Clustering of albumin excretion rate abnormalities in Caucasian patients with NIDDM

Summary Proteinuria and nephropathy have been found to cluster in families of non-insulin-dependent diabetic (NIDDM) Pima Indian, and in Caucasian insulin-dependent diabetic (IDDM) patients. No information is at present available for Caucasian NIDDM patients. The aim of the present study was to determine whether micro-macroalbuminuria (AER + ) is associated with albumin excretion rate abnormalities in diabetic and non-diabetic siblings of probands with NIDDM and AER + . We identified 169 Caucasian families with one NIDDM proband (the patient with longest known NIDDM duration) (101 families with only NIDDM siblings, 33 families with both NIDDM and non-NIDDM siblings and 35 families with only non-NIDDM siblings). Of the probands 56 had AER + [Prob-NIDDM-(AER + )], 78 had AER– [Prob-NIDDM-(AER–)], 74 siblings of Prob-NIDDM-(AER + ), and 113 siblings of Prob-NIDDM-(AER–) also had NIDDM. Data on albuminuria and retinopathy from multiple sibling pairs when the size of the sibship was more than two was adjusted according to a weighting factor. The odds ratio for AER + , in siblings of Prob-NIDDM-(AER + ) adjusted for age, hypertension, glycated haemoglobin A_{1 c} and other confounding variables was 3.94 (95 % confidence intervals: 1.93–9.01) as compared to siblings of Prob-NIDDM-(AER–). The 74 siblings of Prob-NIDDM-(AER + ) had higher prevalence of proliferative retinopathy than siblings of Prob-NIDDM-(AER–) (14 vs 2 %; p < 0.01). We also identified 66 non-diabetic siblings of 41 NIDDM probands with AER + and 36 non-diabetic siblings of 27 NIDDM probands with AER–. Albumin excretion was two times higher, although still within the normal range, in the non-diabetic siblings of Prob-NIDDM-(AER + ) than in siblings of Prob-NIDDM-(AER–) [median = 13.5 (range 0.5–148) vs 6.6 (range 1–17) μg/min (p < 0.05)]. In conclusion higher rates of albumin excretion aggregate in Caucasian families with NIDDM. Proliferative retinopathy is more frequently observed in families showing a clustering of AER + and NIDDM. These findings suggest that familial factors play a role in the pathogenesis of renal and retinal complications in NIDDM. [Diabetologia (1997) 40: 816–823] Received: 6 November 1996 and in revised form: 17 February 1997     

Endothelium-dependent and independent vasodilation studied at normoglycaemia in Type I diabetes mellitus with and without microalbuminuria

Aims/hypothesis. We examined whether endothelial function is impaired in patients with Type I (insulin-dependent) diabetes mellitus under conditions of near-normoglycaemia compared with age-matched healthy control subjects. Our aim was to determine whether microalbuminuria is associated with endothelial dysfunction in Type I diabetes. Methods. Endothelial function, measured as post-ischaemic flow-mediated dilatation of the brachial artery using ultrasound, was compared among 17 microalbuminuric and 17 normoalbuminuric diabetic patients, and 17 control subjects. Glyceryl trinitrate-mediated dilatation of the brachial artery was used to measure endothelium-independent function. All diabetic patients were studied at near-normoglycaemia, using insulin and 5 % dextrose infusions to maintain blood glucose between 3.5 and 8.0 mmol/l. Results. Flow-mediated dilatation was significantly lower in microalbuminuric diabetic patients (3.2 ± 0.3 %) compared with normoalbuminuric diabetic patients (5.4 ± 0.6 %) and control subjects (7.9 ± 0.6 %, p < 0.001). Normoalbuminuric diabetic patients also had significantly lower flow-mediated dilatation than control subjects (p = 0.01). Glyceryl trinitrate mediated dilatation was significantly lower in the microalbuminuric patients compared with the control subjects (11.9 ± 1.1 % vs 20.0 ± 1.2 %, p = 0.001). Albumin excretion rate and glycated haemoglobin showed a significant negative independent correlation with flow-mediated dilatation (both p < 0.05). Conclusion/interpretation. Type I diabetic patients show endothelial dysfunction at near-normoglycaemia compared with the control subjects, and this abnormality is more marked in diabetic patients with microalbuminuria. Endothelial dysfunction in Type I diabetes is related to the albumin excretion rate and glycaemic control. The presence of endothelial dysfunction in normoalbuminuric diabetic patients suggests it could precede microalbuminuria as an early risk marker for cardiovascular disease. [Diabetologia (2001) 44: 593–601] Received: 6 November 2000 and in revised form: 11 January 2001     

Alterations in serum lipids and apolipoproteins in male Type 1 (insulin-dependent) diabetic patients with microalbuminuria

