Antihypertensive treatment and new-onset diabetes mellitus

The comparative risk of new-onset diabetes after prescription of drugs for cardiovascular risk prevention in primary care: a national cohort study

OBJECTIVE

Recent studies suggest that statins increase the risk of subsequent diabetes with a clear dose response effect. However, patients prescribed statins have a higher background risk of diabetes. This national cohort study aims to provide an estimate of the comparative risks for subsequent development of new-onset diabetes in adults prescribed statins and in those with an already higher background risk on cardiovascular risk-modifying drugs and a control drug.

DESIGN

Longitudinal cohort study.

SETTING

Use of routinely collected data from a complete national primary care electronic prescription database in New Zealand.

PARTICIPANTS

32 086 patients aged between 40 and 60 years in 2005 were eligible and assigned to four non-overlapping groups receiving their first prescription for: (1) diclofenac (healthy population) n=7140; (2) antihypertensives thought likely to induce diabetes (thiazides and β-blockers) n=5769; (3) antihypertensives thought less likely to induce diabetes (ACE inhibitors, angiotensin II receptor blockers, calcium channel blocker) n=6565 and (4) statins n=12 612.

OUTCOME

Numbers of first metformin prescriptions were compared between these groups from 2006 to 2011.

RESULTS

Patients prescribed statins have the highest risk of receiving a subsequent metformin prescription (HR 3.31; 95% CI 2.56 to 4.30; p<0.01), followed by patients prescribed antihypertensives thought less likely to induce diabetes (HR 2.32; 95% CI 1.74 to 3.09; p<0.01) and patients prescribed antihypertensives thought more likely to induce diabetes (HR 1.59; 95% CI 1.15 to 2.20; p<0.01) in the subsequent 6 years of follow-up, when compared to diclofenac.

CONCLUSIONS

These findings further support the link between statin use and new-onset diabetes and suggest that the understanding of diabetes risk associated with different antihypertensive drug classes may bear practice modification. This provides important information for future research, and for prescribers and patients when considering the risks and benefits of different types of cardiovascular risk-modifying drugs.

Treatment of hypertension among African Americans: the Jackson Heart Study

Hypertension treatment regimens used by African American adults in the Jackson Heart Study were evaluated at the first two clinical examinations (2415 treated hypertensive persons at examination I [exam I], 2000-2004; 2577 at examination II [exam II], 2005-2008). Blood pressure (BP) was below 140/90 mm Hg for 66% and 70% of treated participants at exam I and exam II, respectively. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure treatment targets were met for 56% and 61% at exam I and exam II, respectively. Persons with diabetes or chronic kidney disease were less likely to have BP at target, as were men compared with women. Thiazide diuretics were the most commonly used antihypertensive medication, and persons taking a thiazide were more likely to have their BP controlled than persons not taking them; thiazides were used significantly less among men than women. Although calcium channel blockers are often considered to be effective monotherapy for African Americans, persons using calcium channel blocker monotherapy were significantly less likely to be at target BP than persons using thiazide monotherapy.

Predictors of blood pressure response to angiotensin receptor blocker/diuretic combination therapy: a secondary analysis of the irbesartan/hydrochlorothiazide blood pressure reductions in diverse patient populations (INCLUSIVE) study

The secondary analysis of the Irbesartan/Hydrochlorothiazide Blood Pressure Reductions in Diverse Patient Populations (INCLUSIVE) clinical trial investigated whether baseline demographic and clinical variables are predictive of different degrees of blood pressure reduction following an angiotensin II receptor blocker/diuretic treatment regimen. Irbesartan/hydrochlorothiazide and other angiotensin receptor blocker combinations with a diuretic have been shown to be effective in reducing systolic blood pressure in a diverse patient population previously uncontrolled on monotherapy. Ordinary least squares regression analysis was performed on the intent-to-treat population of the INCLUSIVE study to identify variables predictive of variations in blood pressure changes in response to irbesartan/hydrochlorothiazide combination therapy. Higher baseline systolic blood pressure, female sex, type 2 diabetes, and statin therapy were found to be predictive of additional blood pressure lowering with this combination. The impact of higher baseline systolic blood pressure and diabetic state on changes in systolic blood pressure were diminished in female patients compared with male patients. In conclusion, a significant correlation may exist between certain clinical/demographic characteristics and the extent of the therapeutic response with irbesartan/hydrochlorothiazide treatment.

Combination therapy with renin-angiotensin system blockers: Will amlodipine replace hydrochlorothiazide?

