Risk factors for coronary artery disease in non-insulin dependent diabetes mellitus: United Kingdom Prospective Diabetes Study (UKPDS: 23)

Therapeutic potential of ACE inhibitors for the treatment of hypertension in Type 2 diabetes

Type 2 diabetes mellitus is associated with hypertension. If untreated, hypertension has a major impact on the clinical course of Type 2 diabetes and its vascular complications. In this review, we discuss rationale for the use of ACE inhibitors (ACEI) in hypertensive Type 2 diabetic patients and compare those theoretical assumptions with results of recent major clinical trials. Furthermore, possible directions for future clinical and experimental research are outlined. The RAS and its effector angiotensin II are important players in a number of cardiovascular and renal disorders. Recent evidence suggests that RAS and factors functionally linked to RAS are activated in Type 2 diabetes. Therefore, there is a theoretical basis for the use of ACEI in the treatment of hypertension in diabetic patients. Some recent studies reported superior outcome in patients treated with ACEI-based antihypertensive regimens compared with non-ACEI based treatments in reducing the risk of macrovascular disease (CAPPP, FACET, ABCD) or both micro- and macrovascular complications in Type 2 diabetes (HOPE). However, at least two of the large prospective studies discussed in this review (UKPDS 38, HOT), supported by results from previously published SHEP study, have recently suggested that the degree of reduction of blood pressure, rather than the choice of a particular class of antihypertensive agent, is associated with decreased risk of cardiovascular events. Studies focusing on renal end-points suggest that ACEI have a superior antiproteinuric effect than the other agents. However, whether ACEI are more nephroprotective, as assessed by the rate of decline in renal function, still remains to be elucidated. Despite promising results from recent trials, large numbers of patients progress despite ACEI treatment. Incomplete inhibition of the RAS may underlie this phenomenon. Treatment strategies that could enhance the degree of RAS inhibition represent one possible direction for clinical research in the near future. However, it is unlikely that the course of such a complex syndrome as Type 2 diabetes could be dramatically changed by just one class of antihypertensive agents. This goal is more likely to be achieved by multifactorial intervention, reflecting the complexity of metabolic syndrome. ACEI should be viewed as an important, but not the only, part of this complex approach.

Efficacy and safety of atorvastatin in hyperlipidemic, type 2 diabetic patients. A 34-week, multicenter, open-label study

Hyperlipidemia is common in type 2 diabetic patients and is an independent risk factor for cardiovascular disease. The aim of this trial was to evaluate the efficacy and safety of once-daily atorvastatin 10-80 mg for the treatment of hyperlipidemia in type 2 diabetics with plasma low-density lipoprotein cholesterol (LDL-C) levels exceeding 3.4 mmol/l (130 mg/dl). One hundred and two patients met the study criteria and received 10 mg/day atorvastatin. Patients who reached the target LDL-C level of </=2.6 mmol/l (100 mg/dl) maintained the same dosage regimen until they had completed 16 weeks of treatment. Patients not reaching the target LDL-C underwent dose titration to atorvastatin 20, 40 and 80 mg/day at Weeks 4, 8 and 12, respectively. All 88 patients who completed the study attained target LDL-C levels and 52 (59%) of patients achieved the target goal at the starting dose of atorvastatin 10 mg/day. In this group the differences between baseline and post-treatment values for LDL-C were 4.3+/-0.7 mmol/l (166+/-26 mg/dl) versus 2. 2+/-0.4 mmol/l (87+/-14 mg/dl) (P<0.0001), respectively, a decrease of 47%. Similar trends were observed for total cholesterol, triglycerides, very low-density lipoprotein cholesterol and apolipoprotein B levels. The safety profile of atorvastatin in these patients was highly favorable and similar to those reported with other statins. Only one patient withdrew due to a possible drug-related adverse event. These data confirm the marked efficacy and safety of atorvastatin in type 2 diabetic patients with hyperlipidemia and the efficacy of atorvastatin 10 mg in helping patients attain their LDL-C goal.

Using semi-automated oscillometric blood pressure measurement in diabetic patients and their offspring

To determine whether a semi-automatic oscillometric blood pressure (BP) monitor Dinamap 1846SX (DIN) can replace the standard mercury sphygmomanometer (SMS) for BP measurements in diabetic patients and their offspring, we compared SMS with DIN in 105 diabetic patients and their families. Their mean age was 50.6 (range 24-86) years, of whom 41 had diabetes mellitus (DM), 32 impaired glucose tolerance and 32 non-DM. After resting quietly for 10 min, their right arm BP were measured twice with each device at random and with 1-min intervals between each measurement. Agreement between measurements was tested by plotting the differences between the methods against means and by intraclass correlation coefficient (r(I)). The DIN was also evaluated by the criteria of American Association for the Advancement of Medical Instrumentation (AAMI), the British Hypertension Society (BHS) criteria and clinical criteria of O'Brien. All measurements by DIN [first readings or averaged readings of duplicate measurements of systolic BP (SBP) or diastolic BP (DBP)] satisfied the AAMI criteria and had good agreement with SMS (r(I)=. 951 for SBP and r(I)=.905 for DBP). The first readings of systolic BP measured by DIN vs. SMS failed to satisfy the criteria by O'Brien and reached BHS grade C level. Other measurements passed the limits of O'Brien and reached BHS grade A or B. In conclusion, averaged readings of duplicate BP measurements by DIN are interchangeable with that by SMS in Chinese diabetic patients and their offspring. Only one single DIN measurement is not acceptable for clinical application.

Association of glycaemia with macrovascular and microvascular complications of type 2 diabetes (UKPDS 35): prospective observational study

OBJECTIVE

To determine the relation between exposure to glycaemia over time and the risk of macrovascular or microvascular complications in patients with type 2 diabetes.

DESIGN

Prospective observational study.