Summary The relationships between serum lipid, apolipoprotein levels and urinary albumin excretion were investigated in 20 male Type 1 (insulin-dependent) diabetic patients with microalbuminuria (overnight urinary albumin excretion between 10 and 200 g/min), in 18 male Type 1 diabetic patients without microalbuminuria and in 18 male control subjects. In the microalbuminuric patients low density lipoprotein cholesterol was higher than in the control subjects (p<0.05); the high density lipoprotein/low density lipoprotein cholesterol ratio was lower than in the normoalbuminuric diabetic patients (p<0.05), and in the control subjects (p<0.01); apolipoprotein B was higher than in the normoalbuminuric patients (p<0.05); the apolipoprotein A₁/B ratio was lower than in the normoalbuminuric diabetic patients (p<0.05). Serum triglyceride was higher in the microalbuminuric diabetic patients and in the control subjects than in the normoalbuminuric diabetic patients (p<0.05, for both), but was not different between the microalbuminuric diabetic patients and the control subjects. No significant differences between the 3 groups were present with respect to serum cholesterol, high density lipoprotein cholesterol and apolipoprotein A₁. In the 2 combined Type 1 diabetic groups there were significant correlations between urinary albumin excretion and the high density lipoprotein/low density lipoprotein cholesterol ratio (R -0.40, p<0.02), apolipoprotein B (R0.35, p<0.05) and the apolipoprotein A₁/B ratio (R -0.44, p<0.01). These results indicate microalbuminuria related differences in lipid and apolipoprotein levels in male Type 1 diabetic patients, which may contribute to an increased risk of cardiovascular disease.     

Baroreflex sensitivity is depressed in microalbuminuric Type I diabetic patients at rest and during sympathetic manoeuvres

Abstract Aims/hypothesis. To evaluate baroreflex sensitivity (BRS) in microalbuminuric and normoalbuminuric Type I (insulin-dependent) diabetic patients without autonomic neuropathy and in healthy control subjects. Methods. Microalbuminuric Type I diabetic patients (n = 15) were matched for age, sex, body mass index (BMI) and smoking habits with 15 normoalbuminuric patients and with 15 healthy control subjects. All subjects had a blood pressure less than 160/95 mmHg, a BMI less than 30 kg/m² and normal autonomic function on standard tests. Blood pressure and heart rate were measured non-invasively (Finapres) at rest and during sympathetic activation (handgrip, mental stress, standing). The baroreflex sensitivity was defined as the mean gain between blood pressure variability and heart rate variability in the 0.07–0.15 Hz frequency band. Results. Resting baroreflex sensitivity was decreased in the microalbuminuric patients (3.5 ± 0.4 ms/mmHg) compared with the normoalbuminuric patients and the healthy subjects (7.6 ± 1.6 and 9.5 ± 1.1 ms/mmHg, respectively, p < 0.001). The sympathetic tests reduced baroreflex sensitivity similarly in the groups without changing the between group differences. Conclusion/interpretation. Baroreflex sensitivity is reduced in Type I diabetic patients with microalbuminuria but without autonomic neuropathy. A prospective study should indicate whether this early abnormality in cardiovascular reflex function is a risk factor of cardiovascular mortality in these patients. [Diabetologia (1999) 42: 1345–1349] Received: 20 May 1999 and in revised form: 8 July 1999     

Ambulatory blood pressure measurements are related to albumin excretion and are predictive for risk of microalbuminuria in young people with type 1 diabetes

Aims/hypothesis  The relationship between BP and microalbuminuria in young people with type 1 diabetes is not completely clear. As microalbuminuria is preceded by a gradual rise in albumin excretion within the normal range, we hypothesised that ambulatory BP (ABP) may be closely related to albumin excretion and progression to microalbuminuria. Methods  ABP monitoring (ABPM) was performed in 509 young people with type 1 diabetes (age median [range]: 15.7 [10.7–22.6] years) followed with annual assessments of three early morning urinary albumin:creatinine ratios (ACRs) and HbA_1c. Systolic BP (SBP) and diastolic BP (DBP) and the nocturnal fall in BP were analysed in relation to ACR. Results  All ABPM variables were significantly related to baseline log₁₀ ACR (p < 0.001). After the ABPM evaluation, 287 patients were followed for a median of 2.2 (1.0–5.5) years. ABP at baseline was independently related to mean ACR during follow-up. Nineteen initially normoalbuminuric patients developed microalbuminuria after 2.0 (0.2–4.0) years and their baseline daytime DBP was higher than in normoalbuminuric patients (p < 0.001). After adjusting for baseline ACR and HbA_1c, there was an 11% increased risk of microalbuminuria for each 1 mmHg increase in daytime DBP. Forty-eight per cent of patients were non-dippers for SBP and 60% for DBP; however, ACR was not different between dippers and non-dippers and there were no differences in the nocturnal fall in BP between normoalbuminuric and future microalbuminuric patients. Conclusions/interpretation  In this cohort of young people with type 1 diabetes, ABP was significantly related to ACR, and daytime DBP was independently associated with progression to microalbuminuria. Increasing albumin excretion, even in the normal range, may be associated with parallel rises in BP. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorised users.     

