Obesity and Hypertension in Children; Caffeine, Stress, and Elevated Blood Pressure; Resistant Hypertension; and Is It Lowering of Blood Pressure Alone That Accounts for Reduction in Cardiovascular Events? Comments on the JCH Contents

The fact that obesity predisposes to hypertension has been repeatedly emphasized in the literature over the past 10 years. The epidemic of obesity continues unabated. More and more people in the United States are classified as obese, with a predisposition to diabetes, hypertension, and cardiovascular disease. It is also known that obese adolescents usually become obese adults. In this issue of JCH, Dr. Lurbe and colleagues discuss obesity, body fat distribution, and ambulatory blood pressure monitoring (ABPM) in children. They highlight the problem that obese children have higher casual as well as ambulatory blood pressures than nonobese children, with the exception of nighttime diastolic blood pressure. Factors relating to obesity that may contribute to the development of elevated blood pressure in these young adults are reviewed. The authors found that waist measurement is a good estimate of central obesity and, as in adults, is predictive of higher blood pressures. Although the authors note that ABPM provides a better assessment of the blood pressure, it is clear from their data that casual blood pressures are also predictive. One must ask, is it really necessary to do ABPM in these children? Dr. Lurbe's data re-emphasize a major point that public health officials have been making for years: prevention of obesity should be a primary public health goal. But preventing obesity is not an easy task. It is true that many young people participate in sports, but too many are more sedentary than in previous generations. Computer and television time, being driven to school, and a decrease in the amount of nonstructured exercise are hallmarks of the present generation. In addition, dietary habits and fast food intake has increased fat consumption—potato chips, etc. have replaced an apple as snack food. Dr. Lurbe's paper raises another warning sign to physicians: guidance about proper diet and exercise should be a major priority in any pediatric practice. This, plus a reduction in sodium intake, which accompanies a lower-fat, lower-calorie diet, will help reduce obesity and the development of hypertension, diabetes, and cardiovascular disease. In another paper in this issue of JCH, Dr. Hartley and colleagues discuss the effect of caffeine intake on blood pressure. Their data indicate that a combination of caffeine and stressful situations will elevate blood pressure to a significant degree. Previous studies had shown that an intake of approximately 3–4 cups of coffee per day increased systolic blood pressure about 2–4 mm Hg. There are, however, patients who are more sensitive to caffeine intake, with greater degrees of blood pressure elevation. The effects of caffeine are noted within 30 minutes to 1 hour and may persist for 3–4 hours; this is one reason for suggesting that blood pressure be taken at least 2 hours after a cup of coffee, several cups of tea, or a caffeinated soft drink. Although the effect of caffeine has been well documented, caffeine intake has not been clearly associated with the development or progression of hypertension. Epidemiologic studies attempting to demonstrate this association have been poorly designed. Dr. Hartley and his group point out that there is little tolerance over time to the effect of caffeine on blood pressure and that the caffeine effects on blood pressure are not only greater in hypertensives than in normotensives, but are exaggerated by stressful situations. A cup of coffee is necessary for many people to “wake up” in the morning or to maintain alertness during the day. People with hypertension do not necessarily have to eliminate coffee as a part of a treatment strategy unless arrhythmias are present. However, patients with elevated blood pressure and those on antihypertensive medication should be advised that having one cup of coffee may be acceptable but having more than two cups, especially at one time, may result in elevation of blood pressure, which, in some people, may be of clinical significance. Spacing coffee intake by 3–4 hours between cups may also be a good idea. For patients who take their blood pressure at home and who are coffee, soft drink, or tea drinkers, it might be of interest to take a reading within 1 hour after drinking a caffeine-containing beverage, to judge sensitivity to caffeine. Drs. Giles and Sander discuss combination therapy in the management of hypertension, especially in patients with comorbidities. New, lower recommendations for goal blood pressures in patients with renal disease and diabetes indicate a greater effort on the part of physicians to reduce blood pressures to as close to 120/80 mm Hg as possible, with a goal of below 130–135/85 mm Hg in these patients. Most practicing physicians are aware that this is not easily accomplished in a majority of patients without utilizing more than one drug. The authors review the effects of the commonly used antihypertensive drugs and point out that all of these will reduce blood pressure, but that monotherapy may not be enough to achieve goal pressures in many patients. The use of combination therapy, i.e., diuretics/potassium-sparing agents, ACE inhibitors/diuretics, angiotensin receptor blockers/diuretics, or β blockers/diuretics, results in greater blood pressure reduction with a higher response rate than that of monotherapy. The authors review the actions of these agents, as well as calcium channel blockers alone and in combinations, and discuss several factors that account for so-called “drug-resistant” hypertension. Although emphasis has been placed on the noncompliant patient in these instances, physician nonadherence to the achievement of goal therapy may be as or more important in drug-resistant cases. Changing therapy if goal pressures are not achieved must be emphasized. If initial therapy is ineffective, another drug in a different drug class should be added or, as the authors note and as the JNC VI suggested, patients might appropriately be started on combination therapy. Antihypertension medications are available to control a large majority of patients. Physicians may not be adequately using these tools for blood pressure control. The authors point out that certain medications may contribute to “resistant hypertension.” Probably the most important of these are the antiarthritic agents that are commonly used, especially in the elderly population, where control rates are poor. Finally, in a roundtable discussion dealing with the question “Is it blood pressure lowering by any means that reduces morbidity or mortality, or do specific medications make a difference?” Drs. Pickering, Weber, and Moser discuss the implications of recent clinical trials. They conclude that the most important factor in reducing cardiovascular events is probably reduction in blood pressure. However, they note that there are some differences in outcome with different medications that similarly lower blood pressure. For example, in the STOP-2 study in the elderly, there were fewer myocardial infarctions and less heart failure with ACE inhibitors than with a dihydropyridine calcium channel blocker (CCB). In the ALLHAT study, fewer cardiovascular events were noted with a diuretic than with an a blocker, and in the CAPPP trial, fewer cardiovascular events were noted in diabetics with an ACE inhibitor than with a β blocker/diuretic regimen. Recent studies have also suggested that in patients with type 2 diabetes and varying degrees of nephropathy, the use of an angiotensin receptor blocker (ARB) (usually with other medications) decreased renal disease progression to a greater degree than a regimen that did not include an ACE inhibitor, an ARB, or a CCB. The recently completed AASK trial also demonstrated less progression of renal disease with an ACE inhibitor-based treatment program than with a CCB treatment program in African American hypertensive diabetics with renal disease. Results of these trials are reviewed and discussed. This panel again emphasized that multiple medications are probably necessary in the majority of hypertensive patients to achieve goal pressures, especially in patients with comorbidities such as diabetes and renal disease. They also agreed that the JNC recommendations should be updated to include the results of recent clinical trials. An updated algorithm is presented. This includes the use of ACE inhibitors or ACE inhibitor/diuretic combinations as an alternative first-step therapy, along with diuretics, (3 blockers, or diuretic/β blocker combinations. In addition, based on recent data in patients with diabetes mellitus with or without proteinuria, the use of an ARB (usually with a diuretic) was recommended in addition to a β blocker/diuretic or an ACE inhibitor/diuretic regimen. The authors concluded that a further update of the treatment algorithm may be necessary when the ALLHAT study is completed. This trial has evaluated outcome differences with CCBs, diuretics, and ACE inhibitors; results should be available in late 2002. Drs. Pickering, Weber, and Moser conclude that blood pressure lowering by any means probably accounts for most of the beneficial effect noted in the clinical trials, but as noted, there are some differences in outcome with different medications.