SETTING

23 hospital based clinics in England, Scotland, and Northern Ireland.

PARTICIPANTS

4585 white, Asian Indian, and Afro-Caribbean UKPDS patients, whether randomised or not to treatment, were included in analyses of incidence; of these, 3642 were included in analyses of relative risk.

OUTCOME MEASURES

Primary predefined aggregate clinical outcomes: any end point or deaths related to diabetes and all cause mortality. Secondary aggregate outcomes: myocardial infarction, stroke, amputation (including death from peripheral vascular disease), and microvascular disease (predominantly retinal photo-coagulation). Single end points: non-fatal heart failure and cataract extraction. Risk reduction associated with a 1% reduction in updated mean HbA(1c) adjusted for possible confounders at diagnosis of diabetes.

RESULTS

The incidence of clinical complications was significantly associated with glycaemia. Each 1% reduction in updated mean HbA(1c) was associated with reductions in risk of 21% for any end point related to diabetes (95% confidence interval 17% to 24%, P<0.0001), 21% for deaths related to diabetes (15% to 27%, P<0.0001), 14% for myocardial infarction (8% to 21%, P<0.0001), and 37% for microvascular complications (33% to 41%, P<0.0001). No threshold of risk was observed for any end point.

CONCLUSIONS

In patients with type 2 diabetes the risk of diabetic complications was strongly associated with previous hyperglycaemia. Any reduction in HbA(1c) is likely to reduce the risk of complications, with the lowest risk being in those with HbA(1c) values in the normal range (<6.0%).

Effects of three months' diet after diagnosis of Type 2 diabetes on plasma lipids and lipoproteins (UKPDS 45). UK Prospective Diabetes Study Group

AIMS

To assess the effect of diet on fasting plasma lipids and lipoproteins in patients with newly diagnosed Type 2 diabetes.

METHODS

A total of 2,906 patients each underwent 3 months' diet therapy before allocation to therapy in a randomized controlled clinical trial. Lipids and lipoproteins were measured at diagnosis and after 3 months' diet.

RESULTS

The mean body weight at diagnosis was 83 kg. Weight decreased after diet by a mean of 4.5 kg; body mass index (BMI) decreased by 1.51 kg/m2; plasma glucose fell by 3 mmol/l from 11 mmol/l; and HbA1c by 2% from 9%. Triglyceride concentrations were reduced in men by -0.41 (95% confidence interval (CI) -0.47 to - 0.35) mmol/l from a geometric mean 1.8 (1 SD interval 1.0-3.0) mmol/l, and in women by -0.23 (-0.28 to -0.18) mmol/l from a similar level. Cholesterol decreased in men by -0.28 (-0.33 to -0.24) mmol/l from 5.5 (1.1) mmol/l, and in women by -0.09 (-0.14 to -0.04) mmol/l from 5.8 (1.2) mmol/l with corresponding changes in LDL cholesterol. HDL cholesterol increased in men by 0.02 (0.01 to 0.04) mmol/l and in women by 0.01 (0 to 0.02) mmol/l. Triglyceride concentration in the top tertile was reduced by 37% in men (> 2.1 mmol/l) and by 23% in women (> 2.2 mmol/l) with regression to mean accounting for 13% and 6%, respectively. Similarly cholesterol in the top tertile was reduced by 12% in men (> 5.8 mmol/l) and 7% in women (> 6.2 mmol/l) with 6% of the decrease in both men and women accounted for by regression to the mean.

CONCLUSIONS

Initial dietary therapy in patients with newly diagnosed Type 2 diabetes substantially reduced plasma triglyceride, marginally improved total cholesterol and subfractions, and resulted in a potentially less atherogenic profile, although this did not eliminate the excess cardiovascular risk in patients with Type 2 diabetes.

Screening for Type 2 diabetes mellitus: a decision analytic approach

AIMS

Screening for asymptomatic Type 2 diabetes mellitus has been advocated on the grounds that diabetes is a common condition associated with increased morbidity and mortality, but uncertainty remains about the impact of early treatment. This study aimed to determine whether the potential benefits of screening are likely to outweigh the potential harm and to explore which variables significantly influence the balance of benefit and harm resulting from screening.

METHODS

A decision analysis comparing the relative impact of using a single fasting blood glucose screening test, between the ages of 45 and 60 years, with the impact of not screening. The model weighs the increase in quality adjusted life years (QALYs) from reduction in microvascular and cardiovascular complications against the potential decrease in QALYs associated with earlier diagnosis and treatment in an asymptomatic population.

RESULTS

The baseline model suggests a saving of 10 QALYs for every 10,000 individuals screened: a gain of four from postponed microvascular complications and 17 from avoided cardiovascular complications, as opposed to a loss of 11 as a result of earlier diagnosis in screening detected cases. The balance of benefit and harm is sensitive to baseline cardiovascular risk, the effectiveness of cardiovascular interventions and the relative disutility assigned to early diagnosis and treatment for an individual without symptoms.

CONCLUSIONS

The immediate disutility of earlier diagnosis and additional treatment may be greater than the potential long-term benefit from postponing microvascular complications. Screening decisions should therefore be based largely on consideration of cardiovascular risk and the availability of evidence based interventions to reduce cardiovascular risk.

