality risk [hazard ratio 1.321 (95% confidence interval 1.196-1.460), P < 0.0001]. However, differences among quartiles disappeared after adjustment for diabetes duration, complications/comorbidities, or other cardiovascular risk factors.

CONCLUSIONS

Type 2 diabetes onset in young adulthood is associated with increased mortality that is mainly driven by longer diabetes duration favoring the development of complications.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT00715481, retrospectively registered 15 July, 2008.

Independent association of history of diabetic foot with all-cause mortality in patients with type 2 diabetes: the Renal Insufficiency And Cardiovascular Events (RIACE) Italian Multicenter Study

BACKGROUND

Foot ulcers and/or infections are common long-term complications of diabetes and are associated with increased mortality, especially from cardiovascular disease, though only a few studies have investigated the independent contribution of these events to risk of death. This study aimed at assessing the association of history of diabetic foot with all-cause mortality in individuals with type 2 diabetes, independent of cardiovascular risk factors, other complications, and comorbidities.

METHODS

This prospective cohort study enrolled 15,773 Caucasian patients in 19 Italian centers in the years 2006-2008. Prior lower extremity, coronary, and cerebrovascular events and major comorbidities were ascertained by medical records, diabetic retinopathy by fundoscopy, diabetic kidney disease by albuminuria and estimated glomerular filtration rate, cardiovascular risk factors by standard methods. All-cause mortality was retrieved for 15,656 patients on 31 October 2015.

RESULTS

At baseline, 892 patients (5.7%) had a history of diabetic foot, including ulcer/gangrene and/or amputation (n = 565; 3.58%), with (n = 126; 0.80%) or without (n = 439; 2.78%) lower limb revascularization, and revascularization alone (n = 330; 2.09%). History of diabetic foot was associated with all-cause death over a 7.42-year follow-up (adjusted hazard ratio, 1.502 [95% confidence interval, 1.346-1.676], p < 0.0001), independent of confounders, among which age, male sex, smoking, hemoglobin A1c, current treatments, other complications, comorbidities and, inversely, physical activity level and total and HDL cholesterol were correlated independently with mortality. Both ulcer/gangrene and amputation alone were independently associated with death, with a higher strength of association for amputation than for ulcer/gangrene (1.874 [1.144-3.070], p = 0.013 vs. 1.567 [1.353-1.814], p < 0.0001). Both ulcer/gangrene/amputation and lower limb revascularization alone were independently associated with death; mortality risk was much higher for ulcer/gangrene/amputation than for revascularization (1.641 [1.420-1.895], p < 0.0001 vs. 1.229 [1.024-1.475], p = 0.018) and further increased only slightly for combined ulcer/gangrene/amputation and revascularization (1.733 [1.368-2.196], p < 0.0001).

CONCLUSIONS

In patients with type 2 diabetes, an history of diabetic foot event, including ulcer/gangrene, amputation, and lower limb revascularization, was associated with a ~ 50% increased risk of subsequent death, independent of cardiovascular risk factors, other complications and severe comorbidities, which were also significantly associated with mortality. The association with mortality was greatest for amputation, whereas that for revascularization alone was relatively modest.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT00715481, retrospectively registered 15 July, 2008.

Circulating tumor necrosis factor-related biomarkers predict kidney function decline in Japanese patients with diabetes: An observational cohort study

AIMS

Tumor necrosis factor (TNF) receptors (TNFRs: TNFR1 and, TNFR2) are reportedly associated with chronic kidney disease (CKD) progression chiefly in Caucasian patients with diabetes. We assessed the prognostic value of TNF-related biomarkers for CKD progression in Japanese patients with diabetes.

METHODS

We estimated TNF-related biomarkers using an enzyme-linked immunosorbent assay in 640 patients with diabetes. Cox proportional hazards analysis was performed to estimate hazard ratios (HRs) per one standard deviation (SD) increase in a log-transformed biomarker. The kidney and the composite outcome were defined as a 30% reduction in estimated glomerular filtration rate (eGFR) from baseline, and kidney outcome plus death before kidney outcome, respectively.

RESULTS

During the median follow-up of 5.4 years, 75 (11.7%) patients reached the kidney outcome and 37 (5.8%) died before reaching the kidney outcome. Each SD increase in baseline circulating TNFR1, TNFR2, and ephrin type-A receptor 2 (EphA2) was associated with a higher risk of the kidney outcome independently from baseline eGFR and urine albumin-to-creatinine ratio. However, circulating osteoprotegerin was associated with the composite outcome only.

CONCLUSIONS

Elevated TNFR1, TNFR2, and EphA2 were associated with both kidney and composite outcomes in Japanese patients with diabetes.

Retinopathy as an independent predictor of all-cause mortality in individuals with type 2 diabetes

AIMS

To assess whether the presence and grade of diabetic retinopathy (DR) predict all-cause mortality, independent of risk factors for cardiovascular disease (CVD) and other complications, including diabetes-related kidney disease (DKD) and CVD, in individuals with type 2 diabetes mellitus.

METHODS

Prospective cohort study that enroled 15,773 patients in 19 Italian centers in 2006-2008. DR ascertained by fundoscopy, DKD by albuminuria and estimated glomerular filtration rate, and prior CVD by hospital discharge records. All-cause mortality retrieved for 15,656 patients on 31 October 2015.

RESULTS

The adjusted risk of death was increased in patients with any DR (hazard ratio, 1.136 [95% confidence interval, 1.054;1.224] P < 0.0001), advanced DR, including severe non-proliferative and proliferative DR and diabetic macula edema (1.213 [1.097;1.340] P < 0.0001), and especially proliferative DR alone (1.381 [1.207;1.580] P < 0.0001), compared with those without DR. The impact of DR was more evident in patients without than in those with DKD or CVD. Mortality risk was increased in participants with DR alone, though much less than in those with DKD or CVD alone and particularly in those with both DR and DKD or CVD. DR grade was related to mortality in individuals without DKD or CVD, whereas it conferred no additional risk to those with albuminuric or nonalbuminuric DKD or established CVD.

CONCLUSIONS

In patients with type 2 diabetes mellitus, the excess mortality risk conferred by DR is relatively small and higher in those without DKD and CVD, suggesting that it may be mediated by the concurrent presence of these complications, even at a subclinical level.

Risk of all-cause mortality according to the European Society of Cardiology risk categories in individuals with type 2 diabetes: the Renal Insufficiency And Cardiovascular Events (RIACE) Italian Multicenter Study

AIMS

The 2019 and 2021 European Society of Cardiology (ESC) classifications stratified patients with type 2 diabetes into three categories according to the 10-year risk of death from atherosclerotic cardiovascular disease (ASCVD). The very high-risk category included individuals with established ASCVD, target organ damage (TOD), and/or, in the 2019 classification only, ≥ 3 additional ASCVD risk factors. We assessed risk of all-cause mortality according to the two ESC classifications in the Renal Insufficiency And Cardiovascular Events cohort.

METHODS

Participants (n = 15,773) were stratified based on the presence of ASCVD, TOD, and ASCVD risk factors at baseline (2006-2008). Vital status was retrieved in 2015.

RESULTS

Less than 1% of participants fell in the moderate-risk category. According to the 2019 classification, ~ 1/3 fell in the high-risk and ~ 2/3 in the very high-risk category, whereas the opposite occurred with the 2021 classification. Mortality risk increased across categories according to both classifications. Among very high-risk patients, mortality was much lower in those with ≥ 3 additional ASCVD risk factors and almost equal in those with TOD and ASCVD ± TOD, using the 2019 classification, whereas it was much higher in those with ASCVD + TOD and, to a lesser extent, TOD only than in those with ASCVD only, using the 2021 classification.

CONCLUSIONS

The negligible number of moderate-risk patients suggests that these classifications might overestimate risk of ASCVD death. Downgrading patients with ≥ 3 additional ASCVD risk factors to the high-risk category is consistent with mortality data. Risk of death is very high in the presence of TOD irrespective of established ASCVD.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT00715481.

Diabetic kidney disease: new clinical and therapeutic issues. Joint position statement of the Italian Diabetes Society and the Italian Society of Nephrology on "The natural history of diabetic kidney disease and treatment of hyperglycemia in patients with type 2 diabetes and impaired renal function"

Aims

This joint document of the Italian Diabetes Society and the Italian Society of Nephrology reviews the natural history of diabetic kidney disease (DKD) in the light of the recent epidemiological literature and provides updated recommendations on anti-hyperglycemic treatment with non-insulin agents.

Data Synthesis

Recent epidemiological studies have disclosed a wide heterogeneity of DKD. In addition to the classical albuminuric phenotype, two new albuminuria-independent phenotypes have emerged, i.e., “nonalbuminuric renal impairment” and “progressive renal decline”, suggesting that DKD progression toward end-stage kidney disease (ESKD) may occur through two distinct pathways, albuminuric and nonalbuminuric. Several biomarkers have been associated with decline of estimated glomerular filtration rate (eGFR) independent of albuminuria and other clinical variables, thus possibly improving ESKD prediction. However, the pathogenesis and anatomical correlates of these phenotypes are still unclear. Also the management of hyperglycemia in patients with type 2 diabetes and impaired renal function has profoundly changed during the last two decades. New anti-hyperglycemic drugs, which do not cause hypoglycemia and weight gain and, in some cases, seem to provide cardiorenal protection, have become available for treatment of these individuals. In addition, the lowest eGFR safety thresholds for some of the old agents, particularly metformin and insulin secretagogues, have been reconsidered.

Conclusions

The heterogeneity in the clinical presentation and course of DKD has important implications for the diagnosis, prognosis, and possibly treatment of this complication. The therapeutic options for patients with type 2 diabetes and impaired renal function have substantially increased, thus allowing a better management of these individuals.

Insulin resistance, diabetic kidney disease, and all-cause mortality in individuals with type 2 diabetes: a prospective cohort study

BACKGROUND

It is unclear whether insulin resistance (IR) contributes to excess mortality in patients with type 2 diabetes independent of diabetic kidney disease (DKD), which is strongly associated with IR and is a major risk factor for cardiovascular disease (CVD), the main cause of death in these individuals. We tested this hypothesis in patients with type 2 diabetes from the Renal Insufficiency And Cardiovascular Events Italian Multicentre Study.

METHODS

This observational, prospective, cohort study enrolled 15,773 patients with type 2 diabetes attending 19 Italian Diabetes Clinics in 2006-2008. Insulin sensitivity was assessed as estimated glucose disposal rate (eGDR), which was validated against the euglycaemic-hyperinsulinemic clamp technique. Vital status on October 31, 2015, was retrieved for 15,656 patients (99.3%). Participants were stratified by eGDR tertiles from T1 (≥ 5.35 mg/kg/min) to T3 (≤ 4.14 mg/kg/min, highest IR).

