Treatment of hypertensive patients with diabetes

The calcium-channel blocker controversy: historical perspective and important lessons for future pharmacotherapies. An international society of pharmacoepidemiology 'hot topic'

Reports of adverse events in association with calcium-channel blockers led to heated controversy over the safety and efficacy of these drugs, as well as to panic among the general public. At the 1998 International Conference of Pharmacoepidemiology, four experts were asked to summarize, and draw lessons from, the controversy's development. We conducted our own review in order to provide a broader historical perspective on the subject and to present the discussants' views within the framework of additional published opinions. Several years after the controversy's onset, many uncertainties still remain about the merits of CCBs. Yet the media scare generated by a few studies might have been prevented had investigators placed greater emphasis, particularly in their reports to the media, on the limitations of their observational and meta-analytic designs. These studies, however, did call attention to the persistent use of CCBs for off-label indications, and the imperative to improve clinician prescribing practices. Moreover, they showed the pitfalls of reliance on surrogate endpoints, stressing the need for data on major clinical outcomes-with funding a responsibility of the pharmaceutical industry-before approving drugs destined for widespread, long-term use. Attention to these lessons will do us well as we evaluate emerging pharmacotherapies. Copyright (c) 2000 John Wiley & Sons, Ltd.

Metabolic effects of manidipine

The calcium channel antagonists (CCAs) were originally introduced as vasodilators for the treatment of coronary heart disease, but are now also noted for their clinical efficacy in the management of hypertension. Data from large clinical studies have shown that CCAs are not associated with the undesirable metabolic effects (e.g. worsening of dyslipidemia and reduction of insulin sensitivity) seen with older agents such as thiazide diuretics and beta-adrenoceptor antagonists (beta-blockers) that are used to treat hypertension. Indeed, reductions in cardiovascular risk and rates of onset of new cases of diabetes mellitus have been reported in trials in patients with hypertension treated with CCAs. These beneficial effects extend beyond those expected to accompany reductions in BP. Until recently, the biochemical effects underlying these metabolic changes were only poorly understood, but pharmacologic studies have now started to shed more light on these issues. Of particular interest are studies with manidipine, some of which suggest that this agent may be associated with greater improvements in insulin sensitivity and may have better renal protective properties than other CCAs. Confirmation of potential differences among CCAs in terms of the relative magnitude of any beneficial metabolic effects requires further study. Ongoing research is expected to clarify further the action of these agents at the cellular level and to assist with the optimization of antihypertensive therapy, particularly in patients with elevated cardiovascular risk profiles.

Control of Hypertension among Type II Diabetics

OBJECTIVES

Numerous studies have confirmed the high prevalence of hypertension among type 2 diabetics, and that intensive hypertensive treatment is more beneficial to diabetics than non diabetics. The aim of this study is to assess blood pressure control in patients with type 2 diabetes mellitus and to study the types of antihypertensives used.

METHODS

A retrospective study was conducted on hypertensive diabetics followed at a health center in Oman within a year. Patients' age, sex, duration of diabetes, hypertension and the type of antihypertensive used were noted. Patients were classified according to the degree of systolic and diastolic BP control into 4 groups.

RESULTS

210 patients with a mean age of 53.7±9.1 years were included with a 2:5 male to female ratio. The mean duration of diabetes was found to be 9 years and 7 years for hypertension. 10% of the subjects were in the systolic group I, 23% in group II, 23% in group III and 41% in group IV. While 56% were in diastolic group I, 19% in group II, 16% in group III, and 7% in group IV. Angiotensin converting enzyme-inhibitors (ACE) were used in 50% of the subjects followed by a combination of angiotensin receptor blockers (ARB) with diuretics in 40%. B blockers were used in 38% of the patients. Calcium channel blockers were used in 18%, while diuretics were used in 16% of the patients.

CONCLUSION

Only 30% of the BP of the hypertensive diabetics met the recommended BP for diabetes. More effort should be dedicated to control the BP in diabetics. Physicians should be careful in the selection of hypertensive medications, because in some combinations, they are not useful.

Treatment of hypertension in patients with diabetes mellitus

Antihypertensive treatment in diabetes mellitus, especially in diabetics known to have cardiac autonomic neuropathy, may have to consider the status of the autonomic nervous system. In diabetic subjects with cardiac autonomic neuropathy, vagal activity during the night is often reduced. The reduction results in relative or absolute sympathetic activation, which could increase cardiovascular risk. Pathophysiological and clinical data suggests that antihypertensive treatment should reduce rather than induce sympathetic activity in this setting. Beta blocking agents, ACE inhibitors, calcium antagonists of verapamil or diltiazem type and selective imidazoline receptor agonists reduce sympathetic activity and, therefore, may have a beneficial effect in diabetic patients with disturbed sympathovagal balance.