Coping with type-2 diabetes: the role of sense of coherence compared with active management

Changes in lifestyle, particularly in dietary and exercise habits, are necessary for the majority of patients with type-2 diabetes but are difficult to carry out. However, Antonovsky describes a salutogenic health perspective grounded in patients' developing what he terms 'a sense of coherence' (SOC). Can a strong SOC help diabetes patients to control the disease? The aim of this study was to analyse the relationship between SOC and treatment results measured as glucolysed haemoglobine (HbA1c) in patients with type-2 diabetes. The aim was further to test the relationship between treatment results and an index of patients' participation in active management and emotional state. Eighty-eight patients answered a questionnaire containing 13 statements about sense of coherence (SOC-13), questions about self-assessed health, diabetes activity such as self-management of diet, exercise and self-control of blood sugar and emotional acceptance. There was no direct relationship between SOC-13 and treatment results measured as HbA1c but there was a positive correlation between SOC-13, self-assessed health and HbA1c (P < 0.02). Self-assessed health was seen as a mediating factor. The better patients' estimation of their own health, the higher were SOC-13 scores and the lower HbA1c. There was also a strong positive correlation between low levels of HbA1c and high levels of an index of active management and emotional acceptance of diabetes (P < 0.001).

Diabetic dyslipidaemia: current treatment recommendations

Insulin deficiency and hyperglycaemia in type 1 (insulin-dependent) diabetes mellitus produce lipid abnormalities, which can be corrected by appropriate insulin therapy. Diabetic nephropathy, which is the main risk factor for coronary heart disease (CHD) in type 1 diabetes, causes pro-atherosclerotic changes in lipid metabolism. Detection and treatment of elevated cholesterol levels is likely to be of benefit in these patients. Type 2 (noninsulin-dependent) diabetes mellitus is associated with abnormal lipid metabolism, even when glycaemic control is good and nephropathy absent. Elevated triglyceride levels, reduced high density lipoprotein (HDL) cholesterol and a preponderance of small, dense low density lipoprotein (LDL) particles are the key abnormalities that constitute diabetic dyslipidaemia. The prevalence of hypercholesterolaemia is the same as for the nondiabetic population, but the relative risk of CHD is greatly increased at every level of cholesterol. Based on effectiveness, tolerability and clinical trial results, treatment with HMG-CoA reductase inhibitors to lower LDL cholesterol is recommended as primary therapy. These agents are also moderately effective at reducing triglyceride and increasing HDL cholesterol levels. If hypertriglyceridaemia predominates, treatment with fibric acid derivatives is appropriate, although there is currently only limited clinical trial evidence that the risk of CHD will be reduced. In type 1 diabetes, but particularly in type 2 diabetes, lipid disorders are likely to contribute significantly to the increased risk of macrovascular complications. especially CHD. Management of the disordered lipid metabolism should be given a high priority in the clinical care of all patients with diabetes.

Bezafibrate and simvastatin combination therapy for diabetic dyslipidaemia: efficacy and safety

OBJECTIVE

To determine the efficacy and safety of a statin-fibrate combination in diabetes patients. DESIGN.: An open 21-month trial in which each patient first received the single drug for 6 months and then a combination of the two for 1 year.

SETTING

Three lipid clinics in university-based tertiary care hospitals.

PATIENTS

One hundred and forty-eight patients with type 2 (non-insulin-dependent, NIDDM) diabetes mellitus under stable control for 3 months by means of diet and oral hypoglycaemic medication.

INTERVENTION

Patients from one clinic (n = 48) received bezafibrate slow release (400 mg day-1), and patients from the other two clinics (n = 100) received simvastatin 20 mg day-1. Six months later, all patients were switched to a daily combination of 400 mg bezafibrate slow release and 20 mg simvastatin for 1 year.

RESULTS

The combination of statin and fibrate led to a 23% reduction in total cholesterol, 42% reduction in triglycerides, 29% reduction in LDL-c, 25% increase in HDL-c, 10% decrease in fibrinogen and 19% reduction of Lp(a) levels, and a decrease in the cholesterol/HDL-c ratio (from 8.9 to 5.4) in all 148 patients. Cardiovascular (CV) event rate was significantly reduced from 9.5% during the first 6 months of the study to less than 2% during the last year of the study (whilst on combination Rx). Side-effects with all treatments included only two patients who developed myopathy when on the combined regimen and one on the single statin regimen. However, plasma creatinine phosphokinase (CPK) levels doubled (but remained within the normal range) in most of the patients on combination therapy, compared with only a mild increase in patients receiving a single medication.

CONCLUSIONS

The statin and fibrate combination was found to be more efficacious than a single medication for treatment of diabetic dyslipidaemia, as evidenced by improvement in the lipoprotein profile, reductions in Lp(a), fibrinogen and CV event rate, and almost no clinically significant side-effects.

Are angiotensin-converting enzyme inhibitors the best treatment for hypertension in type 2 diabetes?

The influence of hypertension on the clinical course and complications of type 2 diabetes is well established. With a special focus on angiotensin-converting enzyme inhibitors, this paper will review recently published results of prospective studies addressing two important aspects: the degree of blood pressure control, and the choice of antihypertensive regimen, in the prevention of complications in hypertensive type 2 diabetic patients. None of the recent studies have shown worse outcomes in patients treated with angiotensin-converting enzyme inhibitor-based regimens compared with alternative treatments. Some studies have suggested that angiotensin-converting enzyme inhibitor-based antihypertensive regimens may be superior to alternative treatments in reducing the risk of micro- and macrovascular complications, whereas other studies found similar effects for beta-blockers or calcium antagonists. Several trials showed beneficial effects of angiotensin-converting enzyme inhibitors over calcium antagonists, and have raised concerns about the use of dihydropyridine calcium antagonists in these patients. However, it remains to be determined whether there should be more reserved use of calcium antagonists in such patients, in the light of more major trials showing the safety and efficacy of calcium antagonists in preventing cardiovascular and renal endpoints. The degree of reduction of blood pressure rather than the choice of a particular drug may be the most important factor. Studies focusing on renal endpoints suggest that angiotensin-converting enzyme inhibitors have a better antiproteinuric effect than other agents, but this phenomenon is not always reflected by a more beneficial effect of angiotensin-converting enzyme inhibitors on the decline in glomerular filtration rate. In many ways, the question of whether angiotensin-converting enzyme inhibitors are the best class of agent in these patients is academic. Angiotensin-converting enzyme inhibitors are sufficiently safe, and, according to recent evidence, equally or more effective than other classes of agents. Tight blood pressure control is usually achievable only with a combination of agents. On the basis of available evidence, it appears that angiotensin-converting enzyme inhibitors, together with a low-dose cardioselective beta-blocker and a diuretic, should be used in most hypertensive type 2 diabetes patients, with calcium antagonists serving as reserve drugs in case of insufficient blood pressure control.

