Can type 2 diabetes mellitus be considered preventable?

The primary prevention of type 2 diabetes mellitus (T2DM) is of great importance. There is now substantial evidence that T2DM can be prevented or delayed by lifestyle modification. A statistically significant reduction of relative risk of newly diagnosed T2DM was observed in large clinical trials with metformin, acarbose or orlistat in subjects with impaired glucose tolerance as well as with troglitazone in women with previous gestational diabetes. A relative risk reduction of newly diagnosed diabetes was observed in prospective, double blind clinical studies evaluating the effect of different antihypertensive drugs (ACE-inhibitors, angiotensin repector blockers, calcium channel blockers) or that of lipid-lowering agents (pravastatin) on the cardiovascular morbidity and mortality in high risk patients. In studies with postmenopausal hormone replacement therapy a relative risk reduction of newly developed T2DM was also observed. Thus, T2DM should be considered as a preventable disease. Nevertheless, it is noteworthy that oral antidiabetic drugs with an indication of preventing T2DM are not registered in several countries at present, so that drug therapy should not be used as a routine for preventing diabetes. On the other hand, patients with pre-diabetes (impaired fasting glycaemia, impaired glucose tolerance) should be given counseling on weight loss as well as instruction for increasing physical activity in order to prevent T2DM.

[Evidence based therapy with insulin in diabetic patients]

A fast development in therapy with insulin was observed after its discovery. Besides the widely used human regular insulin preparations, nowadays ultrashort and long-acting insulin analogues are also available for the patients. At present, the results of large clinical trials enable an evidence based diabetes care. It is well documented, that near-normoglycemia should be achieved by intensive conservative insulin treatment or pump therapy in type 1 diabetic patients. The beneficial effects of the good metabolic control could also be observed years later concerning late specific complications of diabetes. Similarly, as good as possible metabolic control should be aimed with antidiabetic treatment including insulin, if necessary, in type 2 diabetic patients. It is documented that the risk of cardiovascular complications is not increased in type 2 diabetic patients treated with insulin. Hypoglycemia and weight gain are the most important side effects of the insulin treatment. Recently, evidence based recommendations for treatment with ultrashort (insulin lispro, insulin aspart) and long-acting insulin analogues (glargine) can also be determined.

Impairment of the NO/cGMP pathway in the fasting and postprandial state in type 1 diabetes mellitus

The assessment of the postprandial state in diabetes mellitus has gained importance due to postprandial hyperglycemia being considered as an independent risk factor for cardiovascular disease. Hyperglycemia may contribute to vascular dysfunction through the alteration of the nitric oxide/cyclic guanosine monophosphate (NO/cGMP) pathway. The authors assessed the NO/cGMP pathway in the fasting and postprandial state in 20 type 1 diabetic patients (age: 34.1 +/- 2.6 years, body mass index (BMI): 24.1 +/- 1.3 kg/m (2), duration of diabetes: 16 +/- 2.2 years, HbA (1C): 8.3 +/- 0.4 %, [x +/- SEM], 10 without, 10 with late complications) and 20 matched control subjects (age: 39.7 +/- 1.9 years, BMI: 25.3 +/- 1.1 kg/m (2)). In the fasting state NO end product (nitrite/nitrate) levels did not differ between the diabetic and control group, cGMP levels were found to be significantly lower in the diabetic group (2.5 +/- 0.2 vs. 4.6 +/- 0.6 nmol/l, p = 0.01). A higher level of lipid peroxidation end products (TBARS) was found in diabetic subjects (6.7 +/- 0.4 vs. 5.0 +/- 0.3 micro mol/l, p = 0.004). The diabetic subgroup without late complications had significantly higher nitrite/nitrate levels compared to the patients with complications (57.8 +/- 6.6 vs. 30.4 +/- 4.3 micro mol/l, p = 0.006), their TBARS and cGMP levels were similar. The control subjects responded to the test meal with an increase in the cGMP levels (4.6 +/- 0.6 to 5.5 +/- 0.6 nmol/l, p = 0.02), while in the diabetic group no change was detected. Postprandial nitrite/nitrate levels decreased in both groups, they were significantly lower in the diabetic group. There was no difference between postprandial nitrite/nitrate, cGMP, or glucose levels in the diabetic subgroups. Postprandial glucose levels showed a significant negative correlation with cGMP levels in the diabetic group (r = - 0.50, p = 0.02). The results suggest that in subjects with type 1 diabetes mellitus NO might have an impaired ability to induce cGMP production in the fasting state prior to the development of late specific complications or microalbuminuria under hyperglycemic conditions. Postprandial hyperglycemia is suggested to interfere with endothelial NO action, as shown by the decreased nitrite/nitrate and unchanged cGMP plasma levels in the diabetic group. The impairment of the NO/cGMP pathway both in the fasting and postprandial state that was shown in patients without diabetic complications may be an early sign of hyperglycemia induced vascular damage in type 1 diabetes mellitus.