Glomerular hyperfiltration in microalbuminuric NIDDM patients

Summary Glomerular hyperfiltration and microalbuminuria are both regarded as risk factors for the development of diabetic nephropathy in insulin-dependent diabetic patients. Information on glomerular hyperfiltration is scarse in microalbuminuric non-insulin-dependent diabetic (NIDDM) patients. Therefore, we performed a cross-sectional study of glomerular filtration rate (single i. v. bolus injection of ⁵¹Cr-EDTA, plasma clearance for 4 h) in 158 microalbuminuric NIDDM patients compared to 39 normoalbuminuric NIDDM patients and 20 non-diabetic control subjects. The groups were well-matched with regard to sex, age and body mass index. The uncorrected (ml/min) and the adjusted (ml · min^–1· 1.73 m^–2) glomerular filtration rate were both clearly elevated in the microalbuminuric patients: 139 ± 29 and 117 ± 24 as compared to 115 ± 19 and 99 ± 15; 111 ± 23 and 98 ± 21 in normoalbuminuric NIDDM patients and control subjects, respectively (p < 0.001). The glomerular filtration rate (ml · min^–1· 1.73 m^–2) in NIDDM patients who had never received antihypertensive treatment was also clearly elevated in the microalbuminuric patients (n = 96): 119 ± 22 as compared to 100 ± 14 and 98 ± 21 in normoalbuminuric NIDDM patients (n = 27) and control subjects (n = 20), respectively (p < 0.001). Glomerular hyperfiltration (elevation above mean glomerular filtration rate plus 2 SD in normoalbuminuric NIDDM patients) was demonstrated in 37 (95 % confidence interval 30–45)% of the microalbuminuric patients. Multiple regression analysis revealed that HbA_{1 c}, 24-h urinary sodium excretion, age and known duration of diabetes were correlated with glomerular filtration rate in microalbuminuric NIDDM patients (r ² = 0.21, p < 0.01). Our cross-sectional study indicates that NIDDM patients at high risk of developing diabetic nephropathy are also characterized by an additional putative risk factor for progression, glomerular hyperfiltration. [Diabetologia (1996) 39: 1584–1589]     

Orosomucoid in urine predicts cardiovascular and over-all mortality in patients with Type II diabetes

Aims/hypothesis: Urinary orosomucoid excretion rate is increased in a substantial proportion of patients with Type II (non-insulin-dependent) diabetes mellitus and normal urinary albumin excretion rate. The aim of this study was to determine whether increased urinary orosomucoid excretion rate is predictive of increased mortality in patients with Type II diabetes. Methods: In a cohort study including 430 patients with Type II diabetes, baseline urinary samples were analysed for orosomucoid and albumin. Mean follow-up was 2.4 years. Results: We found that 188 (44 %) patients had normal and 242 (56 %) patients had increased urinary orosomucoid excretion rates. During the study period 41 patients died; out of these 23 patients died of cardiovascular diseases. Odds ratio for all-cause mortality was 2.50 (95 % CI 1.00–6.22) and odds ratio for cardiovascular mortality was 9.81 (1.31–73.6) having increased urinary orosomucoid excretion rate at baseline (odds ratios adjusted for age, sex, duration of diabetes, cardiovascular diseases, weight, medication, HbA_{1 c}, plasma creatinine and urinary albumin excretion rate). Urinary albumin excretion rate was an independent predictor of all-cause mortality when urinary orosomucoid excretion rate was not included in the analysis. Subgroup analysis revealed that 39 % of the patients with normal urinary albumin excretion rate (n = 251) had increased urinary orosomucoid excretion rates and that these patients had a higher cardiovascular mortality (p = 0.007) than patients with normal urinary albumin excretion rate and normal urinary orosomucoid excretion rates. Conclusion/interpretation: We found that urinary orosomucoid excretion rate predicted all-cause and cardiovascular mortality in patients with Type II diabetes independently from other risk factors. [Diabetologia (2002) 45: 115–120] Received: 24 July 2001 and in revised form: 17 September 2001     

The impact of a family history of Type II (non-insulin-dependent) diabetes mellitus on the risk of diabetic nephropathy in patients with Type I (insulin-dependent) diabetes mellitus

Aims/hypothesis. There is substantial evidence for a role of genetic factors in the development of diabetic nephropathy. In Pima Indians, a link between susceptibility to diabetic nephropathy and Type II (non-insulin-dependent) diabetes mellitus has been proposed. In this study, our aim was to examine the association between a family history of Type II diabetes and diabetic nephropathy in patients with Type I (insulin-dependent) diabetes mellitus. Methods. In a cross-sectional case-control study, we assessed the prevalence of Type II diabetes in the parents of 137 Type I diabetic patients with diabetic nephropathy (albuminuria > 300 μg/min in two of three overnight urine collections) compared with the parents of 54 Type I diabetic patients without nephropathy (albuminuria < 20 μg/min). Results. Thirty-four (25 %) of the patients with nephropathy compared with five (9 %) of the patients without nephropathy had a parental history of Type II diabetes (p = 0.019). A parental history of Type II diabetes was associated with a three-fold risk [odds ratio 2.95 (95 % confidence interval: 1.03 to 8.40), p = 0.043] of diabetic nephropathy after adjustment for sex, glycaemic control and family history of hypertension. Furthermore, there was an excess of risk factors for development of Type II diabetes (higher fasting plasma glucose concentrations, higher prevalence of hypertension, higher waist-hip ratio and a tendency towards more glucose intolerance) among previously non-diabetic parents of patients with nephropathy. Conclusion/interpretation. Genetic or environmental factors or both related to familial Type II diabetes increase susceptibility to diabetic nephropathy in patients with Type I diabetes. [Diabetologia (1999) 42: 519–526] Received: 30 September 1998 and in final revised form: 28 December 1998     