Amlodipine versus angiotensin II receptor blocker; control of blood pressure evaluation trial in diabetics (ADVANCED-J)

BACKGROUND

The coexistence of type 2 diabetes mellitus and hypertension increases the risk of cardiovascular diseases. The U.K. Prospective Diabetes Study has shown that blood pressure control as well as blood glucose control is efficient for prevention of complications in hypertensive patients with diabetes mellitus. However, some reports have shown that it is difficult to control the blood pressure and the concomitant use of a plurality of drugs is needed in hypertensive patients with diabetes mellitus. In recent years renin-angiotensin system depressants are increasingly used for the blood pressure control in diabetic patients. Particularly in Japan, angiotensin II (A II) antagonists are increasingly used. However, there is no definite evidence of the point of which is efficient for the control, the increase in dose of A II antagonist or the concomitant use of another drug, in hypertensive patients whose blood pressure levels are inadequately controlled with A II antagonist.

METHODS/DESIGN

Hypertensive patients of age 20 years or over with type 2 diabetes mellitus who have been treated by the single use of AII antagonist at usual doses for at least 8 weeks or patients who have been treated by the concomitant use of AII antagonist and an antihypertensive drug other than calcium channel blockers and ACE inhibitors at usual doses for at least 8 weeks are included.

DISCUSSION

We designed a multi-center, prospective, randomized, open label, blinded-endpoint trial, ADVANCED-J, to compare the increases in dose of A II antagonist and the concomitant use of a Ca-channel blocker (amlodipine) and A II antagonist in hypertensive patients with diabetes mellitus, whose blood pressure levels were inadequately controlled with A II antagonist. This study is different from the usual previous studies in that home blood pressures are assessed as indicators of evaluation of blood pressure. The ADVANCED-J study may have much influence on selection of antihypertensive drugs for treatment in hypertensive patients with diabetes mellitus. It is expected to give an important hint for considering the validity of selection of antihypertensive drugs from the aspects not only of the antihypertensive effect but medical cost-effectiveness.

Evidence for a Causal Role of the Renin-Angiotensin System in Vascular Dysfunction Associated With Insulin Resistance

Excess production of superoxide anion in response to angiotensin II plays a central role in the transduction of signal molecules and the regulation of vascular tone. We examined the ability of insulin resistance to stimulate superoxide anion production and investigated the identity of the oxidases responsible for its production. Rats were fed diets containing 60% fructose (fructose-fed rats) or 60% starch (control rats) for 8 weeks. In aortic homogenates from fructose-fed rats, the superoxide anion generated in response to NAD(P)H was more than 2-fold higher than that of control rats. Pretreatment of the aorta from fructose-fed rats with inhibitors of NADPH oxidase significantly reduced superoxide anion production. In the isolated aorta, contraction induced by angiotensin II was more potent in fructose-fed rats compared with control rats. Losartan normalized blood pressure, NAD(P)H oxidase activity, endothelial function, and angiotensin II-induced vasoconstriction in fructose-fed rats. To elucidate the molecular mechanisms of the enhanced constrictor response to angiotensin II, expressions of angiotensin II receptor and subunits of NADPH oxidase were examined with the use of angiotensin II type 1a receptor knockout (AT1a KO) mice. Expression of AT1a receptor mRNA was enhanced in fructose-fed mice, whereas expression of either AT1b or AT2 was unaltered. In addition, protein expression of each subunit of NADPH oxidase was increased in fructose-fed mice, whereas the expression was significantly decreased in fructose-fed AT1a KO mice. The novel observation of insulin resistance-induced upregulation of AT1 receptor expression could explain the association of insulin resistance with endothelial dysfunction and hypertension.

Malfunction of Vascular Control in Lifestyle-Related Diseases: Mechanisms Underlying Endothelial Dysfunction in the Insulin-Resistant State

It is tempting to speculate that increased vasoconstriction and loss of endothelium-dependent vasodilation might be etiological factors of elevated blood pressure in the insulin-resistant state. Vascular contraction induced by angiotensin II and the expression of NAD(P)H oxidase were increased in the aorta of insulin-resistant mice. In addition, both angiotensin II type 1 receptor expression and superoxide anion production were up-regulated in these mice. Another mechanism for imparing endothelial function is the uncoupling of endothelial nitric oxide synthase (eNOS). It has become clear from studies on the aorta of insulin-resistant rat that insulin resistance may be a pathogenic factor for endothelial dysfunction through impaired eNOS activity and increased oxidative breakdown of NO (nitric oxide) due to an enhanced formation of superoxide anion (NO/superoxide anion imbalance), which are caused by relative deficiency of tetrahydrobiopterin, a cofactor of NOS, in vascular endothelial cells. Supplementation of tetrahydrobiopterin restored endothelial function and relieved oxidative tissue damage through activation of eNOS in those rats. These results indicate that generation of superoxide anion from NAD(P)H oxidases and an uncoupled eNOS may be pathogenic factors for impaired endothelial function and hypertension in the insulin-resistant state.