[Decreased first-phase secretion of insulin may play a role in the development of insulin resistance]

Decreased first-phase secretion of insulin may play a role in the development of insulin resistance. In the development of type 2 diabetes an abnormal function of the beta-cells and insulin resistance of liver, fat cells and muscle play the main role. An early sign of beta-cell damage can be the loss of first-phase insulin response. This is supposed to precede the development of insulin resistance. Decrease of first-phase secretion of insulin can induce early postprandial hyperglycaemia and hypertriglyceridaemia damaging endothelium of precapillary arterioles of the nutritive capillaries. Insulin-induced endothelium-dependent dilation of these arterioles is inhibited by high glucose and triglyceride levels preventing metabolic effect of insulin on the parenchymal cells surrounded by nutritive capillaries and leading this way to insulin resistance. Second-phase hyperinsulinaemia develops in the impaired glucose tolerance. With the progression of the disease into the type 2 diabetes, insulin secretion decreases in the second-phase, as well. Because of decrease of first-phase insulin secretion in type 2 diabetic patients, early insulin therapy could be a choice of treatment in type 2 diabetes. Results of the UKPDS suggest that insulin-treated type 2 diabetic patients are longer in the near-euglycaemic state compared to those treated by oral hypoglycaemic agents. Recent data support that early insulin therapy of type 2 diabetic patients retains their own insulin secretion capacity and results in lower haemoglobin A1c. A comparison of before-meal rapid-acting insulin analogue and bedtime NPH insulin regimens verified that rapid-acting insulin analogue decreased haemoglobin A1c compared to NPH insulin treatment in type 2 diabetes. On the basis of these data arises the possibility of the change of the attitude "Oh no, not insulin in type 2 diabetes" to the "early rapid-acting insulin analogue treatment" of these patients.

Equivalence of indapamide SR and enalapril on microalbuminuria reduction in hypertensive patients with type 2 diabetes

OBJECTIVES

To test whether microalbuminuria in patients with type 2 diabetes and hypertension is primarily dependent on the severity of hypertension, and to compare the effectiveness of two antihypertensive drugs with opposite effects on the renin-angiotensin system [the diuretic, indapamide sustained release (SR), and an angiotensin-converting enzyme inhibitor, enalapril] in reducing microalbuminuria.

DESIGN

A multinational, multicentre, controlled, double-blind, double-dummy, randomized, two-parallel-groups study over 1 year.

METHODS

After a 4-week placebo run-in period, 570 patients (ages 60.0 +/- 9.9 years, 64% men) with type 2 diabetes, essential hypertension [systolic blood pressure (SBP) 140-180 mmHg, and diastolic blood pressure (DBP) < 110 mmHg], and persistent microalbuminuria (20-200 microg/min) were allocated randomly to groups to receive indapamide SR 1.5 mg (n = 284) or enalapril 10 mg (n = 286) once a day. Amlodipine, atenolol, or both were added, if necessary, to achieve the target blood pressure of 140/85 mmHg.

RESULTS

There was a significant reduction in the urinary albumin : creatinine ratio. Mean reductions were 35% [95% confidence interval (CI) 24 to 43] and 39% (95% CI 30 to 47%) in the indapamide SR and enalapril groups, respectively. Equivalence was demonstrated between the two groups [1.08 (95% CI 0.89 to 1.31%); P = 0.01]. The reductions in mean arterial pressure (MAP) were 16.6 +/- 9.0 mmHg for the indapamide SR group and 15.0 +/- 9.1 mmHg for the enalapril group (NS); the reduction in SBP was significantly greater (P = 0.0245 ) with indapamide SR. More than 50% of patients in each group required additional antihypertensive therapy, with no differences between groups. Both treatments were well tolerated.