Thrombomodulin Levels in Insulin-dependent Diabetic Patients with Microalbuminuria

Thrombomodulin (TM) plays an important role in the regulation of blood coagulation at the endothelial surface. TM is also present in plasma, where an increase of its level seems to reflect endothelial damage. Since microalbuminuria is associated with an increased atherothrombotic risk and is considered an expression of widespread vascular damage, we evaluated plasma thrombomodulin levels, blood pressure, and plasma lipid values in Type 1 diabetic patients with micro- and normoalbuminuria. Thrombomodulin was measured in 12 microalbuminuric (albumin excretion rate 20–200 μg min^?1 in 2 of 3 overnight urine collections) and in 12 normoalbuminuric (albumin excretion rate < 20 μg min^?1) Type 1 diabetic patients matched for age, sex, body mass index, smoking habits, diabetes duration, and glycated haemoglobin. Mean thrombomodulin was significantly higher in micro- than in normalbuminuric group (59.34 ± 3.58 vs 43.56 ± 3.52 ng ml^?1 p < 0.01). Systolic and diastolic blood pressure were significantly higher in micro- than in normoalbuminuric group (p < 0.05). There was a positive correlation between plasma thrombomodulin and albumin excretion rate (p = 0.013, r = 0.49), and between thrombomodulin and diastolic blood pressure (p = 0.023, r = 0.46) in diabetic patients as a whole but not in the individual groups. These findings suggest the presence of an endothelial injury in microalbuminuric patients.     

Abnormal increases in urinary albumin excretion during pregnancy in IDDM women with pre-existing microalbuminuria

Summary We compared urinary albumin excretion during and after pregnancy in 30 insulin-dependent diabetic (IDDM) women with normoalbuminuria and in 12 IDDM women with microalbuminuria (>15 g·min^–1) prior to conception. There was a 6.7-fold increase in the urinary albumin excretion up until the third trimester in the women with pre-existing microalbuminuria, compared with a 3.8-fold increase in the normoalbuminuric women. In both groups of patients the urinary albumin excretion reached a peak during the third trimester with 492±404 g·min^–1 in the microalbuminuric women vs 43±36g·min^–1 in the normoalbuminuric women (p<0.0005). Two women from each of the groups developed eclampsia with diastolic blood pressure over 90 mm Hg, mild or moderate oedema and macroproteinuria. Four of the pregnant women with pre-existing microalbuminuria showed a transient nephrotic syndrome (33.3%) with protein excretion over 3 g in 24-h urine samples during the third trimester. In contrast, this was not observed in any of the normoalbuminuric women (p<0.05). Within 12 weeks after delivery the urinary albumin excretion rates dropped to the pre-conception values in both patient groups. Renal function remained normal during pregnancy in both of the groups, with a physiological increase in creatinine clearance up until the third trimester (26% increase in the normoalbuminuric women vs 22% in the microalbuminuric women). In conclusion, the effect of pregnancy on the urinary albumin excretion in diabetic women with preexisting microalbuminuria is an exaggeration of the increase of albuminuria in diabetic women with normoalbuminuria; normalization occurs within 12 weeks after delivery in all cases. This enhancement of the albumin excretion in the microalbuminuric women cannot be explained by a larger increase in the hyperfiltration during pregnancy.Abbreviations IDDM Insulin-dependent diabetes mellitus - NIDDM non-insulin-dependent diabetes mellitus     

The relationship of urinary albumin excretion rate to ambulatory blood pressure and erythrocyte sodium-lithium countertransport in NIDDM

