Retinal artery to vein ratio is associated with cerebral microbleeds in individuals with type 1 diabetes

OBJECTIVES

A third of asymptomatic individuals with type 1 diabetes (T1D) show signs of cerebrovascular disease in brain MRI. These signs associate with advanced stages of diabetic retinal disease, but not in mild or moderate retinopathy. We aimed to evaluate a wider spectrum of retinal changes by exploring the relationship between quantitative measures of retinal vessel parameters (RVP) and cerebrovascular changes in T1D.

METHODS

We included 146 neurologically asymptomatic individuals with T1D [51% women, median age 40 (33.0-45.1) years] and 24 healthy, sex-matched and age-matched controls. All individuals underwent a clinical and biochemical work-up and brain MRI, which was evaluated for cerebral microbleeds (CMBs), white matter hyperintensities, and lacunar infarcts. RVPs, including central retinal arteriole (CRAE) and central retinal vein (CRVE) equivalents and the ratio of the two variables (arteriovenous ratio, AVR) were assessed quantitatively by a computer-assisted method (IVAN software, version 3.2.6) from fundus images.

RESULTS

Among T1D participants, those with CMBs had a lower arteriovenous ratio (AVR) compared with those without CMBs ( P  = 0.023). AVR was inversely associated with the amount of CMBs ( r  = -0.063, P  = 0.035). CMB prevalence was higher in those with AVR below the median (31%) compared with above the median (16%, P  < 0.001), and this difference was significant also after individuals with only no-to-mild retinopathy were included (28 vs. 16%, P  = 0.005). A correlation between blood pressure and CRAE ( r  = -0.19, P  = 0.025) appeared among those with T1D.

CONCLUSION

Regardless of the severity of diabetic retinopathy, AVR is associated with the existence of CMBs in T1D.

Insulin sensitivity estimates and their longitudinal association with coronary artery disease in type 1 diabetes. Does it matter?

BACKGROUND

Insulin resistance and chronic kidney disease are both associated with increased coronary artery disease risk. Many formulae estimating glucose disposal rate in type 1 diabetes infer insulin sensitivity from clinical data. We compare associations and performance relative to traditional risk factors and kidney disease severity between three formulae estimating the glucose disposal rate and coronary artery disease in people with type 1 diabetes.

METHODS

The baseline glucose disposal rate was estimated by three (Williams, Duca, and Januszewski) formulae in FinnDiane Study participants and related to subsequent incidence of coronary artery disease, by baseline kidney status.

RESULTS

In 3517 adults with type 1 diabetes, during median (IQR) 19.3 (14.6, 21.4) years, 539 (15.3%) experienced a coronary artery disease event, with higher rates with worsening baseline kidney status. Correlations between the three formulae estimating the glucose disposal rate were weak, but the lowest quartile of each formula was associated with higher incidence of coronary artery disease. Importantly, only the glucose disposal rate estimation by Williams showed a linear association with coronary artery disease risk in all analyses. Of the three formulae, Williams was the strongest predictor of coronary artery disease. Only age and diabetes duration were stronger predictors. The strength of associations between estimated glucose disposal rate and CAD incidence varied by formula and kidney status.

CONCLUSIONS

In type 1 diabetes, estimated glucose disposal rates are associated with subsequent coronary artery disease, modulated by kidney disease severity. Future research is merited regarding the clinical usefulness of estimating the glucose disposal rate as a coronary artery disease risk factor and potential therapeutic target.

Stroke incidence increases with diabetic retinopathy severity and macular edema in type 1 diabetes

BACKGROUND

As the retina is suggested to mirror the brain, we hypothesized that diabetic retinopathy and macular edema are indicative of stroke risk in type 1 diabetes and sought to assess this association in individuals with type 1 diabetes.

METHODS

We included 1,268 adult FinnDiane Study participants with type 1 diabetes (age 38.7 ± 11.8 years, 51.7% men vs. 48.3% women, and 31.5% had diabetic kidney disease), data on baseline diabetic retinopathy severity, and first stroke during our observational follow-up. Retinopathy was graded by the Early Treatment Diabetic Retinopathy Study (ETDRS) scale, and macular edema as clinically significant (CSME) or not. Strokes identified from registries were confirmed from medical files. Adjusted hazard ratios (HR) for stroke by retinopathy severity and CSME were calculated by Cox models adjusted for clinical confounders, including diabetic kidney disease.

RESULTS

During median 18.0 (14.1-19.3) follow-up years, 130 strokes (96 ischemic, 34 hemorrhagic) occurred. With no-very mild (ETDRS 10-20) retinopathy as reference, the adjusted HR for stroke was 1.79 (95%CI 1.02-3.15) in non-proliferative (ETDRS 35-53), and 1.69 (1.02-2.82) in proliferative (ETDRS 61-85) retinopathy. Corresponding adjusted HR for ischemic stroke was 1.68 (0.91-3.10) in non-proliferative and 1.35 (0.77-2.36) in proliferative retinopathy. The adjusted HR for hemorrhagic stroke was 2.84 (0.66-12.28) in non-proliferative and 4.31 (1.16-16.10) in proliferative retinopathy. CSME did not increase HR for any stroke type after adjustment for clinical confounders (data not shown).

CONCLUSIONS

Stroke incidence increases with the severity of diabetic retinopathy independently of comorbid conditions, including diabetic kidney disease.

No correlation between carotid intima-media thickness and long-term glycemic control in individuals with type 1 diabetes

AIMS

To determine whether carotid intima-media thickness (CIMT), a surrogate marker of cardiovascular disease (CVD), is associated with long-term blood glucose control in individuals with type 1 diabetes (T1D).

METHODS

We recruited 508 individuals (43.4% men; median age 46.1, IQR 37.8-55.9 years) with T1D (median diabetes duration of 30.4, IQR 21.2-40.8 years) in a cross-sectional retrospective sub-study, part of the Finnish Diabetic Nephropathy (FinnDiane) Study. Glycated hemoglobin (HbA1c) data were collected retrospectively over the course of ten years (HbA1c-meanoverall) prior to the clinical study visit that included a clinical examination, biochemical sampling, and ultrasound of the common carotid arteries.

RESULTS

Individuals with T1D had a median CIMT of 606 μm (IQR 538-683 μm) and HbA1c of 8.0% (7.3-8.8%) during the study visit and HbA1c-meanoverall of 8.0% (IQR 7.3-8.8%). CIMT did not correlate with HbA1c (p = 0.228) at visit or HbA1c-meanoverall (p = 0.063). After controlling for relevant factors in multivariable linear regression analysis, only age was associated with CIMT (p < 0.001). After further dividing CIMT into quartiles, no correlation between long-term glucose control and CIMT (%, 1st 8.1 [IQR 7.2-8.9] vs 4th 7.9 [7.4-8.7], p = 0.730) was found.

CONCLUSIONS

We observed no correlation between long-term blood glucose control and CIMT in individuals with T1D. This finding suggests that the development of early signs of macrovascular atherosclerosis is not strongly affected by the glycemic control in people with T1D.

Atrophy of the optic chiasm is associated with microvascular diabetic complications in type 1 diabetes

Introduction

Diabetic neuropathy and diabetic eye disease are well known complications of type 1 diabetes. We hypothesized that chronic hyperglycemia also damages the optic tract, which can be measured using routine magnetic resonance imaging. Our aim was to compare morphological differences in the optic tract between individuals with type 1 diabetes and healthy control subjects. Associations between optic tract atrophy and metabolic measures, cerebrovascular and microvascular diabetic complications were further studied among individuals with type 1 diabetes.

Methods

We included 188 subjects with type 1 diabetes and 30 healthy controls, all recruited as part of the Finnish Diabetic Nephropathy Study. All participants underwent a clinical examination, biochemical work-up, and brain magnetic resonance imaging (MRI). Two different raters manually measured the optic tract.

Results

The coronal area of the optic chiasm was smaller among those with type 1 diabetes compared to non-diabetic controls (median area 24.7 [21.0-28.5] vs 30.0 [26.7-33.3] mm2, p<0.001). In participants with type 1 diabetes, a smaller chiasmatic area was associated with duration of diabetes, glycated hemoglobin, and body mass index. Diabetic eye disease, kidney disease, neuropathy and the presence of cerebral microbleeds (CMBs) in brain MRI were associated with smaller chiasmatic size (p<0.05 for all).

Conclusion

Individuals with type 1 diabetes had smaller optic chiasms than healthy controls, suggesting that diabetic neurodegenerative changes extend to the optic nerve tract. This hypothesis was further supported by the association of smaller chiasm with chronic hyperglycemia, duration of diabetes, diabetic microvascular complications, as well as and CMBs in individuals with type 1 diabetes.

Genome-wide mRNA profiling in urinary extracellular vesicles reveals stress gene signature for diabetic kidney disease

Urinary extracellular vesicles (uEV) are a largely unexplored source of kidney-derived mRNAs with potential to serve as a liquid kidney biopsy. We assessed ∼200 uEV mRNA samples from clinical studies by genome-wide sequencing to discover mechanisms and candidate biomarkers of diabetic kidney disease (DKD) in Type 1 diabetes (T1D) with replication in Type 1 and 2 diabetes. Sequencing reproducibly showed >10,000 mRNAs with similarity to kidney transcriptome. T1D DKD groups showed 13 upregulated genes prevalently expressed in proximal tubules, correlated with hyperglycemia and involved in cellular/oxidative stress homeostasis. We used six of them (GPX3, NOX4, MSRB, MSRA, HRSP12, and CRYAB) to construct a transcriptional "stress score" that reflected long-term decline of kidney function and could even identify normoalbuminuric individuals showing early decline. We thus provide workflow and web resource for studying uEV transcriptomes in clinical urine samples and stress-linked DKD markers as potential early non-invasive biomarkers or drug targets.

Haptoglobin genotype and its relation to asymptomatic cerebral small-vessel disease in type 1 diabetes

AIM

Cerebral small-vessel disease (SVD) is prevalent in type 1 diabetes and has been associated with the haptoglobin variant allele Hp1. Contrarily, the Hp2-allele has been linked to cardiovascular disease and the role of haptoglobin-genotype in asymptomatic SVD is unknown. We, therefore, aimed to evaluate the alleles' association with SVD.