CONCLUSIONS

Indapamide-SR-based therapy is equivalent to enalapril-based therapy in reducing microalbuminuria with effective blood pressure reduction in patients with hypertension and type 2 diabetes.

[Risk factors to be considered at the beginning of antihypertensive therapy in diabetes mellitus]

The treatment of hypertension in diabetic patients due to its high prevalence rate belongs to the everyday clinical practice of internists, diabetologists and general practitioners. The main points of the initiation on of antihypertensive treatment in diabetic patients are reviewed. In order to decrease the target organ damages the treatment of early recognized cardiovascular risk factors are of great importance. The target value of antihypertensive treatment in diabetic patients is < 130/80 mmHg (in case of proteinuria > 1 g daily: < 125/75 mmHg). The global cardiovascular risk is high or very high in diabetic patients both with grade I-III hypertension and with high normal blood pressure, therefore, treatment with antihypertensive drug (besides life style optimalisation) should be initiated promptly in these cases. In case of micro- or macroalbuminuria antihypertensive drug (mainly with characteristics of blocking the renin-angiotensin-system) should be given to each diabetic subject irrespective of actual blood pressure values. Success of antihypertensive treatment in diabetic patients could be achieved mainly with combination therapy only. It is reasonable to initiate antihypertensive therapy primarily with a low dose combination of two agents in diabetic patients with hypertension.

Clinical consequences of cardiovascular autonomic neuropathy in diabetic patients

A wide range of clinical consequences of cardiovascular autonomic neuropathy (CAN) can be observed in diabetic patients and contributes to the clinical picture of the diabetic heart. Resting heart rate and cardiovascular reflexes as well as circadian heart rate variability may be altered by CAN in diabetes. Moreover, blood pressure is also influenced by sympathovagal imbalance. Postural hypotension is a clinical characteristic in diabetic subjects with CAN. Painless myocardial infarction, ischaemia and left ventricular dysfunction are also observed in some cases. Impairment of cardiac parasympathetic and sympathetic innervation as well as QT-interval prolongation may play a partial role in the pathogenic mechanism of sudden unexpected death in diabetic patients. The risk of surgical intervention and that of anaesthesia are increased due to abnormal cardiovascular reactions. Clinical symptoms and signs of CAN should be assessed as severe diabetic complication and the therapy is difficult in some cases. Taken together, symptoms and signs of CAN carry a poor prognosis in diabetic patients.

[Is type-2 diabetes mellitus preventable?]

The public health burden of type 2 diabetes mellitus has been dramatically increased worldwide. Not only its prevalence rate at present but the increase of its incidence in the near future can create a global health problem. The rapid increase of the total number of newly diagnosed diabetic patients proved to be associated with the increasing prevalence rate of obesity. The metabolic syndrome and type 2 diabetes can contribute to accelerated atherosclerosis and, therefore, the target organ damages can carry a serious problem for the individuals and also for the whole society. It is obvious, that the primary prevention of type 2 diabetes mellitus is of great importance. There is now substantial evidence that type 2 diabetes can be prevented or delayed by lifestyle interventions, i.e. diet and exercise should be the first choice in order to avoid weight gain when preventing diabetes. Pharmacological intervention should not be routinely used to prevent diabetes although results of large clinical trials with metformin and acarbose in subjects with impaired glucose tolerance are available. It is noteworthy that a decrease in the number of newly diagnosed diabetes was observed in prospective, double blind clinical studies evaluating the effect of new antihypertensive drugs (captopril, ramipril, lisinopril, nifedipine GITS, amlodipine, losartan) or lipid-lowering agents (pravastatin) on the cardiovascular morbidity and mortality in high risk patients. In these studies the relative risk reduction of newly diagnosed diabetes was evaluated in comparison to placebo or other drugs in a subgroup of non-diabetic patients at baseline. In addition, the incidence of newly diagnosed type 2 diabetes decreased parallel with weight loss in clinical trials with orlistat, an anti-obesity drug. Although new results were provided by evidence based clinical trials a lot of questions remained to be solved. Further research is necessary to understand better how to facilitate effective primary prevention of type 2 diabetes. Further data are needed to evaluate the clinical significance of currently used antidiabetic drugs and, in addition, the possible role of other drugs (antihypertensives, lipid lowering agents, anti-obesity drugs) should also be investigated in order to identify the optimal primary prevention policy of type 2 diabetes.

