Special considerations in the therapy of diabetic hypertension

Effect of treatment with nebivolol on parameters of oxidative stress in type 2 diabetics with mild to moderate hypertension

AIM

The aim of this study was to examine the effect of the cadioselective B(1)-adrenoceptor blocker nebivolol on glycaemic control, lipid profile and markers of oxidative stress in patients with type 2 diabetes over a 6-month period.

METHODS

Twenty-six patients with mild to moderate hypertension (140-160 mmHg systolic, 90-105 mmHg diastolic) confirmed on 24-h blood pressure monitoring, were treated with nebivolol 5 mg daily for 6 months. Total serum cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol and low-density lipoprotein (LDL) subfractions, lipid hydroperoxides (LHPs) and total antioxidant capacity (TAC) were measured before and after 6 months of treatment.

RESULTS

Nebivolol, as expected, reduced mean daytime systolic and diastolic pressures on ambulatory monitoring (149 +/- 9 to 140 +/- 13 mmHg, P = 0.02 and 84 +/- 7 to 77 +/- 9 mmHg, P < 0.001). There were no significant changes in serum cholesterol or triglycerides following treatment but a significant increase in HDL cholesterol was noted (1.12 +/- 0.19 to 1.25 +/- 0.36 mmol/L, P = 0.008). Patients showed a highly significant reduction in TAC from 501 +/- 57 to 422 +/- 29 trolox equivalent (P < 0.001). Baseline LHPs were very high and showed no significant change over the 6-month period (18.7 +/- 7.4 and 18.7 +/- 10.9 micromol/L). The LDL score increased significantly from 1.7 +/- 0.7 to 2.3 +/- 0.7 (P = 0.0002) at 6 months suggesting a change to a more atherogenic lipid profile. Neither weight nor glycaemic control changed during treatment.

CONCLUSION

Nebivolol appears to be lipid neutral and may even have a positive effect on HDL cholesterol. Despite this it may promote the formation of potentially atherogenic LDL subfractions possibly as a result of reduced antioxidant defences. Further studies are needed to clarify the changes observed in parameters of oxidative stress.

Pharmacotherapy and blood pressure control in elderly hypertensives in a primary care setting in Bahrain

BACKGROUND AND AIMS

Antihypertensive treatment in the elderly has important beneficial effects in terms of reduced cardiovascular morbidity and mortality. The aim of this study was to determine, in elderly hypertensives, the adherence of primary care physicians to World Health Organization/International Society of Hypertension (WHO/ISH) guidelines for the drug management of hypertension and extent of blood pressure (BP) control.

METHODS

A multicentric therapeutic audit of medical records of elderly hypertensives was performed in nine primary care health centers in the Kingdom of Bahrain.

RESULTS

In elderly hypertensives (> or =60 years), the WHO/ISH-1999 recommended BP targets of <140/<90 mmHg and BP<130/85 mmHg were achieved in 11.1% of elderly hypertensives and 4.1% of elderly diabetic hypertensives, respectively. Antihypertensive combination therapy was used in approximately half of the elderly. No significant difference in BP was found in elderly hypertensives treated either with monotherapy or combination therapy. As regards mono- and overall drug utilization, beta-blockers were the most frequently prescribed drugs in hypertensives, and angiotensin-converting enzyme (ACE) inhibitors in diabetic hypertensives. Diuretics and calcium channel blockers, the preferred antihypertensives for the elderly, were less often prescribed, particularly in patients with isolated systolic hypertension.

CONCLUSIONS

Approximately one out of 9 elderly hypertensives and one out of 24 diabetic hypertensives achieved optimal BP control. Although preference for antihypertensives was markedly influenced by comorbidity with diabetes, tailoring of drug therapy was suboptimal and did not adhere to the recommended guidelines in elderly hypertensives. Efforts to improve the drug management of hypertension at primary care level, particularly in the elderly, are required.