The health status of diabetic patients receiving orthotic therapy

Diabetes has a major impact on the quality of life and those with related foot ulcers are among those most affected. The main aim of the study, which was carried out over an 18-month time period, was to compare the self-reported health status of a group of diabetic patients receiving orthotic therapy with that of other groups who did not receive the therapy. A sample of 280 was recruited from patients with type I and type II diabetes. The study group comprised four groups of patients: those receiving orthotic therapy (insoles) for pedal complications as a result of their diabetes; those with diabetes mellitus, without complications of the disease affecting their foot; those with unilateral lower limb amputation and those with active ulceration who had not been prescribed footwear. The specialised orthotic intervention resulted in statistically significant improvements in health status (p < 0.05), (measured using the SF-36) both physically and mentally, for patients with at-risk feet and should become an integral part of the treatment regime for diabetics with at-risk feet.

The use of insulin alone and in combination with oral agents in type 2 diabetes

To achieve optimal outcomes in patients with type 2 diabetes, clinical trial data suggest that near normal glycemic control should be targeted. Insulin is arguably the most effective treatment available for diabetes and yet many patients remain poorly controlled without the benefit of insulin therapy. Discussion of its putative risks and benefits as well as the barriers to its wider use both in the context of monotherapy and in combination with oral antidiabetic agents is provided. Application of the strategies and principles of insulin therapy in type 2 diabetes should minimize the burden of complications in patients with the disease.

Hyperglycemia as a risk factor for cardiovascular disease in type 2 diabetes

According to several prospective population-based studies, glycemic control influences the risk for cardiovascular disease, including coronary heart disease, independently of conventional risk factors in patients with type 2 diabetes. Recent clinical trials, particularly the United Kingdom Prospective Diabetes Study, have shown that microvascular complications and macrovascular complications, although to a lesser extent, can be prevented in patients with type 2 diabetes with correction of glycemic control. However, in the treatment and prevention of cardiovascular disease in type 2 diabetes, all known cardiovascular risk factors should be attacked simultaneously.

Controversies surrounding the treatment of the hypertensive patient with diabetes

Diabetes mellitus without previous myocardial infarction carries the same risk of a future myocardial infarction as someone who has had one. Intense glucose, lipid, and blood pressure control in diabetic patients is advocated to reduce cardiovascular events and decrease the incidence of end-stage renal disease, retinal damage, and peripheral vascular disease. Recent studies, including the Systolic Hypertension in the Elderly Program, indicate that low-dose diuretics, compared with placebo, reduce fatal and nonfatal myocardial infarctions but not fatal and nonfatal strokes in diabetic patients. Similarly, captopril (and diuretics) compared with diuretics and beta-blockers decreased fatal and nonfatal myocardial infarctions but not fatal and nonfatal strokes in the Captopril Prevention Project. Intense blood pressure therapy with captopril and intense blood pressure therapy with atenolol equally lowered macrovascular and microvascular events compared with less intense blood pressure treatment in the United Kingdom Prospective Diabetes Study. Fewer myocardial infarctions were seen with enalapril than with nisoldipine in the Appropriate Blood Pressure Control in Diabetes trial. Intense blood pressure control with felodipine, enalapril, and hydrochlorothiazide reduced overall cardiovascular events and mortality but not myocardial infarction and strokes in the Hypertension Optimal Treatment trial. Nitrendipine alone or together with enalapril and hydrochlorothiazide decreased fatal and nonfatal strokes and cardiovascular mortality but not myocardial infarctions in the Systolic Hypertension in Europe trial. These trials, in aggregate, reinforce the importance of intense blood pressure control, which can be achieved only with combination drug therapy rather than a specific monotherapy drug class recommendation.

The narrow therapeutic window of glycated hemoglobin and assay variability

Glycated hemoglobin is measured by a variety of assays, each of which has a unique normal level. Our purpose is to show that among the different assays available in the United States, using the same patient's blood sample, assay results may vary widely and may more or less easily achieve a glycated hemoglobin value within the normal range. The following assays were compared using the same patient's blood sample for each pair of assays: glycohemoglobin affinity assay (GHB Reader; Isolab, Akron, OH) versus gel electrophoresis assay (n = 76); Isolab versus ion capture assay (IMX; Abbott Laboratories, Irving, TX) (n = 57); monoclonal antibody assay (DCA2000; Bayer Diagnostics, Pittsburgh, PA) versus IMX (n = 100); and high-performance liquid chromatography (HPLC) assay (Bio-Rad Variant A1c; Bio-Rad Laboratories, Richmond, CA) versus IMX assay (n = 55). Our analyses indicate that a relative ranking can be established for the ease of achieving a normal glycated hemoglobin level. The ranking indicates that the most stringent or difficult assays for achieving a normal level are the Isolab and DCA2000 assays. The intermediate assays are the IMX and Bio-Rad Variant, and the easiest method for achieving a normal value is the gel electrophoresis assay. Our results indicate that various glycated hemoglobin assays vary widely and are associated with more or less difficulty for an individual patient to achieve a glycated hemoglobin level within the normal range. These results are especially significant with respect to (1) the clinically narrow therapeutic window of glycated hemoglobin values in type 1 diabetes to avoid rapidly advancing severe hypoglycemia rates and chronic microvascular complication rates, and (2) the glycated hemoglobin threshold for rapidly advancing macrovascular disease in both type 1 and type 2 patients.