METHODS

This cross-sectional study included 179 neurologically asymptomatic adults with type 1 diabetes (women 53%, mean age 39 ± 7 years, diabetes duration 23 ± 10 years, HbA_1c 8.1 ± 3.2% [65 ± 12 mmol/mol]). Examinations included genotyping (genotypes Hp1-1, Hp2-1, Hp2-2) by polymerase chain reaction, clinical investigation, and magnetic resonance brain images assessed for SVD manifestations (white matter hyperintensities, cerebral microbleeds, and lacunar infarcts).

RESULTS

SVD prevalence was 34.6%. Haptoglobin genotype frequencies were 15.6% (Hp1-1), 43.6% (Hp1-2), and 40.8% (Hp2-2). Only diastolic blood pressure differed between the genotypes Hp1-1, Hp1-2, and Hp2-2 (81 [74-83], 75 [70-80], and 75 [72-81] mmHg, p = 0.019). Haptoglobin genotype frequencies by presence versus absence of SVD were 16.1%; 46.8%; 37.1% versus 15.4%; 41.9%; 42.7% (p = 0.758). Minor allele frequencies were 39.5% versus 36.3% (p = 0.553). Hp1 homozygotes and Hp2 carriers displayed equal proportions of SVD (35.7% vs 34.4%, p > 0.999) and SVD manifestations (white matter hyperintensities 14.3% vs 17.9%, p = 0.790; microbleeds 25.0% vs 21.9%, p = 0.904; lacunar infarcts 0% vs 3.6%, p > 0.999). Hp1-1 was not associated with SVD (OR 1.19, 95% CI 0.46-2.94, p = 0.712) when adjusting for age, blood pressure, and diabetic retinopathy.

CONCLUSIONS

Although the SVD prevalence was high, we detected no significant association between SVD and haptoglobin-genotype.

Prognosis After First-Ever Myocardial Infarction in Type 1 Diabetes Is Strongly Affected by Chronic Kidney Disease

OBJECTIVE

To study prognosis after a first-ever myocardial infarction (MI) in type 1 diabetes, as well as how different MI- and diabetes-related factors affect the prognosis and risk of secondary cardiovascular events.

RESEARCH DESIGN AND METHODS

In this observational follow-up study of 4,217 individuals from the Finnish Diabetic Nephropathy (FinnDiane) Study with no prior MI or coronary revascularization, we verified 253 (6.0%) MIs from medical records or death certificates. Mortality from cardiovascular or diabetes-related cause was our main end point, whereas hospitalization due to heart failure, coronary revascularization, and recurrent MI were secondary end points, while accounting for death as a competing risk.

RESULTS

Of the individuals studied, 187 (73.9%) died during the median post-MI follow-up of 3.07 (interquartile range 0.02-8.45) years. Independent risk factors for cardiovascular and diabetes-related mortality were estimated glomerular filtration rate categories grade 3 (G3) (hazard ratio [HR] 3.27 [95% CI 1.76-6.08]), G4 (3.62 [1.69-7.73]), and G5 (4.03 [2.24-7.26]); prior coronary heart disease diagnosis (1.50 [1.03-2.20]); and older age at MI (1.03 [1.00-1.05]). Factors associated with lower mortality were acute revascularization (HR 0.35 [95% CI 0.18-0.72]) and subacute revascularization (0.39 [0.26-0.59]). In Fine and Gray competing risk analyses, kidney failure was associated with a higher risk of recurrent MI (subdistribution HR 3.27 [95% CI 2.01-5.34]), heart failure (3.76 [2.46-5.76]), and coronary revascularization (3.04 [1.89-4.90]).

CONCLUSIONS

Individuals with type 1 diabetes have a high cardiovascular and diabetes-related mortality after their first-ever MI. In particular, poor kidney function is associated with high mortality and excessive risk of secondary cardiovascular events.

Haptoglobin Genotype Does Not Confer a Risk of Stroke in Type 1 Diabetes

The exon copy number variant in the haptoglobin gene is associated with cardiovascular and kidney disease. For stroke, previous research is inconclusive. We aimed to study the relationship between the haptoglobin Hp1/2 genotype and stroke in individuals with type 1 diabetes from the Finnish Diabetic Nephropathy Study. We included two partially overlapping cohorts: one with haptoglobin genotypes determined using genotyping for 179 individuals with stroke and 517 matched control subjects, and the other using haptoglobin genotype imputation for a larger cohort of 500 individuals with stroke and 3,806 individuals without stroke. We observed no difference in the Hp1-1, Hp2-1, and Hp2-2 genotype frequencies between individuals with or without stroke, neither in the genotyping nor the imputation cohorts. Haptoglobin genotypes were also not associated with the ischemic or hemorrhagic stroke subtypes. In our imputed haptoglobin cohort, 61% of individuals with stroke died during follow-up. However, the risk of death was not related to the haptoglobin genotype. Diabetic kidney disease and cardiovascular events were common in the cohort, but the haptoglobin genotypes were not associated with stroke when stratified by these complications. To conclude, the Hp1/2 genotypes did not affect the risk of stroke or survival after stroke in our cohort with type 1 diabetes.

Glycemic control is not related to cerebral small vessel disease in neurologically asymptomatic individuals with type 1 diabetes

AIMS

To determine if medium- and long-term blood glucose control as well as glycemic variability, which are known to be strong predictors of vascular complications, are associated with underlying cerebral small vessel disease (cSVD) in neurologically asymptomatic individuals with type 1 diabetes.

METHODS

A total of 189 individuals (47.1% men; median age 40.0, IQR 33.0-45.2 years) with type 1 diabetes (median diabetes duration of 21.7, IQR 18.3-30.7 years) were enrolled in a cross-sectional retrospective study, as part of the Finnish Diabetic Nephropathy (FinnDiane) Study. Glycated hemoglobin (HbA_1c) values were collected over the course of ten years before the visit including a clinical examination, biochemical sampling, and brain magnetic resonance imaging. Markers of glycemic control, measured during the visit, included HbA_1c, fructosamine, and glycated albumin.

RESULTS

Signs of cSVD were present in 66 (34.9%) individuals. Medium- and long-term glucose control and glycemic variability did not differ in individuals with signs of cSVD compared to those without. Further, no difference in any of the blood glucose variables and cSVD stratified for cerebral microbleeds (CMBs) or white matter hyperintensities were detected. Neither were numbers of CMBs associated with the studied glucose variables. Additionally, after dividing the studied variables into quartiles, no association with cSVD was observed.

CONCLUSIONS

We observed no association between glycemic control and cSVD in neurologically asymptomatic individuals with type 1 diabetes. This finding was unexpected considering the large number of signs of cerebrovascular pathology in these people after two decades of chronic hyperglycemia and warrants further studies searching for underlying factors of cSVD.

Urinary metabolite profiling and risk of progression of diabetic nephropathy in 2670 individuals with type 1 diabetes

AIMS/HYPOTHESIS

This prospective, observational study examines associations between 51 urinary metabolites and risk of progression of diabetic nephropathy in individuals with type 1 diabetes by employing an automated NMR metabolomics technique suitable for large-scale urine sample collections.

METHODS

We collected 24-h urine samples for 2670 individuals with type 1 diabetes from the Finnish Diabetic Nephropathy study and measured metabolite concentrations by NMR. Individuals were followed up for 9.0 ± 5.0 years until their first sign of progression of diabetic nephropathy, end-stage kidney disease or study end. Cox regressions were performed on the entire study population (overall progression), on 1999 individuals with normoalbuminuria and 347 individuals with macroalbuminuria at baseline.

RESULTS

Seven urinary metabolites were associated with overall progression after adjustment for baseline albuminuria and chronic kidney disease stage (p < 8 × 10^-4): leucine (HR 1.47 [95% CI 1.30, 1.66] per 1-SD creatinine-scaled metabolite concentration), valine (1.38 [1.22, 1.56]), isoleucine (1.33 [1.18, 1.50]), pseudouridine (1.25 [1.11, 1.42]), threonine (1.27 [1.11, 1.46]) and citrate (0.84 [0.75, 0.93]). 2-Hydroxyisobutyrate was associated with overall progression (1.30 [1.16, 1.45]) and also progression from normoalbuminuria (1.56 [1.25, 1.95]). Six amino acids and pyroglutamate were associated with progression from macroalbuminuria.

CONCLUSIONS/INTERPRETATION

Branched-chain amino acids and other urinary metabolites were associated with the progression of diabetic nephropathy on top of baseline albuminuria and chronic kidney disease. We found differences in associations for overall progression and progression from normo- and macroalbuminuria. These novel discoveries illustrate the utility of analysing urinary metabolites in entire population cohorts.

The Low-Expression Variant of FABP4 Is Associated With Cardiovascular Disease in Type 1 Diabetes

Fatty acid binding protein 4 (FABP4) is implicated in the pathogenesis of cardiometabolic disorders. Pharmacological inhibition or genetic deletion of FABP4 improves cardiometabolic health and protects against atherosclerosis in preclinical models. As cardiovascular disease (CVD) is common in type 1 diabetes, we examined the role of FABP4 in the development of complications in type 1 diabetes, focusing on a functional, low-expression variant (rs77878271) in the promoter of the FABP4 gene. For this, we assessed the risk of CVD, stroke, coronary artery disease (CAD), end-stage kidney disease, and mortality using Cox proportional hazards models for the FABP4 rs77878271 in 5,077 Finnish individuals with type 1 diabetes. The low-expression G allele of rs77878271 increased the risk of CVD, independent of confounders. Findings were tested for replication in 852 Danish and 3,678 Finnish individuals with type 1 diabetes. In the meta-analysis, each G allele increased the risk of stroke by 26% (P = 0.04), CAD by 26% (P = 0.006), and CVD by 17% (P = 0.003). In Mendelian randomization, a 1-SD unit decrease in FABP4 increased risk of CAD 2.4-fold. Hence, in contrast with the general population, among patients with type 1 diabetes the low-expression G allele of rs77878271 increased CVD risk, suggesting that genetically low FABP4 levels may be detrimental in the context of type 1 diabetes.