Is there a rationale for angiotensin blockade in the management of obesity hypertension?

Obesity, currently affecting >20% of the adult population in most Western countries, is a major risk factor for the development of hypertension. Hypertension in obese patients is, in the majority of instances, further complicated by the concomitant presence of dyslipidemia and insulin resistance. The latter is reflected by derangement of glucose homeostasis, ranging from hyperinsulinemia to frank type 2 diabetes. Hypertension in obese patients is also associated with an increased risk for left ventricular hypertrophy, endothelial dysfunction, renal hyperfiltration, microalbuminuria, and elevated markers of inflammation. Sodium retention, volume expansion, and increased cardiac output are common findings in obese individuals. These changes are largely attributable to increased activity of the sympathetic nervous system and insufficient suppression of the renin-angiotensin system. Recent data show increased expression of angiotensin II-forming enzymes in adipose tissue, and increased activity of the renin-angiotensin system has recently been implicated in the development of insulin resistance and type 2 diabetes. Accordingly, antihypertensive agents that block the renin-angiotensin system might be a beneficial strategy for treatment of obesity-related hypertension. Both angiotensin-converting enzyme inhibitors and angiotensin type-1 receptor blockers have been associated with favorable metabolic properties and end-organ protection in addition to their antihypertensive effects. Data from ongoing large trials will provide an indication of the protective and preventive effects of these treatment strategies while offering insights into the mechanisms linking obesity, hypertension, and other facets of the metabolic syndrome.

Antihypertensive drug-associated sexual dysfunction: a prescription analysis-based study

PURPOSE

To determine whether primary care physicians take into consideration age, gender and diabetes mellitus as risk factors for sexual dysfunction (SD) when prescribing antihypertensives.

METHODS

A prescribing survey on hyperternsive patients with or without diabetes mellitus in primary care setting of Bahrain was carried out.

RESULTS

In 5301 hypertensive patients, we found that a beta-blocker (atenolol) was the most commonly prescribed drug and was significantly more often prescribed for young male hypertensives (< 45 years). A relatively high dose of atenolol (100 mg/d) was extensively used as both mono- and combination-therapies. With the exception of middle-aged hypertensives (45-64 years) and elderly diabetic-hypertensives (> or = 65 years), no significant age- and gender-related differences were observed regarding the prescription of thiazide diuretics. A significant trend of prescribing methyldopa in females as monotherapy was evident. Angiotensin converting enzyme (ACE) inhibitors, the second most commonly prescribed drugs, were significantly more often prescribed for young, middle-aged hypertensive males and for middle-aged diabetic-hypertensive males. beta-blocker/diuretic combination was prescribed least for the young and elderly hypertensive males. However, prescription of an ACE inhibitor with either a diuretic or a calcium channel blocker (CCBs) was less frequent and lacked gender-related differences.

CONCLUSIONS

We infer that antihypertensive-induced SD received little attention as was evident from: (a) over-prescription of relatively high dose of beta-blockers to young hypertensive males; (b) lack of gender- and age-related difference regarding the type and dose of diuretics prescribed; (c) underutilization of effective and complementary combinations expected to cause least impact on sexual function, such as ACE inhibitors with either a diuretic or with a CCB; and (d) a relative lack of discrimination while selecting antihypertensive drugs, particularly as monotherapy between hypertensive versus diabetic-hypertensive patients. With the exception of ACE inhibitors alone and combination of diuretic/beta-blocker, the choice of antihypertensives did not conform to international guidelines. In view of drug-induced SD adversely influencing the quality of life and thereby drug-compliance, interventions aimed at improving physicians' awareness should be attempted.

Family physicians' and general practitioners' approaches to drug management of diabetic hypertension in primary care

RATIONALE, AIMS AND OBJECTIVES

To compare the pharmacotherapeutic approaches to diabetic hypertension of family physicians (FPs) and general practitioners (GPs).