Strategies for the management of diabetic dyslipidaemia

Atherosclerosis, the complication most prominently associated with type 2 diabetes and cardiovascular disease, represents a major burden for both individuals and society. Mortality rates associated with cardiovascular disease among patients with type 2 diabetes are at least 3 times those in the general population, and although 'traditional' cardiovascular risk factors affect patients with this disorder as they do other individuals, they do not account for the excess risk attached to type 2 diabetes. There is a growing body of evidence to show that hyperglycaemia and dyslipidaemia are connected with this excess cardiovascular risk: hypertriglyceridaemia has been implicated in several prospective clinical studies, and available data suggest that low density lipoprotein (LDL)-cholesterol is more atherogenic in patients with type 2 diabetes than in other individuals. It is possible that this increased atherogenicity is associated with a preponderance of small, dense LDL particles that are more prone to oxidation and glycation than larger fractions and that may be involved in endothelial dysfunction. These findings lead to the recommendation of mandatory global risk assessment, accompanied by good glycaemic control, aggressive lowering of serum levels of LDL-cholesterol and maintenance of serum levels of triglyceride at the lowest possible level in patients with type 2 diabetes.

Prevention of type 2 diabetes: role of metformin

Metformin lowers moderate (nondiabetic) fasting hyperglycaemia in individuals at risk for type 2 diabetes without causing hypoglycaemia. In addition, it has demonstrated favourable action on several cardiovascular risk factors that are often present in these individuals: it favours the maintenance of diet-induced weight loss and its associated improvement in fibrinolysis; and it lowers plasma concentrations of fasting insulin, total and low density lipoprotein-cholesterol, free fatty acids, and of two markers of endothelial damage--tissue plasminogen activator antigen and von Willebrand factor. These effects together with the good tolerability profile of the drug position metformin as a first-line agent for the prevention of type 2 diabetes.

Impaired postprandial tissue regulation of blood flow in insulin resistance: a determinant of cardiovascular risk?

The insulin resistant state is a major risk factor for coronary artery disease. This increased risk is likely to be due to associated lipid and coagulation abnormalities rather than just abnormalities in glucose metabolism or hyperinsulinaemia alone. Exaggerated postprandial lipaemia is a well-recognised associate of insulin resistance and postprandial hypertriglyceridaemia is particularly important in the development of coronary atheroma. It seems likely that insulin is one of the hormonal regulators of adipose tissue and skeletal muscle blood flow. The reduced blood flow and blunting of the postprandial rise of peripheral blood flow in insulin resistance may decrease chylomicron-triglyceride delivery to muscle in subjects with insulin resistance. This, in turn, will lead to increased production of atherogenic particles. We propose that impaired postprandial vasodilation, already recognised as a key feature of glucose intolerance, is also the cause of impaired lipid metabolism in insulin resistant subjects and predisposes them to cardiovascular disease.

Incidence and determinants of mortality and cardiovascular events in diabetes mellitus: a meta-analysis

Patients with diabetes mellitus are at increased risk of developing atherosclerotic disease. The extent of this additional risk and its determinants are not well known, but this information is needed for sample-size estimations in intervention studies. Therefore, a meta-analysis of epidemiologic studies on this subject was performed. Medline was searched from 1966 onwards, including the reference lists of all relevant publications. A total of 27 prospective follow-up studies in the English language that allowed calculation of the unadjusted incidence of one of the predefined outcome events were included. The influence of age, sex, type of diabetes, duration of diabetes, year of study, HbA1c, cholesterol level, blood pressure and smoking on these incidences was studied by means of univariate Poisson regression analysis. Overall total mortality was 2.9% per year (95% CI 2.8-3.0; 27 studies), and for death from all vascular causes was 1.4% per year (95% CI 1.3-1.4; 16 studies). Only two studies were found that reported on the incidence of the composite outcome 'event death from all vascular causes, non-fatal myocardial infarction, or non-fatal stroke'. In univariate analysis, age, year of study, total cholesterol and systolic blood pressure were positively related to total mortality and death from all vascular causes. After adjustment for age, or limiting the analyses to studies in patients with type 2 diabetes only (n = 11), these relationships remained statistically significant. In conclusion, the overall yearly total mortality in diabetes mellitus is 2.9% and for death from all vascular causes is 1.4%. There are few data on the incidence of composite cardiovascular outcome events.

Drug treatment for hypertensive patients in special situations: diabetes and hypertension

Diabetes mellitus and hypertension is often associated, but with a different type of development in type 1 and type 2 diabetes. Type 1 diabetes, renal disease, starting with microalbuminuria, is associated with increasing blood pressure or hypertension, whereas the patient without renal disease is most often normotensive. Poor metabolic control is a predictor of microalbuminuria or incipient nephropathy, but with microalbuminuria hypertension is an important risk factor for progression along with poor glycemic control. The same is the case for overt renal disease, and metabolic control is important in all stages of renal disease in type 1 diabetes. It has also been shown that good metabolic control as well as antihypertensive treatment, especially with ACE-inhibitors, often combined with other agents is quite effective in preventing progression in renal disease in all its stages. In type 2 diabetes, blood pressure elevation is often found as early as at the actual diagnosis, and blood pressure significantly increases according to the degree of albuminuria, normo-microalbuminuria and clinical proteinuria (macroalbuminuria). Elevated blood pressure is an important risk for renal disease but more importantly so also for cardiovascular disease. Several studies document that antihypertensive treatment in particular with ACE-inhibitors is important in preventing microalbuminuria, in treating microalbuminuria and thus preventing progression, also in overt renal disease. Near-normalization of blood pressure is vital. Regarding cardiovascular disease, a series of studies now document that antihypertensive treatment with various antihypertensive agents is able to significantly reduce a number of major cardiovascular complications in diabetes, such as cardiac disease, stroke, and also microvacular disease, including retinopathy. Several studies show that antihypertensive treatment should be started at a level higher than 140-150/90. The blood pressure to be achieved during treatment is probably around 140/85 mmHg or even 130/80 mmHg as a pragmatic goal. However, there is no sign of a J-shaped curve in any of the studies, and therefore even lower blood pressure could be advantageous. Even mortality, at least from diabetes-related causes can be effected by antihypertensive treatment. With more advanced renal disease, normalization of blood pressure is increasingly difficult, especially systolic blood pressure, and therefore it is recommendable to screen patients much earlier on with focus on blood pressure recordings and measurements of albuminuria, including microalbuminuria, and to treat early.