Prevention and treatment of diabetic nephropathy in older patients

Renal disease in older diabetic patients is costly in terms of morbidity, mortality and expenditure. Therefore, prevention and treatment of diabetic nephropathy has become a prominent goal in the treatment of patients with diabetes mellitus. Preventive treatment should begin no later than at the stage of microalbuminuria, and regular screening for microalbuminuria is recommended for all patients with diabetes, irrespective of age. Improved metabolic control has been demonstrated to lower urinary albumin excretion. Target glycosylated haemoglobin levels should be below 7%, or 1% above the upper limit of normal of non-diabetic subjects. The use of an intensified treatment regimen is recommended. Insulin therapy has no adverse effects on renal indexes. To preserve renal function in older diabetic patients, blood pressure should be kept at or below 130/80 mm Hg. Treatment with ACE inhibitors or angiotensin II receptor antagonists (angiotensin II receptor blockers; ARBs) is superior to other pharmacological therapy, and should be initiated as first-line treatment. Most of the calcium channel antagonists have been found to increase or to have no effect on microalbuminuria despite blood pressure reduction. Moreover, there is substantial controversy as to whether they may be associated with increased cardiovascular morbidity. Non-dihydropyridine derivatives and calcium channel antagonists, such as nitrendipine, may be nephroprotective and have favourable effects on patients outcomes. A renoprotective action of diuretics may be confined to indapamide. Although beta-adrenoreceptor blockers are effective antihypertensive agents, they may not adequately preserve kidney function in older diabetic patients. However, as add-on treatment to ACE inhibitors or ARBs, they are particularly beneficial in nephropathic patients at risk of cardiovascular disease or with arrhythmias, in whom they may prove life-saving.

A randomized, double-blind, controlled, parallel-group comparison of perindopril and candesartan in hypertensive patients with type 2 diabetes mellitus

BACKGROUND

When choosing an antihypertensive drug for patients with hypertension and diabetes mellitus (DM), the metabolic side effects, possibility of improving some metabolic parameters, and need for adequate blood pressure control must all be considered.

OBJECTIVE

The goal of this study was to compare the impacts of perindopril and candesartan on blood pressure, glucose metabolism, serum lipid profile, and metabolic parameters in patients with mild hypertension and type 2 DM during therapy and after a 1-month washout period.

METHODS

Type 2 DM patients with mild hypertension and good glucose control who were not taking hypercholesterolemic drugs were enrolled. Perindopril 4 mg QD or candesartan 16 mg QD was administered for 12 months in this randomized, double-blind, controlled, parallel-group clinical trial. Fasting plasma glucose (FPG), fasting plasma insulin (FPI), glycosylated hemoglobin, homeostasis model assessment (HOMA) index, systolic blood pressure (SBP), diastolic blood pressure (DBP), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol, triglycerides, lipoprotein(a) (Lp[a]), plasminogen activator inhibitor 1 (PAI-1), homocysteine, body mass index (BMI), and albumin excretion rate (AER) were assessed.

RESULTS

Ninety-six patients (49 women and 47 men; mean [SD] ages, 53 [10] years [perindopril] and 55 [9] years [candesartan]) were enrolled. Mean (SD) body weight, height, and BMI were 78.2 (9.4) kg, 1.69 (0.05) m, and 27.2 (2.0) kg/m(2) in the perindopril group and 77.5 (8.6) kg, 1.70 (0.06) m, and 26.8 (2.5) kg/m(2) in the candesartan group. A significant change occurred from baseline to month 12 during treatment with perindopril in SBP and DBP (both P < 0.01), FPG (P < 0.05), FPI (P < 0.05), TC (P < 0.05), LDL-C (P < 0.05), Lp(a) (P < 0.05), PAM (P < 0.05), and AER (P < 0.05). Significant changes from baseline to month 12 occurred with candesartan in SBP and DBP (both P < 0.01) and AER (P < 0.05). The HOMA index was significantly lower at month 12 in the perindopril group than in the candesartan group (P < 0.05). When we interrupted perindopril and candesartan therapy for a 1-month washout period, changes in SBP and DBP values were significant compared with month 12 in both groups (all P < 0.05). Changes in TC and LDL-C from month 12 to the end of washout were significant only in the perindopril group (both P < 0.05).