METHODS

A retrospective prescription-based study was conducted in 15 out of a total of 20 health centres, involving 115 primary care physicians--77 FPs and 38 GPs, representing 74% of the primary care physicians of Bahrain. Prescriptions were collected during May and June 2000 to comprise a study population of 1266 diabetic-hypertensive patients.

RESULTS

As monotherapy, angiotensin-converting enzyme (ACE) inhibitors (37.9%) and beta-blockers (38.3%) were the most commonly prescribed classes of antihypertensives by FPs and GPs, respectively. Calcium channel blockers (CCBs) were ranked third by both categories of physicians. For two-drug combinations, a beta-blocker and an ACE inhibitor was the combination of choice for both physician categories. Patients managed by the FPs were more likely to receive a beta-blocker-CCB combination (17.4 vs. 14.9%) or a diuretic-ACE inhibitor combination (16.7 vs. 11.4%) and less likely to receive a beta-blocker-diuretic combination (11.8 vs. 16.7%) than those managed by the GPs. The proportion of patients receiving antihypertensive combinations was 40.6 and 38.5% for FPs and GPs, respectively. While the GPs prescribed CCB as a monotherapy to the elderly most often, the FPs choice was a beta-blocker. Diuretics were less preferred by both FPs and GPs. Beta-blocker-ACE inhibitor was again the most preferred combination of both FPs and GPs. FPs prescribed CCB-beta-blocker combinations more often than GPs (P = 0.01), whereas CCB-ACE inhibitor combinations were less preferred (P = 0.09). A trend towards excessive use of short-acting nifedipine as monotherapy for elderly patients, both by FPs and by GPs, was noticed. Glibenclamide, alone or in combination with metformin, was the foremost antidiabetic drug prescribed by FPs and GPs. Middle-aged (45-64 years) patients seen by GPs were more likely to receive glibenclamide than those treated by FPs (P = 0.001) and less likely to receive gliclazide (P = 0.01). Combinations of a beta-blocker with either glibenclamide or insulin were prescribed considerably more often by GPs.

CONCLUSIONS

Within the same practice setting, a substantial difference was observed between FPs and GPs in terms of preference for different classes of drugs in the management of diabetic hypertension. The compliance of both FPs and GPs was suboptimal; overall, the compliance of the FPs was closer to the recommended guidelines, however. Educational programmes should specifically address these inadequacies in order to improve the quality of health care.

Step care therapy for hypertension in diabetic patients

For diabetic patients, a goal blood pressure lower than 130/80-85 mm Hg is strongly supported by clinical trial results. We review the agents, sequence, and dosing used in clinical trials and propose a treatment algorithm. Multiagent antihypertensive therapy is required to attain goal blood pressure in most patients. Step sequences to obtain this goal are suggested. In general, we favor initial therapy with an angiotensin-converting enzyme inhibitor, followed by the addition of a diuretic. The presence of comorbid conditions may dictate variation from this scheme. The effect of antihypertensive agents on established cardiovascular diseases, proteinuria, renal function, and metabolic factors is discussed. Tailored recommendations for specific clinical scenarios are described.

Prescribing patterns and therapeutic implications for diabetic hypertension in Bahrain

OBJECTIVE

To determine drug prescription patterns and the extent of conformity with World Health Organization/international Society of Hypertension (WHO/ISH) guidelines in diabetic hypertension.

DESIGN

Retrospective prescription-based survey.

SETTING

Seven primary-care health centers, comprising approximately one-third of primary-care health centers in Bahrain.

PATIENTS

Patients with type 2 diabetes and hypertension.

MAIN OUTCOME MEASURE

The prescribing pattern of antihypertensive and antidiabetic drugs.