RESULTS

CVD risk profile was worse in T2 and T3 vs T1. eGDR tertiles were independently associated with micro- and macroalbuminuria and the albuminuric DKD phenotypes (albuminuria with preserved or reduced estimated glomerular filtration rate [eGFR]) as well as with eGFR categories or the nonalbuminuric DKD phenotype. Over a 7.4-year follow-up, unadjusted death rates and mortality risks increased progressively across eGDR tertiles, but remained significantly elevated after adjustment only in T3 vs T1 (age- and gender- adjusted death rate, 22.35 vs 16.74 per 1000 person-years, p < 0.0001, and hazard ratio [HR] adjusted for multiple confounders including DKD, 1.140 [95% confidence interval [CI], 1.049-1.238], p = 0.002). However, eGDR was independently associated with mortality in participants with no DKD (adjusted HR, 1.214 [95% CI, 1.072-1.375], p = 0.002) and in those with nonalbuminuric DKD (1.276 [1.034-1.575], p = 0.023), but not in those with the albuminuric DKD phenotypes. Moreover, the association was stronger in males and in younger individuals and was observed in those without but not with prior CVD, though interaction was significant only for age.

CONCLUSIONS

The proxy of insulin sensitivity eGDR predicts all-cause mortality in type 2 diabetes, independent of confounders including DKD. However, the impact of IR in individuals with albuminuric DKD may be mediated by its relationship with albuminuria.

TRIAL REGISTRATION

ClinicalTrials.gov , NCT00715481, retrospectively registered 15 July 2008.

Obstructive sleep apnea is associated with impaired renal function in patients with diabetic kidney disease

Obstructive sleep apnea (OSA) is a recognized risk factor for the development of diabetic kidney disease (DKD). Our objectives were to compare the urinary albumin-creatinine ratio (UACR) and estimated glomerular filtration rate (eGFR) of patients with DKD according to OSA severity, and to evaluate the contribution of sleep parameters to their renal function. In a multicenter, observational, cross-sectional study, 214 patients with DKD were recruited. After a sleep study, UACR and eGFR were measured, as well as serum creatinine, fasting glucose, glycated hemoglobin, insulin resistance, lipid profile and C-reactive protein. UACR was higher in severe OSA patients (920 ± 1053 mg/g) than in moderate (195 ± 232 mg/g, p < 0.001) or mild OSA/non-OSA subjects (119 ± 186 mg/g, p < 0.001). At the same time, eGFR showed an OSA severity-dependent reduction (48 ± 23 vs. 59 ± 21 vs. 73 ± 19 ml/min per 1.73 m², respectively; p < 0.001). Apnea-hypopnea index (AHI and desaturation index (ODI) were identified as independent predictors for UACR and eGFR, respectively. Therefore, in patients with DKD under optimized treatment, severe OSA is associated with a higher UACR and a lower eGFR, reflecting an additional contribution to the impairment of their renal function, although no causality can be inferred.

Independent association of atherogenic dyslipidaemia with all-cause mortality in individuals with type 2 diabetes and modifying effect of gender: a prospective cohort study

Background

Atherogenic dyslipidaemia has been implicated in the residual risk for cardiovascular morbidity and mortality, which remains despite attainment of LDL cholesterol goals especially in individuals with type 2 diabetes. However, its relationship with all-cause death has not been sufficiently explored. This analysis evaluated the independent association of increased triglycerides and triglyceride:HDL cholesterol ratio (TG:HDL) and decreased HDL cholesterol with total mortality and the possible modifying effect of gender in a large cohort of patients with type 2 diabetes.

Methods

This observational, prospective study enrolled 15,773 patients in 19 Diabetes Clinics throughout Italy in the years 2006–2008. Triglycerides and total and HDL cholesterol were measured by colorimetric enzymatic methods. Vital status was retrieved on 31 October 2015 for 15,656 patients (99.3%). Participants were stratified by quartiles of triglycerides, HDL cholesterol, and TG:HDL.

Results

There were 3,602 deaths over a follow-up 7.42 ± 2.05 years (31.0 × 1000 person-years). In the unadjusted analyses, the highest TG:HDL (but not triglyceride) and the lowest HDL cholesterol quartile were associated with increased death rate and mortality risk. When sequentially adjusting for confounders, including total, LDL, or non-HDL cholesterol and lipid-lowering treatment, mortality risk was significantly higher in the highest triglyceride (hazard ratio 1.167 [95% confidence interval 1.055–1.291], p = 0.003) and TG:HDL (1.192 [1.082–1.314], p < 0.0001) and the lowest HDL cholesterol (1.232 [1.117–1.360], p < 0.0001) quartile, though the association of triglycerides and HDL cholesterol disappeared after further adjustment for each other. Interaction with gender was significant only for HDL cholesterol (p = 0.0009). The relationship with death was stronger for triglycerides in males and HDL cholesterol in females, with these associations remaining significant even after adjustment for HDL cholesterol (1.161 [1.019–1.324], p = 0.025, for the highest vs the lowest triglyceride quartile) and triglycerides (1.366 [1.176–1.587], p < 0.0001, for the lowest vs the highest HDL cholesterol quartile).

Conclusions

In patients with type 2 diabetes, higher triglycerides and TG:HDL and lower HDL cholesterol were independently associated with increased all-cause mortality, with a modifying effect of gender for triglycerides and HDL cholesterol. These data suggest that atherogenic dyslipidaemia, especially TG:HDL, may serve as predictor of all-cause death in these individuals.

Trial registration ClinicalTrials.gov, NCT00715481, 15 July, 2008

Elevated circulating luteinizing hormone levels are associated with diabetic macroalbuminuria in Chinese men and postmenopausal women: A cross-sectional study

BACKGROUND

Associations between sex hormones and diabetic vascular complications have recently been studied, but the role luteinizing hormone (LH) plays in diabetic kidney disease (DKD) remains uncertain. We aimed to investigate the relationship of LH and DKD in Chinese men and postmenopausal women with type 2 diabetes mellitus (T2DM).

METHODS

Data were collected from 1775 T2DM men and postmenopausal women in hospital. The odds ratios (OR) and corresponding 95% confidence intervals (CI) in relation to LH quartiles were obtained by multiple logistic regression analysis.

RESULTS

LH levels were significantly higher in patients with macroalbuminuria than in those with microalbuminuria, but were not higher in patients with microalbuminuria than in those with normoalbuminuria. Consistently, LH in those with an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73m² were significantly higher than in those with eGFR≥60 mL/min/1.73m² . The prevalence of macroalbuminuria was obviously increased for subjects of the fourth quartile of LH vs the first to third quartile (20.4% vs 6.2%, 8.0%, 12.2% in men; 25.3% vs 5.5%, 3.8%, 9.3% in postmenopausal women). Multivariate logistic regression demonstrated that subjects within the highest quartile of LH had higher odds of macroalbuminuria than those within the lowest quartile (OR 4.00, 95% CI, 1.87-8.55 for men; OR 9.62, 95% CI, 3.42-27.08 for postmenopausal women), independent of age, diabetes duration, or other metabolic factors. The area under the curve for detecting macroalbuminuria based on LH was 0.662 for men, and 0.767 for postmenopausal women.

CONCLUSION

High LH levels are positively associated with established DKD among Chinese men and postmenopausal women. Elevated LH may be a promising clinical factor for identifying established DKD.

Renal hyperfiltration is independently associated with increased all-cause mortality in individuals with type 2 diabetes: a prospective cohort study

INTRODUCTION

In addition to favoring renal disease progression, renal 'hyperfiltration' has been associated with an increased risk of death, though it is unclear whether and how excess mortality is related to increased renal function. We investigated whether renal hyperfiltration is an independent predictor of death in patients with type 2 diabetes from the Renal Insufficiency And Cardiovascular Events Italian multicenter study.

RESEARCH DESIGN AND METHODS

This observational, prospective cohort study enrolled 15 773 patients with type 2 diabetes consecutively attending 19 Italian diabetes clinics in 2006-2008. Serum creatinine, albuminuria, cardiovascular risk factors, and complications/comorbidities were assessed at baseline. Vital status on 31 October 2015 was retrieved for 15 656 patients (99.26%). Patients were stratified (A) by absolute estimated glomerular filtration rate (eGFR) values in eGFR deciles or Kidney Disease: Improving Global Outcomes (KDIGO) categories and (B) based on age-corrected thresholds or age and gender-specific 95th and 5th percentiles in hyperfiltration, hypofiltration, and normofiltration groups.

RESULTS

The highest eGFR decile/category and the hyperfiltration group included (partly) different individuals with similar clinical features. Age and gender-adjusted death rates were significantly higher in deciles 1, 9, and 10 (≥103.9, 50.9-62.7, and <50.9 mL/min/1.73 m², respectively) versus the reference decile 3 (92.9-97.5 mL/min/1.73 m²). Mortality risk, adjusted for multiple confounders, was also increased in deciles 1 (HR 1.461 (95% CI 1.175 to 1.818), p=0.001), 9 (1.312 (95% CI 1.107 to 1.555), p=0.002), and 10 (1.976 (95% CI 1.673 to 2.333), p<0.0001) versus decile 3. Similar results were obtained by stratifying patients by KDIGO categories. Death rates and adjusted mortality risks were significantly higher in hyperfiltering and particularly hypofiltering versus normofiltering individuals.

CONCLUSIONS

In type 2 diabetes, both high-normal eGFR and hyperfiltration are associated with an increased risk of death from any cause, independent of confounders that may directly impact on mortality and/or affect GFR estimation. Further studies are required to clarify the nature of this relationship.

TRIAL REGISTRATION NUMBER

NCT00715481.

Association between On-Treatment Haemoglobin A1c and All-Cause Mortality in Individuals with Type 2 Diabetes: Importance of Personalized Goals and Type of Anti-Hyperglycaemic Treatment

The increased mortality reported with intensive glycaemic control has been attributed to an increased risk of treatment-related hypoglycaemia. This study investigated the relationships of haemoglobin (Hb) A_1c, anti-hyperglycaemic treatment, and potential risks of adverse effects with all-cause mortality in patients with type 2 diabetes. Patients (n = 15,773) were stratified into four categories according to baseline HbA_1c and then assigned to three target categories, based on whether HbA_1c was ≤0.5% below or above (on-target), >0.5% below (below-target) or >0.5% above (above-target) their HbA_1c goal, personalized according to the number of potential risks among age > 70 years, diabetes duration > 10 years, advanced complication(s), and severe comorbidity (ies). The vital status was retrieved for 15,656 patients (99.26%). Over a 7.4-year follow-up, mortality risk was increased among patients in the highest HbA_1c category (≥8.5%) (adjusted hazard ratio, 1.34 (95% confidence interval, 1.22–1.47), p < 0.001) and those above-target (1.42 (1.29–1.57), p < 0.001). Risk was increased among individuals in the lowest HbA_1c category (<6.5%) and those below-target only if treated with agents causing hypoglycaemia (1.16 (1.03–1.29), p = 0.01 and 1.10 (1.01–1.22), p = 0.04, respectively). These data suggest the importance of setting both upper and lower personalized HbA_1c goals to avoid overtreatment in high-risk individuals with type 2 diabetes treated with agents causing hypoglycaemia.