CONCLUSIONS

Perindopril and candesartan both effectively lowered blood pressure in this group of patients with mild hypertension and type 2 DM. Perindopril showed an improvement on some metabolic parameters compared with candesartan. However, the inclusion/exclusion criteria could limit the ability to extrapolate the results to a general population.

The use of calcium antagonists in the treatment of hypertensive persons with kidney disease

The treatment of hypertension is proven to reduce cardiovascular and renal risk. Combination drug therapy is becoming recognized as a necessity in most patients with hypertension and kidney disease. Allegations about the safe use of calcium antagonists in patients with kidney disease have led to questions and confusion about their use in this common condition. This article reviews the cardiovascular and renal safety of the long-acting calcium antagonists from studies comparing calcium antagonists with placebo and with angiotensin converting enzyme inhibitors or angiotensin receptor blockers in patients with kidney disease and hypertension. Patients with proteinuria and kidney disease should have their blood pressure brought as close to target (< 130/80 mm Hg) as possible for cardiovascular and renal protection. Lowering blood pressure in this setting will require an average of three antihypertensive agents. In patients with hypertension and proteinuria, angiotensin converting enzyme inhibitors or angiotensin receptor blockers must be part of the regimen, and calcium antagonists are safe and effective in this condition when used with them in combination.

Risk and benefit of treatment of isolated systolic hypertension in the elderly: evidence from the Systolic Hypertension in Europe Trial

The Syst-Eur trial investigated whether active treatment starting with the dihydropyridine calcium channel blocker (CCB) nitrendipine, could reduce the cardiovascular complications of isolated systolic hypertension (ISH) in the elderly. The intention-to-treat analysis showed that active treatment improved outcome. The per-protocol analysis largely confirmed these results. The effect of treatment on total and cardiovascular mortality might be attenuated in very old patients. Further analysis also suggested benefit in those patients who remained on nitrendipine monotherapy. Active treatment was more beneficial in patients with diabetes as compared with those without diabetes at entry and reduced the incidence of dementia by 50%. Analyses of data from the Ambulatory Blood Pressure Monitoring (ABPM) Side Project suggested that most of the benefit of treatment was seen in patients with a daytime systolic BP > or = 160 mm Hg. Finally, a meta-analysis partly based on Syst-Eur data showed that in older hypertensive patients pulse pressure and not mean pressure is the major determinant of cardiovascular risk.

Hypertension trials: 1990 to 2000

A large number of randomized controlled trials have been published over the past decade. The earlier ones established the benefits of low-dose diuretic-based therapy. The more recent ones have documented the equal overall effectiveness of therapy based on an angiotensin-converting enzyme inhibitor or a calcium antagonist. The comparative data do not clearly define a single superior drug for most hypertensive patients, so the initial choice should be individualized, on the basis of the concomitant conditions. For the rapidly increasing population of diabetic hypertensive patients, similar conclusions are obvious, with the caveat that an angiotensin-converting enzyme inhibitor should usually be the initial choice, with diuretics and calcium antagonists usually needed to accomplish adequate control. There are no concerns about the use of calcium antagonists in diabetic patients.

Blood pressure in diabetic nephropathy--current controversies

Hypertension has been recognized as an early and constant feature of diabetic nephropathy, but recent studies also suggest that a genetic predisposition to hypertension is an important risk factor for diabetic nephropathy. Antihypertensive treatment attenuates progression in diabetic nephropathy, but there is increasing evidence that very early treatment and very low target blood pressures should be implemented. There is also evidence for local activation of the renin system in the kidney as a result of hyperglycaemia. Apart from blood pressure, proteinuria should be monitored and dosing of ACE inhibitors should be guided, also by reduction of protein excretion.

Systolic hypertension in older patients: are calcium channel antagonists safe?

The Editor and Associate Editors are pleased that our readership will have the opportunity to benefit from a series of contributions by Dr John Rutherford addressing current issues in pharmacology and therapeutics pertinent to coronary artery disease. We are pleased also that Dr Rutherford will provide authoritative perspectives on topics of immediate interest on a regular basis.