Cerebral small-vessel disease is associated with the severity of diabetic retinopathy in type 1 diabetes

INTRODUCTION

Cerebral small-vessel disease is common in neurologically asymptomatic individuals with type 1 diabetes. The retinal vasculature is thought to mirror the brain's vasculature, but data on this association are limited in type 1 diabetes. Our aim was to study associations between diabetic retinopathy severity and cerebral small-vessel disease in type 1 diabetes.

RESEARCH DESIGN AND METHODS

For this cross-sectional study, we enrolled 189 participants with type 1 diabetes (median age 40 (33-45) years; 53% female; diabetes duration 21.6 (18.2-30.7) years) and 29 healthy age-matched and sex-matched controls as part of the Finnish Diabetic Nephropathy Study. Participants underwent a clinical investigation, brain MRI, and fundus imaging. Signs of cerebral small-vessel disease in brain MRIs were analyzed in relation to diabetic retinopathy severity (Early Treatment Diabetic Retinopathy Study (ETDRS) score).

RESULTS

In type 1 diabetes, participants with cerebral small-vessel disease had higher ETDRS scores (35 (20-61) vs 20 (20-35), p=0.022) and a higher prevalence of proliferative diabetic retinopathy than those without cerebral small-vessel disease (25% vs 9%, p=0.002). In adjusted analysis, proliferative diabetic retinopathy was associated with cerebral small-vessel disease (OR 2.57 (95% CI 1.04 to 6.35)). Median ETDRS score (35 (20-65) vs 20 (20-35), p=0.024) and proliferative diabetic retinopathy prevalence were higher (29% vs 13%, p=0.002) in participants with versus without cerebral microbleeds. ETDRS scores increased by number of cerebral microbleeds (p=0.001), both ETDRS score (OR 1.05 (95% CI 1.02 to 1.09)) and proliferative diabetic retinopathy (8.52 (95% CI 1.91 to 37.94)) were associated with >2 cerebral microbleeds in separate multivariable analysis. We observed no association with white matter hyperintensities or lacunar infarcts.

CONCLUSIONS

Presence of cerebral small-vessel disease on brain MRI, particularly cerebral microbleeds, is associated with the severity of diabetic retinopathy.

The impact of parental risk factors on the risk of stroke in type 1 diabetes

BACKGROUND

Individuals with type 1 diabetes have a markedly increased risk of stroke. In the general population, genetic predisposition has been linked to increased risk of stroke, but this has not been assessed in type 1 diabetes. Our aim was, therefore, to study how parental risk factors affect the risk of stroke in individuals with type 1 diabetes.

METHODS

This study represents an observational follow-up of 4011 individuals from the Finnish Diabetic Nephropathy Study, mean age at baseline 37.6 ± 11.9 years. All strokes during follow-up were verified from medical records or death certificates. The strokes were classified as either ischemic or hemorrhagic. All individuals filled out questionnaires concerning their parents' medical history of hypertension, diabetes, stroke, and/or myocardial infarction.

RESULTS

During a median follow-up of 12.4 (10.9-14.2) years, 188 individuals (4.6%) were diagnosed with their first ever stroke; 134 were ischemic and 54 hemorrhagic. In Cox regression analysis, a history of maternal stroke increased the risk of hemorrhagic stroke, hazard ratio 2.86 (95% confidence interval 1.27-6.44, p = 0.011) after adjustment for sex, age, BMI, retinal photocoagulation, and diabetic kidney disease. There was, however, no association between maternal stroke and ischemic stroke. No other associations between parental risk factors and ischemic or hemorrhagic stroke were observed.

CONCLUSION

A history of maternal stroke increases the risk of hemorrhagic stroke in individuals with type 1 diabetes. Other parental risk factors seem to have limited impact on the risk of stroke.

Carotid intima-media thickness and arterial stiffness in relation to cerebral small vessel disease in neurologically asymptomatic individuals with type 1 diabetes

AIMS

To determine if arterial functional and structural changes are associated with underlying cerebral small vessel disease in neurologically asymptomatic individuals with type 1 diabetes.

METHODS

We enrolled 186 individuals (47.8% men; median age 40.0, IQR 33.0-45.0 years) with type 1 diabetes (median diabetes duration of 21.6, IQR 18.2-30.3 years), and 30 age- and sex-matched healthy controls, as part of the Finnish Diabetic Nephropathy (FinnDiane) Study. All individuals underwent a biochemical work-up, brain magnetic resonance imaging (MRI), ultrasound of the common carotid arteries and arterial tonometry. Arterial structural and functional parameters were assessed by carotid intima-media thickness (CIMT), pulse wave velocity and augmentation index.

RESULTS

Cerebral microbleeds (CMBs) were present in 23.7% and white matter hyperintensities (WMHs) in 16.7% of individuals with type 1 diabetes. Those with type 1 diabetes and CMBs had higher median (IQR) CIMT 583 (525 - 663) μm than those without 556 (502 - 607) μm, p = 0.016). Higher CIMT was associated with the presence of CMBs (p = 0.046) independent of age, eGFR, ApoB, systolic blood pressure, albuminuria, history of retinal photocoagulation and HbA_1c. Arterial stiffness and CIMT were increased in individuals with type 1 diabetes and WMHs compared to those without; however, these results were not independent of cardiovascular risk factors.

CONCLUSIONS

Structural, but not functional, arterial changes are associated with underlying CMBs in asymptomatic individuals with type 1 diabetes.

The pattern-recognition molecule H-ficolin in relation to diabetic kidney disease, mortality, and cardiovascular events in type 1 diabetes

H-ficolin recognizes patterns on microorganisms and stressed cells and can activate the lectin pathway of the complement system. We aimed to assess H-ficolin in relation to the progression of diabetic kidney disease (DKD), all-cause mortality, diabetes-related mortality, and cardiovascular events. Event rates per 10-unit H-ficolin-increase were compared in an observational follow-up of 2,410 individuals with type 1 diabetes from the FinnDiane Study. DKD progression occurred in 400 individuals. The unadjusted hazard ratio (HR) for progression was 1.29 (1.18–1.40) and 1.16 (1.05–1.29) after adjustment for diabetes duration, sex, HbA_1c, systolic blood pressure, and smoking status. After adding triglycerides to the model, the HR decreased to 1.07 (0.97–1.18). In all, 486 individuals died, including 268 deaths of cardiovascular causes and 192 deaths of complications to diabetes. HRs for all-cause mortality and cardiovascular mortality were 1.13 (1.04–1.22) and 1.05 (0.93–1.17), respectively, in unadjusted analyses. These estimates lost statistical significance in adjusted models. However, the unadjusted HR for diabetes-related mortality was 1.19 (1.05–1.35) and 1.18 (1.02–1.37) with the most stringent adjustment level. Our results, therefore, indicate that H-ficolin predicts diabetes-related mortality, but neither all-cause mortality nor fatal/non-fatal cardiovascular events. Furthermore, H-ficolin is associated with DKD progression, however, not independently of the fully adjusted model.

Frequent physical activity is associated with reduced risk of severe diabetic retinopathy in type 1 diabetes

AIMS

The aim of this study was to investigate whether leisure-time physical activity (LTPA) is associated with the development of severe diabetic retinopathy in individuals with type 1 diabetes.

METHODS

Prospective observational analysis as part of the Finnish diabetic nephropathy (FinnDiane) Study with a mean follow-up time of 10.7 years was performed. A total of 1612 individuals with type 1 diabetes were recruited, and LTPA was assessed at baseline using a validated self-report questionnaire. Severe diabetic retinopathy was defined as the initiation of laser treatment due to severe nonproliferative, proliferative retinopathy or diabetic maculopathy (identified from the Care Register for Health Care).

RESULTS

A total of 261 patients received laser treatment during the follow-up. Higher frequency of LTPA was associated with a lower incidence of severe diabetic retinopathy (p = 0.024), a finding that remained significant after adjustment for gender, duration, age at onset of diabetes, kidney function, BMI, triglycerides and systolic blood pressure. However, when HbA_1c and smoking were added to the Cox regression model the association was no more significant.

CONCLUSIONS

Frequent LTPA is associated with a lower incidence of severe diabetic retinopathy during the follow-up. The total amount or the other components of LTPA (intensity or duration of a single session) were not associated with severe diabetic retinopathy.

Comparison of Manual Cross-Sectional Measurements and Automatic Volumetry of the Corpus Callosum, and Their Clinical Impact: A Study on Type 1 Diabetes and Healthy Controls

Background and purpose: Degenerative change of the corpus callosum might serve as a clinically useful surrogate marker for net pathological cerebral impact of diabetes type 1. We compared manual and automatic measurements of the corpus callosum, as well as differences in callosal cross-sectional area between subjects with type 1 diabetes and healthy controls. Materials and methods: This is a cross-sectional study on 188 neurologically asymptomatic participants with type 1 diabetes and 30 healthy age- and sex-matched control subjects, recruited as part of the Finnish Diabetic Nephropathy Study. All participants underwent clinical work-up and brain MRI. Callosal area was manually measured and callosal volume quantified with FreeSurfer. The measures were normalized using manually measured mid-sagittal intracranial area and volumetric intracranial volume, respectively. Results: Manual and automatic measurements correlated well (callosal area vs. volume: ρ = 0.83, p < 0.001 and mid-sagittal area vs. intracranial volume: ρ = 0.82, p < 0.001). We found no significant differences in the callosal measures between cases and controls. In type 1 diabetes, the lowest quartile of normalized callosal area was associated with higher insulin doses (p = 0.029) and reduced insulin sensitivity (p = 0.033). In addition, participants with more than two cerebral microbleeds had smaller callosal area (p = 0.002). Conclusion: Manually measured callosal area and automatically segmented are interchangeable. The association seen between callosal size with cerebral microbleeds and insulin resistance is indicative of small vessel disease pathology in diabetes type 1.