Summary Increased erythrocyte sodium-lithium countertransport rate is found in non-diabetic subjects with essential hypertension, and in insulin-dependent diabetic subjects with nephropathy. However, relationships between these variables in non-insulin-dependent diabetic subjects are ill-defined. In order to characterise the relationships between blood pressure, urinary albumin excretion, and erythrocyte sodium-lithium countertransport, 66 subjects with non-insulin-dependent diabetes were studied. Urinary albumin excretion rate correlated with mean 24-h ambulatory systolic blood pressure (r=0.57; p<0.001), but not with sodium-lithium countertransport (r=0.06; p=0.31). No significant relationship was observed between 24-h systolic blood pressure and erythrocyte sodium-lithium countertransport (r = 0.16; p=0.17). The principal differences between microalbuminuric and normoalbuminuric subjects (albumin excretion rate >15 g·min^–1 [n=20], and <15 g·min^–1, [n=46]) were: higher 24-h systolic blood pressure (145.9 [16.8] mm Hg vs 131.9 [16.8] mm Hg; p=0.006), nocturnal heart rate (72.4 [8.9] vs 67.4 [8.9] beats·min^–1; p=0.042), and HbA₁ (11.3 [1.5]% vs 10.1 [2.0]%; p=0.028), and a longer median duration of diabetes (10.0 vs 5.0 years; p = 0.02). In contrast, there was no significant difference in sodium-lithium countertransport rate between microalbuminuric (0.41 [0.18] mmol·l^–1·h^–1) and normoalbuminuric subjects (0.39 [0.15] mmol·l^–1· h^–1; p=0.687). In multiple regression analysis controlling for race, age, body mass index and HbA₁, the significant determinants of albumin excretion rate were 24-h systolic blood pressure (B [regression coefficient]=0.029, SE[B] [standard error of B]=0.009, t=2.95, p=0.005), duration of diabetes (B=0.430, SE[B]=0.169, t=2.54, p=0.016) and male gender (B=–1.170, SE[B]=0.457, t=–2.56, p=0.015). In conclusion, albumin excretion rates in non-insulin-dependent diabetic subjects are linked to hypertension and glycaemic exposure, but show no relationship to erythrocyte sodium-lithium countertransport.Abbreviations IDDM Insulin-dependent diabetes mellitus - NIDDM non-insulin dependent diabetes mellitus - SLC sodium lithium countertransport - AER albumin excretion rate - B regression - SE coefficient; standard error of B     

The influence of improved glycaemic control with insulin and sulphonylureas on acute phase and endothelial markers in Type II Diabetic subjects

Aims/hypothesis. Improved glycaemic control might reduce both microvascular and macrovascular complications of Type II diabetes (non-insulin-dependent) mellitus. To explore such possible mechanisms, we investigated the effects of intensive treatment on markers of endothelial dysfunction and of acute phase activation, using both sulphonylureas and insulin. Methods. In a randomised cross-over study we gave sulphonylureas or insulin each for a period of 16 weeks to 22 poorly controlled Type II diabetic subjects who were being treated by diet. There was a 4 week washout period between each treatment. Subjects were studied at baseline and at the end of each treatment. Results. Treatment with sulphonylureas and insulin resulted in similar improvements in glycaemic control (glycated haemoglobin, baseline: 11.8 [(SD 2.2)%; after sulphonylureas: 8.6 (1.2)%, p < 0.001; after insulin: 8.6 (1.2)%, p < 0.001] and in insulin sensitivity {metabolic clearance rate of glucose, baseline: median 1.75 [interquartile (IQ) range 1.41, 2.27] ml · kg^–1· min^–1; after sulphonylureas: 2.41 (1.82, 3.01) ml · kg^–1· min^–1, p = 0.001; after insulin: 2.23 (1.92, 2.75) ml · kg^–1· min^–1, p = 0.027}. There were no significant changes in concentrations of endothelial markers von Willebrand factor, cellular fibronectin, thrombomodulin, tissue plasminogen activator, soluble E-selectin or soluble intercellular adhesion molecule-1 or in urinary albumin excretion rate after either treatment period. Concentrations of C-reactive protein were not significantly influenced by sulphonylureas but fell after insulin [baseline: median 4.50 (IQ range 1.37, 6.44) μg · ml^–1; sulphonylureas: 2.69 (0.88, 9.65) μg · ml^–1 (p = 0.53); insulin: 2.07 (1.16, 5.24) μg · ml^–1 (p = 0.017)]. There were, however, no significant effects of either treatment on circulating concentrations of fibrinogen (p = 0.28–0.34) or of the proinflammatory cytokines interleukin-6 or tumour necrosis factor-α (p = 0.65–0.79). Conclusion/interpretation. Markers of endothelial dysfunction and concentrations of proinflammatory cytokines in Type II diabetes are not influenced by improved glycaemic control over 16 weeks. Improved metabolic control with insulin could, however, be associated with reduced concentrations of the acute phase marker C-reactive protein. [Diabetologia (2000) 43: 1099–1106] Received: 11 May 2000 and in revised form: 19 June 2000     

A nationwide population-based study of the familial aggregation of Type 1 (insulin-dependent) diabetes mellitus in Denmark