Current status of safety and efficacy of calcium channel blockers in cardiovascular diseases: a critical analysis based on 100 studies

Recently, serious concerns have been expressed about the long-term safety of the calcium channel blockers (CCBs) as a group. Safety and efficacy are, however, ultimately linked to each other; therefore both must be evaluated especially in the therapy of angina and hypertension, the main clinical indications for CCBs. The structural, functional, and pharmacokinetic heterogeneity of CCBs means that the efficacy and dangers of one subclass, such as the short-acting dihydropyridines (DHPs), in one situation, such as unstable angina, do not necessarily apply in other clinical situations. One hundred studies are reviewed according to their methods of data collection: case series, case control, cohort, randomized controlled trials (RCTs), and meta-analyses. Large, well-designed RCTs and the meta-analyses based on these trials remain the gold standard. Observational studies, though potentially less reliable sources of information because of selection bias, may nevertheless produce hypotheses that must then be tested in RCTs. Regarding safety, both observational studies and RCTs suggest that adverse effects of CCBs may be linked to short-acting agents, specifically short-acting nifedipine. Two good studies favor the safety of verapamil, even in short-acting form. Incomplete but increasing overall evidence favors the safety of longer-acting DHPs. Heart failure remains a class contraindication to the use of all CCBs, with some exceptions. Regarding efficacy, there are positive results of RCTs with CCBs in 2 specific clinical situations, namely, verapamil in postinfarct protection in the absence of pre-existing heart failure, and 2 outcome studies on hypertension with longer acting DHPs. These results cannot automatically be applied to other clinical situations and to other CCBs. For example, there is no evidence for the safety or efficacy of DHPs used without beta blockers in postinfarct patients. In diabetic hypertensives, 2 relatively large RCTs show that the blood pressure can be reduced by DHP-based therapy in diabetics, with a reduction in hard end points. To achieve current blood pressure goals, combination therapy is almost always necessary, and in diabetics there is strong evidence that 1 essential component should be an angiotensin converting enzyme inhibitor. The future aim with CCBs must be to obtain a large database gathered from RCTs, which will give the same certainty about efficacy and safety that already holds for use of the diuretics in hypertension, beta-blockers in postmyocardial infarction patients, and the angiotensin converting enzyme inhibitors in heart failure.

Diabetes risk score: towards earlier detection of type 2 diabetes in general practice

BACKGROUND

Type 2 diabetes is common, costly and often goes unrecognised for many years. When patients are diagnosed, the majority exhibit associated tissue damage or established cardiovascular risk. Evidence is accumulating that earlier detection and management of diabetes and related metabolic abnormalities may be beneficial. We aimed to develop and evaluate a score based on routinely collected information to identify people at risk of having undetected diabetes.

METHODS

A population-based sample of 1077 people, aged 40 to 64 years, without known diabetes, from a single Cambridgeshire general practice, underwent clinical assessment including an oral glucose tolerance test. In a separate 12-month study, 41 practices in southern England reported clinical details of patients aged 40 to 64 years with newly diagnosed Type 2 diabetes. A notional population was created by random selection and pooling of half of each dataset. Data were entered into a regression model to produce a formula predicting the risk of diabetes. The performance of this risk score in detecting diabetes was tested in an independent, randomly selected, population-based sample.

RESULTS

Age, gender, body mass index, steroid and antihypertensive medication, family and smoking history contributed to the score. In the test population at 72% specificity, the sensitivity of the score was 77% and likelihood ratio 2.76. The area under the receiver-operating characteristic curve was 80%.

CONCLUSIONS

A simple score, using only data that are routinely collected in general practice, can help identify those at risk of diabetes. This score could contribute to efficient earlier detection through case-finding or targeted screening.

Large multicentre hypertension trials

The earlier large multicentre trials in hypertensive patients addressed questions of whether mild to moderate hypertension should be treated and whether similar approaches would be effective in elderly hypertensive patients or those with isolated systolic hypertension. The research focus of recent trials has now shifted to how rather than whether such patients should be treated. Trials such as the Hypertension Optimal Treatment study attempted to discern optimal targets for long-term blood pressure control. Although unsuccessful in this primary aim, they have established the safety of aggressive blood pressure lowering to diastolic targets of less than 80 mmHg as well as the safety and efficacy of a calcium entry blocker as a first line antihypertensive approach. The Captopril Prevention Project study and Swedish Trial in Old Patients with Hypertension-2 trial focussed on whether there might be specific antiatherosclerotic advantages of the newer agents (angiotensin converting enzyme inhibitors and calcium entry blockers) over conventional therapy in comparison studies with beta blockers and diuretics. Similar efficacy for cardiovascular outcomes appears to be emerging for each of the major classes of drugs with the degree of blood pressure lowering of prime importance in cardiovascular disease prevention.

The best way to manage hypertension after renal transplantation

Hypertension in renal allograft recipients is a common problem arising from multiple factors, including peripheral vascular damage caused by pretransplant hypertension, side effects of immunosuppressive medications, allograft dysfunction, renal artery stenosis, recurrent glomerulonephritis, synthesis of vasoconstrictive hormones by the native kidneys, and excessive dietary salt intake. Identification of modifiable factors causing hypertension and concurrent medical conditions, and measurement of glomerular filtration rate, cyclosporine/tacrolimus blood levels, and magnitude of proteinuria are essential to tailor treatment for an individual patient. Lifestyles that exacerbate hypertension should be modified. For pharmacological therapy, diuretics and calcium channel blockers are first-line agents in patients on cyclosporine shortly after transplant. Angiotensin-converting enzyme inhibitors are good choices for patients with significant proteinuria. Reduction of immunosuppression will improve hypertension in some patients, but entails a potential risk of rejection or graft loss. Angioplasty is necessary in patients with a functionally significant stenosis of the allograft renal artery. Other patients on maximal medical therapy may benefit from native nephrectomy.