RESULTS

Among a study sample of 1,463 patients with type 2 diabetes and hypertension, antidiabetic agents were prescribed as monotherapy in the following descending order: glyburide, gliclazide, insulin, and metformin. As combinations, sulfonylureas plus metformin was most popular, followed by metformin plus insulin, and sulfonylureas plus insulin. Sulfonylurea and metformin with insulin was rarely used. There was no significant difference in prescribing of glyburide and metformin between the elderly and young middle-aged diabetic patients; many patients older than 65 years were treated with a beta-blocker along with a long-acting sulfonylurea. Both as monotherapy and in overall use, beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, and calcium-channel blockers were most often prescribed. Among 35.5% patients treated with antihypertensive combinations, various two- and three-drug combinations of beta-blockers, ACE inhibitors, calcium-channel blockers, and diuretics were often used. The proportion of patients taking atenolol 100 mg/d was higher with combination regimens. Hydrochlorothiazide 25 mg or equivalent thiazide diuretics were extensively used.

CONCLUSIONS

The prescribing pattern of antihypertensives in diabetic hypertension differs in many instances from WHO/ISH guidelines, especially regarding the choice of antihypertensive drugs and their combinations. The appropriateness of antidiabetic drug choice is questionable in relation to the antihypertensive used.

Beta-blockers in the management of hypertension in patients with type 2 diabetes mellitus: is there a role?

It has been conclusively established that treatment of hypertension in patients with type 2 (non-insulin-dependent) diabetes mellitus will significantly reduce the incidence of stroke, heart failure and progression of diabetic complications. Beta-blockers are effective antihypertensive agents which, in long term studies, have proven beneficial in reducing important clinical end-points. However nonselective beta-blockers may have a negative effect on lipid profiles and contribute to hypoglycaemic unawareness, thus preventing their use in some patients with diabetes mellitus. The development of newer and more selective beta-blockers has overcome many of these problems. In addition, some of the newer agents have novel properties such as release of nitric oxide, which theoretically would make them more attractive in patients with diabetes mellitus. Overall, the adverse metabolic effects of beta-blockers do not appear to be important in clinical practice and these agents should no longer be contraindicated in patients with type 2 diabetes mellitus. Their proven cardiovascular benefits would seem to easily tip the balance in favour of their use.

Close relationship of abnormal glucose tolerance with endothelial dysfunction in hypertension

Hypertension is frequently accompanied by left ventricular hypertrophy, endothelial dysfunction, and abnormal glucose metabolism. However, no study has examined the relative pathological significance of left ventricular hypertrophy and abnormal glucose metabolism on endothelial dysfunction in hypertension. This study was conducted to evaluate whether abnormal glucose tolerance assessed by 75-g oral glucose tolerance test or left ventricular hypertrophy is more closely associated with endothelial dysfunction in never-treated hypertensive patients without elevated fasting blood glucose. We studied 107 unmedicated hypertensive patients (mean age, 54+/-10 years) whose fasting blood glucose was <7.0 mmol/L. Endothelial function was assessed by change in brachial artery diameter in response to reactive hyperemia, and left ventricular mass index was determined by ultrasonography. Simple linear regression analysis demonstrated that endothelial function significantly correlated with left ventricular mass index and 2-hour blood glucose in 75-g oral glucose tolerance test, but not with fasting blood glucose. Multiple linear regression analysis revealed that endothelial function significantly correlated with 2-hour blood glucose (beta=-2.68, P<0.05) after we controlled for other clinical variables. Patients were divided into 3 groups according to 2-hour blood glucose levels. Endothelial function was more impaired in patients with diabetes (n=12; 4.7+/-1.8%) and in those with impaired glucose tolerance (n=31; 6.3+/-2.9%) than in those with normal glucose tolerance (n=64; 8.4+/-4.5%) (P<0.05), but left ventricular mass index was similar in these 3 groups. Abnormal glucose tolerance assessed by 75-g oral glucose tolerance test, rather than left ventricular hypertrophy, may have direct pathophysiological relevance to endothelial dysfunction in borderline to moderate hypertensive patients.