Summary The objective of the present study was to assess the prevalence of familial aggregation of Type 1 (insulin-dependent) diabetes mellitus among Danish families with a diabetic child aged 20 years or less and to compare epidemiological data for familial and sporadic cases. We attempted to identify all patients with Type 1 diabetes aged 0–19 years in Denmark treated at paediatric departments or at departments of internal medicine. This comprises more than 98% of all patients with Type 1 diabetes in this age group. Patients were identified through the local diabetic out-patient registry and asked to complete a questionnaire regarding data on diabetes onset and family history. Of 1574 probands 1419 agreed to participate (90.2%). Additional cases of Type 1 diabetes were found in 171 families (12.8%). Of these 115 were parent-offspring affected families, and in 56 families at least two siblings had Type 1 diabetes and healthy parents. Significant correlation in age at onset of Type 1 diabetes in concordant siblings was observed (r=0.5, p=0.0004). Significantly more probands had an affected father with Type 1 diabetes than a mother affected (p<0.0001). Heterogeneity in epidemiological characteristics was observed between familial and sporadic cases, i.e. familial index cases were younger at onset of the disease, their parents were younger at birth of the index case, and there was no difference in gender of familial cases in contrast to sporadic cases where significantly more males were found. Over a 4-year period (1986–1989) an increasing trend in incidence was observed. However, an increase in incidence compared to previous Danish data from the 1970s and 1980 s could not be demonstrated.The Danish Study Group of Diabetes in Childhood is an association of paediatricians with a special interest in diabetes research. For participating departments in the present study see Acknowledgements     

Glomerular hypertension as one cause of albuminuria in Type II diabetic patients

Aims/hypothesis. Results from animal models of glomerular hypertension have suggested that this disorder is one cause of albuminuria in diabetic nephropathy. We evaluated this hypothesis clinically. Methods. The subjects were 20 patients with Type II (non-insulin-dependent) diabetes mellitus but without uraemia or hypertension: 8 had normoalbuminuria and 12 had albuminuria ( ≥ 20 μg/min). In the 2-week study, patients were on a diet with ordinary amounts of sodium for 1 week and on a sodium-restricted diet for 1 week. Urinary excretion of sodium and albumin and the systemic blood pressure were measured daily. Intrarenal haemodynamics, in terms of the glomerular pressure and resistance of afferent and efferent arterioles, were calculated from renal clearance, the plasma total protein concentration, and the pressure-natriuresis relation. In 8 of the 12 patients with albuminuria, an angiotensin-converting enzyme inhibitor, cilazapril, was given orally (2 mg/day) and the 2-week study was repeated. Results. In patients with albuminuria, resistance of efferent arterioles and the glomerular pressure were higher than in patients with normoalbuminuria (glomerular pressure, 53 ± 5 vs 43 ± 5 mmHg, means ± SD, p < 0.001). Urinary excretion of albumin correlated (n = 20, r = 0.675, p < 0.001) with the glomerular pressure but not with systemic pressure. The increased glomerular pressure and the albuminuria were decreased by cilazapril but systemic pressure was not. Conclusion/interpretation. These findings are consistent with the hypothesis that glomerular hypertension is present in Type II diabetic patients with early nephropathy and can cause albuminuria. [Diabetologia (1999) 42: 999–1005] Received: 25 January 1999 and in revised form: 15 March 1999     

Prevalence of left ventricular hypertrophy in Type I diabetic patients with diabetic nephropathy

Summary The increased mortality of patients with diabetic nephropathy is mainly due to cardiovascular disease and end stage renal failure. Left ventricular hypertrophy is an independent risk factor for myocardial ischaemia and sudden death. The aim of our cross-sectional study was to evaluate left ventricular structure and function in Type I (insulin-dependent) diabetic patients with diabetic nephropathy. M-mode and Doppler echocardiography were done on 105 Type I diabetic patients with diabetic nephropathy [61 men, age (means ± SD) 44 ± 9 years, and albuminuria [median(range)] 567(10–8188) mg/24 h, serum creatinine 109 (53–558) μmol/l], and 140 Type I diabetic patients with persistent normoalbuminuria [79 men, 47 ± 10 years, urinary albumin excretion rate 8 (0–30) mg/24 h, and serum creatinine 81 (55–121) μmol/l]. Patients with and without nephropathy were comparable with respect to sex, body mass index, and duration of diabetes. Arterial blood pressure was slightly higher in patients with nephropathy: 140/79 ± 17/9 mm Hg vs 134/78 ± 15/8 mm Hg, p < 0.01, and the majority of proteinuric patients received antihypertensive drugs, 84 vs 17 %, respectively, p < 0.001. Left ventricular mass index was increased in the nephropathic group (means ± SD) 100.6 ± 23.9 g/m² compared with the normoalbuminuric group 91.4 ± 21.9 g/m², p = 0.002. Left ventricular hypertrophy was found more often in patients with nephropathy 23 (14–31)% compared with patients with normoalbuminuria 9 (5–14)%, p < 0.005. Diastolic function, assessed by the ratio between the peak diastolic velocity and the peak atrial systolic velocity (E/A ratio) and isovolumic relaxation time, was reduced in patients with vs without nephropathy: 1.17 ± 0.29 vs 1.34 ± 0.32, and 81.7 ± 16.5 vs 74.6 ± 14.5, p < 0.001 and p = 0.002, respectively. Systolic function was about the same and normal in both groups. Our study suggests that an increase in left ventricular mass index and a decrease in diastolic function occurs early in the course of diabetic nephropathy. [Diabetologia (1999) 42: 76–80] Received: 16 April 1998 and in final revised form: 5 August 1998     