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.

Antihypertensive drug therapy and hypoglycemia in elderly diabetic patients treated with insulin and/or sulfonylureas. Gruppo Italiano di Farmacovigilanza nell'Anziano (GIFA)

We performed this case control study to evaluate the risk of hypoglycemia associated with the use of antihypertensive drugs in older hospitalized diabetic patients treated with sulfonylureas and/or insulin. All diabetic patients admitted during 4 months in 1988, month in 1991, 4 months in 1993 and 4 months in 1995 (n = 3477, mean age 71.4 +/- 0.2 years, 1542 males and 1935 females) were enrolled in the study. During the four annual surveys 86 patients (mean age 71.1 +/- 1.4 years, 33 males and 53 females) presented hypoglycemia during hospital stay. The patients who presented hypoglycemia were less frequently users of sulfonylureas and more frequently users of a combination of insulin and sulfonylureas. Use of antihypertensive drugs was similar in the two groups studied, and among potentially interacting drugs considered in the analysis, sulfonamides were more frequently used in patients who experienced hypoglycemia. Moreover, patients with hypoglycemia used a higher number of drugs, had a longer length of stay and had a greater prevalence of hypoglycemia as admission problem. Finally, although not significant, liver and renal diseases were more frequent among patients with hypoglycemia. In the multivariate analysis, contemporary use of insulin and sulfonylureas, liver disease and length of stay were significantly associated with hypoglycemia, while none of the antihypertensive drugs showed a significant association with the occurrence of hypoglycemia during hospital stay. Our results indicate that antihypertensive drugs do not increase the risk of hypoglycemia in elderly diabetic patients.

Treatment of diabetic patients with hypertension

This review attempts to highlight the potential of calcium-channel blockers in the prevention of sequelae of diabetes mellitus and hypertension in patients who have both disorders. Evidence-based medicine is driven by the results of randomized, clinical trials. Major contributions were therefore derived from post hoc analyses of the diabetic patients enrolled in placebo-controlled trials, such as Systolic Hypertension in the Elderly Program (SHEP), Systolic Hypertension in Europe (Syst-Eur), and Systolic Hypertension in China (Syst-China), and stepped-care blood-pressure-oriented trials, such as the Hypertension Optimal Treatment (HOT) and United Kingdom Prospective Diabetes Study (UKPDS). Several studies, such as the Fosiniprl; versus Amlodipine Cardiovascular Events Trial (FACET) and Appropriate Blood Pressure Control in Diabetes (ABCD) Trial, have compared the relative merits of angiotensin-converting enzyme and calcium-channel blockers in preserving renal function and metabolic balance in diabetic patients with hypertension, but their publications focused on cardiovascular disorders, which were only secondary end points. On balance, the articles reviewed prove that dihydropyridine calcium-channel blockers score particularly well in the prevention of cardiovascular complications in diabetic patients with hypertension.

Effects of calcium-channel blockade in older patients with diabetes and systolic hypertension. Systolic Hypertension in Europe Trial Investigators

BACKGROUND

Recent reports suggest that calcium-channel blockers may be harmful in patients with diabetes and hypertension. We previously reported that antihypertensive treatment with the calcium-channel blocker nitrendipine reduced the risk of cardiovascular events. In this post hoc analysis, we compared the outcome of treatment with nitrendipine in diabetic and nondiabetic patients.

METHODS

After stratification according to center, sex, and presence or absence of previous cardiovascular complications, 4695 patients (age, > or =60 years) with systolic blood pressure of 160 to 219 mm Hg and diastolic pressure below 95 mm Hg were randomly assigned to receive active treatment or placebo. Active treatment consisted of nitrendipine (10 to 40 mg per day) with the possible addition or substitution of enalapril (5 to 20 mg per day) or hydrochlorothiazide (12.5 to 25 mg per day) or both, titrated to reduce the systolic blood pressure by at least 20 mm Hg and to less than 150 mm Hg. In the control group, matching placebo tablets were administered similarly.