Amlodipine is a highly effective and safe antihypertensive dihydropyridine calcium channel blocker. It is even more effective when used in combination with other antihypertensive medications, including hydrochlorothiazide. When antihypertensive calcium channel blockers were first introduced, evidence in the laboratory that they had some natriuretic properties was adduced to suggest that they would be "the diuretics of the 1990s." This turned out not to be the case. Because of its clinical efficacy, amlodipine is frequently used in fixed-dose combination products, but it is not likely to replace hydrochlorothiazide.

Complications of hypertension and the role of angiotensin receptor blockers in hypertension trials

Hypertension is a high-prevalence disease that may affect several organs. In recent years, data have accumulated indicating that angiotensin II receptor blockers (ARBs) may have a supplementary effect beyond lowering blood pressure. The aim of this review is to evaluate the impact of ARBs on the most important complications of hypertension--heart, cerebrovascular and renal diseases, and metabolic complications--based on the findings from large clinical hypertension trials. The results may indicate that ARBs have a superior effect compared with placebo or other antihypertensive drugs in order to prevent left ventricular hypertrophy, atrial fibrillation, stroke, renal disease and diabetes mellitus, while there appears to be no blood pressure-independent superior effect of ARBs regarding prevention of myocardial infarction or heart failure.

Update of Diuretics in the Treatment of Hypertension

Diuretics, which are primarily used to modify the volume and the composition of body fluids, are widely used to treat hypertension. The diuretics include a) the thiazides and thiazide-like agents, which are the most common drugs used to treat high blood pressure (these drugs inhibit sodium reabsorption in the early distal convoluted tubule); b) loop diuretics, such as furosemide, block chloride and sodium reabsorption by inhibition of the Na/K/2Cl cotransport system in the thick ascending limb of the loop of Henle; and c) potassium-sparing (retaining) diuretics, including aldosterone receptor blockers (such as spironolactone and eplerenone) and epithelial sodium channel blockers (such as amiloride and triamterene, which interfere with the reabsorption of sodium and excretion of potassium and hydrogen that takes place in the late distal tubule, the connecting tubule, and the cortical collecting duct). Hydrochlorothiazide 12.5 mg once daily or equivalent low dosages of other similar agents reduce blood pressure in approximately one-half to two-thirds of patients who are responsive to this class of drugs; higher doses add little to the effect on blood pressure and also increase side effects. Some combinations of very small doses of thiazide diuretics - for example, 6.25 mg hydrochlorothiazide or 0.625 mg indapamide, with a low dose of an antihypertensive drug of a different class - have average antihypertensive efficacy when used once daily. Furosemide is used in patients with renal failure or severe heart failure and is best given by continuous intravenous infusion. The potassium-sparing diuretics are generally used in combination with thiazide diuretics to treat hypertension. Side effects occur at about the same frequency and severity with equipotent doses of all diuretics. The incidence of side effects is dose-dependent and also increases as a function of the duration of the renal excretory and antihypertensive actions. However, longer-acting diuretics provide better 24-hour control of blood pressure and increase compliance and adherence to the treatment regimen.

Mechanism for blockade of angiotensin subtype 1 receptors to lower plasma glucose in streptozotocin-induced diabetic rats

AIMS

We investigated the mechanism(s) by which valsartan, a selective antagonist of angiotensin subtype 1 (AT(1)) receptor, decreased plasma glucose in streptozotocin (STZ)-induced diabetic rats.

METHODS

The plasma glucose concentration was assessed by the glucose oxidase method. The concentration of beta-endorphin in plasma or medium incubating adrenal medulla was measured using an enzyme-linked immunosorbent assay. The mRNA levels of the subtype 4 form of glucose transporter (GLUT4) in soleus muscle and phosphoenolpyruvate carboxykinase (PEPCK) in the liver were detected by Northern blotting analysis, while the protein levels of GLUT4 in isolated soleus muscle and hepatic PEPCK were investigated using Western blotting analysis.

RESULTS

A single intravenous injection of valsartan dose-dependently increased plasma beta-endorphin-like immunoreactivity (BER) in parallel with the lowering of plasma glucose concentration in STZ-induced diabetic rats. Naloxone and naloxonazine inhibited the plasma glucose-lowering action of valsartan at doses sufficient to block opioid micro-receptors. In contrast to its action in wild-type diabetic mice, valsartan failed to modify plasma glucose in opioid micro-receptor knockout diabetic mice. Bilateral adrenalectomy in STZ-induced diabetic rats eliminated both the plasma glucose-lowering action and the plasma BER-elevating action of valsartan. In the isolated adrenal medulla of STZ-induced diabetic rats, angiotensin II (Ang II) or valsartan did not affect spontaneous BER secretion. Activation of cholinergic receptors by 1.0 micromol/l acetylcholine (ACh) enhanced BER secretion from the isolated adrenal medulla of STZ-induced diabetic rats, but not in the presence of 1.0 nmol/l Ang II, while valsartan reversed this inhibition by Ang II in a concentration-dependent manner. Treatment of STZ-induced diabetic rats with valsartan (0.2 mg/kg) three times daily for 3 days resulted in an increase in gene expression of GLUT4 in soleus muscle and impeded the reduction of elevated mRNA or protein level of hepatic PEPCK. Both of these effects were blocked by opioid micro-receptor antagonist.

