Hypertension is a risk parameter in the diagnosis of the metabolic syndrome. A raised systolic blood pressure >/= 135 mm Hg and/or a raised diastolic blood pressure >/=85 mm Hg are the criteria leading to the diagnosis of hypertension.
At the same time, it is now accepted that the relationship between BP and risk of cardiovascular disease (ASCVD) events is continuous, consistent, and independent of other risk factors, although the presence of the other risks does significantly increase the ASCVD risk posed by the high blood pressure levels. The classification prehypertension, introduced in the JNC-7 report, recognizes this relationship and introduced a new category of "prehypertension" (120 to 139/80 to 89 mm Hg), in recognition of the fact that underlying risk factors raise blood pressure to ranges that increase risk for CVD.
|Blood Pressure Stages|
|Prehypertension (120 to 139/80 to 89 mm Hg)|
|Stage 1 (140 to 159/90 to 99 mm Hg)|
|Stage 2 (>=160/>=100 mm Hg)|
JNC = Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure.
For individuals aged 40 to 70 years, each increment of 20 mm Hg in systolic BP or 10 mm Hg in diastolic BP doubles the risk of CVD across the entire BP range from 115/75 to 185/115 mm Hg.
When overt hypertension is present without diabetes or chronic kidney disease, the goal for antihypertensive therapy is a blood pressure of </=130 systolic and </= 85 mm Hg. In the presence of diabetes or chronic kidney disease, the blood pressure goal is <120/80 mm Hg.
Lifestyle changes deserve increased emphasis in people with the metabolic syndrome; Mild elevations of blood pressure often can be effectively controlled with lifestyle therapies: weight control, increased physical activity, alcohol moderation, sodium reduction, and increased consumption of fresh fruits and vegetables and low-fat dairy products.
|Lose weight if overweight, even a loss of 4 to 5 kg lowers blood pressure in many hypertensives.|
|Increase aerobic physical activity (30 to 45 min most days of the week).|
|Reduce sodium intake to no more than 100 meq/day (2.4 g of sodium or 6 g of sodium chloride/ one teaspoon).|
|Consumption of an overall healthy diet such as a carbohydrate-rich diet that emphasizes fruits, vegetables, and low-fat dairy products; includes whole grains, poultry, fish, and nuts; and is reduced in fats, red meat, sweets, and sugar-containing beverages. Replacement of some carbohydrates with either protein from plant sources or with monounsaturated fat can further lower BP.|
|Reduce intake of dietary saturated fat and cholesterol.|
|Maintain adequate intake of dietary potassium (approximately 90 meq/day) Increase intake of fruit and vegetables (which provides a substantial intake of potassium) unless there are contraindications.|
|Maintain adequate intake of dietary calcium and magnesium for general health.|
|Limit alcohol intake to no more than 1 oz (30 ml) of ethanol (eg, 24 oz [720 ml] of beer, 10 oz [300 ml] of wine, or 2 oz [60 ml] of 100-proof whiskey) per day or 0.5 oz (15 ml) of ethanol per day for women and lighter-weight people.|
Many of these aspects have been discussed in detail in the section dealing with diet and exercise.
If hypertension cannot be adequately controlled by lifestyle therapies, antihypertensive drugs usually are necessary to prevent long-term adverse effects.
The selection of an appropriate drug regimen for the management of hypertension in diabetics entails special consideration as many of the drugs used for hypertension may have adverse consequences on other risk factors, especially diabetes.
No particular antihypertensive agent has been recommended as a first line drug to be used in patients with hypertension having the metabolic syndrome.
Some investigators support angiotensin-converting enzyme (ACE) inhibitors as first-line therapy for hypertension in the metabolic syndrome, especially when either type 2 diabetes mellitus or chronic renal disease is present. Indeed, inhibition of the renin-angiotensin system with ACE inhibitors or angiotensin receptor blockers (ARBs) may lower risk for diabetes itself. ARBs may be used in those who cannot tolerate ACE inhibitors or as an alternative to ACE inhibitors in people who have left ventricular dysfunction.
Thiazides and ß-blockers are the preferred initial drugs for uncomplicated hypertensives but may increase insulin resistance and worsen atherogenic dyslipidemia. Use of diuretics in patients with IFG or IGT may increase the likelihood of progression to type 2 diabetes mellitus, although diuretics do in fact lower the risk for cardiovascular events. For thiazide diuretics, doses should be kept relatively low. Most investigators in the hypertension field believe that the potential benefit of low-dose diuretics in combination antihypertensive therapy outweighs their risk.
ß-Blockers, especially the newer and more selective drugs are cardioprotective in patients with established CHD and are no longer contraindicated in patients with type 2 diabetes.
At this time, however, the evidence suggests that most of the risk reduction associated with antihypertensive drugs is the result of blood pressure lowering alone.
For a more detailed discussion on the suggested drug therapy approach to achievement of blood pressure goal, see Appendix 14.
All patients must be prescribed lifestyle changes and this should be continued even if drug therapy is started.