Current therapeutic options in type 2 diabetes

The prevalence of Type 2 diabetes rises steeply with age and involves beta-cell dysfunction and diminished sensitivity to insulin. beta-cell dysfunction is important in the development of hyperglycaemia while insulin resistance seems to play a major role in the atherogenic process resulting in cardiovascular disease. Current therapeutic options include lifestyle adjustments (exercise and diet), oral hypoglycaemic agents (sulphonylureas, newer beta-cell mediated insulin releasing drugs, alpha-glucosidase inhibitors, biguanides and thiazolidinediones) and insulin treatment. Oral hypoglycaemic agents are effective only temporarily in maintaining good glycaemic control, their efficacy should be determined from changes in fasting and postprandial glucose levels. Recent studies have shown that the early initiation of insulin therapy can establish good glycaemic control.

Diabetes and exercise

Exercise is frequently recommended in the management of type 1 and 2 diabetes mellitus and can improve glucose uptake by increasing insulin sensitivity and lowering body adiposity. Both alone and when combined with diet and drug therapy, physical activity can result in improvements in glycaemic control in type 2 diabetes. In addition, exercise can also help to prevent the onset of type 2 diabetes, in particular in those at higher risk, and has an important role in reducing the significant worldwide burden of this type of diabetes. Recent studies have improved our understanding of the acute and long term physiological benefits of physical activity, although the precise duration, intensity, and type of exercise have yet to be fully elucidated. However, in type 1 diabetes, the expected improvements in glycaemic control with exercise have not been clearly established. Instead significant physical and psychological benefits of exercise can be achieved while careful education, screening, and planning allow the metabolic, microvascular, and macrovascular risks to be predicted and diminished.

Prandial glucose regulation and cardiovascular disease in type 2 diabetes

Type 2 diabetes is associated with an increased risk for cardiovascular disease. In recent years, prospective studies have indicated that, in addition to conventional risk factors, glycaemic control of diabetes predicts cardiovascular disease in both middle-aged and elderly patients with Type 2 diabetes. However, there are no consistent data from different studies to indicate that postprandial glucose is a better predictor for cardiovascular risk than fasting glucose level. Although no clinical trials are available to show that improving glycaemic control prevents cardiovascular mortality and morbidity, recent studies imply that hyperglycaemia in patients with Type 2 diabetes should be treated more intensively than recommended by current guidelines

The future of best practice

Evidence from epidemiological and clinical studies continues to improve our understanding of the pathogenesis of coronary heart disease (CHD). However, despite major advances in the development of diagnostic methods and effective treatment, CHD remains the leading cause of mortality in the Western world. That cholesterol lowering is of major importance in lowering the risk of developing coronary artery disease (CAD) is now an accepted principle in medicine. Most patients with CAD will require drug therapy to achieve target lipid levels. Subgroup analyses of data from the landmark statin trials show that this benefit is seen in all patient groups: male and female, older and younger patients, diabetics and non-diabetics, and patients with and without myocardial revascularization. Recent evidence suggests that the extent to which cholesterol is lowered is also important and that the attainment of reduced low-density lipoprotein cholesterol levels is associated with greater reductions in the risk of cardiovascular events. Unfortunately, data from studies to date do not provide a definitive answer to the question of whether there is a benefit in lowering cholesterol to very low levels.

Type 2 diabetes towards the new millennium--the relative importance of glycaemic versus lipid control

The prevalence of type 2 diabetes is set to increase. The UKPDS has shown that better average glycaemic control over time leads to a reduction in microvascular complications. Macrovascular outcomes are also reduced in overweight subjects treated with metformin. The UKPDS and our own data, however, show that the natural history of type 2 diabetes is one of progressive deterioration in glycaemic control despite treatment. Lipid parameters emerges as the strongest predictors of outcomes in type 2 diabetes and suggest where therapeutic endeavours might best be directed. Ongoing trials of lipid-modifying therapies in type 2 diabetes will help to substantiate this. In the meantime, efforts to improve glycaemic control should not be pursued to the exclusion of other abnormalities that may have a greater relevance to outcomes of type 2 diabetes. There is an urgent need for better prevention and intervention strategies as we approach the new millennium.

Causes of death and associated factors among patients with non-insulin-dependent diabetes mellitus in Taipei, Taiwan

A cohort of 766 patients with non-insulin-dependent diabetes mellitus (NIDDM) from a general teaching hospital in Taipei, Taiwan were followed prospectively to assess survival experience and associated risk factors. Data were abstracted from the medical records and additional information was obtained from patients or their closest relatives using a structured questionnaire. Date and cause of death were determined from death certificates. Standardized mortality ratios were calculated by the direct method. Chi2-Square test and Cox's proportional hazard analysis were used to control for potential confounders. During a median follow-up of 3.5 years (range 1 month to 4.6 years), 131 deaths occurred. Of these, 29.8% were due to cardiopulmonary disease (ICD 401-429), 13.0% due to cerebrovascular disease (ICD 430-438), 13.0% due to acute diabetes metabolic complications (250.1, 250.2), and 11.4% due to nephropathy (580-589). Adjusted for age, people with NIDDM had 2.2 (95% CI 1.6-2.9) times the risk of death than members of the general population, and cause-specific standardized mortality ratios were: CPD 4.6, nephropathy 8.8, cerebrovascular disease 1.9, and neoplasm 0.7. Age, fasting plasma glucose, hypertension, and proteinuria were positively and independently associated with all-cause mortality (P < 0.05 for each). Thus, NIDDM patients have higher mortality rates than the general population in Taiwan, and age, fasting plasma glucose, hypertension, and proteinuria are associated with this excess risk. Proper application of available interventions may control these factors with a consequent reduction in mortality. Particular attention is needed to prevent deaths from the acute metabolic complications of diabetes.