Body Mass Index and Mortality in Individuals With Type 1 Diabetes

CONTEXT

The relationship between body mass index (BMI) and mortality may differ between patients with type 1 diabetes and the general population; it is not known which clinical characteristics modify the relationship.

OBJECTIVE

Our aim was to assess the relationship between BMI and mortality and the interaction with clinically meaningful factors.

DESIGN, SETTING, AND PARTICIPANTS

This prospective study included 5836 individuals with type 1 diabetes from the FinnDiane study.

MAIN OUTCOME MEASURE AND METHODS

We retrieved death data for all participants on 31 December 2015. We estimated the effect of BMI on the risk of mortality using a Cox proportional hazards model with BMI as a restricted cubic spline as well as effect modification by adding interaction terms to the spline.

RESULTS

During a median of 13.7 years, 876 individuals died. The relationship between baseline BMI and all-cause mortality was reverse J-shaped. When analyses were restricted to those with normal albumin excretion rate, the relationship was U-shaped. The nadir BMI (BMI with the lowest mortality) was in the normal weight region (24.3 to 24.8 kg/m2); however, among individuals with diabetic nephropathy, the nadir BMI was in the overweight region (25.9 to 26.1 kg/m2). Diabetic nephropathy, diabetes-onset age, and sex modified the relationship between BMI and mortality (Pinteraction < 0.05).

CONCLUSIONS

Normal weight is optimal for individuals with type 1 diabetes to delay mortality, whereas underweight might be an indication of underlying complications. Maintaining normal weight may translate into reduced risk of mortality in type 1 diabetes, particularly for individuals of male sex, later diabetes-onset age, and normal albumin excretion rate.

The role of blood pressure in risk of ischemic and hemorrhagic stroke in type 1 diabetes

Background

Hypertension is one of the strongest risk factors for stroke in the general population, while systolic blood pressure has been shown to independently increase the risk of stroke in type 1 diabetes. The aim of this study was to elucidate the association between different blood pressure variables and risk of stroke in type 1 diabetes, and to explore potential nonlinearity of this relationship.

Methods

We included 4105 individuals with type 1 diabetes without stroke at baseline, participating in the nationwide Finnish Diabetic Nephropathy Study. Mean age at baseline was 37.4 ± 11.9 years, median duration of diabetes 20.9 (interquartile range 11.5–30.4) years, and 52% were men. Office systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured. Based on these pulse pressure (PP) and mean arterial pressure (MAP) were calculated. Strokes were classified based on medical and autopsy records, as well as neuroimaging. Cox proportional hazard models were performed to study how the different blood pressure variables affected the risk of stroke and its subtypes.

Results

During median follow-up time of 11.9 (9.21–13.9) years, 202 (5%) individuals suffered an incident stroke; 145 (72%) were ischemic and 57 (28%) hemorrhagic. SBP, DBP, PP, and MAP all independently increased the risk of any stroke. SBP, PP, and MAP increased the risk of ischemic stroke, while SBP, DBP, and MAP increased the risk of hemorrhagic stroke. SBP was strongly associated with stroke with a hazard ratio of 1.20 (1.11–1.29)/10 mmHg. When variables were modeled using restricted cubic splines, the risk of stroke increased linearly for SBP, MAP, and PP, and non-linearly for DBP.

Conclusions

The different blood pressure variables are all independently associated with increased risk of stroke in individuals with type 1 diabetes. The risk of stroke, ischemic stroke, and hemorrhagic stroke increases linearly at blood pressure levels less than the current recommended treatment guidelines.

Electronic supplementary material

The online version of this article (10.1186/s12933-019-0891-4) contains supplementary material, which is available to authorized users.

Soluble receptor for AGE in diabetic nephropathy and its progression in Finnish individuals with type 1 diabetes

AIMS/HYPOTHESIS

Activation of the receptor for AGE (RAGE) has been shown to be associated with diabetic nephropathy. The soluble isoform of RAGE (sRAGE) is considered to function as a decoy receptor for RAGE ligands and thereby protects against diabetic complications. A possible association between sRAGE and diabetic nephropathy is still, however, controversial and a more comprehensive analysis of sRAGE with respect to diabetic nephropathy in type 1 diabetes is therefore warranted.

METHODS

sRAGE was measured in baseline serum samples from 3647 participants with type 1 diabetes from the nationwide multicentre Finnish Diabetic Nephropathy (FinnDiane) Study. Associations between sRAGE and diabetic nephropathy, as well as sRAGE and diabetic nephropathy progression, were evaluated by regression, competing risks and receiver operating characteristic curve analyses. The non-synonymous SNP rs2070600 (G82S) was used to test causality in the Mendelian randomisation analysis.

RESULTS

Baseline sRAGE concentrations were highest in participants with diabetic nephropathy, compared with participants with a normal AER or those with microalbuminuria. Baseline sRAGE was associated with progression from macroalbuminuria to end-stage renal disease (ESRD) in the competing risks analyses, but this association disappeared when eGFR was entered into the model. The SNP rs2070600 was strongly associated with sRAGE concentrations and with progression from macroalbuminuria to ESRD. However, Mendelian randomisation analysis did not support a causal role for sRAGE in progression to ESRD.

CONCLUSIONS/INTERPRETATION

sRAGE is associated with progression from macroalbuminuria to ESRD, but does not add predictive value on top of conventional risk factors. Although sRAGE is a biomarker of diabetic nephropathy, in light of the Mendelian randomisation analysis it does not seem to be causally related to progression from macroalbuminuria to ESRD.

Clinical and MRI Features of Cerebral Small-Vessel Disease in Type 1 Diabetes

OBJECTIVE

To assess the prevalence of cerebral small-vessel disease (SVD) in subjects with type 1 diabetes compared with healthy control subjects and to characterize the diabetes-related factors associated with SVD.

RESEARCH DESIGN AND METHODS

This substudy was cross-sectional in design and included 191 participants with type 1 diabetes and median age 40.0 years (interquartile range 33.0-45.1) and 30 healthy age- and sex-matched control subjects. All participants underwent clinical investigation and brain MRIs, assessed for cerebral SVD.

RESULTS

Cerebral SVD was more common in participants with type 1 diabetes than in healthy control subjects: any marker 35% vs. 10% (P = 0.005), cerebral microbleeds (CMBs) 24% vs. 3.3% (P = 0.008), white matter hyperintensities 17% vs. 6.7% (P = 0.182), and lacunes 2.1% vs. 0% (P = 1.000). Presence of CMBs was independently associated with systolic blood pressure (odds ratio 1.03 [95% CI 1.00-1.05], P = 0.035).

CONCLUSIONS

Cerebral SVD, CMBs in particular, is more common in young people with type 1 diabetes compared with healthy control subjects.

Regression of albuminuria and its association with incident cardiovascular outcomes and mortality in type 1 diabetes: the FinnDiane Study

AIMS/HYPOTHESIS

Our aim was to assess regression of albuminuria and its clinical consequences in type 1 diabetes.

METHODS

The analysis included 3642 participants from the Finnish Diabetic Nephropathy (FinnDiane) Study with a 24 h urine sample and a history of albuminuria available at baseline. A total of 2729 individuals had normal AER, 438 a history of microalbuminuria and 475 a history of macroalbuminuria. Regression was defined as a change from a higher category of albuminuria pre-baseline to a lower category in two out of the three most recent urine samples at baseline. The impact of regression on cardiovascular events (myocardial infarction, stroke, coronary procedure) and mortality was analysed over a follow-up of 14.0 years (interquartile range 11.9-15.9).

RESULTS

In total, 102 (23.3%) individuals with prior microalbuminuria and 111 (23.4%) with prior macroalbuminuria had regressed at baseline. For individuals with normal AER as a reference, the age-adjusted HRs (95% CI) for cardiovascular events were 1.42 (0.75, 2.68) in individuals with regression from microalbuminuria, 2.62 (1.95, 3.54) in individuals with sustained microalbuminuria, 3.15 (2.02, 4.92) in individuals with regression from macroalbuminuria and 5.49 (4.31, 7.00) in individuals with sustained macroalbuminuria. Furthermore, for all-cause and cardiovascular mortality rates, HRs in regressed individuals were comparable with those with sustained renal status at the achieved level (i.e. those who did not regress but remained at the most advanced level of albuminuria noted pre-baseline).

CONCLUSIONS/INTERPRETATION

Progression of diabetic nephropathy confers an increased risk for cardiovascular disease and premature death. Notably, regression reduces the risk to the same level as for those who did not progress.

Diabetes and intracerebral hemorrhage: baseline characteristics and mortality

BACKGROUND AND PURPOSE

Acknowledging the conflicting evidence for diabetes as a predictor of short- and long-term mortality following an intracerebral hemorrhage (ICH), we compared baseline characteristics and 30-day and long-term mortality between patients with and without diabetes after an ICH, paying special attention to differences between type 1 (T1D) and type 2 (T2D) diabetes.

METHODS

Patients with a first-ever ICH were followed for a median of 2.3 years. Adjusting for demographics, comorbidities and documented ICH characteristics increasing mortality after ICH, logistic regression analysis assessed factors associated with case fatality and 1-year survival among the 30-day survivors. Diabetes was compared with patients without diabetes in separate models as (i) any diabetes and (ii) T1D or T2D.

RESULTS

Of our 969 patients, 813 (83.9%) had no diabetes, 41 (4.2%) had T1D and 115 (11.9%) had T2D. Compared with patients without diabetes, those with diabetes were younger, more often men and more frequently had hypertension, coronary heart disease and chronic kidney disease, with similar ICH characteristics. Patients with T1D were younger, more often had chronic kidney disease and brainstem ICH, and less often had atrial fibrillation and lobar ICH, than did patients with T2D. Diabetes had no impact on case fatality. Any diabetes (odds ratio, 2.57; 1.19-5.52), T1D (odds ratio, 7.04; 1.14-43.48) and T2D (odds ratio, 2.32; 1.04-5.17) were independently associated with 1-year mortality.