Preventing CKD in Low- and Middle-Income Countries: A Call for Urgent Action

The epidemiologic transition occurring in low- and middle-income countries (LMICs) has led to a surge in chronic kidney disease (CKD) prevalence because of a combination of highly prevalent chronic noncommunicable diseases (NCDs) and communicable diseases (CDs). The progressive rise in CKD prevalence in LMICs threatens the existing weak health systems in these countries as care for advanced CKD remains largely unavailable and unaffordable. An interplay of low literacy levels, poor health-seeking behavior, inadequate health care funding, weak health systems, and lack of skilled nephrology workforce has made it difficult for adequate CKD preventive measures to be implemented. Primary, secondary, and tertiary prevention measures need to be instituted in LMICs by a collaboration of governmental and nongovernmental organizations to stem this tide and help prevent deaths from other NCDs that share similar risk factors with CKD. For these to be effective, locally relevant knowledge is needed to contextualize existing prevention and control solutions, or to develop novel and more appropriate solutions for LMICs.

Diabetic kidney disease: New clinical and therapeutic issues. Joint position statement of the Italian Diabetes Society and the Italian Society of Nephrology on "The natural history of diabetic kidney disease and treatment of hyperglycemia in patients with type 2 diabetes and impaired renal function"

AIMS

This joint document of the Italian Diabetes Society and the Italian Society of Nephrology reviews the natural history of diabetic kidney disease (DKD) in the light of the recent epidemiological literature and provides updated recommendations on anti-hyperglycemic treatment with non-insulin agents.

DATA SYNTHESIS

Recent epidemiological studies have disclosed a wide heterogeneity of DKD. In addition to the classical albuminuric phenotype, two new albuminuria-independent phenotypes have emerged, i.e., "nonalbuminuric renal impairment" and "progressive renal decline", suggesting that DKD progression toward end-stage kidney disease (ESKD) may occur through two distinct pathways, albuminuric and nonalbuminuric. Several biomarkers have been associated with decline of estimated glomerular filtration rate (eGFR) independent of albuminuria and other clinical variables, thus possibly improving ESKD prediction. However, the pathogenesis and anatomical correlates of these phenotypes are still unclear. Also the management of hyperglycemia in patients with type 2 diabetes and impaired renal function has profoundly changed during the last two decades. New anti-hyperglycemic drugs, which do not cause hypoglycemia and weight gain and, in some cases, seem to provide cardiorenal protection, have become available for treatment of these individuals. In addition, the lowest eGFR safety thresholds for some of the old agents, particularly metformin and insulin secretagogues, have been reconsidered.

CONCLUSIONS

The heterogeneity in the clinical presentation and course of DKD has important implications for the diagnosis, prognosis, and possibly treatment of this complication. The therapeutic options for patients with type 2 diabetes and impaired renal function have substantially increased, thus allowing a better management of these individuals.

Phthalates Exposure as Determinant of Albuminuria in Subjects With Type 2 Diabetes: A Cross-Sectional Study

CONTEXT

Recent epidemiological observations have reported an association among phthalates exposure and insulin resistance, obesity, and diabetes but have not related exposure to these environmental pollutants with microvascular complications of diabetes.

OBJECTIVE

To explore the relationship between phthalates and renal function in subjects with diabetes.

DESIGN

Cross-sectional, case-only study. Concentrations of three urinary metabolites of di-2-ethylhexylphthalate were quantified in a spot morning urine sample, normalized for creatinine urinary excretion, and related to clinical parameters and phenotype, adjusting for confounders.

PATIENTS

Two hundred and nine patients with diabetes consecutively referred to our clinic.

MAIN OUTCOME MEASURES

Relationship between phthalates and renal function [evaluated with estimated glomerular filtration rate (eGFR) and albuminuria].

RESULTS

Creatinine-adjusted urinary concentrations of mono-2-ethylhexyl phthalate (MEHP), mono-2-ethyl-5-oxohexyl phthalate (MEOHP), and mono-2-ethyl-5-hydroxyhexyl phthalate were 7.53 µg/g (range, 4.84 to 12.60), 3.04 µg/g (range, 1.03 to 5.14), and 10.70 µg/g (7.02 to 17.40), respectively. Age, sex, body mass index, diabetes duration, smoking, blood pressure, glycated Hb, and eGFR did not influence their levels. Exposure to MEHP and MEOHP was greater in individuals with microalbuminuria/macroalbuminuria (MEHP, P = 0.0173; MEOHP, P = 0.0306). The fourth vs first quartile showed a greater risk of albuminuria (MEHP: OR, 4.83; 95% CI, 1.45 to 16.06; P = 0.0297; MEOHP: OR, 3.29; 95% CI, 1.08 to 10.04); P = 0.0352). MEOHP was greater (P = 0.034) in subjects with cardiovascular events; MEHP showed a positive trend (P = 0.061).

CONCLUSION

Our findings have revealed an association between exposure to di-2-ethylhexylphthalate metabolites and the degree of albuminuria in subjects with diabetes; the lack of a relationship with eGFR suggests their urinary levels are independent of renal function.

Is resistant hypertension an independent predictor of all-cause mortality in individuals with type 2 diabetes? A prospective cohort study

BACKGROUND

Resistant hypertension is independently associated with an increased risk of death in the general hypertensive population. We assessed whether resistant hypertension is an independent predictor of all-cause mortality in individuals with type 2 diabetes from the Renal Insufficiency And Cardiovascular Events (RIACE) Italian Multicentre Study.

METHODS

On 31 October 2015, vital status information was retrieved for 15,656 of the 15,773 participants enrolled in 2006-2008. Based on baseline blood pressure (BP) values and treatment, participants were categorized as normotensive, untreated hypertensive, controlled hypertensive (i.e., on-target with < 3 drugs), uncontrolled hypertensive (i.e., not on-target with 1-2 drugs), or resistant hypertensive (i.e., uncontrolled with > 3 drugs or controlled with > 4 drugs). Kaplan-Meier and Cox proportional hazards regression analyses were used to assess the association with all-cause mortality.

RESULTS

Using the 130/80 mmHg targets for categorization, crude mortality rates and Kaplan-Meier estimates were highest among resistant hypertension participants, especially those with controlled resistant hypertension. As compared with resistant hypertension, risk for all-cause mortality was significantly lower for all the other groups, including individuals with controlled hypertension (hazard ratio 0.81 [95% confidence interval 0.74-0.89], P < 0.0001), but became progressively similar between resistant and controlled hypertension after adjustment for cardiovascular risk factors and complications/comorbidities. Also when compared with controlled resistant hypertension, mortality risk was significantly lower for all the other groups, including controlled hypertension, even after adjusting for cardiovascular risk factors (0.77 [0.63-0.95], P = 0.012), but not for complications/comorbidities (0.88 [0.72-1.08], P = 0.216). BP was well below target in the controlled hypertensive groups (resistant and non-resistant) and values < 120/70 mmHg were associated with an increased mortality risk. Results changed only partly when using the 140/90 mmHg targets for categorization.

CONCLUSIONS

In the RIACE cohort, at variance with the general hypertensive population, resistant hypertension did not predict death beyond target organ damage. Our findings may be explained by the high mortality risk conferred by type 2 diabetes and the low BP values observed in controlled hypertensive patients, which may mask risk associated with resistant hypertension. Less stringent BP goals may be preferable in high-risk patients with type 2 diabetes.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT00715481 , retrospectively registered 15 July, 2008.

Higher albumin:creatinine ratio and lower estimated glomerular filtration rate are potential risk factors for decline of physical performance in the elderly: the Cardiovascular Health Study

Introduction

Mildly reduced renal function and elevated urine protein levels are each prospectively associated with hip fracture risk in older adults. Here we determine whether these markers are associated with reduced appendicular muscle performance.

Methods

We prospectively examined the associations of urine albumin:creatinine ratio (ACR) and reduced estimated glomerular filtration rate (eGFR) with longitudinal changes in grip strength and gait speed >2 years in 2317 older community-dwelling men and women (median age 77 years). The median ACR was 9.8 [interquartile range (IQR) 5.40–21.50] mg/g creatinine and the median eGFR was 71.6 (IQR 59.1–83.56) mL/min/1.73 m². Models were adjusted for demographic factors, clinical history and biochemical measures in four candidate pathways: diabetes, oxidative stress, inflammation and fibrosis.

Results

In demographic- and covariate-adjusted models, a 2-fold higher baseline urine ACR was associated with longitudinal changes of −0.17 kg [95% confidence interval (CI) −0.29 to −0.06) in grip strength and −1.10 cm/s (95% CI −1.67 to −0.53) gait speed per year. Corresponding estimates for a 10 mL/min/1.73 m² lower baseline eGFR were −0.13 kg (95% CI −0.23 to −0.04) and −0.89 cm/s (95% CI −1.37 to −0.40), respectively. The associations of a 2-fold higher baseline ACR and a 10 mL/min/1.73 m² lower baseline eGFR using cystatin C with grip strength and gait speed were equivalent to ∼1.2–1.9 additional years of age. Adjustment for covariates in candidate pathways did not attenuate these estimates.

Conclusions

In older adults, higher ACR and lower eGFR are potential risk factors for a decline of physical performance >2 years.

Effectiveness of dapagliflozin versus comparators on renal endpoints in the real world: A multicentre retrospective study

AIM

To evaluate the changes in renal endpoints in type 2 diabetes patients treated with dapagliflozin versus other glucose-lowering medications in routine clinical practice.

MATERIALS AND METHODS

DARWIN-T2D was a retrospective study conducted at 46 outpatient diabetes clinics in Italy. An automated software collected data on 17 285 patients who received dapagliflozin, glucagon-like peptide-1 receptor agonists, dipeptidyl peptidase-4 inhibitors, or gliclazide, 6751 of whom had a follow-up visit. We analysed changes in albumin excretion rate (AER) and estimated glomerular filtration rate (eGFR).

RESULTS

Patients who received dapagliflozin (n = 473) were younger, more obese, and had a poorer glucose control than those who received a comparator (n = 2973). After ~6 months, median (interquartile range) AER declined by 37%, from 19.5 (7.5-78.2) to 13.2 (6.5-45.0) mg/g (P < 0.0001) in the dapagliflozin group and did not change in the comparator group. After adjusting for confounders, therapy with dapagliflozin versus comparators was associated with an AER reduction of 26.4 ± 13.1 mg/g (P = 0.045), and eGFR (mL/min/1.73 m² ) diminished by 1.1 ± 0.5 (P = 0.049) in the dapagliflozin group and by 0.6 ± 9.1 (P = 0.002) in the comparator group (P = 0.35 between groups). No patient treated with dapagliflozin versus four patients treated with comparators experienced a doubling of serum creatinine.