United Kingdom prospective diabetes study (UKPDS): what now or so what?

The UKPDS was a 20-year study involving 23 centres in the United Kingdom. More than 5000 patients with Type 2 diabetes were recruited. The aim of the study was to determine the impact of intensive blood glucose control on 21 predetermined clinical endpoints using, in the care of blood glucose control, sulphonylureas or insulin therapy or, in the overweight patient, treatment with metformin. In addition, the study investigated the impact of intensive blood pressure control on macro- and microvascular complications of diabetes and compared captopril treatment with atenolol. UKPDS found that improved control of blood glucose or blood pressure reduced the risk of major diabetic eye disease by one quarter, serious deterioration of vision by nearly one half, early kidney damage by one third, strokes by one third, and death from diabetes-related causes by one third. Blood glucose control had little or no effect on macrovascular events. There was no evidence of a major detrimental effect of the drugs or insulin on survival or outcome other than the expected risk of hypoglycaemia. Metformin appeared to be the drug of choice in obese diabetic patients. The targets of glucose and blood pressure control were often achieved by using several drugs. Many patients at the end of the studies were on four or five drugs for blood glucose and blood pressure treatment. The results and implications of the study are discussed. It is proposed that the results of UKPDS herald a new era of more focused therapy of Type 2 diabetes.

Relationship between blood glucose level and mortality in type 2 diabetes mellitus: a systematic review

AIM

To review the relationship between blood glucose level and mortality in patients with Type 2 diabetes mellitus (DM) as reported in the literature.

METHODS

Literature search using Medline Search: January 1966 - April 1998.

KEYWORDS

Diabetes, Non Insulin Dependent, Mortality. Inclusion criteria for papers were: Type 2 DM; follow-up for at least 3 years; glucose or glycated haemoglobin (HbA1c) was used as parameter; published in the form of an article. Additionally all references in the selected articles that dealt with the relationship between blood glucose level and mortality in Type 2 DM were included in the search.

RESULTS

Twenty-seven eligible articles were found. Twenty-three of them showed a positive association: measures of elevated blood glucose concentrations were associated with higher mortality; in 15 out of 23 studies the positive association was statistically significant, in two only for postprandial blood glucose. One study found a nonsignificant negative relationship in a very old population.

CONCLUSION

In the literature there is a positive, but rather weak, association between the measures of blood glucose control and the risk of dying of patients with Type 2 DM. In the six larger studies (more than 100 deceased patients) that used a continuous categorization of glycaemia, the Risk ratio per unit varies from 1.03 to 1.12.

Diabetic dyslipidemia

Usual risk factors for coronary artery disease account for only 25-50% of increased atherosclerotic risk in diabetes mellitus. Other obvious risk factors are hyperglycemia and dyslipidemia. However, hyperglycemia is a very late stage in the sequence of events from insulin resistance to frank diabetes, whereas lipoprotein abnormalities are manifested during the largely asymptomatic diabetic prodrome and contribute substantially to the increased risk of macrovascular disease. The insulin-resistant diabetes course affects virtually all lipids and lipoproteins. Chylomicron and very-low-density lipoprotein (VLDL) remnants accumulate, and triglycerides enrich high-density lipoprotein (HDL) and low-density lipoprotein (LDL), leading to high levels of potentially atherogenic particles and low levels of HDL cholesterol. Hyperglycemia eventually impairs removal of triglyceride-rich lipoproteins, the accumulation of which accentuates hypertriglyceridemia. As triglycerides increase-still within the so-called normal range-abnormalities in HDL and LDL became more apparent. Thus, when triglycerides are >200 mg/dL, LDL particles are small and dense (when they are <90 mg/dL, the particles are of the large, buoyant variety). The atherogenicity of small, dense LDL particles is attributed to their increased susceptibility to oxidation, but in many patients they may be a marker for insulin resistance or the presence of atherogenic VLDL. Hypertriglyceridemia is associated with atherosclerosis because (1) it is a marker for insulin resistance and atherogenic metabolic abnormalities; and (2) the small size of triglyceride-enriched lipoproteins enables them to infiltrate the blood vessel wall where they are oxidized, bind to receptors on macrophages, and ingested, leading to the development of the atherosclerotic lesion. Various studies (primary prevention with gemfibrozil: Helsinki Heart Study; secondary prevention with simvastatin and pravastatin: Scandinavian Simvastatin Survival Study [4S] and Cholesterol and Recurrent Events [CARE], respectively) have demonstrated that lipid-lowering therapy in type 2 diabetes is effective in decreasing the number of cardiac events. Risk reduction was 22% to 50% (statins) and approximately 65% (fibrate) relative to placebo. It was also noted (in 4S and CARE) that the risk of major coronary events in untreated diabetic patients was 1.5-1.7-fold greater than in untreated nondiabetic patients. Although gemfibrozil (fibric acid derivative) is more effective in decreasing triglycerides and increasing HDL cholesterol in diabetic patients than the statins, it does not change and may even increase LDL-cholesterol levels (fenofibrate may be an exception, decreasing LDL cholesterol by 20-25% in some studies). However, gemfibrozil does increase LDL particle size. Nevertheless, the statins are the current lipid-lowering drugs of choice because the change in LDL-cholesterol-to-HDL-cholesterol ratio is better than with gemfibrozil. Moreover, the diabetic patient may be more likely to benefit from statin therapy than the nondiabetic patient. It should be noted that, in theory, nicotinic acid can correct or improve all lipid or lipoprotein abnormalities in patients with type 2 diabetes. Unfortunately, it is relatively contraindicated because it causes insulin resistance and may precipitate or aggravate hyperglycemia (in addition to its other well-known side effects such as flushing, gastric irritation, development of hepatotoxicity, and hyperuricemia). It is unknown at present whether newer formulations such as once-daily Niaspan may be better tolerated in diabetes. In any case, most patients with type 2 diabetes have risk factors for coronary artery disease and qualify for aggressive LDL cholesterol-lowering therapy. At the same time, it is presently unknown whether improved glycemic control decreases coronary artery disease risk in such patients.