CONCLUSIONS

Patients with ICH with diabetes exhibited a distinct pattern of comorbidities and disease characteristics with specific differences between T1D and T2D. Despite their younger age, T1D seems to carry a substantially higher likelihood of long-term mortality after an ICH than does T2D.

Physical Activity Reduces Risk of Premature Mortality in Patients With Type 1 Diabetes With and Without Kidney Disease

OBJECTIVE

The aims of the study were to assess how baseline leisure-time physical activity (LTPA) and its exercise components intensity, duration, and frequency are associated with all-cause and cardiovascular mortality in patients with type 1 diabetes 1) overall, 2) stratified by presence or absence of chronic kidney disease (CKD), and 3) stratified by sex.

RESEARCH DESIGN AND METHODS

The study design was prospective and observational and included 2,639 patients with type 1 diabetes from the ongoing nationwide multicenter Finnish Diabetic Nephropathy (FinnDiane) Study. Mean follow-up time was 11.4 ± 3.5 years. LTPA was assessed by using a validated self-report questionnaire. Three hundred ten patients (11.7%) had CKD defined as an estimated glomerular filtration rate of ≤60 mL/min/1.73 m².

RESULTS

During follow-up, 270 deaths occurred. LTPA and all its components were associated with all-cause mortality, even after adjustment for the potential confounders sex, diabetic nephropathy, duration of diabetes, age at onset of diabetes, systolic blood pressure, triglycerides, BMI, and HbA_1c. Only exercise intensity was associated with cardiovascular mortality after adjustment for the confounders. Of the patients with CKD, 127 died during follow-up. The total amount of LTPA and exercise frequency were independently associated with lower risk of all-cause mortality when adjusted for covariates.

CONCLUSIONS

Exercise is associated with a lower risk of premature all-cause and cardiovascular mortality in patients with type 1 diabetes. This study also demonstrates that physical activity is associated with a lower risk of mortality in patients with type 1 diabetes and CKD.

Prognosis and Its Predictors After Incident Stroke in Patients With Type 1 Diabetes

OBJECTIVE

Although patients with type 1 diabetes have a poor prognosis after a stroke, predictors of survival after an incident stroke in these patients are poorly studied.

RESEARCH DESIGN AND METHODS

In this observational study, a total of 144 patients of 4,083 with type 1 diabetes from the Finnish Diabetic Nephropathy (FinnDiane) Study suffered an incident stroke in 1997-2010, and were followed for a mean 3.4 ± 3.1 years after the stroke. Information was recorded on hard cardiovascular events and death as a result of cardiovascular or diabetes-related cause, collectively referred to as vascular composite end point. Information was collected from medical records, death certificates, and the National Care Register of Health Care. Predictors at the time of the incident stroke were studied for the end points.

RESULTS

During follow-up, 104 (72%) patients suffered a vascular composite end point. Of these, 33 (32%) had a recurrent stroke, 33 (32%) a hard cardiovascular event, and 76 (53%) died of cardiovascular or diabetes-related causes, with an overall 1-year survival of 76% and 5-year survival of 58%. The predictors of a vascular composite end point were hemorrhagic stroke subtype (hazard ratio 2.03 [95% CI 1.29-3.19]), as well as chronic kidney disease stage 2 (2.48 [1.17-5.24]), stage 3 (3.04 [1.54-6.04]), stage 4 (3.95 [1.72-9.04]), and stage 5 (6.71 [3.14-14.34]). All-cause mortality increased with deteriorating kidney function.

CONCLUSIONS

Patients with type 1 diabetes with an incident stroke have a poor cardiovascular prognosis and a high risk of all-cause mortality. In particular, hemorrhagic stroke subtype and progression of diabetic kidney disease conveys worse outcome.

Urinary liver-type fatty acid binding protein is an independent predictor of stroke and mortality in individuals with type 1 diabetes

AIMS/HYPOTHESIS

In type 1 diabetes, cardiovascular disease (CVD) and diabetic nephropathy progress in parallel, thereby potentiating the risk of premature death during their development. Since urinary liver-type fatty acid binding protein (L-FABP) predicts the progression of diabetic nephropathy, the aim of this study was to investigate whether urinary L-FABP also predicts cardiovascular outcomes and mortality.

METHODS

We tested our hypothesis in a Finnish cohort of 2329 individuals with type 1 diabetes and a median follow-up of 14.1 years. The L-FABP to creatinine ratio was determined from baseline urine samples. The predictive value of urinary L-FABP was evaluated using Cox regression models, while its added predictive benefit for cardiovascular outcomes and mortality was evaluated using a panel of statistical indexes.

RESULTS

Urinary L-FABP predicted incident stroke independently of traditional risk factors (HR 1.33 [95% CI 1.20, 1.49]) and after further adjustment for eGFR (HR 1.28 [95% CI 1.14, 1.44]) or AER (HR 1.24 [95% CI 1.06, 1.44]). In addition, it predicted mortality independently of traditional risk factors (HR 1.34 [95% CI 1.24, 1.45]), and after adjustment for eGFR (HR 1.29 [95% CI 1.18, 1.39]) or AER (HR 1.22 [95% CI 1.09, 1.36]). Urinary L-FABP was as good a predictor as eGFR or AER, and improved the AUC for both outcomes on top of traditional risk factors, with no reclassification benefit (integrated discrimination improvement/net reclassification improvement) for stroke or mortality when AER or eGFR were added to traditional risk factors. However, urinary L-FABP was not a predictor of other cardiovascular endpoints (coronary artery disease, peripheral vascular disease and overall CVD events) when adjusted for the AER.

CONCLUSIONS/INTERPRETATION

Urinary L-FABP is an independent predictor of stroke and mortality in individuals with type 1 diabetes.

Frequent and intensive physical activity reduces risk of cardiovascular events in type 1 diabetes

AIMS/HYPOTHESIS

Cardiovascular disease (CVD) is the most common cause of premature death and disability among patients with type 1 diabetes. Diabetic nephropathy accounts for the increased cardiovascular morbidity and mortality of these patients. We recently showed that the intensity of exercise predicts the incidence and progression of diabetic nephropathy in patients with type 1 diabetes. Little is known about the relationship between physical activity and CVD. Therefore, we studied how physical activity affects the risk of CVD events in patients with type 1 diabetes.

METHODS

A 10 year follow-up study including 2180 type 1 diabetes patients from the nationwide multicentre Finnish Diabetic Nephropathy Study (FinnDiane). Leisure time physical activity (LTPA) was assessed by a previously validated self-report questionnaire. A CVD event was defined as a verified myocardial infarction, coronary procedure or stroke. Patients were analysed separately for the risk of developing a first ever CVD event and for the risk of a recurrent CVD event following a baseline event.

RESULTS

A total of 206 patients had an incident CVD event during follow-up. A higher total LTPA and higher intensity, frequency and duration of activity were associated with a lower risk of incident CVD events. The observed association between exercise frequency and incident CVD remained significant when adjusted for classic risk factors. Exercise intensity also had a borderline effect on the recurrence-free time in patients with a major CVD event at baseline.

CONCLUSIONS/INTERPRETATION

This study suggests that exercise, particularly high frequency and high intensity exercise, may reduce the risk of CVD events in patients with type 1 diabetes.

The Presence and Consequence of Nonalbuminuric Chronic Kidney Disease in Patients With Type 1 Diabetes

OBJECTIVE

This study investigated the prevalence of nonalbuminuric chronic kidney disease in type 1 diabetes to assess whether it increases the risk of cardiovascular and renal outcomes as well as all-cause mortality.

RESEARCH DESIGN AND METHODS

This was an observational follow-up of 3,809 patients with type 1 diabetes from the Finnish Diabetic Nephropathy Study. All patients were Caucasians and thoroughly examined at baseline. Their mean age was 37.6 ± 11.8 years and duration of diabetes 21.2 ± 12.1 years. Follow-up data on cardiovascular and renal outcomes and mortality were retrieved from registers. During 13 years of median follow-up, 378 developed end-stage renal disease, 415 suffered an incident cardiovascular event, and 406 died.

RESULTS

At baseline, 78 (2.0%) had nonalbuminuric chronic kidney disease. This was associated with older age, female sex, history of retinal laser treatment, cardiovascular events, and the number of antihypertensive drugs in use, but not with blood pressure levels or specific antihypertensive agents. Nonalbuminuric chronic kidney disease did not increase the risk of albuminuria (hazard ratio [HR] 2.0 [95% CI 0.9-4.4]) or end-stage renal disease (HR 6.4 [0.8-53.0]) but did increase the risk of cardiovascular events (HR 2.0 [1.4-3.5]) and all-cause mortality (HR 2.4 [1.4-3.9]). The highest risk of cardiovascular and renal end points was observed in the patients with albuminuria.

CONCLUSIONS

Nonalbuminuric chronic kidney disease is not a frequent finding in patients with type 1 diabetes, but when present, it is associated with an increased risk of cardiovascular morbidity and all-cause mortality but not with renal outcomes.

Kidney injury molecule-1 and the loss of kidney function in diabetic nephropathy: a likely causal link in patients with type 1 diabetes

OBJECTIVE

We evaluated the predictive value and clinical benefit of urinary kidney injury molecule (KIM)-1 for progression of diabetic nephropathy (DN) in type 1 diabetes. We also investigated its causal role for the decrease of estimated glomerular filtration rate (eGFR) by a Mendelian randomization (MR) approach.

RESEARCH DESIGN AND METHODS

We followed 1,573 patients with type 1 diabetes for 6 years. KIM-1 was measured at baseline and normalized with urinary creatinine. KIM-1 predictive value was evaluated by Cox regression, while its added predictive benefit was evaluated using a panel of statistical indexes. The causality for the loss of renal function was evaluated with MR, utilizing the top signal from our genome-wide association study (GWAS) as the instrumental variable.

RESULTS

KIM-1 was not an independent predictor of progression of DN when adjusted for albumin excretion rate (AER) and added no prognostic benefit to AER or eGFR. In multiple regressions, KIM-1 was associated with lower eGFR independently of diabetes duration (β = -4.066; P < 0.0001) but not of AER. In our GWAS, rs2036402 in the KIM1 gene was strongly associated with KIM-1 (β = -0.51; P = 6.5 × 10(-38)). In the MR, KIM-1 was associated with lower eGFR, independently of diabetes duration and AER (β = -5.044; P = 0.040), suggesting a causal relationship.