[Cardiologic and diabetologic aspects of therapy with angiotensin receptor blocking agents]

Authors based on studies fullfiling the principles of evidence based medicine review the efficiency and benefits of angiotensin receptor blocking agents in congestive heart failure and hypertension. Special attention is focused on their application in diabetes mellitus. The data support efficacy, good tolerability, beneficial side effect profile as well as cardio- and renoprotective properties of these drugs. Their safety in diabetic as well as and in non-diabetic persons can be underlined.

[Theoretical background of angiotensin II receptor blockade and its features in clinical pharmacology]

The angiotensin (II) receptor (1) blockers are known first of all as antihypertensive drugs, however, due to the role of the tissue renin-angiotensin system (RAS) in different pathological conditions, their clinical importance became more pronounced and are at present more widely used. The article gives an overview of the recent knowledge in this field. Beside of summarizing physiological and the most important pathophysiological aspects of the RAS, as well as pharmacokinetic properties of the different angiotensin receptor blocker drugs used at present in Hungary, the potential differences in blocking of the converting enzyme and the angiotensin II receptors are also reviewed.

Screening for metabolic syndrome in hypertensive and/or obese subjects registered in primary health care in Hungary

BACKGROUND

The screening of subjects at risk for metabolic syndrome is of considerable importance in order to prevent atherosclerosis.

MATERIAL/METHODS

In order to assess the clinical-laboratory characteristics of metabolic syndrome,a screening procedure was performed in subjects (age 20 -65)who exhibited hypertension and/or abnormal body mass index (BMI)and/or elevated waist-hip ratio,excluding patients with known diabetes. An oral glucose tolerance test with 75 g glucose was performed. Plasma glucose and insulin values were measured,as well as plasma lipids.

RESULTS

In subjects available for complete statistical analysis (n=944;women/men ratio 1.37:1),hyperinsulinemia was detected in 52.9%. Hyperinsulinemia with normal glucose tolerance was more often detected (33.2%),hyperinsulinemia with impaired glucose tolerance [IGT ]or diabetes less frequently (13.0%and 6.7%,respectively). When abnormal clinical signs were separately analysed,hyperinsulinemia was found in 56.8%of subjects with abnormal BMI,in 43.8% of subjects with abnormal waist-hip ratio,and in 27.1% of subjects with hypertension. Metabolic syndrome (WHO criteria,modified)was diagnosed in 35.2%of subjects,with male predominance (men:40.6%;women:31.2%;p<0.01).

CONCLUSIONS

Obesity (abnormal BMI;abnormal waist-hip ratio)is of greater importance than hypertension alone for detecting subjects with hyperinsulinemia.Routine clinical and laboratory investigations (anthropometric data,measuring blood pressure,oral glucose tolerance test)are simple but useful for identifying subjects with metabolic syndrome,enabling the implementation of a primary strategy to prevent cardiovascular morbidity.

Intima-media thickness of the carotid arteries in subjects with hyperinsulinaemia (insulin resistance)