CONCLUSIONS

The antiproteinuric effect of dapagliflozin is confirmed here for the first time by real-world data. Despite a mild decline in eGFR, there was no evidence of clinically relevant worsening in renal function.

Phenotyping normal kidney function in elderly patients with type 2 diabetes: a cross-sectional multicentre study

AIMS

Type 2 diabetes (T2D) accelerates the decline in glomerular function; however, some individuals do not develop chronic kidney disease despite advanced age and long-lasting T2D. We aimed to phenotype patients with T2D aged 80 years or older who presented with a fully preserved kidney function.

METHODS

From an Italian population of 281,217 T2D outpatients, we collected data on demographics, anthropometrics, diabetes duration, HbA1c, fasting plasma glucose, lipids, liver enzymes, estimated glomerular filtration rate (eGFR), albumin excretion rate (AER), chronic complications, and medication use. We primarily compared patients with a fully preserved kidney function (eGFR > 90 ml/min/1.73 m² and AER < 30 mg/24 h, or G1A1) with those with mild kidney impairment (eGFR 60-90 ml/min/1.73 m² and AER < 30 mg/24 h, or G2A1).

RESULTS

N = 113,860 had available data for eGFR and AER, 21,648 of whom were aged ≥ 80. G1A1 (n = 278) and G2A1 (n = 6647) patients represented 1.3 and 30.7% of aged T2D patients, respectively, with an average diabetes duration of 16 years. Differences between the G1A1 and G2A1 groups were entered in a multiple logistic regression analysis with and without imputation of missing data. After adjustment and in both imputed and non-imputed datasets, younger age, lower BMI and lower triglycerides were associated with fully preserved versus mildly impaired kidney function. The comparison between G1A1 and G1A2/3 yielded different results.

CONCLUSIONS

In a rare population of patients with a fully preserved kidney function despite old age and long-lasting diabetes, lower BMI and triglycerides suggest that protection from lipotoxicity may preserve kidney function over time.

Non-albuminuric renal impairment is a strong predictor of mortality in individuals with type 2 diabetes: the Renal Insufficiency And Cardiovascular Events (RIACE) Italian multicentre study

AIMS/HYPOTHESIS

Non-albuminuric renal impairment has become the prevailing diabetic kidney disease (DKD) phenotype in individuals with type 2 diabetes and an estimated GFR (eGFR) <60 ml min^-1 1.73 m^-2. In the present study, we compared the rate and determinants of all-cause death in individuals with this phenotype with those in individuals with albuminuric phenotypes.

METHODS

This observational prospective cohort study enrolled 15,773 individuals with type 2 diabetes in 2006-2008. Based on baseline albuminuria and eGFR, individuals were classified as having: no DKD (Alb^-/eGFR^-), albuminuria alone (Alb⁺/eGFR^-), reduced eGFR alone (Alb^-/eGFR⁺), or both albuminuria and reduced eGFR (Alb⁺/eGFR⁺). Vital status on 31 October 2015 was retrieved for 15,656 individuals (99.26%).

RESULTS

Mortality risk adjusted for confounders was lowest for Alb^-/eGFR^- (reference category) and highest for Alb⁺/eGFR⁺ (HR 2.08 [95% CI 1.88, 2.30]), with similar values for Alb⁺/eGFR^- (1.45 [1.33, 1.58]) and Alb^-/eGFR⁺ (1.58 [1.43, 1.75]). Similar results were obtained when individuals were stratified by sex, age (except in the lowest age category) and prior cardiovascular disease. In normoalbuminuric individuals with eGFR <45 ml min^-1 1.73 m^-2, especially with low albuminuria (10-29 mg/day), risk was higher than in microalbuminuric and similar to macroalbuminuric individuals with preserved eGFR. Using recursive partitioning and amalgamation analysis, prevalent cardiovascular disease and lower HDL-cholesterol were the most relevant correlates of mortality in all phenotypes. Higher albuminuria within the normoalbuminuric range was associated with death in non-albuminuric DKD, whereas the classic 'microvascular signatures', such as glycaemic exposure and retinopathy, were correlates of mortality only in individuals with albuminuric phenotypes.

CONCLUSIONS/INTERPRETATION

Non-albuminuric renal impairment is a strong predictor of mortality, thus supporting a major prognostic impact of renal dysfunction irrespective of albuminuria. Correlates of death partly differ from the albuminuric forms, indicating that non-albuminuric DKD is a distinct phenotype.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00715481.

Haemoglobin A1c variability is a strong, independent predictor of all-cause mortality in patients with type 2 diabetes

AIMS

To evaluate various measures of haemoglobin (Hb) A1c variability, compared with average HbA1c, as independent predictors of mortality.

MATERIALS AND METHODS

The Renal Insufficiency And Cardiovascular Events Italian multicentre study enroled 15 733 patients with type 2 diabetes from 19 diabetes clinics during 2006-2008. A total of 3 to 5 HbA1c measures, obtained during the 2-year period before enrolment, were available from 9 centres (8290 patients) and were used to calculate average HbA1c (HbA1c -MEAN) and HbA1c variability, measured as intra-individual standard deviation (HbA1c-SD), SD adjusted for the number of HbA1c assessments (HbA1c-AdjSD) and coefficient of variation (HbA1c-CV), that is, the HbA1c-SD to HbA1c-MEAN ratio. Vital status on October 31, 2015 was retrieved for 8252 patients (99.5%).

RESULTS

The measures of HbA1c variability increased according to quartiles of HbA1c-MEAN and vice versa. HbA1c-MEAN and measures of HbA1c variability were associated with all-cause mortality; however, the strength of association of HbA1c-MEAN was lower than that of HbA1c -SD, HbA1c-CV or HbA1c-AdjSD, and disappeared after adjusting for confounders and any of the measures of HbA1c variability. Mortality increased with quartiles of HbA1c-MEAN, HbA1c -SD, HbA1c-CV and HbA1c-AdjSD, but only the association with HbA1c variability measures remained after adjustment for confounders and/or each other measure. In the fully adjusted model, mortality risk was lower for HbA1c-SD below the median and higher for HbA1c-SD above the median, regardless of whether HbA1c-MEAN was below or above the median. Conclusions HbA1c variability is a strong, independent predictor of all-cause mortality in type 2 diabetes and appears to be even more powerful than average HbA1c in predicting mortality.

Effects of retinopathy and chronic kidney disease on long-term mortality in type 2 diabetic inpatients with normal urinary albumin or protein: a retrospective cohort study

OBJECTIVE

Normoalbuminuric chronic kidney disease (NA-CKD) is recognised as a distinct phenotype of diabetic kidney disease, but the role of diabetic retinopathy (DR) in predicting long-term mortality among these patients remains unclear. Here, we aimed to investigate the effects of DR and CKD on mortality in type 2 diabetic patients with normoalbuminuria.

DESIGN

We conducted this study as a retrospective cohort study.

SETTING

We collected clinical information from the medical records of a public medical centre in central Taiwan.

PARTICIPANTS

Patients with type 2 diabetes (n=665) who were hospitalised due to poor glucose control were consecutively enrolled and followed for a median of 6.7 years (IQR 4.1‒9.6 years). Patients with either urinary protein excretion >150 mg/day or urine albumin excretion >30 mg/day were excluded.

PRIMARY OUTCOME MEASURE

All-cause mortality served as the primary follow-up outcome, and the mortality data were obtained from the national registry in Taiwan.

RESULTS

The patients with CKD and DR showed the highest mortality rate (log-rank p<0.001). The risks of all-cause mortality (HR 2.263; 95% CI 1.551 to 3.302) and cardiovascular mortality (HR 2.471; 95% CI 1.421 to 4.297) were significantly greater in patients with CKD and DR than in those without CKD or DR, after adjusting for the associated risk factors.

CONCLUSIONS

DR is an independent predictor for all-cause and cardiovascular mortality in type 2 diabetic inpatients with normoalbuminuria. Moreover, DR with CKD shows the highest risks of all-cause and cardiovascular mortality among these patients. Funduscopy screening can provide additive information on mortality in patients with type 2 diabetes, even among those with NA-CKD.

Defining the contribution of chronic kidney disease to all-cause mortality in patients with type 2 diabetes: the Renal Insufficiency And Cardiovascular Events (RIACE) Italian Multicenter Study

AIMS

To define the contribution of chronic kidney disease (CKD) to excess mortality in patients with type 2 diabetes and identify the baseline variables associated with all-cause death in those with and without CKD using the RECursive Partitioning and Amalgamation (RECPAM) method.

METHODS

This observational, longitudinal, cohort study enrolled 15,773 consecutive non-dialytic patients with type 2 diabetes in 19 Diabetes Clinics throughout Italy in 2006-2008. Based on the presence of albuminuria ≥ 30 mg day^-1 and/or estimated glomerular filtration rate (eGFR) < 60 mL min^-1·1.73 m^-2 at baseline, patients were classified as having or not CKD. Vital status was verified on October 31, 2015 for 99.26% of patients.

RESULTS

Mortality increased with increasing albuminuria and eGFR category. Excess risk versus the general population was maximal in patients aged < 55 years in the worse albuminuria or eGFR category. Conversely, in subjects aged ≥ 75 years with albuminuria < 10 mg day^-1 or eGFR ≥ 75 mL min^-1·1.73 m^-2, excess mortality was no longer detectable. At RECPAM analysis, the main correlates of death in the whole cohort were albuminuria > 44 mg day^-1, prevalent CVD, and eGFR < ~ 75 mL min^-1·1.73 m^-2; gender, prevalent CVD, and higher albuminuria in the normoalbuminuric range, in patients without CKD; and CVD, eGFR ~ < 50 mL min^-1·1.73 m^-2, and albuminuria > 53 mg day^-1, in those with CKD.

CONCLUSIONS

CKD is a major contributor to excess mortality in type 2 diabetes, conferring a very high risk in younger patients and fully accounting for excess risk in the older ones. Higher albuminuria and lower eGFR, even in the normal range, identify individuals with increased mortality risk. Trial registration ClinicalTrials.gov (NCT00715481; https://clinicaltrials.gov/ct2/show/NCT00715481 ).

Normoalbuminuric kidney impairment in patients with T1DM: insights from annals initiative

BACKGROUND

We described, in a large sample of patients with type 1 diabetes mellitus (T1DM) and GFR ≤ 60 mL/min/1.73 m² (with or without albuminuria), the differences in the clinical features associated with the two different chronic kidney disease phenotypes and we investigated, in a subset of patients, the modulating role of albuminuria on kidney disease progression.

METHODS

Clinical data of 1395 patients with T1DM were extracted from electronic medical records.

RESULTS

Albuminuria was detected in 676 (48.5%) patients, with the remaining 719 (51.5%) patients having normoalbuminuric renal impairment. Those with albuminuria showed an evident worse cardiovascular risk profile as compared to patients with normoalbuminuria. A subgroup of 582 patients was followed up over a 4-year period. One hundred and twenty five patients (21.5%) showed a loss of eGFR > 30%. The proportion of patients reaching the renal outcome was significantly higher among those with baseline albuminuria as compared to patients with normoalbuminuria (P < 0.0001). At the multivariate logistic analysis microalbuminuria, macroalbuminuria and proliferative retinopathy were the only parameters independently associated to eGFR reduction.

