Effects of intensive blood pressure reduction on myocardial infarction and stroke in diabetes: a meta-analysis in 73 913 patients

Blood pressure treatment target in patients with diabetes mellitus--current evidence

Hypertension is a very common cardiovascular disease (CVD) risk factor in diabetes, affecting more than half of diabetic patients. Major guidelines on the management of hypertension recommend to start antihypertensive drugs in all diabetic patients with a systolic blood pressure (SBP) 140 mmHg or more and/or a diastolic blood pressure (DBP) 90 mmHg or more, and to adjust the treatment strategy in order to lower their BP below these values. The present body of evidence suggests that in patients with type 2 diabetes mellitus/impaired fasting glucose/impaired glucose tolerance, a SBP treatment goal of 130 to 135 mmHg is acceptable. Aiming at SBP levels of 130 mmHg decreases stroke risk, but the risk of serious adverse events may increase with very low BP levels. The results regarding the attained DBP level is somewhat complex, since middle-aged people with diastolic hypertension and pre-existing CVD may have increased CVD mortality if their DBP is lowered drastically to a very low level. With the currently available very limited trial data on low attained BP level, it is not possible to set a specific treatment target regarding BP levels for diabetic hypertensive patients, but it is important to use a personalized approach in their antihypertensive treatment.

Beyond blood pressure: evidence for cardiovascular, cerebrovascular, and renal protective effects of renin-angiotensin system blockers

For patients with hypertension, effective control of blood pressure (BP) reduces cardiovascular (CV), and renal risk. Antihypertensive agents that offer benefits that extend beyond those associated with BP reduction alone, to include tissue protective effects and effects on the vasculature, may be of benefit for many patients with increased CV risk due to comorbidities or prior history of CV events. Renin-angiotensin system (RAS) blockers [angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs)] are guideline-recognized, highly effective antihypertensive agents that exert their BP-lowering action through different mechanisms at different levels of the RAS. Large-scale clinical studies suggest that small, between-treatment differences in BP lowering do not account for observed outcome differences between RAS blockers and other antihypertensive agents. Analysis of data from seminal clinical studies and meta-analyses identify that, controlling for effects on BP control, RAS blockers may be more effective than calcium channel blockers (CCBs) in reducing risk of myocardial infarction and congestive heart failure; ARBs may be more effective than either ACEIs or β blockers in stroke prevention; CCBs may be more effective than RAS blockers in stroke prevention; and ARBs may be more effective than β blockers in reducing left ventricular hypertrophy. This review considers the rationale and evidence for benefits of RAS blockade beyond BP lowering, and highlights the differences between ARBs and ACEIs, and between agents within these drug classes.

Tight blood pressure control in diabetes: evidence-based review of treatment targets in patients with diabetes

Blood pressure (BP) targets in diabetic patients stills represent the object of a major debate, fueled by the recent publication of post hoc observational analyses of the INVEST and the ONTARGET trials, suggesting an increased risk of cardiovascular events with tighter control, the J-curve effect, and by the results of the ACCORD trial, showing no improvements in the composite primary outcome of nonfatal myocardial infarction, stroke, or cardiovascular death in the intensive BP-lowering arm (<120/80 mmHg). In the present review, we focus on existing evidence about different BP targets in diabetic subjects and we present the results of our recent meta-analysis, showing that tight BP control may significantly reduce the risk of stroke in these patients without increasing the risk of myocardial infarction. Therapeutic inertia (leaving diabetic patients with BP values of 140/90 mmHg or higher) should be avoided at all costs, as this would lead to an unacceptable toll in terms of human lives, suffering, and socioeconomic costs.

Effects of intensive blood pressure lowering on cardiovascular and renal outcomes: a systematic review and meta-analysis

BACKGROUND

Guidelines recommend intensive blood pressure (BP) lowering in patients at high risk. While placebo-controlled trials have demonstrated 22% reductions in coronary heart disease (CHD) and stroke associated with a 10-mmHg difference in systolic BP, it is unclear if more intensive BP lowering strategies are associated with greater reductions in risk of CHD and stroke. We did a systematic review to assess the effects of intensive BP lowering on vascular, eye, and renal outcomes.

METHODS AND FINDINGS

We systematically searched Medline, Embase, and the Cochrane Library for trials published between 1950 and July 2011. We included trials that randomly assigned individuals to different target BP levels. We identified 15 trials including a total of 37,348 participants. On average there was a 7.5/4.5-mmHg BP difference. Intensive BP lowering achieved relative risk (RR) reductions of 11% for major cardiovascular events (95% CI 1%-21%), 13% for myocardial infarction (0%-25%), 24% for stroke (8%-37%), and 11% for end stage kidney disease (3%-18%). Intensive BP lowering regimens also produced a 10% reduction in the risk of albuminuria (4%-16%), and a trend towards benefit for retinopathy (19%, 0%-34%, p = 0.051) in patients with diabetes. There was no clear effect on cardiovascular or noncardiovascular death. Intensive BP lowering was well tolerated; with serious adverse events uncommon and not significantly increased, except for hypotension (RR 4.16, 95% CI 2.25 to 7.70), which occurred infrequently (0.4% per 100 person-years).