The metabolic syndrome is characterised by hyperinsulinaemia (insulin resistance) leading to an increased risk of atherosclerotic cardiovascular diseases. Carotid intima-media thickness (IMT) can be easily measured to detect early atherosclerosis. In order to evaluate the clinical characteristics of the metabolic syndrome a screening procedure was performed and carotid IMT was determined by high-resolution B-mode ultrasonography in a cohort of middle-aged (40-60 years) subjects who proved to be hyperinsulinaemic [fasting plasma insulin >15 microU/ml and/or post-prandial (120 min) insulin > 45 microU/ml; n = 91; men/women: 35/56; homeostasis model assessment (HOMA)-index: 6.42 +/- 3.65; x +/- SD]. Subjects known to have diabetes were not involved. Subjects were divided into subgroups according to the stages of glucose intolerance (normal glucose tolerance, n = 46; impaired glucose tolerance, n = 26; diabetes mellitus, n = 19). As controls, age- and sex-matched non-diabetic and non-hyperinsulinaemic subjects (n = 20; HOMA-index: 2.09 +/- 0.85) were investigated. The values of IMT of the internal carotid arteries were higher in hyperinsulinaemic subjects than in controls (0.93 +/- 0.39 mm vs 0.57 +/- 0.13 mm,p < 0.001), whereas the lumen diameter proved to be smaller than in control subjects (5.04 +/- 0.75 mm vs 5.45 +/- 0.71 mm; p < 0.05). In hyperinsulinaemic subjects only a trend of increasing IMT values and that of decreasing lumen diameter of the internal carotid arteries were observed when subgroups classified according to the stages of glucose intolerance were compared. No significant changes in IMT or lumen diameter of the common carotid arteries were observed. Early and asymptomatic signs of atherosclerosis could be detected in middle-aged subjects who proved to be hyperinsulinaemic in a screening procedure. The prevention of clinically manifest cardiovascular diseases in these subjects could be of great importance.

Effect of low-dose perindopril/indapamide on albuminuria in diabetes: preterax in albuminuria regression: PREMIER

Microalbuminuria in diabetes is a risk factor for early death and an indicator for aggressive blood pressure (BP) lowering. We compared a combination of 2 mg perindopril/0.625 mg indapamide with enalapril monotherapy on albumin excretion rate (AER) in patients with type 2 diabetes, albuminuria, and hypertension in a 12-month, randomized, double-blind, parallel-group international multicenter study. Four hundred eighty-one patients with type 2 diabetes and hypertension (systolic BP > or =140 mm Hg, <180 mm Hg, diastolic BP <110 mm Hg) were randomly assigned (age 59+/-9 years, 77% previously treated for hypertension). Results from 457 patients (intention-to-treat analysis) were available. After a 4-week placebo period, patients with albuminuria >20 and <500 microg/min were randomly assigned to a combination of 2 mg perindopril/0.625 mg indapamide or to 10 mg daily enalapril. After week 12, doses were adjusted on the basis of BP to a maximum of 8 mg perindopril/2.5 mg indapamide or 40 mg enalapril. The main outcome measures were overnight AER and supine BP. Both treatments reduced BP. Perindopril/indapamide treatment resulted in a statistically significant higher fall in both BP (-3.0 [95% CI -5.6, -0.4], P=0.012; systolic BP -1.5 [95% CI -3.0, -0.1] diastolic BP P=0.019) and AER -42% (95% CI -50%, -33%) versus -27% (95% CI -37%, -16%) with enalapril. The greater AER reduction remained significant after adjustment for mean BP. Adverse events were similar in the 2 groups. Thus, first-line treatment with low-dose combination perindopril/indapamide induces a greater decrease in albuminuria than enalapril, partially independent of BP reduction. A BP-independent effect of the combination may increase renal protection.

Effect of pioglitazone compared with metformin on glycemic control and indicators of insulin sensitivity in recently diagnosed patients with type 2 diabetes

Pioglitazone, a thiazolidinedione, improves glycemic control primarily by increasing peripheral insulin sensitivity in patients with type 2 diabetes, whereas metformin, a biguanide, exerts its effect primarily by decreasing hepatic glucose output. In the first head-to-head, double-blind clinical trial comparing these two oral antihyperglycemic medications (OAMs), we studied the effect of 32-wk monotherapy on glycemic control and insulin sensitivity in 205 patients with recently diagnosed type 2 diabetes who were naive to OAM therapy. Subjects were randomized to either 30 mg pioglitazone or 850 mg metformin daily with titrations upward to 45 mg (77% of pioglitazone patients) and 2550 mg (73% of metformin patients), as indicated, to achieve fasting plasma glucose levels of less than 7.0 mmol/liter (126 mg/dl). Pioglitazone was comparable to metformin in improving glycemic control as measured by hemoglobin A1C and fasting plasma glucose. At endpoint, pioglitazone was significantly more effective than metformin in improving indicators of insulin sensitivity, as determined by reduction of fasting serum insulin (P = 0.003) and by analysis of homeostasis model assessment for insulin sensitivity (HOMA-S; P = 0.002). Both OAM therapies were well tolerated. Therefore, pioglitazone and metformin are equally efficacious in regard to glycemic control, but they exert significantly different effects on insulin sensitivity due to differing mechanisms of action. The more pronounced improvement in indicators of insulin sensitivity by pioglitazone, as compared with metformin monotherapy in patients recently diagnosed with type 2 diabetes who are OAM-naive, may be of interest for further clinical evaluation.