CONCLUSIONS

KIM-1 did not predict progression to end-stage renal disease independently of AER and added no prognostic benefit to current biomarkers. Nevertheless, the MR showed that the inverse association of increased KIM-1 levels with lower eGFR is likely to represent a causal link.

Leisure-time physical activity and development and progression of diabetic nephropathy in type 1 diabetes: the FinnDiane Study

AIMS/HYPOTHESIS

The aim of this study was to assess how physical activity predicts the development and progression of diabetic nephropathy in patients with type 1 diabetes.

METHODS

This prospective study (follow-up time 6.4 ± 3.1 years) included 1,390 patients (48.5% men, mean age 37.0 ± 12.4 years, duration of diabetes 20.4 ± 12.3 years) participating in the nationwide multicentre Finnish Diabetic Nephropathy (FinnDiane) Study. Leisure-time physical activity (LTPA) was assessed using a validated self-report questionnaire. Renal status was defined according to standard clinical cut-off values for urinary AER.

RESULTS

The total amount of LTPA was not associated with progression in renal status. For the intensity of LTPA, however, the 10 year cumulative progression rate was 24.0% (95% CI 18.8, 28.8), 13.5% (95% CI 10.3, 16.6) or 13.1% (95% CI 10.3%, 16.6%; p = 0.01) of the patients with low, moderate or high intensity LTPA. This pattern was similar to that for the development of de novo microalbuminuria. Corresponding progression rates for LTPA frequency of <1, 1-2 or >2 sessions/week was 24.7% (95% CI 18.3, 30.7), 14.7% (95% CI 10.2, 19.0) or 12.6% (95% CI 9.4, 15.7), respectively (p = 0.003).

CONCLUSIONS/INTERPRETATION

This study demonstrates for the first time in a prospective setting the relationship between physical activity and the risk of diabetic nephropathy in patients with type 1 diabetes. The data suggest that physical activity, and in particular its intensity, may have an impact on the initiation and progression of diabetic nephropathy in type 1 diabetes.

Urinary adiponectin is an independent predictor of progression to end-stage renal disease in patients with type 1 diabetes and diabetic nephropathy

OBJECTIVE

We investigated the predictive value of urinary adiponectin (uADP) for the progression of diabetic nephropathy (DN) as well as for the principal determinants of uADP concentrations.

RESEARCH DESIGN AND METHODS

uADP was measured in 2,090 patients with type 1 diabetes followed for a median of 5.8 (4.4-6.9) years and in 111 subjects without diabetes. Progression was defined as a change in albuminuria (albumin excretion rate [AER]) to a higher stage or development of end-stage renal disease (ESRD). Various Cox regression and competing risk models were used to evaluate the predictive value of uADP for DN progression. The added predictive benefit to AER or estimated glomerular filtration rate (eGFR) was estimated by the area under the receiver operating characteristic curve, integrated discrimination improvement (IDI), continuous net reclassification improvement (NRI), and other statistical indexes. The determinants of uADP were investigated by multiple regression analyses.

RESULTS

uADP was an independent predictor of progression to ESRD (hazard ratio 1.60, P < 0.001) and was an even better predictor than AER (P = 0.04) or as good as eGFR (P = 0.79). Furthermore, uADP added a significant benefit when used together with AER (NRI 0.794, P = 0.03; IDI 0.115, P < 0.0001) or eGFR (NRI 0.637, P < 0.001; IDI 0.087, P < 0.0001). The common determinants of uADP were glycemic control, tubular injury, and AER.

CONCLUSIONS

uADP is a strong independent predictor of DN progression from macroalbuminuria to ESRD and adds a significant predictive benefit to current biomarkers in patients with type 1 diabetes.

Different lipid variables predict incident coronary artery disease in patients with type 1 diabetes with or without diabetic nephropathy: the FinnDiane study

OBJECTIVE

To study the ability of lipid variables to predict incident coronary artery disease (CAD) events in patients with type 1 diabetes at different stages of nephropathy.

RESEARCH DESIGN AND METHODS

Patients (n = 3,520) with type 1 diabetes and available lipid profiles participating in the Finnish Diabetic Nephropathy Study (FinnDiane) were included in the study. During a follow-up period of 10.2 years (8.6-12.0), 310 patients suffered an incident CAD event.

RESULTS

Apolipoprotein B (ApoB)/ApoA-I ratio was the strongest predictor of CAD in normoalbuminuric patients (hazard ratio 1.43 [95% CI 1.17-1.76] per one SD increase), and ApoB was the strongest in macroalbuminuric patients (1.47 [1.19-1.81]). Similar results were seen when patients were stratified by sex or glycemic control. LDL cholesterol was a poor predictor of CAD in women, normoalbuminuric patients, and patients with HbA1c below the median (8.3%, 67 mmol/L). The current recommended triglyceride cutoff of 1.7 mmol/L failed to predict CAD in normoalbuminuric patients, whereas the cohort median 0.94 mmol/L predicted incident CAD events.

CONCLUSIONS

In patients with type 1 diabetes, the predictive ability of the lipid variables differed substantially depending on the patient's sex, renal status, and glycemic control. In normoalbuminuric patients, the ratios of atherogenic and antiatherogenic lipoproteins and lipids were the strongest predictors of an incident CAD event, whereas in macroalbuminuric patients, no added benefit was gained from the ratios. Current treatment recommendations may need to be revised to capture residual CAD risk in patients with type 1 diabetes.

Novel genetic susceptibility loci for diabetic end-stage renal disease identified through robust naive Bayes classification

AIMS/HYPOTHESIS

Diabetic nephropathy is a major diabetic complication, and diabetes is the leading cause of end-stage renal disease (ESRD). Family studies suggest a hereditary component for diabetic nephropathy. However, only a few genes have been associated with diabetic nephropathy or ESRD in diabetic patients. Our aim was to detect novel genetic variants associated with diabetic nephropathy and ESRD.

METHODS

We exploited a novel algorithm, 'Bag of Naive Bayes', whose marker selection strategy is complementary to that of conventional genome-wide association models based on univariate association tests. The analysis was performed on a genome-wide association study of 3,464 patients with type 1 diabetes from the Finnish Diabetic Nephropathy (FinnDiane) Study and subsequently replicated with 4,263 type 1 diabetes patients from the Steno Diabetes Centre, the All Ireland-Warren 3-Genetics of Kidneys in Diabetes UK collection (UK-Republic of Ireland) and the Genetics of Kidneys in Diabetes US Study (GoKinD US).

RESULTS

Five genetic loci (WNT4/ZBTB40-rs12137135, RGMA/MCTP2-rs17709344, MAPRE1P2-rs1670754, SEMA6D/SLC24A5-rs12917114 and SIK1-rs2838302) were associated with ESRD in the FinnDiane study. An association between ESRD and rs17709344, tagging the previously identified rs12437854 and located between the RGMA and MCTP2 genes, was replicated in independent case-control cohorts. rs12917114 near SEMA6D was associated with ESRD in the replication cohorts under the genotypic model (p < 0.05), and rs12137135 upstream of WNT4 was associated with ESRD in Steno.

CONCLUSIONS/INTERPRETATION

This study supports the previously identified findings on the RGMA/MCTP2 region and suggests novel susceptibility loci for ESRD. This highlights the importance of applying complementary statistical methods to detect novel genetic variants in diabetic nephropathy and, in general, in complex diseases.

Different risk factor profiles for ischemic and hemorrhagic stroke in type 1 diabetes mellitus

BACKGROUND AND PURPOSE

Despite the fact that patients with type 1 diabetes mellitus have a markedly increased risk of experiencing a stroke, independent risk factors for stroke and its subtypes in these patients have remained unclear.

METHODS

A total of 4083 patients with type 1 diabetes mellitus from the Finnish Diabetic Nephropathy (FinnDiane) Study, without a history of stroke at baseline, were included. Strokes were classified based on medical files and brain imaging. At baseline, mean age was 37.4±11.8 years, duration of diabetes mellitus was 20.0 (11.0-30.0) years, and 51% were men. During 9.0±2.7 years (36 680 patient-years) of follow-up, 105 patients experienced an ischemic stroke and 44 a hemorrhagic stroke. Cox proportional hazards analyses were performed to determine independent risk factors.

RESULTS

Independent risk factors for ischemic stroke were duration of diabetes mellitus, presence of diabetic nephropathy, higher hemoglobin A1c, higher systolic blood pressure, insulin resistance, and history of smoking, whereas sex, lipids, high-sensitivity C-reactive protein, and the metabolic syndrome were not associated with an increased risk. Diabetic nephropathy, severe diabetic retinopathy, higher systolic blood pressure, and lower body mass index were independently associated with hemorrhagic stroke.

CONCLUSIONS

The risk factor profile for ischemic stroke seems partly different from that of hemorrhagic stroke in patients with type 1 diabetes mellitus.

Genome-wide association study of urinary albumin excretion rate in patients with type 1 diabetes

AIMS/HYPOTHESIS

An abnormal urinary albumin excretion rate (AER) is often the first clinically detectable manifestation of diabetic nephropathy. Our aim was to estimate the heritability and to detect genetic variation associated with elevated AER in patients with type 1 diabetes.

METHODS

The discovery phase genome-wide association study (GWAS) included 1,925 patients with type 1 diabetes and with data on 24 h AER. AER was analysed as a continuous trait and the analysis was stratified by the use of antihypertensive medication. Signals with a p value <10(-4) were followed up in 3,750 additional patients with type 1 diabetes from seven studies.