Prothrombin Fragment 1 + 2 and Antithrombin III-Thrombin Complex in Microalbuminuric Type 2 Diabetic Patients

In microalbuminuria there is an increased cardiovascular risk not fully explained by the excess of conventional risk factors. To investigate whether or not microalbuminuria is associated with haemostatic abnormalities in Type 2 diabetic patients, we measured the prothrombin fragment 1 + 2, a marker of thrombin generation, and the thrombin-antithrombin complex, a marker of thrombin neutralization. Plasma levels of prothrombin fragment 1 + 2 and thrombin-antithrombin complex were assayed in 17 microalbuminuric patients (albumin excretion rate, AER 20–200 μg min^?1) and in 17 comparable normoalbuminuric (AER < 20 μg min^?1) Type 2 diabetic patients. Plasma prothrombin fragment 1 + 2 was significantly higher in microalbuminuric than in normoalbuminuric patients (1.09 ± 0.06 vs 0.86 ± 0.04 nM, p = 0.003). Individual values of F1 + 2 were above the upper limit of the normal range in 8/17 microalbuminuric and in none of the normoalbuminuric Type 2 diabetic patients. Plasma thrombin-antithrombin complex values were not significantly different in the two groups and were not correlated with AER. These results suggest that microalbuminuria is associated with a prethrombotic state and a relatively defective thrombin neutralization. Coagulation abnormalities might be part of the cardiovascular risk in microalbuminuric patients.     

Comparison of Platelet Aggregability in Japanese Type 2 Diabetic Patients With and Without Microalbuminuria

Microalbuminuria is associated with higher cardiovascular morbidity and mortality in Type 2 (non-insulin-dependent) diabetic patients. This study was designed to assess whether Type 2 diabetic patients with microalbuminuria (urinary albumin excretion rate (AER) 20–200 μg min^?1) is associated with alterations in platelet aggregability as compared with those with normal urinary albumin excretion (AER < 20 μg min^?1). Platelet aggregability was compared between 21 Japanese Type 2 diabetic patients with microalbuminuria and 21 individually pair-matched (for age, sex, body mass index, treatment, and HbA_1c level) patients with normoalbuminuria. The in vitro platelet aggregation induced by 1.0 and 3.0 μmol I^?1 ADP and 0.5 and 1.0 mg I^?1 collagen was measured using platelet-rich plasma. No significant differences were observed between the two groups in the values for maximum percent platelet aggregation, percent aggregation at 3 min, and aggregation velocities after adding ADP or collagen. Microalbuminuric patients had significantly higher mean values for systolic (p < 0.004) and diastolic (p < 0.02) blood pressures and plasma fibrinogen level (p < 0.03) as compared with the respective mean values in normoalbuminuric patients. The results suggest that Japanese microalbuminuric Type 2 diabetic patients do not differ in the degree of platelet aggregability as compared with normoalbuminuric patients, despite an increase in certain other coronary risk factors.     

24-h ambulatory blood pressure and retinopathy in normoalbuminuric IDDM patients

Summary The role of blood pressure elevation in the incidence and progression of diabetic retinopathy is not clearly established and results have been conflicting. Blood pressure and urinary albumin excretion (UAE) are closely related. In order to evaluate the independent relationship between retinopathy and blood pressure elevation, precise information on UAE is essential, as confounding by renal disease (incipient or overt), cannot otherwise be excluded.The aim of the present study was to evaluate the association between diabetic retinopathy and 24-h ambulatory blood pressure (AMBP) in a group of well-characterized normoalbuminuric IDDM patients. In 65 normoalbuminuric (UAE < 20 μg/min) IDDM patients we performed 24-h AMBP (Spacelabs 90 207) with readings at 20-min intervals. Fundus photographs were graded independently by two experienced ophthalmologists. UAE was measured by RIA and expressed as geometric mean of three overnight collections made within 1 week. HbA_{1 c} was determined by HPLC. Tobacco use and level of physical activity were assessed by questionnaire. Fifteen patients had no detectable retinal changes [grade 1], 35 had grade 2 retinopathy; and 15 had more advanced retinopathy [grade 3–6]. Diastolic night blood pressure was significantly higher in patients with diabetic retinopathy compared to patients without retinopathy (68 ± 8 mmHg [grade 3–6] and 65 ± 6 mmHg [grade 2], compared to 61 ± 4 mmHg [grade 1], p = 0.02). Diurnal blood pressure variation was significantly blunted in the patients with retinopathy as indicated by a higher night/day ratio of diastolic blood pressure (84.6 % ± 4 [grade 3–6], and 81.2 % ± 6 [grade 2] compared to 79.1 % ± 4 [grade 1], p = 0.01). Heart rate tended to be higher in patients in group 2 and 3–6 compared to patients without retinopathy with p values of 0.07 and 0.11 for day-time and 24 h values, respectively. Mean HbA_{1 c} increased significantly with increasing levels of retinopathy (p < 0.01). Patients were similar regarding sex, age, tobacco use, and level of physical activity. Notably, UAE was almost identical in the three groups (5.0 × /÷1.7 [grade 1], 3.9 × /÷1.8 [grade 2], and 5.1 × /÷1.6 μg/min [grade 3–6]). In conclusion, night blood pressure is higher and circadian blood pressure variation blunted in patients with retinopathy compared to patients without retinopathy despite strict normoalbuminuria and similar UAE levels in the groups compared. Our data suggest that the association between blood pressure and diabetic retinopathy is present also when coexisting renal disease is excluded. Disturbed diurnal variation of blood pressure is a pathophysiological feature related to the development of both retinopathy and nephropathy in IDDM patients. [Diabetologia (1998) 41: 105–110] Received: 27 May 1997 and in revised form: 5 September 1997     