Effect of indapamide SR on microalbuminuria--the NESTOR study (Natrilix SR versus Enalapril Study in Type 2 diabetic hypertensives with micrOalbuminuRia)--rationale and protocol for the main trial

In type 2 diabetic hypertensive patients, microalbuminuria can be due to hypertension and/or diabetic nephropathy. Angiotensin-converting enzyme (ACE) inhibitors act preferentially on microalbuminuria due to diabetic nephropathy. The objective is to demonstrate the efficacy of a thiazide-like diuretic, indapamide sustained release (SR), at reducing microalbuminuria in hypertensive type 2 diabetic patients in comparison with an ACE inhibitor, enalapril. The study is an international multicentre, 12-month, randomized, double-blind, controlled, two parallel group study of type 2 diabetic patients with hypertension (140 mmHg < or = systolic blood pressure <180 mmHg and diastolic blood pressure <110 mmHg) and microalbuminuria. Intervention is after a 4-week placebo period, patients with microalbuminuria > or = 20 and < or = 200 microg/min are randomized to indapamide SR 1.5 mg or to enalapril 10 mg once a day for a one-year treatment period. An additional label treatment by amlodipine 5-10 mg (1st step) and atenolol 50-100 mg (2nd step) a day is permitted after 6 weeks of treatment based upon blood pressure response. The main outcome measures are microalbuminuria expressed as urinary albumin to creatinine ratio, albumin fractional clearance, and albumin excretion rate evaluated on overnight urine collections. Secondary criteria are supine and standing systolic, diastolic and mean blood pressure; and biological and clinical safety. This study will complete the knowledge of the efficacy of indapamide SR in hypertension and target organ damage and will provide valuable information on the management of type 2 diabetic hypertensives with microalbuminuria.

[Fasting or post-challenge blood glucose values for detection of glucose intolerance in screening for metabolic syndrome?]

INTRODUCTION

The normal-pathological threshold of fasting blood glucose values was modified by the new WHO diagnostic criteria (1999) and, in addition, impaired fasting glucose (IFG) was introduced as a new clinical entity. Nevertheless, the 2-h post-glucose challenge criteria and the concept of the impaired glucose tolerance (IGT) remained unchanged. There is no unequivocal agreement whether new fasting or unchanged post-challenge blood glucose criteria should be used for classification of glucose intolerance.

AIMS

To assess the clinical-laboratory characteristics of metabolic syndrome a screening procedure was performed in hypertensive or obese subjects registered within primary health care and the reliability of the new fasting blood glucose criteria was analysed.

PATIENTS AND METHODS

For inclusion, subjects of both sexes aged from 20 to 65 years exhibited at least one of the following clinical characteristics: hypertension (ongoing antihypertensive treatment or raised (> or = 140/90 mmHg) actual blood pressure), abnormal (> 30.0 kg/m2) body mass index [BMI] or elevated waist-hip ratio (> 0.85 in women, > 0.90 in men). Subjects with known diabetes were not involved. An oral glucose tolerance test (OGTT) with 75 g glucose was performed in each subject. Subjects with complete clinical and laboratory findings were statistically analysed (n = 944; women/men: 545/399; age: 46.1 +/- 7.3 years; BMI 32.2 +/- 5.4 kg/m2; waist-hip ratio 0.90 +/- 0.09; x +/- SD).