CONCLUSIONS

The proportion of T1DM patients with normoalbuminuria renal impairment is high (about 50%). These patients have a slower eGFR decline as compared to that observed in patients with albuminuria renal impairment.

Long-term intra-individual variability of albuminuria in type 2 diabetes mellitus: implications for categorization of albumin excretion rate

BACKGROUND

Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease in the Western world. Early and accurate identification of DKD offers the best chance of slowing the progression of kidney disease. An important method for evaluating risk of progressive DKD is abnormal albumin excretion rate (AER). Due to the high variability in AER, most guidelines recommend the use of more than or equal to two out of three AER measurements within a 3- to 6-month period to categorise AER. There are recognised limitations of using AER as a marker of DKD because one quarter of patients with type 2 diabetes may develop kidney disease without an increase in albuminuria and spontaneous regression of albuminuria occurs frequently. Nevertheless, it is important to investigate the long-term intra-individual variability of AER in participants with type 2 diabetes.

METHODS

Consecutive AER measurements (median 19 per subject) were performed in 497 participants with type 2 diabetes from 1999 to 2012 (mean follow-up 7.9 ± 3 years). Baseline clinical characteristics were collected to determine associations with AER variability. Participants were categorised as having normo-, micro- or macroalbuminuria according to their initial three AER measurements. Participants were then categorised into four patterns of AER trajectories: persistent, intermittent, progressing and regressing. Coefficients of variation were used to measure intra-individual AER variability.

RESULTS

The median coefficient of variation of AER was 53.3%, 76.0% and 67.0% for subjects with normo-, micro- or macroalbuminuria at baseline. The coefficient of variation of AER was 37.7%, 66% and 94.8% for subjects with persistent, intermittent and progressing normoalbuminuria; 43%, 70.6%, 86.1% and 82.3% for subjects with persistent, intermittent, progressing and regressing microalbuminuria; and 55.2%, 67% and 82.4% for subjects with persistent, intermittent and regressing macroalbuminuria, respectively.

CONCLUSION

High long-term variability of AER suggests that two out of three AER measurements may not always be adequate for the optimal categorisation and prediction of AER.

Variability in HbA1c, blood pressure, lipid parameters and serum uric acid, and risk of development of chronic kidney disease in type 2 diabetes

AIM

Variability in HbA1c and blood pressure is associated with the risk of diabetic kidney disease (DKD). No evidence exists on the role of variability in lipids or serum uric acid (UA), or the interplay between the variability of different parameters, in renal outcomes.

METHODS

Within the AMD Annals database, we identified patients with ≥5 measurements of HbA1c, systolic blood pressure (SBP) and diastolic blood pressure (DBP), total-, high-density lipoprotein (HDL)- and low-density lipoprotein (LDL)-cholesterol, triglycerides, and UA. Patients were followed-up for up to 5 years. The impact of measures of variability on the risk of DKD was investigated by Cox regression analysis and recursive partitioning techniques.

RESULTS

Four-thousand, two-hundred and thirty-one patients were evaluated for development of albuminuria, and 7560 for decreased estimated glomerular filtration rate (eGFR; <60 mL/min/1.73 m² ). A significantly higher risk of developing albuminuria was associated with variability in HbA1c [upper quartile hazard ratio (HR) = 1.3; 95% confidence interval (CI) 1.1-1.6]. Variability in SBP, DBP, HDL-C, LDL-C and UA predicted the decline in eGFR, the association with UA variability being particularly strong (upper quartile HR = 1.8; 95% CI 1.3-2.4). The concomitance of high variability in HbA1c and HDL-C conferred the highest risk of developing albuminuria (HR = 1.47; 95% CI 1.17-1.84), while a high variability in UA (HR = 1.54; 95% CI 1.19-1.99) or DBP (HR = 1.47; 95% CI 1.11-1.94) conferred the highest risk of decline in eGFR.

CONCLUSION

The variability of several parameters influences the development of DKD, having a different impact on albuminuria development and on the decline in GFR.

Association of sleep-disordered breathing with diabetes-associated kidney disease

INTRODUCTION

Diabetes-associated kidney disease is characterized by impairment of renal function and albuminuria. The aim of the present study was to assess whether sleep-disordered breathing is associated with decreased estimated glomerular filtration rate or increased urine-albumin-to-creatinine-ratio independently from known modulators of diabetes-associated kidney disease.

MATERIAL AND METHODS

Estimated glomerular filtration rate and urine-albumin-to-creatinine-ratio were determined in the baseline survey of the DIACORE-SDB substudy, a prospectively planned study of Diabetes mellitus 2 patients. As a measure of the severity of sleep-disordered breathing, the apnea-hypopnea-index was assessed using a 2-channel ambulatory SDB-monitoring device.

RESULTS

A total of 679 patients (mean age 66 years, men 61%, mean body-mass-index 31.2 kg/m²) were analyzed. In multivariable linear regression models adjusting for known modulators of diabetes-associated kidney disease, such as sex, age, body-mass-index, systolic blood pressure, duration of diabetes and HbA1c, apnea-hypopnea-index [beta-estimate -0.2 ml/min/1.73 m², 95% CI (-0.3; -0.1), p = .004], duration of diabetes and age were associated with estimated glomerular filtration rate. Apnea-hypopnea-index [beta-estimate 0.01 mg/g, 95% CI (0.00; 0.02), p = .009], duration of diabetes, HbA1c and systolic blood pressure were associated with ln(urine-albumin-to-creatinine-ratio).

CONCLUSION

In patients with diabetes mellitus type 2, more severe sleep-disordered breathing is significantly associated with lower estimated glomerular filtration rate and increased albuminuria, independent of known modulators of diabetes-associated kidney disease.

Epidemiology of diabetic kidney disease in adult patients with type 1 diabetes in Italy: The AMD-Annals initiative

BACKGROUND

Patients with type 1 diabetes mellitus are at increased risk of death. This risk appears to be modulated by kidney dysfunction. The aim of this study was to evaluate the prevalence of diabetic kidney disease (DKD), its traits, and clinical correlates in a large sample of patients with type 1 diabetes.

METHODS

Clinical data of 20 464 patients with type 1 diabetes were extracted from electronic medical records. Estimated glomerular filtration rate (eGFR) and increased urinary albumin excretion were considered.

RESULTS

Mean age of the patients was 46 ± 16 years, 55.0% were males, and duration of diabetes 19 ± 13 years. The frequency of diabetic kidney disease, low eGFR, and albuminuria was 23.5%, 8.1%, and 19.5%, respectively. In the multivariate analysis the presence of diabetic kidney disease was associated with age (odds ratio [OR] = 1.14, 95% confidence interval [CI]: 1.10-1.18), duration of diabetes (OR = 1.05, 95% CI: 1.03-1.07), and worse glycemic control (OR = 1.24, 95% CI: 1.21-1.28, for every 1% glycated hemoglobin increase). Diabetic kidney disease was also independently associated with an atherogenic lipid profile and increased systolic blood pressure. Glucose control, systolic blood pressure, triglycerides, and high density lipoprotein cholesterol were associated with both low eGFR and albuminuria. Male gender, retinopathy and smoke were related to albuminuria, being female was related to low eGFR, while SUA levels were associated with DKD, low eGFR and albuminuria.

CONCLUSIONS

In our sample of patients with type 1 diabetes, diabetic kidney disease entails an unsafe cardiovascular risk profile. Hyperglycemia, arterial hypertension, and atherogenic lipid profile affected both low eGFR and albuminuria. Retinopathy and smoking were related only to albuminuria while being female and elevated serum uric acid were associated only with low eGFR.

Elevated Squamous Cell Carcinoma Antigen, Cytokeratin 19 Fragment, and Carcinoembryonic Antigen Levels in Diabetic Nephropathy

OBJECTIVE

We aimed to explore whether squamous cell carcinoma antigen (SCC), cytokeratin 19 fragment (Cyfra21-1), neuron-specific enolase (NSE), and carcinoembryonic antigen (CEA) are elevated in diabetic nephropathy (DN) and the association between urinary albumin-to-creatinine ratio (UACR) and tumor markers in diabetic patients.

METHODS

Nondialysis patients with diabetes (n = 261) and 90 healthy controls were enrolled. DN was defined as an UACR ≥ 30 mg/g in the absence of a urinary tract infection or other renal abnormalities.

RESULTS

Patients with DN had significantly higher serum SCC, Cyfra21-1, and CEA levels than those with normoalbuminuria and healthy controls. The rates of positive SCC, Cyfra21-1, and CEA significantly increased with increasing urinary albumin excretion (all P for trend < 0.001). In contrast, NSE was not affected by DN. SCC, Cyfra21-1, and CEA were significantly and positively correlated with UACR. In logistic regression, after multivariable adjustment, increased UACR was associated with increased odds ratio of elevated tumor marker levels (all P for trend < 0.05).

CONCLUSIONS

Serum levels of SCC, Cyfra21-1, and CEA are markedly increased with increasing urinary albumin excretion, which affects the specificity for diagnosis for lung cancer. Appropriate interpretation of tumor markers in diabetic patients is mandatory to avoid unnecessary and even hazardous biopsies.

Correlates of Calcaneal Quantitative Ultrasound Parameters in Patients with Diabetes: The Study on the Assessment of Determinants of Muscle and Bone Strength Abnormalities in Diabetes

OBJECTIVE

Quantitative ultrasound (QUS) provides an estimate of bone mineral density (BMD) and also evaluates bone quality, which has been related to increased fracture risk in people with diabetes. This study aimed at assessing the correlates of calcaneal QUS parameters in diabetic subjects encompassing various degrees of micro and macrovascular complications and a wide-range of peripheral nerve function.

METHODS

Four hundred consecutive diabetic patients were examined by QUS to obtain values of broadband ultrasound attenuation (BUA), the speed of sound (SOS), quantitative ultrasound index (QUI), and BMD.

RESULTS

Among surrogate measures of complications, sensory and motor nerve amplitude and heart rate response to cough test and standing correlated with QUS parameters at univariate analysis, together with age, body mass index (BMI), waist circumference, lipid profile, and renal function. Multivariate analysis revealed that BUA, SOS, QUI, and BMD were independently associated with age, male gender, hemoglobin A_1c, BMI (or fat, but not fat-free mass), and somatic and autonomic nerve function parameters.

CONCLUSIONS

These data indicate that peripheral nerve dysfunction is associated with worse QUS parameters, possibly contributing to increased fracture risk in diabetes. The positive relation of QUS measures with adiposity needs further investigation. This trial is registered with ClinicalTrials.gov (NCT01600924).