RESULTS

The narrow-sense heritability, captured with our genotyping platform, was estimated to explain 27.3% of the total AER variability, and 37.6% after adjustment for covariates. In the discovery stage, five single nucleotide polymorphisms in the GLRA3 gene were strongly associated with albuminuria (p < 5 × 10(-8)). In the replication group, a nominally significant association (p = 0.035) was observed between albuminuria and rs1564939 in GLRA3, but this was in the opposite direction. Sequencing of the surrounding genetic region in 48 Finnish and 48 UK individuals supported the possibility that population-specific rare variants contribute to the synthetic association observed at the common variants in GLRA3. The strongest replication (p = 0.026) was obtained for rs2410601 between the PSD3 and SH2D4A genes. Pathway analysis highlighted natural killer cell mediated immunity processes.

CONCLUSIONS/INTERPRETATION

This study suggests novel pathways and molecular mechanisms for the pathogenesis of albuminuria in type 1 diabetes.

Incidence of stroke according to presence of diabetic nephropathy and severe diabetic retinopathy in patients with type 1 diabetes

OBJECTIVE

Type 1 diabetes is associated with a markedly increased risk of stroke, but only a few studies on the incidence of stroke in type 1 diabetes exist. Therefore, we assessed the incidence of stroke in patients with type 1 diabetes and studied the impact of diabetic nephropathy (DN) and severe diabetic retinopathy (SDR) on this risk.

RESEARCH DESIGN AND METHODS

We studied 4,083 patients with type 1 diabetes from the Finnish Diabetic Nephropathy Study. Mean age was 37.4 ± 11.8 years, duration of diabetes was 21.6 ± 12.1 years, and 52% were men. Strokes were identified from medical records, death certificates, and the National Hospital Discharge Register and classified based on medical files and brain images.

RESULTS

During 36,680 person-years of follow-up, 149 (4%) patients suffered an incident stroke (105 infarctions and 44 hemorrhages). Of the infarctions, 58 (55%) were lacunar. The incidence of stroke, cerebral infarction, and cerebral hemorrhage was 406 (95% CI 344-477), 286 (234-347), and 120 (87-161) per 100,000 person-years, respectively. In an adjusted analysis, microalbuminuria increased the risk of stroke with a hazard ratio (HR) of 3.2 (1.9-5.6), macroalbuminuria 4.9 (2.9-8.2), and end-stage renal disease 7.5 (4.2-13.3), and SDR increased the risk with an HR of 3.0 (1.9-4.5). The risk of cerebral infarction, cerebral hemorrhage, and lacunar infarction increased in a similar manner. The proportion of lacunar versus nonlacunar infarction did not change across DN groups.

CONCLUSIONS

The presence of SDR and DN, independently, increases the risk of stroke, cerebral infarction, and cerebral hemorrhage in patients with type 1 diabetes.

Subarachnoid hemorrhage in type 1 diabetes: a prospective cohort study of 4,083 patients with diabetes

OBJECTIVE

To estimate for the first time the incidence of subarachnoid hemorrhage (SAH) in type 1 diabetes.

RESEARCH DESIGN AND METHODS

Using the nationwide Finnish Diabetic Nephropathy (FinnDiane) Study cohort of 4,083 patients with type 1 diabetes (mean age of 37.4 ± 11.8 years at enrollment), we analyzed the incidence of first-ever SAH events.

RESULTS

During the follow-up time of 36,680 person-years (median 9.4 years), 15 patients with type 1 diabetes experienced an aneurysmal or nonaneurysmal SAH, and thus the crude incidence of SAH was 40.9 (95% CI 22.9-67.4) per 100,000 person-years. One patient had a verified aneurysmal SAH, and four patients died suddenly of an SAH, which was most likely caused by an aneurysm. SAHs in 10 out of 15 patients were classified as nonaneurysmal SAH, and thus the crude incidence of nonaneurysmal SAH was 27.3 (13.1-50.1) per 100,000 person-years. None of the nonaneurysmal SAHs were fatal. In univariate analysis, current smokers had a hazard ratio of 4.82 (95% CI 1.31-17.81) for nonaneurysmal SAH.

CONCLUSIONS

The incidence of nonaneurysmal SAH is high among patients with type 1 diabetes. Our findings suggest that nonaneurysmal SAH is a distinct new microvascular complication in type 1 diabetes.

Associations and interactions between lipid profiles, retinopathy and nephropathy in patients with type 1 diabetes: the FinnDiane Study

OBJECTIVES

The aim of this study was to investigate the associations between lipid profiles and retinopathy in the large nationwide FinnDiane Study and to examine interactions and correlations between retinopathy, nephropathy and lipid variables.

DESIGN AND SUBJECTS

A total of 1465 patients with type 1 diabetes, available lipid profiles, ophthalmic records and fundus photographs were included in the study. The Early Treatment of Diabetic Retinopathy Study scale was used to assess the severity of retinopathy. In an independent cohort of 1100 patients, laser treatment was used to define severe diabetic retinopathy.

RESULTS

HDL cholesterol was associated with proliferative retinopathy (PDR), and triglycerides were associated with mild nonproliferative retinopathy (NPDR) independently of nephropathy and other conventional risk factors (P < 0.01). Significant interactions were seen between albumin excretion rate (AER), retinopathy status and lipid parameters (including triglycerides, non-HDL cholesterol and apolipoprotein B; P < 0.001). Highly different correlations between AER and lipid variables were observed in patients without retinopathy or with mild NPDR compared with patients with moderate to severe NPDR or PDR. Similar interactions and correlations were observed in an independent cohort stratified by laser treatment. In patients without retinopathy or with mild NPDR, AER was low despite HDL cholesterol in the lowest or triglycerides, total cholesterol or LDL cholesterol in the highest quartiles.

CONCLUSIONS

Nephropathy had a strong effect on the associations between lipid variables and retinopathy, whilst dyslipidaemia was associated with nephropathy only in the presence of retinopathy. This finding suggests the existence of shared pathogenic mechanisms between retinopathy and nephropathy which could be targeted to prevent complications in patients with metabolic risk factors.

Triglyceride-cholesterol imbalance across lipoprotein subclasses predicts diabetic kidney disease and mortality in type 1 diabetes: the FinnDiane Study

BACKGROUND

Circulating cholesterol (C) and triglyceride (TG) levels are associated with vascular injury in type 1 diabetes (T1DM). Lipoproteins are responsible for transporting lipids, and alterations in their subclass distributions may partly explain the increased mortality in individuals with T1DM.

DESIGN AND SUBJECTS

A cohort of 3544 individuals with T1DM was recruited by the nationwide multicentre FinnDiane Study Group. At baseline, six very low-density lipoprotein VLDL, one intermediate-density lipoprotein IDL, three low-density lipoprotein LDL and four higher high-density lipoprotein HDL subclasses were quantified by proton nuclear magnetic resonance spectroscopy. At follow-up, the baseline data were analysed for incident micro- or macroalbuminuria (117 cases in 5.3 years), progression from microalbuminuria (63 cases in 6.1 years), progression from macroalbuminuria (109 cases in 5.9 years) and mortality (385 deaths in 9.4 years). Univariate associations were tested by age-matched cases and controls and multivariate lipoprotein profiles were analysed using the self-organizing map (SOM).

RESULTS

TG and C levels in large VLDL were associated with incident albuminuria, TG and C in medium VLDL were associated with progression from microalbuminuria, and TG and C in all VLDL subclasses were associated with mortality. Large HDL-C was inversely associated with mortality. Three extreme phenotypes emerged from SOM analysis: (i) low C (<3% mortality), (ii) low TG/C ratio (6% mortality), and (iii) high TG/C ratio (40% mortality) in all subclasses.

CONCLUSIONS

TG-C imbalance is a general lipoprotein characteristic in individuals with T1DM and high vascular disease risk.

HLA class II is a factor in cardiovascular morbidity and mortality rates in patients with type 1 diabetes

AIMS/HYPOTHESIS

Patients with type 1 diabetes and kidney disease have a higher risk of cardiovascular events. HLA class II genes are expressed on infiltrated inflammatory cells and smooth-muscle cells in atherosclerotic plaques. We hypothesised that HLA class II haplotypes or genotypes might influence the risk of cardiovascular complications and death in Finnish type 1 diabetic patients.

METHODS

We included 3,082 patients with type 1 diabetes from the Finnish Diabetic Nephropathy Study. We analysed the 12 and ten most common HLA II haplo- and genotypes, respectively, using χ (2) tests. The positive findings were analysed with three differently adjusted regression models with cardiovascular morbidity and death as endpoints. Different kidney status groups were analysed separately.

RESULTS

At baseline, the common (DR1/10)-DQB1*05:01 haplotype (20.4%) and the (DR1/10)-DQB1*05:01/DRB1*04:01-DQB1*03:02 genotype (8.7%) were independently associated with cardiovascular disease in all kidney status groups, except in patients with normal AER. At follow-up (9.45 years; range 0.1-16.1 years), the (DR1/10)-DQB1*05:01/DRB1*04:01-DQB1*03:02 genotype was associated with cardiovascular mortality rates in patients with normal AER and microalbuminuria.

CONCLUSIONS/INTERPRETATION

The (DR1/10)-DQB1*05:01 haplotype and the (DR1/10)-DQB1*05:01/DRB1*04:01-DQB1*03:02 genotype are independently associated with cardiovascular events and death in Finnish type 1 diabetic patients.

Arterial stiffness and vascular complications in patients with type 1 diabetes: the Finnish Diabetic Nephropathy (FinnDiane) Study

INTRODUCTION/AIMS

While patients with type 1 diabetes (T1D) are known to suffer from early cardiovascular disease (CVD), we examined associations between arterial stiffness and diabetic complications in a large patient group with T1D.

METHODS

This study included 807 subjects (622 T1D and 185 healthy volunteers (age 40.6 ± 0.7 versus 41.6 ± 1.2 years; P = NS)). Arterial stiffness was measured by pulse wave analysis from each participant. Furthermore, information on diabetic retinopathy, nephropathy, and CVD was collected. The renal status was verified from at least two out of three urine collections.