RESULTS

In the total cohort newly diagnosed diabetes mellitus (based on the 120 min post-challenge glucose values) was found in 87 subjects (9.2%), IGT was detected in 136 cases (14.4%) while normal glucose tolerance was documented in 721 subjects (76.4%). Using fasting blood glucose values for classification, diabetes mellitus was detected in 79 subjects (8.4%), IFG was found in 124 cases (13.1%) while 741 subjects (78.5%) had normal glucose tolerance. Impaired glucoregulation (IGT + IFG) was found in 223 subjects (IGT alone 99 cases [44.4%], IFG alone 87 cases [39.0%], IGT and IFG in combination 37 cases [16.6%]). The sensitivity and specificity of fasting blood glucose criteria for detecting diabetes were 63.2% and 97.1%, respectively, while those for detecting glucose intolerance (IFG and diabetes as well as IGT and diabetes) were 52.9% and 88.2%, respectively. Clinical characteristics of subjects with abnormal post-challenge but normal fasting blood glucose values (n = 105) did not differ significantly from those of subjects with normal post-challenge but abnormal fasting blood glucose values (n = 85) (age: 46.7 +/- 6.9 years vs 46.7 +/- 6.1 years; BMI: 33.1 +/- 5.4 kg/m2 vs 32.3 +/- 4.5 kg/m2; waist-hip ratio: 0.91 +/- 0.09 vs 0.92 +/- 0.07; p > 0.05).

CONCLUSION

OGTT and 2-h post-glucose challenge criteria should be used for the diagnosis of different categories of glucose intolerance in screening for metabolic syndrome.

The diabetic heart: A review of the lifework of Sophie Maria Koltai

It is well known that cardiovascular alterations are the principal causes of mortality in patients with diabetes. Premature and accelerated atherosclerosis cannot be the sole cause of diabetic heart disease because functional disorders develop both in experimental and in clinical diabetes before the onset of the detectable morphological changes of the vessel wall. Namely, altered adrenergic responses and prostaglandin metabolism and diminished vasodilatory ability can be seen in diabetic vessels. This leads to enhanced vasoconstriction, which - combined with increased sympathetic activity - may induce myocardial edema and an increase in myocardial stiffness, resulting in diminished heart function. Increased myocardial stiffness due to myocardial dehydration caused by hyperglycemic hyperosmolality can also result in impaired heart function. Thus, myocardial water content plays a key role in the development of diabetic heart dysfunction. Disturbances in the myocardial energy metabolism may also contribute to the diminished cardiac performance in the diabetic state. Some antidiabetic agents may also have deleterious cardiovascular effects. Whether the functional abnormalities observed in the reviewed studies lead to clinically manifest heart disease in diabetes may depend on the superimposition of the classical cardiovascular risk factors. Thus, adequate control of carbohydrate and lipid metabolism and the possible concomitant hypertension may prevent the further impairment of heart function and the development of overt heart disease.

[Advanced microangiopathic complications at the diagnosis of diabetes mellitus]

A case of a 59-year-old male patient with advanced microangiopathic complications at the diagnosis of diabetes mellitus is reported. The patient was referred to ophthalmological investigation due to progressive loss of visual acuity. Although diabetes mellitus was not known, proliferative diabetic retinopathy with significant visual loss was found at fundus examination. Not only newly diagnosed diabetes mellitus (initial fasting blood glucose 19.0 mmol/, HbA1c: 11.6%) but the presence of advanced sensory, motor and autonomic diabetic neuropathy (nervus peroneus motor conduction velocity: 32.1 m/s, nervus suralis sensory conduction velocity could not be detected, postural decrease in systolic blood pressure: 20 mmHg, beat-to-beat variation 6 beats/min, 30:15 ratio 1.03) as well as signs of advanced diabetic nephropathy (daily urinary protein excretion: 1.2-5.7 g, serum creatinine value: 101 mumol/l, sitting blood pressure: 150/100-180/100 mmHg) could be documented by further investigations at Medical Department. Avoiding short-term strict metabolic control insulin therapy was initiated and adequate long-term diabetic control was achieved later (HbA1c: 6.5-6.2%). In order to classify the diabetes, repeated measurements of serum C-peptide, ICA, GADA and IA2-antibodies were performed and type 2 diabetes was diagnosed. After a transient deterioration the proliferative retinopathy remained unchanged. Although laser photocoagulation was performed, no improvement in the visual acuity could be achieved. Only a minor improvement of neurological alterations was documented by repeated electrophysiological investigation at follow-up. Although the antihypertensive treatment (ACE-inhibitor drug in combination with calcium channel blocker) resulted in a significant decrease of elevated blood pressure, only a transient improvement of proteinuria could be achieved. Despite regular control, the advanced microangiopathic complications of diabetes mellitus carry poor prognosis.