Urinary Excretion of Kidney Aquaporins as Possible Diagnostic Biomarker of Diabetic Nephropathy

Diabetic nephropathy (DN) is a microangiopathic complication of diabetes mellitus (DM) affecting one-third of diabetic patients. The large variability in the clinical presentation of renal involvement in patients with DM makes kidney biopsy a prerequisite for a correct diagnosis. However, renal biopsy is an invasive procedure associated with risk of major complications. Numerous studies aimed to identify a noninvasive biomarker of DN but, so far, none of these is considered to be sufficiently specific and sensitive. Water channel aquaporins (AQPs), expressed at the plasma membrane of epithelial tubular cells, are often dysregulated during DN. In this work, we analyzed the urine excretion of AQP5 and AQP2 (uAQP5 and uAQP2), via exosomes, in 35 diabetic patients: 12 normoalbuminuric with normal renal function (DM), 11 with proteinuric nondiabetic nephropathy (NDN), and 12 with histological diagnosis and classification of DN. ELISA and WB analysis independently showed that uAQP5 was significantly increased in DN patients. Interestingly, linear regression analysis showed a positive correlation between uAQP5 and the histological class of DN. The same analysis, focusing on uAQP2, showed comparable results. Taken together, these data suggest a possible use of AQP5 and AQP2 as novel noninvasive biomarkers to help in classifying the clinical stage of DN.

Foot insensitivity is associated with renal function decline in patients with type 2 diabetes: a cohort study

BACKGROUND

Identifying patients with diabetes at increased risk of chronic kidney disease (CKD) is essential to prevent/slow the progression to end-stage renal disease (ESRD). CKD and diabetic peripheral neuropathy (DPN) share common mechanisms. Hence, we aimed to examine the relationship between foot insensitivity and CKD in patients with Type 2 diabetes.

METHODS

A prospective observational cohort study in adults with Type 2 diabetes. Patients with ESRD were excluded. Foot insensitivity was assessed using the 10-g monofilament test. Renal function was assessed using estimated glomerular filtration rate (eGFR) based on the MDRD equation. Albuminuria was defined as the presence of urinary albumin/creatinine ratio (ACR) >3.4 mg/mmol.

RESULTS

Two hundred and twenty eight patients were recruited and followed-up for 2.5 years. One hundred and ninety patients (83.4%) had eGFR ≥ 60 ml/min/1.73 m². Seventy six (33.3%) patients had foot insensitivity (i.e. abnormal monofilament test). Patients with foot insensitivity had lower eGFR and higher prevalence of albuminuria compared to patients with normal monofilament test. After adjustment for age, gender, ethnicity, diabetes duration, HbA1c, body mass index, insulin treatment, number of anti-hypertensives, history of peripheral vascular disease, and baseline eGFR (R² 0.87), baseline foot insensitivity was associated with study-end eGFR (B = -3.551, p = 0.036).

CONCLUSIONS

Patients with Type 2 diabetes and foot insensitivity are at increased risk of eGFR decline. Identifying these patients offers an opportunity to intensify metabolic and blood pressure control to prevent/retard the development of CKD. Future studies of larger sample size and longer follow up from multiple centres are needed to assess the diagnostic performance of our findings in predicting CKD development, and to compare the performance of the monofilament test with albuminuria.

Resistant hypertension in patients with type 2 diabetes: clinical correlates and association with complications

OBJECTIVE

The phenotype of resistant hypertension in patients with type 2 diabetes has been poorly characterized. This cross-sectional analysis of the large cohort from the Renal Insufficiency and Cardiovascular Events (RIACE) study was aimed at assessing the clinical correlates and association with complications of resistant hypertension in patients with type 2 diabetes.

METHODS

The RIACE study enrolled 15,773 patients consecutively visiting 19 diabetes clinics during the years 2007-2008. Resistant hypertension, defined as BP values not on target (i.e. >130/80 mmHg, respectively) with three antihypertensive agents, was detected in 2363 individuals (15% of the whole RIACE cohort, 17.4% of hypertensive individuals, and 21.2% of treated hypertensive patients). Patients without resistant hypertension [nonresistant hypertension (NRH)], that is on target with one (n = 1569), two (n = 1369), and three (n = 803) drugs, and individuals with uncontrolled hypertension, that is untreated or not on target with less than three drugs (n = 7440), served as controls.

RESULTS

As compared with NRH and uncontrolled hypertension patients, patients with resistant hypertension were older and more frequently women and had significantly higher waist circumference, albuminuria, and serum creatinine, and lower glomerular filtration rate. Prevalence values of chronic kidney disease and advanced retinopathy were significantly higher in resistant hypertension than in both nonresistant hypertension and uncontrolled hypertension individuals, whereas cardiovascular disease was more frequent in resistant hypertension versus uncontrolled hypertension, but not nonresistant hypertension patients, especially those on 2-3 drugs.

CONCLUSIONS

Resistant hypertension is relatively common in patients with type 2 diabetes. In these individuals, age, female sex and waist circumference are independent correlates of resistant hypertension, which is strongly associated with microvascular (especially renal) disease, whereas relation with macrovascular complications is unclear.

Abnormalities of retinal ganglion cell complex at optical coherence tomography in patients with type 2 diabetes: a sign of diabetic polyneuropathy, not retinopathy

AIMS

To compare optical coherence tomography (OCT)-derived neuro-retinal parameters in patients with type 2 diabetes and non-diabetic controls and to evaluate their correlation with diabetic retinopathy (DR) and polyneuropathy (DPN).

METHODS

One-hundred consecutive patients with type 2 diabetes were examined by spectral-domain (SD) OCT for evaluating ganglion cell complex (GCC) and retinal nerve fibre layer (RNFL) thickness and two new pattern-based quantitative measures of GCC damage, global and focal loss volume (GLV and FLV). Fifty sex- and age-matched non-diabetic subjects served as control.

RESULTS

RNFL thickness (101.0±10.6 vs. 106.4±10.3 μm, P=0.003) was significantly lower and GLV (6.58±4.98 vs. 4.52±3.10 %, P=0.008) and FLV (1.90±1.97 vs. 0.89±0.84 %, P<0.0001) were significantly higher in diabetic versus control subjects. The OCT parameters did not differ significantly according to DR grade. Conversely, RNFL thickness was lower and GLV and FLV were higher in patients with versus those without DPN, and the extent of changes increased significantly with quartiles of DPN score. At both bivariate and multivariate analysis, OCT parameters, especially FLV, correlated significantly with DPN measures.

CONCLUSIONS

The GCC is significantly affected in patients with type 2 diabetes and SD-OCT might represent a useful tool to detect DPN, but not DR in these individuals.

The Impact of Creatinine Clearance Rate, Daily Urinary Albumin, and Their Joint Effect on Predicting Death in Diabetic Inpatients After Discharge: An Observational Study

Renal clearance function and urinary albumin excretion are important markers for diabetic nephropathy. We assessed whether the creatinine clearance rate (CCR) and daily urinary albumin (DUA) excretion, which both require 24-hour urine data, are better predictors of mortality in diabetic inpatients compared with the estimated glomerular filtration rate (eGFR) and urine albumin-creatinine ratio (ACR).We enrolled 1011 patients who were hospitalized due to poor glucose control, and collected clinical information, including 24-hour urine data, from their medical records. We determined the mortality rate after discharge by examining the national registry data in Taiwan.The subjects had a median follow-up of 6.5 years (interquartile range between 3.5 and 9.6 years). Subjects with a CCR < 60 mL/min and a DUA ≥ 300 mg/d had the highest mortality rate, with a hazard ratio of 3.373 (95% confidence interval = 2.469-4.609), compared with the mortality rate in subjects with a CCR ≥ 60 mL/min and a DUA < 300 mg/d. In terms of predicting mortality in diabetic inpatients, ACR had a similar sensitivity to DUA (40.3% versus 38.0%), but eGFR provided lower sensitivity than CCR (54.5% versus 66.5%).Creatinine clearance rate and DUA have an additive effect on predicting mortality in diabetic inpatients after discharge. Moreover, CCR is a more sensitive predictor of mortality than eGFR. Therefore, determining CCR using 24-hour urine data, as well as either ACR or DUA, should provide better prediction of mortality in diabetic nephropathy patients.

Independent correlates of urinary albumin excretion within the normoalbuminuric range in patients with type 2 diabetes: The Renal Insufficiency And Cardiovascular Events (RIACE) Italian Multicentre Study

AIMS

Within the normoalbuminuric range, low albuminuria (LA, 10-29 mg/24 h) is associated with higher adverse cardiovascular and renal outcomes than normal albuminuria (NA, <10 mg/24 h). This cross-sectional analysis of the cohort from the Renal Insufficiency And Cardiovascular Events (RIACE) Italian Multicentre Study was aimed at assessing the independent correlates of LA versus NA in patients with type 2 diabetes.

METHODS

This analysis involved 11,538 normoalbuminuric patients (73.2 % of the entire RIACE cohort): 6023 (52.2 %) with NA and 5515 (47.8 %) with LA. Binary logistic regression analysis with backward conditional variable selection was applied to assess the independent correlates of LA versus NA.

RESULTS

Compared with NA subjects, LA patients were more frequently males, older and with family history of hypertension, had longer diabetes duration, lower HDL cholesterol, and higher haemoglobin (Hb) A1c, triglycerides, and blood pressure (BP), use of anti-hyperglycaemic and anti-hypertensive drugs, and prevalence of metabolic syndrome, retinopathy, chronic kidney disease, any cardiovascular disease, myocardial infarction, and coronary and peripheral events. Men with LA were also more frequently current or former smokers and had higher body mass index, waist circumference, and non-HDL cholesterol. Independent correlates of LA were age (OR 1.018), family history of hypertension (OR 1.321), smoking status (former, OR 1.158; current, OR 1.237), HbA1c (OR 1.062), waist circumference (OR 1.050), triglycerides (OR 1.001), and diastolic BP (OR 1.014), together with use of anti-hyperglycaemic and anti-hypertensive agents.

CONCLUSIONS

Several risk factors are associated with increased albuminuria within the normoalbuminuric range. As most of these factors are potentially modifiable, treating them aggressively might reduce the excess risk associated with LA.

TRIAL REGISTRATION

NCT00715481; www.ClinicalTrials.gov .

Diabetic kidney disease

The kidney is arguably the most important target of microvascular damage in diabetes. A substantial proportion of individuals with diabetes will develop kidney disease owing to their disease and/or other co-morbidity, including hypertension and ageing-related nephron loss. The presence and severity of chronic kidney disease (CKD) identify individuals who are at increased risk of adverse health outcomes and premature mortality. Consequently, preventing and managing CKD in patients with diabetes is now a key aim of their overall management. Intensive management of patients with diabetes includes controlling blood glucose levels and blood pressure as well as blockade of the renin-angiotensin-aldosterone system; these approaches will reduce the incidence of diabetic kidney disease and slow its progression. Indeed, the major decline in the incidence of diabetic kidney disease (DKD) over the past 30 years and improved patient prognosis are largely attributable to improved diabetes care. However, there remains an unmet need for innovative treatment strategies to prevent, arrest, treat and reverse DKD. In this Primer, we summarize what is now known about the molecular pathogenesis of CKD in patients with diabetes and the key pathways and targets implicated in its progression. In addition, we discuss the current evidence for the prevention and management of DKD as well as the many controversies. Finally, we explore the opportunities to develop new interventions through urgently needed investment in dedicated and focused research. For an illustrated summary of this Primer, visit: http://go.nature.com/NKHDzg.