RESULTS

Patients with T1D without signs of diabetic nephropathy had stiffer arteries measured as the augmentation index (AIx) than age-matched control subjects (17.3% ± 0.6% versus 10.0% ± 1.2%; P < 0.001). Moreover, AIx (OR 1.08; 95% CI 1.03-1.13; P = 0.002) was associated with diabetic laser-treated retinopathy in patients with normoalbuminuria in a multivariate logistic regression analysis. The same was true for AIx and diabetic nephropathy (1.04 (1.01-1.08); P = 0.004) as well as AIx and CVD (1.06 (1.00-1.12); P = 0.01) in patients with T1D.

CONCLUSIONS

Arterial stiffness was associated with microvascular and macrovascular complications in patients with T1D.

Metabolic diversity of progressive kidney disease in 325 patients with type 1 diabetes (the FinnDiane Study)

Type 1 diabetic patients with varying severity of kidney disease were investigated to create multimetabolite models of the disease process. Urinary albumin excretion rate was measured for 3358 patients with type 1 diabetes. Prospective records were available for 1051 patients, of whom 163 showed progression of albuminuria (8.3-year follow-up), and 162 were selected as stable controls. At baseline, serum lipids, lipoprotein subclasses, and low-molecular weight metabolites were quantified by NMR spectroscopy (325 samples). The data were analyzed by the self-organizing map. In cross-sectional analyses, patients with no complications had low serum lipids, less inflammation, and better glycemic control, whereas patients with advanced kidney disease had high serum cystatin-C and sphingomyelin. These phenotype extremes shared low unsaturated fatty acids (UFAs) and phospholipids. Prospectively, progressive albuminuria was associated with high UFAs, phospholipids, and IDL and LDL lipids. Progression at longer duration was associated with high HDL lipids, whereas earlier progression was associated with poor glycemic control, increased saturated fatty acids (SFAs), and inflammation. Diabetic kidney disease consists of diverse metabolic phenotypes: UFAs, phospholipids, IDL, and LDL may be important in the subclinical phase, high SFAs and low HDL suggest accelerated progression, and the sphingolipid pathway in advanced kidney injury deserves further research.

Competing-risk analysis of ESRD and death among patients with type 1 diabetes and macroalbuminuria

Patients with both type 1 diabetes and CKD have an increased risk of adverse outcomes. The competing risks of death and ESRD may confound the estimates of risk for each outcome. Here, we sought to determine the major predictors of the cumulative incidence of ESRD and pre-ESRD mortality in patients with type 1 diabetes and macroalbuminuria while incorporating the competing risk for the alternate outcome into a Fine-Gray competing-risks analysis. We followed 592 patients with macroalbuminuria for a median of 9.9 years. During this time, 56 (9.5%) patients died and 210 (35.5%) patients developed ESRD. Predictors of incident ESRD, taking baseline renal function and the competing risk for death into account, included an elevated HbA(1c), elevated LDL cholesterol, male sex, weight-adjusted insulin dose, and a shorter duration of diabetes. By contrast, predictors of pre-ESRD death, taking baseline renal function and the competing risk for ESRD into account, included only age, the presence of established macrovascular disease, and elevated cholesterol levels. This competing-risks approach has potential to highlight the appropriate targets and strategies for preventing premature mortality in patients with type 1 diabetes.

Depression is associated with the metabolic syndrome among patients with type 1 diabetes

BACKGROUND

Both depression and the metabolic syndrome are frequently found among patients with type 1 diabetes, but their potential association has not yet been investigated. In this paper the relationship between depression and the metabolic syndrome among patients with type 1 diabetes was evaluated.

METHODS

A total of 1226 patients participating in the Finnish Diabetic Nephropathy Study between 2003 and 2009 were included. Depression was defined as use of antidepressive medication or Beck Depression Inventory (BDI) score ≥16. The metabolic syndrome was defined using the criteria established by the International Diabetes Federation Task Force on Epidemiology and Prevention (IDF); National Heart, Lung, and Blood Institute (NHLBI); American Heart Association (AHA); World Heart Federation (WHF); International Atherosclerosis Society (IAS); and International Association for the Study of Obesity (IASO).

RESULTS

The metabolic syndrome was more frequently observed among depressed patients (57% versus 46%, P = 0.008). Of the individual components of the metabolic syndrome, waist, triglyceride, and HDL components were more frequently fulfilled among patients with depression. The BDI score increased with the number of components of the metabolic syndrome present. The BDI score was independently associated with the waist component (odds ratio 1.03, 95% confidence interval 1.01-1.05) when adjusted for gender, age, socio-economic status, smoking, nephropathy, and HbA(1c).

CONCLUSION

The metabolic syndrome is frequently found among depressed patients with type 1 diabetes. Whether this association influences the development of diabetic complications is not known.

A1C variability predicts incident cardiovascular events, microalbuminuria, and overt diabetic nephropathy in patients with type 1 diabetes

OBJECTIVE

Recent data from the Diabetes Control and Complications Trial (DCCT) indicated that A1C variability is associated with the risk of diabetes microvascular complications. However, these results might have been influenced by the interventional study design. Therefore, we investigated the longitudinal associations between A1C variability and diabetes complications in patients with type 1 diabetes in the observational Finnish Diabetic Nephropathy (FinnDiane) Study.

RESEARCH DESIGN AND METHODS

A total of 2,107 patients in the FinnDiane Study had complete data on renal status and serial measurements of A1C from baseline to follow-up (median 5.7 years), and 1,845 patients had similar data on cardiovascular disease (CVD) events. Intrapersonal SD of serially measured A1C was considered a measure of variability.

RESULTS

During follow-up, 10.2% progressed to a higher albuminuria level or to end-stage renal disease, whereas 8.6% had a CVD event. The SD of serial A1C was 1.01 versus 0.75 (P < 0.001) for renal status and 0.87 versus 0.79 (P = 0.023) for CVD in progressors versus nonprogressors, respectively. In a Cox regression model, SD of serial A1C was independently associated with progression of renal disease (hazard ratio 1.92 [95% CI 1.49-2.47]) and of a CVD event (1.98 [1.39-2.82]) even when adjusting for mean A1C and traditional risk factors. Interestingly for CVD, mean serial A1C itself was not predictive even though SD of A1C was.

CONCLUSIONS

In patients with type 1 diabetes, A1C variability was not only predictive of incident microalbuminuria and progression of renal disease but also of incident CVD events.

Network of vascular diseases, death and biochemical characteristics in a set of 4,197 patients with type 1 diabetes (the FinnDiane Study)

Background

Cardiovascular disease is the main cause of premature death in patients with type 1 diabetes. Patients with diabetic kidney disease have an increased risk of heart attack or stroke. Accurate knowledge of the complex inter-dependencies between the risk factors is critical for pinpointing the best targets for research and treatment. Therefore, the aim of this study was to describe the association patterns between clinical and biochemical features of diabetic complications.

Methods

Medical records and serum and urine samples of 4,197 patients with type 1 diabetes were collected from health care centers in Finland. At baseline, the mean diabetes duration was 22 years, 52% were male, 23% had kidney disease (urine albumin excretion over 300 mg/24 h or end-stage renal disease) and 8% had a history of macrovascular events. All-cause mortality was evaluated after an average of 6.5 years of follow-up (25,714 patient years). The dataset comprised 28 clinical and 25 biochemical variables that were regarded as the nodes of a network to assess their mutual relationships.

Results

The networks contained cliques that were densely inter-connected (r > 0.6), including cliques for high-density lipoprotein (HDL) markers, for triglycerides and cholesterol, for urinary excretion and for indices of body mass. The links between the cliques showed biologically relevant interactions: an inverse relationship between HDL cholesterol and the triglyceride clique (r < -0.3, P < 10^-16), a connection between triglycerides and body mass via C-reactive protein (r > 0.3, P < 10^-16) and intermediate-density cholesterol as the connector between lipoprotein metabolism and albuminuria (r > 0.3, P < 10^-16). Aging and macrovascular disease were linked to death via working ability and retinopathy. Diabetic kidney disease, serum creatinine and potassium, retinopathy and blood pressure were inter-connected. Blood pressure correlations indicated accelerated vascular aging in individuals with kidney disease (P < 0.001).

Conclusion

The complex pattern of links between diverse characteristics and the lack of a single dominant factor suggests a need for multifactorial and multidisciplinary paradigms for the research, treatment and prevention of diabetic complications.

Adult stature and diabetes complications in patients with type 1 diabetes: the FinnDiane Study and the diabetes control and complications trial

OBJECTIVE

Short adult stature has previously been associated with cardiovascular disease, but its relationship with the microvascular complications of diabetes is uncertain. Therefore, we evaluated the association between adult stature and prevalence and incidence of diabetic microvascular complications.

RESEARCH DESIGN AND METHODS

This cross-sectional and longitudinal study comprises 3,968 adult patients with type 1 diabetes from the Finnish Diabetic Nephropathy (FinnDiane) Study and 1,246 adult patients from the Diabetes Control and Complications Trial (DCCT). In FinnDiane, diabetic nephropathy was defined as urinary albumin excretion > or = 300 mg/24 h, dialysis, or renal transplantation. Retinopathy was divided into background and proliferative (laser-treated) retinopathy. In the DCCT, original nephropathy (class 1-6) and retinopathy (Early Treatment of Diabetic Retinopathy Study) classifications were used.

RESULTS

In the FinnDiane study, patients in the lowest quartile of adult height had increased risks of prevalent diabetic nephropathy (odds ratio [OR] 1.71, 95% CI 1.44-2.02) and prevalent laser-treated retinopathy (1.66, 1.43-1.93) compared with other patients. Similarly, in the DCCT, patients in the lowest quartile of adult height had increased risks of incident diabetic nephropathy class 4-6 (hazard ratio 2.70, 95% CI 1.59-4.59) and incident proliferative retinopathy (2.06, 1.15-3.71). In the FinnDiane study, the associations were largely explained by childhood exposure to diabetes. However, in the DCCT, where a greater proportion of patients had diabetes onset >18 years, the association with nephropathy was independent of childhood diabetes exposure.

CONCLUSIONS

Short adult stature is associated with microvascular complications in patients with type 1 diabetes. These findings are compatible with either childhood diabetes exposure or "common soil" or both as potential explanations.