Indomethacin But Not Metoprolol Reduces Exercise-induced Albumin Excretion Rate in Type 1 Diabetic Patients with Microalbuminuria

The effects of a single oral dose of indomethacin (1 mg kg^?1), metoprolol (1.5 mg kg^?1) and placebo on exercise-induced albumin excretion rate (AER) were compared in a randomized, crossover design in 14 normotensive, young Type 1 diabetes patients, nine of them with microalbuminuria (AER > 15 μg min^?1) and five without microalbuminuria at rest. The albumin excretion rate, blood pressure, heart rate, blood glucose, and plasma concentrations of indomethacin and metoprolol were determined before and after 30 min submaximal physical exercise. In microalbuminuric patients the rise in albumin excretion rate after exercise on indomethacin (7 μg min^?1) was lower than after placebo (29 μg min^?1, p < 0.001) whereas the rise in albumin excretion rate with metoprolol during exercise (18 μg min^?1) did not differ from placebo (p = 0.48), in spite of the expected less marked increase in blood pressure. In normoalbuminuric patients no significant increase in albumin excretion rate was noted by exercise in any of the treatment periods. A tendency to a linear correlation (r = ?0.54, p = 0.07) was seen between the plasma concentration of indomethacin and the inhibition of exercise-induced increase in albumin excretion rate. No correlations were observed between exercise-induced changes in albumin excretion rate and systolic blood pressure, heart rate or blood glucose. In conclusion, acute indomethacin treatment, presumably through inhibition of renal prostaglandin synthesis, reduces the exercise-induced rise in albumin excretion rate in Type 1 diabetic patients with microalbuminuria. Such an effect was not seen after acute administration for the beta-1-adrenoceptor blocking drug metoprolol, in spite of a less marked rise in blood pressure.     

24-h blood pressure and autonomic function is related to albumin excretion within the normoalbuminuric range in IDDM patients

Summary Significant changes in both blood pressure, autonomic function and kidney ultrastructure are observed in insulin-dependent diabetic (IDDM) patients with microalbuminuria. Intervention strategies are evaluated at even earlier stages of disease. Identification of patients at risk of developing microalbuminuria must be based on a thorough knowledge of the relations between key pathophysiological parameters in patients with normoalbuminuria. The aim of the present study was to characterize the interactions of urinary albumin excretion (UAE), 24-h ambulatory blood pressure (AMBP), and sympathovagal balance in a large group of normoalbuminuric IDDM patients. In 117 normoalbuminuric (UAE < 20 μg/min) patients we performed 24-h AMBP (Spacelabs 90 207), with assessment of diurnal blood pressure and heart rate (HR) variation, and short-term (three times 5 min) power spectral analysis of RR interval oscillations, as well as cardiovascular reflex tests (HR variation to deep breathing, postural HR and blood pressure response). Patients with UAE above the median (4.2 μg/min) had significantly higher 24-h systolic and diastolic AMBP (125 ± 10.1/76 ± 7.2 mmHg) compared to the low normoalbuminuric group (120 ± 8.4/74 ± 5.1 mmHg), p < 0.01 and 0.02, respectively. Patients with UAE above the median had significantly reduced short-term RR interval variability including both the high frequency component (5.47 ± 1.36 vs 6.10 ± 1.43 ln ms²), and low frequency component (5.48 ± 1.18 ln ms² compared to 5.80 ± 1.41 ln ms²), p < 0.02 and p = 0.04 (ANOVA). In addition, patients with high-normal UAE had reduced mean RR level (faster heart rates) 916 ± 108 compared to 963 ± 140 ms, p < 0.04. These differences were not explained by age, duration of diabetes, gender, level of physical activity, or cigarette smoking. HbA_{1 c} was significantly higher (8.6 ± 1.2 vs 8.2 ± 1.0 %, p = 0.03) in the group with high normal UAE. Comparing normoalbuminuric IDDM patients with UAE above and below the median value, we found significantly higher AMBP in combination with significant differences in sympathovagal balance and significantly poorer glycaemic control in the group with high-normal albumin excretion. Our data demonstrate interactions between albumin excretion, blood pressure, autonomic function, and glycaemic status, already present in the normoalbuminuric range and may describe a syndrome indicative of later complications. [Diabetologia (1997) 40: 718–725] Received: 9 January 1997 and in revised form: 12 March 1997