CONCLUSIONS

Intensive BP lowering regimens provided greater vascular protection than standard regimens that was proportional to the achieved difference in systolic BP, but did not have any clear impact on the risk of death or serious adverse events. Further trials are required to more clearly define the risks and benefits of BP targets below those currently recommended, given the benefits suggested by the currently available data.

Target blood pressure in diabetes patients with hypertension--what is the accumulated evidence in 2011?

There is overwhelming evidence that hypertension is an important risk factor for both macrovascular and microvascular complications in patients with diabetes, but the problem remains to identify appropriate goals for preventive therapies. A number of guidelines (the European Society of Cardiology (ESC)/European Association for the Study of Diabetes (EASD) 2007, the Joint National Committee (JNC)-VII 2003, the American Diabetes Association (ADA) 2011) have for example advocated a blood pressure goal of less than 130/80 mmHg, but this suggestion has been challenged by findings in recent trials and meta-analyses (2011). The European Society of Hypertension (ESH) therefore recommends a systolic blood pressure goal of "well below" 140 mmHg. Based on evidence from both randomized controlled trials (hypertension optimal treatment (HOT), action in diabetes and vascular disease: preterax and diamicron MR controlled evaluation (ADVANCE), action to control cardiovascular risk in diabetes (ACCORD)) and observational studies (ongoing telmisartan alone and in combination with ramipril global endpoint trial (ONTARGET), international verapamil-trandolapril study (INVEST), treat to new targets (TNT), and the National Diabetes Register (NDR)), it has been shown that the benefit for stroke reduction remains even at lower achieved blood pressure levels, but the risk of coronary events may be uninfluenced or even increased at lower systolic blood pressure levels. In a recent meta-analysis, it was therefore concluded that the new recommended goal should be 130-135 mmHg systolic blood pressure for most patients with type 2 diabetes. Other risk factors should also be controlled with a more ambitious strategy applied in the younger patients with shorter diabetes duration, but a more cautious approach in the elderly and frail patients with a number of vascular or non-vascular co-morbidities. In patients from East Asia, such as China, the stroke risk is relatively higher than the risk of coronary events. This must also be taken into consideration for individualized goal setting in relation to total risk, for example in patients from stroke-prone families. In conclusion, the current strategy is to have a more individualized approach to risk factor control in patients with type 2 diabetes, also relevant for blood pressure control.

Subclinical coronary atherosclerosis predicts cardiovascular risk in different stages of hypertension: result of the Heinz Nixdorf Recall Study

Prehypertension is a frequent condition and has been demonstrated to increase cardiovascular risk. However, the association with coronary atherosclerosis as part of target organ damage is not well understood. We investigated the cross-sectional relationship and longitudinal outcome between blood pressure categories and coronary artery calcification (CAC), quantified by electron beam computed tomography, in 4181 participants from the population-based Heinz Nixdorf Recall Study cohort. At baseline, we observed a continuous increase in calcium scores with increasing blood pressure categories. During a median follow-up period of 7.18 years, 115 primary end points (2.8%; fatal and nonfatal myocardial infarction) and 152 secondary end points (3.6%; stroke and coronary revascularization) occurred. We observed a continuous increase in age- and risk factor-adjusted secondary endpoints (hazard ratios [95% CI]) with increasing blood pressure categories (referent: normotension) in men: prehypertension, 1.80 (0.53-6.13); stage 1 hypertension, 2.27 (0.66-7.81); and stage 2 hypertension, 4.10 (1.27-13.24) and in women: prehypertension, 1.13 (0.34-3.74); stage 1 hypertension, 2.14 (0.67-6.85); and stage 2 hypertension, 3.33 (1.24-8.90), respectively, but not in primary endpoints. Cumulative event rates were determined by blood pressure categories and the CAC. In prehypertension, the adjusted hazard ratios for all of the events were, for CAC 1 to 99, 2.05 (0.80-5.23; P=0.13); 100 to 399, 3.12 (1.10-8.85; P=0.03); and ≥400, 7.72 (2.67-22.27; P=0.0002). Risk of myocardial infarction and stroke in hypertension but also in prehypertension depends on the degree of CAC. This marker of target-organ damage might be included, when lifestyle modification and pharmacotherapeutic effects in prehypertensive individuals are tested to avoid exposure to risk and increase benefit.

Current challenges in the clinical management of hypertension

Elevated blood pressure (BP) is probably the most-important modifiable risk factor for cardiovascular disease (CVD). BP influences the development of CVD, even if levels of BP are well below the usual cut-off point that defines the presence of arterial hypertension. Adequate measurement of BP is the most-important requirement for the diagnosis and treatment of patients with suspected hypertension. The use of methodologies such as ambulatory and home BP monitoring have become powerful tools for defining the 'real' BP of patients, discarding the white-coat effect, and discovering masked hypertension. Early intervention with life-style changes and antihypertensive drugs is required to obtain the best outcome for the patient. In this sense, early use of combination antihypertensive drug therapy is recommended. The treatment of resistant hypertension-the type of elevated BP that is most difficult to control-has clearly improved over the past decade. Further studies are required to define how antihypertensive therapy should be used in the earliest stages of hypertension and for the treatment of patients with a mild-to-moderate increase in global cardiovascular risk.