RESULTS

At randomization, 492 patients (10.5 percent) had diabetes. After a median follow-up of two years, the systolic and diastolic blood pressures in the placebo and active-treatment groups differed by 8.6 and 3.9 mm Hg, respectively, among the diabetic patients. Among the 4203 patients without diabetes, systolic and diastolic pressures differed by 10.3 and 4.5 mm Hg, respectively, in the two groups. After adjustment for possible confounders, active treatment was found to have reduced overall mortality by 55 percent (from 45.1 deaths per 1000 patients to 26.4 deaths per 1000 patients), mortality from cardiovascular disease by 76 percent, all cardiovascular events combined by 69 percent, fatal and nonfatal strokes by 73 percent, and all cardiac events combined by 63 percent in the group of patients with diabetes. Among the nondiabetic patients, active treatment decreased all cardiovascular events combined by 26 percent and fatal and nonfatal strokes by 38 percent. In the group of patients receiving active treatment, reductions in overall mortality, mortality from cardiovascular disease, and all cardiovascular events were significantly larger among the diabetic patients than among the nondiabetic patients (P=0.04, P=0.02, and P=0.01, respectively).

CONCLUSIONS

Nitrendipine-based antihypertensive therapy is particularly beneficial in older patients with diabetes and isolated systolic hypertension. Thus, our findings do not support the hypothesis that the use of long-acting calcium-channel blockers may be harmful in diabetic patients.

Critique of a biologic mechanism linking calcium antagonists to increased risk for cardiovascular events in diabetes

Calcium antagonists represent a chemically and pharmacologically diverse group of agents that function by modulating the transmembrane influx of Ca2+ into contractile cells. These compounds, widely used for the treatment of hypertension and angina, bind in a highly specific and reversible fashion to voltage-sensitive Ca2+ channels in vascular smooth muscle cells. A recent study raised concerns about the safety of certain calcium antagonists for treatment of hypertension in diabetic patients. The safety issue has not been resolved and is the subject of other articles in this supplement. However, a biologic mechanism has been proposed to rationalize the potentially deleterious effects of calcium antagonists in this group of patients. This mechanism is based on an assumption that the biochemical composition of cellular membranes in patients with diabetes is fundamentally different, leading to an abnormal increase in the membrane concentration of calcium antagonists and, hence, adverse pharmacologic effects. In support of this model, original research on the lipid composition of membranes from patients with diabetes was cited, along with our own published findings, showing that accumulation of calcium antagonists in membranes is influenced by the molar ratio of cholesterol to phospholipid (C:P). A careful review of these and other related scientific reports, however, yields no evidence for reproducible changes in the membrane C:P molar ratio of diabetic patients that would lead to adverse pharmacologic effects of calcium antagonists.

Calcium antagonists and the diabetic patient: a response to recent controversies

The results of 2 recently published studies have been interpreted as suggesting that calcium antagonists are unsafe for the management of hypertension in patients with diabetes. These 2 studies, the Fosinopril versus Amlodipine Cardiovascular Events Randomized Trial (FACET) and Appropriate Blood Pressure Control in Diabetes (ABCD), showed that angiotensin-converting enzyme (ACE) inhibitors may be preferable to calcium antagonists for managing hypertension in diabetic patients; they do not, however, show any harm attributable to calcium antagonists. Indeed, results of the FACET study suggest that the combination of an ACE inhibitor and a calcium antagonist is effective antihypertensive therapy. This suggestion is supported by findings in the Systolic Hypertension in Europe (Syst-Eur) Study, which revealed outstanding benefits of either a calcium antagonist alone or a calcium antagonist combined with an ACE inhibitor among diabetic patients with hypertension. The premature termination of the hypertensive arm of the ABCD study was puzzling because, although 2 of 13 subgroups of 1 of the 5 possible secondary endpoints in this part of the trial were apparently favorably affected by the use of the ACE inhibitor rather than the calcium antagonist, such a finding was compatible with chance alone. If the results of the FACET and ABCD studies are considered in the context of the best available data arising from large randomized controlled trials, one may conclude that calcium antagonists are not harmful or contraindicated in hypertensive patients with diabetes and that the combination of an ACE inhibitor and a calcium antagonist is effective for the management of hypertension in diabetic patients.

Rationale and design of the International Verapamil SR/Trandolapril Study (INVEST): an Internet-based randomized trial in coronary artery disease patients with hypertension

OBJECTIVES

The primary objective of the International Verapamil SR/Trandolapril Study (INVEST) is to compare the risk for adverse outcomes (all-cause mortality, nonfatal myocardial infarction [MI] or nonfatal stroke) in hypertensive patients with coronary artery disease (CAD) treated with either a calcium antagonist-based or a noncalcium antagonist-based strategy.