Natural history of cardiovascular and renal disease in patients with type 2 diabetes: effect of therapeutic interventions and risk modification

Several observational studies document a considerably increased risk of advanced renal disease, cardiovascular disease, and early mortality in persons with diabetes. Both epidemiologic and observational studies indicate that progression of cardiovascular disease and renal disease is associated not only with high blood glucose levels, but also with hypertension and dyslipidemia. In persons with type 1 diabetes, hypoglycemic and antihypertensive therapy are important in the prevention of cardiovascular and renal disease. In those with type 2 diabetes, hypoglycemic therapy can help to prevent microvascular disease in the retina and in the kidney, and recent studies show that antihypertensive treatment is important in preventing cardiovascular disease. Thus, a multifactorial intervention program is key to preventing complications of hyperglycemia and, equally important, elevated blood pressure and dyslipidemia.

Hypertensive patients and diabetes: a high-risk population

Rising worldwide rates of diabetes mellitus heighten the need to maintain adequate metabolic control in diabetic patients and to control for other cardiovascular risk factors, such as lipid profile disturbances, high blood pressure, and smoking habits. This is especially the case in diabetic patients who also present with hypertension, a co-morbid state that is present in at least 50% of Type 1 and Type 2 diabetic patients. Cardiovascular disease is present in 75% of all diabetes-related deaths, and the concomitant condition of diabetes and hypertension is believed to act synergistically on elevating the risk for cardiovascular disease. A number of trials have demonstrated a greater incidence of cardiovascular disease end points in diabetic hypertensive patients than in diabetic normotensive patients. Furthermore, hypertension is associated not only with an increased risk for cardiovascular mortality but also for microvascular complications in patients with diabetes. Adequate treatment of high blood pressure is imperative in these patients. The effectiveness of antihypertensive treatment can be measured not only by the degree of reduction in blood pressure but also by assessment of the effects on urinary albumin excretion rate. It is assumed that the greater the reduction in urinary albumin excretion rate, the greater the renoprotective effect. Treatment choices should be evidence-based, i.e., physicians should concentrate not only on the treatment of hypertension but also on improving glycemic control and lipid profile disorders, when necessary. When viewed in this regard, angiotensin-converting enzyme inhibitors, low-dose diuretics, and in some cases beta-blockers, should be considered agents of choice in hypertensive diabetic patients.

Tight blood pressure control and risk of macrovascular and microvascular complications in type 2 diabetes: UKPDS 38. UK Prospective Diabetes Study Group

OBJECTIVE

To determine whether tight control of blood pressure prevents macrovascular and microvascular complications in patients with type 2 diabetes.

DESIGN

Randomised controlled trial comparing tight control of blood pressure aiming at a blood pressure of <150/85 mm Hg (with the use of an angiotensin converting enzyme inhibitor captopril or a beta blocker atenolol as main treatment) with less tight control aiming at a blood pressure of <180/105 mm Hg.

SETTING

20 hospital based clinics in England, Scotland, and Northern Ireland.

SUBJECTS

1148 hypertensive patients with type 2 diabetes (mean age 56, mean blood pressure at entry 160/94 mm Hg); 758 patients were allocated to tight control of blood pressure and 390 patients to less tight control with a median follow up of 8.4 years.

MAIN OUTCOME MEASURES

Predefined clinical end points, fatal and non-fatal, related to diabetes, deaths related to diabetes, and all cause mortality. Surrogate measures of microvascular disease included urinary albumin excretion and retinal photography.

RESULTS

Mean blood pressure during follow up was significantly reduced in the group assigned tight blood pressure control (144/82 mm Hg) compared with the group assigned to less tight control (154/87 mm Hg) (P<0.0001). Reductions in risk in the group assigned to tight control compared with that assigned to less tight control were 24% in diabetes related end points (95% confidence interval 8% to 38%) (P=0.0046), 32% in deaths related to diabetes (6% to 51%) (P=0.019), 44% in strokes (11% to 65%) (P=0.013), and 37% in microvascular end points (11% to 56%) (P=0.0092), predominantly owing to a reduced risk of retinal photocoagulation. There was a non-significant reduction in all cause mortality. After nine years of follow up the group assigned to tight blood pressure control also had a 34% reduction in risk in the proportion of patients with deterioration of retinopathy by two steps (99% confidence interval 11% to 50%) (P=0.0004) and a 47% reduced risk (7% to 70%) (P=0.004) of deterioration in visual acuity by three lines of the early treatment of diabetic retinopathy study (ETDRS) chart. After nine years of follow up 29% of patients in the group assigned to tight control required three or more treatments to lower blood pressure to achieve target blood pressures.

CONCLUSION

Tight blood pressure control in patients with hypertension and type 2 diabetes achieves a clinically important reduction in the risk of deaths related to diabetes, complications related to diabetes, progression of diabetic retinopathy, and deterioration in visual acuity.