CONCLUSIONS

The results suggest that blockade of AT(1) receptor by valsartan may enhance the adrenal beta-endorphin secretion induced by ACh, activating the opioid micro-receptors to increase glucose utilization and/or to decrease hepatic gluconeogenesis, resulting in the reduction of plasma glucose in STZ-induced diabetic rats.

Improved insulin sensitivity with the angiotensin II-receptor blocker losartan in patients with hypertension and other cardiovascular risk factors

We aimed to compare the effects of two different vasodilating principles, angiotensin II-receptor blockade and calcium channel blockade, on peripheral insulin-mediated glucose uptake in patients with hypertension and other cardiovascular risk factors. Twenty-one hypertensive patients (11 women and 10 men) with mean age 58.6 years (range 46-75 years), body mass index 29.2 +/- 1.0 kg/m(2) and blood pressure 160 +/- 3/96 +/- 2 mm Hg entered a 4-week run-in period with open-label amlodipine 5 mg. Thereafter they were randomized double-blindly to additional treatment with amlodipine 5 mg or losartan 100 mg. After 8 weeks of treatment, all patients underwent clinical examination and laboratory testing, and 17 of them underwent a hyperinsulinaemic isoglycaemic glucose clamp. After a 4-week open-label wash-out phase, the participants crossed over to the opposite treatment regimen and final examinations with hyperinsulinaemic isoglycaemic glucose clamp after another 8 weeks. Blood pressure was lowered to the same level in both treatment periods. The glucose disposal rate was significantly higher after treatment with losartan 100 mg + amlodipine 5 mg compared to amlodipine 10 mg (4.9 +/- 0.4 vs 4.2 +/- 0.5 mg/kg/min, P = 0.039). Thus our data suggest that angiotensin II-receptor blockade with losartan improves glucose metabolism at the cellular level beyond what can be expected by the vasodilatation and blood pressure reduction alone.

Long-Term and Short-Term Changes in Antihypertensive Prescribing by Office-Based Physicians in the United States

Medication choices for the treatment of elevated blood pressure have a large potential impact on both patient outcomes and health care costs. Historic trends of prescribing for hypertension will advance the understanding of physician practice of evidence-based medicine. This study describes both long- and short-term trends in US antihypertensive prescribing from 1990 through 2004. Data were extracted from the National Disease and Therapeutic Index, a continuing survey of a national sample of US office-based physicians. Cox and Stuart and z tests were performed. Diuretics ranked among the top 3 antihypertensive drug classes throughout the entire study time span. Angiotensin-converting enzyme (ACE) inhibitors and calcium channel blockers (CCBs) were preferred over diuretics beginning in 1993, with diuretics surpassing CCBs in 2000. β-Blockers were consistently the fourth most common class until 2002, when exceeded by angiotensin II receptor antagonists (ARBs). Most recent trends indicated an immediate but short-lived increase in the prescription of thiazide diuretics after the new clinical evidence released in December 2002 demonstrating clinical equivalence of thiazides to ACE inhibitors and CCBs. In contrast, prescription of ACE inhibitors declined, accompanied by continuation of a pre-existing increase in the prescription of ARBs, whereas prescription of CCBs remained essentially stable after the new evidence was released. The recorded long- and short-term trends indicate that evidence-based clinical recommendations had an impact on antihypertensive prescribing practices, but the magnitude of impact may be smaller and of more limited duration than desired.

Fixed-Drug Combinations as First-Line Treatment for Hypertension

As combinations of drugs from different classes that have synergistic or additive effect and properties to cancel out each others' untoward hemodynamic and metabolic effects become more and more widely used, their use as first-line therapy for the treatment of newly diagnosed hypertensive patients is growing in popularity as well. The possibility to begin therapy with a fixed 2-drug combination may be preferable to starting with monotherapy followed by upward titration and addition of other agents. More and more combinations are coming out on the market and proving their effectiveness in randomized controlled trials and in large multicenter studies. One suggestion is the "polypill," a fixed combination of multiple agents that address various components of the metabolic syndrome and coexisting common risk factors in both high-risk patients with conditions requiring polypharmacy, and in healthy asymptomatic individuals.