Prevalence of chronic kidney disease among individuals with diabetes in the SUPREME-DM Project, 2005-2011

AIMS

Diabetes is a leading cause of chronic kidney disease (CKD). Different methods of CKD ascertainment may impact prevalence estimates. We used data from 11 integrated health systems in the United States to estimate CKD prevalence in adults with diabetes (2005-2011), and compare the effect of different ascertainment methods on prevalence estimates.

METHODS

We used the SUPREME-DM DataLink (n = 879,312) to estimate annual CKD prevalence. Methods of CKD ascertainment included: diagnosis codes alone, impaired estimated glomerular filtration rate (eGFR) alone (eGFR < 60 mL/min/1.73 m(2)), albuminuria alone (spot urine albumin creatinine ratio > 30 mg/g or equivalent), and combinations of these approaches.

RESULTS

CKD prevalence was 20.0% using diagnosis codes, 17.7% using impaired eGFR, 11.9% using albuminuria, and 32.7% when one or more method suggested CKD. The criteria had poor concordance. After age- and sex-standardization to the 2010 U.S. Census population, prevalence using diagnosis codes increased from 10.7% in 2005 to 14.3% in 2011 (P < 0.001). The prevalence using eGFR decreased from 9.7% in 2005 to 8.6% in 2011 (P < 0.001).

CONCLUSIONS

Our data indicate that CKD prevalence and prevalence trends differ according to the CKD ascertainment method, highlighting the necessity for multiple sources of data to accurately estimate and track CKD prevalence.

Hypertriglyceridemia Is Independently Associated with Renal, but Not Retinal Complications in Subjects with Type 2 Diabetes: A Cross-Sectional Analysis of the Renal Insufficiency And Cardiovascular Events (RIACE) Italian Multicenter Study

Objective

Atherogenic dyslipidemia seems to play a major role in microvascular complications and in residual microvascular risk after statin therapy, which reduces triglycerides up to 40%. We assessed whether raised TG levels are associated with an increased burden from microvascular complications in patients with type 2 diabetes.

Methods

Subjects from the Renal Insufficiency And Cardiovascular Events (RIACE) Italian Multicentre Study (n=15,773) were divided in 4 groups depending on whether they had plasma triglycerides below (NTG, 67.8%) or above (HTG, 32.2%) 1.7 mmol/L and were (42.4%) or not on (57.6%) statin therapy. Estimated GFR (eGFR) was calculated from serum creatinine, albuminuria was measured by immunonephelometry or immunoturbidimetry, and retinopathy was evaluated by fundus examination.

Results

HTG subjects, either with or without statin, had higher prevalence of albuminuria, reduced eGFR and chronic kidney disease (CKD), especially the albuminuric forms, but not of retinopathy, than NTG subjects. In contrast, cardiovascular disease and advanced DR were more prevalent in subjects on statin than in those not, independently of triglyceride levels. Logistic regression analysis confirmed that HTG, without or with statin, was independently associated with micro and macroalbuminuria, mildly to severely reduced eGFR, and all CKD phenotypes, but not with retinopathy. The adjusted odd ratios for CKD increased linearly for every 0.26 mmol/L increase (approximately one decile) in triglyceride levels. The increase was higher with increasing severity of albuminuria, eGFR loss and CKD phenotype as well as in subjects receiving than in those not receiving statin treatment.

Conclusions

Triglycerides are associated with CKD, but not retinopathy in subjects with type 2 diabetes, independently of statin treatment. These data point to a possible role of hypertriglyceridemia in the development of CKD, though it remains to be demonstrated that diabetic individuals might benefit from triglyceride reduction with statins and eventually with combination therapy with fibrates.

Trial Registration

www.ClinicalTrials.gov NCT00715481

Updating the natural history of diabetic nephropathy

Diabetic nephropathy (DN) is a major cause of morbidity and mortality in patients with both types of diabetes and the leading cause of end-stage renal disease (ESRD) worldwide. The classical, five-stage natural history of DN, after an initial phase of hyperfiltration, is characterized by a progressive increase of albuminuria from normoalbuminuria to proteinuria, followed by a decline of glomerular filtration rate (GFR). Accumulating evidence indicates that clinical course of DN has changed profoundly, likely as a consequence of changes in treatment. In fact, remission/regression of microalbuminuria is a common feature of both type 1 and 2 diabetes which far outweighs progression to proteinuria. Moreover, GFR loss has been shown to occur independently of albuminuria or even in the absence of it. Nonalbuminuric renal impairment probably represents a different pathway to loss of renal function, which might recognize different pathogenic mechanisms, prognostic implications, and possibly therapeutic measures, as compared with the albuminuric pathway. The nonalbuminuric phenotype might be related to macroangiopathy instead of microangiopathy and/or be the consequence of repeated and/or unresolved episodes of acute kidney injury, even of mild degree. Reduced GFR and albuminuria are both powerful risk factor for cardiovascular events, whereas albuminuria appears to predict death and progression to ESRD better than GFR loss. Finally, it is unclear whether reduced GFR and albuminuria warrant different interventions and whether GFR decline may also regress in response to treatment, as proteinuria does. Further epidemiological, pathologic, pathophysiological, and intervention studies are needed to clarify the distinctive features of nonalbuminuric renal impairment.

Chronic kidney disease in type 2 diabetes: lessons from the Renal Insufficiency And Cardiovascular Events (RIACE) Italian Multicentre Study

The Renal Insufficiency And Cardiovascular Events (RIACE) Italian Multicentre Study is an ongoing observational survey that examines the role of estimated glomerular filtration rate (eGFR) as an independent predictor of cardiovascular and renal outcomes in 15,773 Italian subjects with type 2 diabetes. The analysis of data collected at the enrollment visit provided a picture of chronic kidney disease (CKD) and its association with other complications, risk factors for cardiovascular disease (CVD) and treatments in a large contemporary cohort. Main results of this analysis were that (a) non-albuminuric renal impairment is the predominant clinical phenotype in patients, particularly women, with reduced eGFR; (b) concordance between CKD and diabetic retinopathy is low, with only a minority of patients with renal dysfunction presenting with any or advanced retinal lesions; (c) the non-albuminuric form is associated with a significant prevalence of CVD, especially at the level of the coronary vascular bed; (d) CKD is associated with hemoglobin (Hb) A1c variability more than with average HbA1c, whereas retinopathy and CVD are not; (e) in elderly individuals with moderate-to-severe eGFR reduction, use of agents which are not recommended, such as sulphonylureas and metformin, is still frequent; and (f) though complications are generally more prevalent in men (except non-albuminuric renal impairment) women show a less favorable CVD risk profile and achieve therapeutic targets to a lesser extent than men, despite the fact that treatment intensity is not lower. These data update existing information on the natural history of CKD in patients with type 2 diabetes.

Pharmacokinetics, safety, and efficacy of DPP-4 inhibitors and GLP-1 receptor agonists in patients with type 2 diabetes mellitus and renal or hepatic impairment. A systematic review of the literature

Renal or hepatic impairment, often encountered in patients with type 2 diabetes, influences the pharmacokinetics and bioavailability of antihyperglycemic agents. An emerging concern is whether pharmacotherapy with incretin-based agents, the most recent drug classes to be introduced for type 2 diabetes, can be safely used in patients with renal insufficiency or hepatic damage. This literature review examines the results of studies on these novel drug classes, with a view to provide the practitioner with a balanced, evidence-based position when considering incretin-based therapies in patients with type 2 diabetes and impaired kidney or liver function. All currently available dipeptidyl peptidase-4 (DPP-4) inhibitors appear to be appropriate pharmacotherapeutic choices in patients with declining renal function, with linagliptin affording the added advantage of not requiring dose adjustment or periodic monitoring of drug-related kidney function. In contrast, caution is warranted with the use of glucagon-like peptide-1 (GLP-1) receptor agonists in patients with moderate or severe renal impairment. The slightly wider evidence base for liraglutide than for exenatide or lixisenatide is not sufficient to support its use in severe renal impairment. What little evidence there is for incretin-based therapies in hepatic impairment has come from a few past hoc analysis of clinical trials, with most precautions and warnings reflecting the paucity of knowledge about incretin efficacy or safety in this condition.

Early renal abnormalities as an indicator of cardiovascular risk in type 2 diabetes

Accurate assessment of cardiovascular (CV) risk is a prerequisite for devising effective therapeutic strategies in patients with type 2 diabetes (T2DM) as it allows to refine prognosis and treatment targets as well as the cost-benefit ratio for specific pharmacological interventions. The presence of subclinical vascular organ damage plays a well known role in determining overall risk and a wider use of low cost, easy to perform diagnostic tools to stratify CV risk is very much needed. Besides their well known prognostic value for progression to end stage renal disease (ESRD), subclinical renal abnormalities such as microalbuminuria and/or a slight reduction in estimation of glomerular filtration rate (eGFR), have been shown to be powerful, independent predictors of CV diseases in patients with T2DM. Through the combined evaluation of these two biomarkers of chronic kidney disease (CKD), clinicians can usefully and reliably get a perspective on global and CV outcome of their diabetic patients.

Implications of different laboratory-based incident diabetic kidney disease definitions on comparative effectiveness studies

Background: Comparative effectiveness studies using electronic health records (EHRs) often define chronic kidney disease (CKD) outcomes using laboratory-based definitions. Recommendations for defining CKD require multiple longitudinal measurements. The implications of applying these definitions to EHR data are poorly understood. Methods: Using a cohort of 36,025 individuals with diabetes from three health systems who initiated a new glucose-lowering medication, we compared concordance and CKD incidence rates and rate ratios for glucose-lowering medication classes for laboratory-based CKD definitions requiring one versus multiple abnormal tests. Results & conclusion: CKD incidence rates differed more than twofold based on the definition. Reassuring for CER, incidence rate ratios for glucose-lowering medication classes on risk of developing CKD were relatively unaffected by CKD definition.

Cardiac autonomic neuropathy predicts renal function decline in patients with type 2 diabetes: a cohort study

AIMS/HYPOTHESIS

The aim of this work was to assess the impact of cardiac autonomic neuropathy (CAN) on the development and progression of chronic kidney disease (CKD) in patients with type 2 diabetes.