BACKGROUND

Treatment recommendations for hypertension include initial therapy with a diuretic or beta-adrenergic blocking agent, for which reductions in morbidity and mortality are documented from randomized trials but are less than expected from epidemiologic data. For this reason, recent attention has focused on calcium antagonists or angiotensin-converting enzyme inhibitors. While these agents reduce blood pressure, outcome data from large randomized trials are lacking, but some case-control data, dominated by short-acting dihydropyridines, suggest an increased risk of cardiovascular events. These studies had methodologic limitations and did not differentiate among calcium antagonist types and formulations. Several studies differentiating among calcium antagonist types and an overview of published randomized trials show no increased risk with verapamil and suggestion for benefit in CAD patients.

METHODS

A total of 27,000 CAD patients with hypertension will be randomized at 1,500 primary care sites to receive either a calcium antagonist-based (verapamil) or beta-blocker/diuretic-based (atenolol/hydrochlorothiazide) antihypertensive care strategy. The study uses a novel, electronic "paper-less" system for direct on-screen data entry, randomization and drug distribution from a mail pharmacy linked to the coordination center via the Internet.

RESULTS

Contract negotiations with the United States and international sites are ongoing. Patients being enrolled are predominantly elderly (72% aged 60 years or older) men (54%), with either an abnormal coronary angiogram or prior MI (71%). In addition to hypertension, CAD and elderly age, most patients (89%) have one or more associated conditions (diabetes, dyslipidemia, smoking, cerebral or peripheral vascular disease, etc.) contributing to increased risk for adverse outcome. While 26% have diabetes, most of these are noninsulin dependent. Using the protocol strategies, target blood pressures (according to JNC VI) have been reached in 58% at the fourth visit, and as expected most (89%) are requiring multiple antihypertensive drugs.

CONCLUSION

The design and baseline characteristics of the initial patients recruited for a prospective, randomized, international, multicenter study comparing two therapeutic strategies to control hypertension in CAD patients are described.

New evidence on the prevention of cardiovascular events in hypertensive patients with type 2 diabetes

Recent trials in hypertensive patients with type 2 diabetes reveal important differences in the risk for major cardiovascular events when individual agents are compared. In the Fosinopril Amlodipine Cardiovascular Events Trial (FACET), 380 patients with hypertension and type 2 diabetes were randomized to fosinopril or amlodipine and followed for up to 3.5 years to assess effects on serum lipids. Although both agents effectively controlled blood pressure, amlodipine caused a significantly greater decrease in systolic pressure. At the end of the trial, serum cholesterol, high-density lipoprotein cholesterol, triglycerides, HbA1c, serum glucose, plasma insulin, serum creatinine, and microalbuminuria were similar in both groups. The patients randomized to fosinopril were significantly less likely to experience the prospectively defined combined outcome of acute myocardial infarction (MI), hospitalized angina, or stroke compared to those randomized to amlodipine (RR 0.49; 95% CI 0.26-0.95). In the Appropriate Blood pressure Control in Diabetes (ABCD) trial, 470 patients with hypertension and type 2 diabetes who were randomized to long-acting nisoldipine had an adjusted sevenfold increased risk for acute MI compared to those randomized to enalapril (RR 7.0; 95% CI 2.3-21.4). In the Multicenter Isradipine Diuretic Atherosclerosis Study (MIDAS) trial, the patients with hypertension and above the median of HbA1c (> or =6.7%) randomized to isradipine had a threefold increased risk for major cardiovascular events compared to those randomized to hydrochlorothiazide (RR 2.81; 95% CI 1.09-7.26). These findings are supported by several observational studies. Therefore, evidence is emerging that angiotensin-converting enzyme inhibitors and low-dose diuretics may be more effective than calcium antagonists for prevention of cardiovascular events in hypertensive patients with diabetes or impaired glucose control.

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.

Pathogenesis, prevention, and treatment of diabetic nephropathy

It is likely that the pathophysiology of diabetic nephropathy involves an interaction of metabolic and haemodynamic factors. Relevant metabolic factors include glucose-dependent pathways such as advanced glycation, increased formation of polyols, and activation of the enzyme, protein kinase C. Specific inhibitors of the various pathways are now available, enabling investigation of the role of these processes in the pathogenesis of diabetic nephropathy and potentially to provide new therapeutic approaches for the prevention and treatment of diabetic nephropathy. Haemodynamic factors to consider include systemic hypertension, intraglomerular hypertension, and the role of vasoactive hormones, such as angiotensin II. The mainstay of therapy remains attaining optimum glycaemic control. Antihypertensive therapy has a major role in slowing the progression of diabetic nephropathy. Agents that interrupt the renin-angiotensin system such as angiotensin-converting enzyme inhibitors and angiotensin II receptor antagonists may be particularly useful as renoprotective agents in both the hypertensive and normotensive context.