Practical aspects of measuring microalbuminuria in diabetic patients

The importance of measuring microalbuminuria is well established; however, controversy still exists regarding the type of urine specimen to be used for detecting early renal impairment of diabetic patients. To evaluate practical aspects, albumin concentration and albumin/creatinine ratio of first void urine samples as well as urinary albumin excretion in timed specimens were determined by immunoturbidimetric method 3 times within 3 weeks in 192 adult diabetic patients (136 men, 56 women; Type 1/Type 2 diabetes: 90/102; age: 51.4+/-10.8 yr; duration of diabetes: 15.3+/-9.1 yr; body mass index: 27.9+/-4.6 kg/m2; HbA1c: 8.54+/-1.46%; actual blood pressure: 138+/-14/82+/-8 mmHg; serum creatinine: 94+/-20 pmol/l; x+/-SD). According to the urinary albumin excretion values one-third of patients (31.2%-30.7%-34.4%) were normoalbuminuric (<30 mg/24 hr), more than half of the patients (55.8%-57.3%-53.6%) proved to be microalbuminuric (30-300 mg/24 hr), while the remaining group of patients (13.0%-12.0%-12.0%) was macroalbuminuric (>300 mg/24 hr). Comparing the results of successive measurements, good correlation was found between the same laboratory values (urinary albumin excretion: kappa=0.64, kappa=0.67; urinary albumin concentration: kappa=0.60, kappa=0.62; albumin/creatinine ratio: kappa=0.54, kappa=0.61; first vs second and second vs third measurements, respectively). The percentage of patients being in the same range of albuminuria (ie normo-, micro- or macroalbuminuria) at successive measurements was 79.7-81.2% with urinary albumin excretion values, 77.1-77.6% with urinary albumin concentration and 74.5-78.6% with albumin/creatinine ratio. Good correlation was found between urinary albumin excretion and urinary albumin concentration (kappa=0.54; 0.54; 0.57) and nearly the same correlation was observed between urinary albumin excretion and albumin/creatinine ratio (kappa=0.49; 0.47; 0.54) at the three consecutive measurements (n=192). Using values of urinary albumin excretion for comparison at all measurements, 79.3% sensitivity and 69.5% specificity were found for urinary albumin concentration, whereas 74.6% sensitivity and 68.8% specificity were documented for albumin/creatinine ratio. Beside the standard measurement of urinary albumin excretion in timed urine samples, the use of the more convenient morning urinary spot collection could also provide useful results (urinary albumin concentration or albumin/creatinine ratio) for detecting early renal involvement in diabetic patients.

[Thiazolidinediones--a new class of oral antidiabetic drugs]

The discovery of a new class of oral antidiabetic drugs was stimulated by difficulties with the treatment currently available for patients with type 2 diabetes mellitus. Thiazolidinediones can lower blood glucose values due to their special insulin-sensitiser effect. In this way, these drugs seem to be very effective in the treatment of type 2 diabetic patients with characteristics of metabolic syndrome. The intracellular action caused by thiazolidinediones differs markedly from that of other oral antidiabetic drugs available. Apart from antihyperglycaemic effect, thiazolidinediones have further beneficial effects in experimental diabetes which require corroboration by clinical studies. Troglitazone was the first drug which reached the market. Unfortunately, this drug was withdrawn soon due to its hepatotoxicity. Rosiglitazone proved to be much safer in clinical studies. Pioglitazone is being tested nowadays in clinical studies. Thiazolidinediones have been already listed among oral antidiabetic drugs in international therapeutical guidelines. Nevertheless, further clinical studies and experiences are needed to determine the final exact indication of thiazolidinediones for the treatment of type 2 diabetic patients.