METHODS

We conducted a cohort study in adults with type 2 diabetes. Patients with end-stage renal disease were excluded. CKD was defined as the presence of albuminuria (albumin/creatinine ratio GFR > 3.4 mg/mmol) or an estimated (eGFR) < 60 ml min(-1) 1.73 m(-2). CKD progression was based on repeated eGFR measurements and/or the development of albuminuria. CAN was assessed using heart rate variability.

RESULTS

Two hundred and four patients were included in the analysis. At baseline, the prevalence of CKD and CAN was 40% and 42%, respectively. Patients with CAN had lower eGFR and higher prevalence of albuminuria and CKD. Spectral analysis variables were independently associated with eGFR, albuminuria and CKD at baseline. After a follow-up of 2.5 years, eGFR declined to a greater extent in patients with CAN than in those without CAN (-9.0 ± 17.8% vs -3.3 ± 10.3%, p = 0.009). After adjustment for baseline eGFR and baseline differences, CAN remained an independent predictor of eGFR decline over the follow-up period (β = -3.5, p = 0.03). Spectral analysis variables were also independent predictors of eGFR decline.

CONCLUSIONS/INTERPRETATION

CAN was independently associated with CKD, albuminuria and eGFR in patients with type 2 diabetes. In addition, CAN was an independent predictor of the decline in eGFR over the follow-up period. CAN could be used to identify patients with type 2 diabetes who are at increased risk of rapid decline in eGFR, so that preventative therapies might be intensified.

Distribution of cardiovascular disease and retinopathy in patients with type 2 diabetes according to different classification systems for chronic kidney disease: a cross-sectional analysis of the renal insufficiency and cardiovascular events (RIACE) Italian multicenter study

Background

The National Kidney Foundation’s Kidney Disease Outcomes Quality Initiative (NKF’s KDOQI) staging system for chronic kidney disease (CKD) is based primarily on estimated GFR (eGFR). This study aimed at assessing whether reclassification of subjects with type 2 diabetes using two recent classifications based on both eGFR and albuminuria, the Alberta Kidney Disease Network (AKDN) and the Kidney Disease: Improving Global Outcomes (KDIGO), provides a better definition of burden from cardiovascular disease (CVD) and diabetic retinopathy (DR) than the NKF’s KDOQI classification.

Methods

This is a cross-sectional analysis of patients with type 2 diabetes (n = 15,773) from the Renal Insufficiency And Cardiovascular Events Italian Multicenter Study, consecutively visiting 19 Diabetes Clinics throughout Italy in years 2007-2008. Exclusion criteria were dialysis or renal transplantation. CKD was defined based on eGFR, as calculated from serum creatinine by the simplified Modification of Diet in Renal Disease Study equation, and albuminuria, as measured by immunonephelometry or immunoturbidimetry. DR was assessed by dilated fundoscopy. Prevalent CVD, total and by vascular bed, was assessed from medical history by recording previous documented major acute events.

Results

Though prevalence of complications increased with increasing CKD severity with all three classifications, it differed significantly between NKF’s KDOQI stages and AKDN or KDIGO risk categories. The AKDN and KDIGO systems resulted in appropriate reclassification of uncomplicated patients in the lowest risk categories and a more graded independent association with CVD and DR than the NKF’s KDOQI classification. However, CVD, but not DR prevalence was higher in the lowest risk categories of the new classifications than in the lowest stages of the NKF’s KDOQI, due to the inclusion of subjects with reduced eGFR without albuminuria. CVD prevalence differed also among eGFR and albuminuria categories grouped into AKDN and KDIGO risk category 1 and moderate, respectively, and to a lesser extent into higher risk categories.

Conclusions

Though the new systems perform better than the NKF’s KDOQI in grading complications and identifying diabetic subjects without complications, they might underestimate CVD burden in patients assigned to lower risk categories and should be tested in large prospective studies.

Trial registration

ClinicalTrials.gov; NCT00715481

Kidney dysfunction and related cardiovascular risk factors among patients with type 2 diabetes

BACKGROUND

Kidney dysfunction is a strong predictor of end-stage renal disease and cardiovascular (CV) events. The main goal was to study the clinical correlates of diabetic kidney disease in a large cohort of patients with type 2 diabetes mellitus (T2DM) attending 236 Diabetes Clinics in Italy.

METHODS

Clinical data of 120 903 patients were extracted from electronic medical records by means of an ad hoc-developed software. Estimated glomerular filtration rate (GFR) and increased urinary albumin excretion were considered. Factors associated with the presence of albuminuria only, GFR < 60 mL/min/1.73 m(2) only or both conditions were evaluated through multivariate analysis.

RESULTS

Mean age of the patients was 66.6 ± 11.0 years, 58.1% were male and mean duration of diabetes was 11.1 ± 9.4 years. The frequency of albuminuria, low GFR and both albuminuria and low GFR was 36.0, 23.5 and 12.2%, respectively. Glycaemic control was related to albuminuria more than to low GFR, while systolic and pulse pressure showed a trend towards higher values in patients with normal kidney function compared with those with both albuminuria and low GFR. Multivariate logistic analysis showed that age and duration of disease influenced both features of kidney dysfunction. Male gender was associated with an increased risk of albuminuria. Higher systolic blood pressure levels were associated with albuminuria, with a 4% increased risk of simultaneously having albuminuria and low GFR for each 5 mmHg increase.

CONCLUSIONS

In this large cohort of patients with T2DM, reduced GFR and increased albuminuria showed, at least in part, different clinical correlates. A worse CV risk profile is associated with albuminuria more than with isolated low GFR.

Obstructive sleep apnea and diabetic nephropathy: a cohort study

OBJECTIVE

Diabetic nephropathy (DN) is a leading cause of end-stage renal disease (ESRD). Obstructive sleep apnea (OSA) is common in type 2 diabetes and increases oxidative stress. Hence, OSA could promote the development and progression of DN.

RESEARCH DESIGN AND METHODS

This was a cohort study in adults with type 2 diabetes. Patients with known OSA or ESRD were excluded. DN was defined as the presence of albuminuria or an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2. DN progression was based on eGFR measurements. OSA was defined as apnea hypopnea index (AHI) ≥5 events/h. Serum nitrotyrosine abundance (a marker of nitrosative stress) was measured by ELISA.

RESULTS

A total of 224 patients were included. OSA and DN prevalence was 64.3 and 40.2, respectively. DN prevalence was higher in patients with OSA (OSA+) compared with those without OSA (OSA-) (49.3% vs. 23.8%, P < 0.001). After adjustment, OSA (odds ratio 2.64 [95% CI 1.13-6.16], P = 0.02) remained independently associated with DN. After an average follow-up of 2.5 (0.7) years, eGFR decline was greater in OSA+ compared with OSA- patients (median -6.8% [interquartile range -16.1 to 2.2] vs. -1.6% [-7.7 to 5.3%], P = 0.002). After adjusting, both baseline OSA (B = -3.8, P = 0.044) and AHI (B = -4.6, P = 0.02) remained independent predictors of study-end eGFR. Baseline serum nitrotyrosine abundance (B = -0.24, P = 0.015) was an independent predictor of study-end eGFR after adjustment.

CONCLUSIONS

OSA is independently associated with DN in type 2 diabetes. eGFR declined faster in patients with OSA. Nitrosative stress may provide a pathogenetic link between OSA and DN. Interventional studies assessing the impact of OSA treatment on DN are needed.

Gender differences in cardiovascular disease risk factors, treatments and complications in patients with type 2 diabetes: the RIACE Italian multicentre study

OBJECTIVES

Poorer control of risk factors for cardiovascular disease (CVD) has been reported in diabetic women, as compared with diabetic men. It has been proposed that this finding is due to gender disparities in treatment intensity. We investigated this hypothesis in a large contemporary cohort of subjects with type 2 diabetes.

DESIGN

Observational, cross-sectional study.

SUBJECTS AND SETTING

Consecutive patients with type 2 diabetes from the Renal Insufficiency And Cardiovascular Events (RIACE) Italian multicentre study (n = 15 773), attending 19 hospital-based diabetes clinics in 2007-2008.

MAIN OUTCOME MEASURES

Traditional CVD risk factors, macro- and microvascular complications and current glucose-, lipid- and blood pressure (BP)-lowering treatments were assessed.

RESULTS

Although CVD was more prevalent in men, women showed a less favourable CVD risk profile and worse performance in achieving treatment targets for haemoglobin A1c , LDL, HDL and non-HDL cholesterol, systolic blood pressure (BP) and in particular obesity [body mass index (BMI) and waist circumference], but not for triglycerides and diastolic BP. However, women were more frequently receiving pharmacological treatment for hypertension and to a lesser extent hyperglycaemia and dyslipidaemia than men, and female gender remained an independent predictor of unmet therapeutic targets after adjustment for confounders such as treatments, BMI, duration of diabetes and, except for the systolic BP goal, age.

CONCLUSIONS

In women with type 2 diabetes from the RIACE cohort, a more adverse CVD risk profile and a higher likelihood of failing treatment targets, compared with men, were not associated with treatment differences. This suggests that factors other than gender disparities in treatment intensity are responsible.

HbA1c variability as an independent correlate of nephropathy, but not retinopathy, in patients with type 2 diabetes: the Renal Insufficiency And Cardiovascular Events (RIACE) Italian multicenter study

OBJECTIVE

To examine the association of hemoglobin (Hb) A1c variability with microvascular complications in the large cohort of subjects with type 2 diabetes from the Renal Insufficiency And Cardiovascular Events (RIACE) Italian Multicenter Study.

RESEARCH DESIGN AND METHODS

Serial (3-5) HbA1c values collected in a 2-year period before enrollment were available from 8,260 subjects from 9 centers (of 15,773 patients from 19 centers). HbA1c variability was measured as the intraindividual SD of 4.52 ± 0.76 values. Diabetic retinopathy (DR) was assessed by dilated funduscopy. Chronic kidney disease (CKD) was defined based on albuminuria, as measured by immunonephelometry or immunoturbidimetry, and estimated glomerular filtration rate (eGFR) was calculated from serum creatinine.

RESULTS

Median and interquartile range of average HbA1c (HbA1c-MEAN) and HbA1c-SD were 7.57% (6.86-8.38) and 0.46% (0.29-0.74), respectively. The highest prevalence of microalbuminuria, macroalbuminuria, reduced eGFR, albuminuric CKD phenotypes, and advanced DR was observed when both HbA1c parameters were above the median and the lowest when both were below the median. Logistic regression analyses showed that HbA1c-SD adds to HbA1c-MEAN as an independent correlate of microalbuminuria and stages 1-2 CKD and is an independent predictor of macroalbuminuria, reduced eGFR, and stages 3-5 albuminuric CKD, whereas HbA1c-MEAN is not. The opposite was found for DR, whereas neither HbA1c-MEAN nor HbA1c-SD affected nonalbuminuric CKD.

CONCLUSIONS

In patients with type 2 diabetes, HbA1c variability affects (albuminuric) CKD more than average HbA1c, whereas only the latter parameter affects DR, thus suggesting a variable effect of these measures on microvascular complications.