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Background: As early as the 1920's, researchers noted a relationship between caloric restriction, weight loss and a decreased incidence of hypertension (Terry 1922, Preble 1923, Bauman 1928, Master 1929). In 1988 a meta-analysis of aggregate data from 12 prospective studies, including 5 randomized controlled trials (RCTs), found that on average each 1 kilogram decrease in body weight in obese hypertensive patients was associated with a 2.4 mm Hg systolic and 1.5 mm Hg diastolic decrease in blood pressure (Staessen 1988). Blood pressure reductions were not dependent upon degree of baseline obesity.This review aims to: 1) update the work of Staessen (Staessen 1988) looking specifically at randomized controlled trials, and 2) assess whether any of the trials assess effects of weight-reducing diets on clinical outcomes such as quality of life, morbidity or mortality., Objectives: Evaluate whether weight-loss diets are more effective than regular diets or other antihypertensive therapies in controlling blood pressure and preventing morbidity and mortality in hypertensive adults., Search Strategy: MEDLINE and The Cochrane Library were searched through November 1997. Trials known to experts in the field were included through June 1998., Selection Criteria: For inclusion in the review, trials were required to meet each of the following criteria: 1) randomized controlled trials with one group assigned to a weight-loss diet and the other group assigned to either normal diet or antihypertensive therapy; 2) ambulatory adults with a mean blood pressure of at least 140 mm Hg systolic and/or 90 mm Hg diastolic; 3) active intervention consisting of a calorie-restricted diet intended to produce weight loss (excluded studies simultaneously implementing multiple lifestyle interventions where the effects of weight loss could not be disaggregated); and 4) outcome measures included weight loss and blood pressure., Data Collection and Analysis: Studies were dual abstracted by two independent reviewers using a standardized form designed specifically for this review. The primary mode of analysis was qualitative; graphs of effect sizes for individual studies were also used., Main Results: Eighteen trials were found. Only one small study of inadequate power reported morbidity and mortality outcomes. None addressed quality of life or general well being issues. In general, participants assigned to weight-reduction groups lost weight compared to control groups.Six trials involving 361 participants assessed a weight-reducing diet versus a normal diet. The data suggested weight loss in the range of 4% to 8% of body weight was associated with a decrease in blood pressure in the range of 3 mm Hg systolic and diastolic. Three trials involving 363 participants assessed a weight-reducing diet versus treatment with antihypertensive medications. These suggested that a stepped-care approach with antihypertensive medications produced greater decreases in blood pressure (in the range of 6/5 mm Hg systolic/diastolic) than did a weight-loss diet. Trials that allowed adjustment of participants' antihypertensive regimens suggested that patients required less intensive antihypertensive drug therapy if they followed a weight-reducing diet. Data was insufficient to determine the relative efficacy of weight-reduction versus changes in sodium or potassium intake or exercise., Authors' Conclusions: Weight-reducing diets in overweight hypertensive persons can affect modest weight loss in the range of 3-9% of body weight and are probably associated with modest blood pressure decreases of roughly 3 mm Hg systolic and diastolic. Weight-reducing diets may decrease dosage requirements of persons taking antihypertensive medications.

Objective: To conduct a systematic review of evidence relating to management of mild chronic hypertension during pregnancy, including associated risks, benefits, and harms of treatment with antihypertensive agents, nonpharmacologic measures, and aspirin and benefits of various monitoring strategies., Data Sources: Using four broad search strategies, we searched English and non-English-language citations in 16 electronic databases from their inception to February 1999 and consulted relevant textbooks, references, and experts., Study Selection: Reviewers screened 6228 abstracts and found 215 articles that met multiple prespecified patient selection, study population, and design criteria., Tabulation, Integration, and Results: Forty-six studies consistently showed that chronic hypertension triples the risk for perinatal mortality (odds ratio [OR] 3.4; 95% confidence interval [CI] 3.0, 3.7) and doubles the risk for placental abruption (OR 2.1; 95% CI 1.1, 3.9). Thirteen small, randomized controlled trials had inadequate power to rule in or rule out moderate-to-large (20%-50%) benefits of antihypertensive treatment. Possible adverse effects were fetal renal failure when angiotensin-converting enzyme inhibitors are used in the second or third trimester and growth restriction when atenolol is used early in pregnancy. Trials showed that aspirin neither reduces nor increases perinatal and maternal morbidity, but they did not rule out possible small-to moderate beneficial or adverse effects. No studies provide guidance on benefits or consequences of various nonpharmacologic therapies or monitoring strategies., Conclusion: Mild chronic hypertension is associated with increased maternal and fetal risks. Beneficial treatment and monitoring regimens are not clear, but some treatments, such as angiotensin-converting enzyme inhibitors, are best avoided.

Objectives: Evaluate whether weight-loss diets are more effective than regular diets or other antihypertensive therapies in controlling blood pressure and preventing morbidity and mortality in hypertensive adults., Search Strategy: MEDLINE and The Cochrane Library were searched through November 1997. Trials known to experts in the field were included through June 1998., Selection Criteria: For inclusion in the review, trials were required to meet each of the following criteria: 1) randomized controlled trials with one group assigned to a weight-loss diet and the other group assigned to either normal diet or antihypertensive therapy; 2) ambulatory adults with a mean blood pressure of at least 140 mm Hg systolic and/or 90 mm Hg diastolic; 3) active intervention consisting of a calorie-restricted diet intended to produce weight loss (excluded studies simultaneously implementing multiple lifestyle interventions where the effects of weight loss could not be disaggregated); and 4) outcome measures included weight loss and blood pressure., Data Collection and Analysis: Studies were dual abstracted by two independent reviewers using a standardized form designed specifically for this review. The primary mode of analysis was qualitative; graphs of effect sizes for individual studies were also used., Main Results: Eighteen trials were found. Only one small study of inadequate power reported morbidity and mortality outcomes. None addressed quality of life or general well being issues. In general, participants assigned to weight-reduction groups lost weight compared to control groups. Six trials involving 361 participants assessed a weight-reducing diet versus a normal diet. The data suggested weight loss in the range of 4% to 8% of body weight was associated with a decrease in blood pressure in the range of 3 mm Hg systolic and diastolic. Three trials involving 363 participants assessed a weight-reducing diet versus treatment with antihypertensive medications. These suggested that a stepped-care approach with antihypertensive medications produced greater decreases in blood pressure (in the range of 6/5 mm Hg systolic/diastolic) than did a weight-loss diet. Trials that allowed adjustment of participants' antihypertensive regimens suggested that patients required less intensive antihypertensive drug therapy if they followed a weight-reducing diet. Data was insufficient to determine the relative efficacy of weight-reduction versus changes in sodium or potassium intake or exercise., Reviewer's Conclusions: Weight-reducing diets in overweight hypertensive persons can affect modest weight loss in the range of 3-9% of body weight and are probably associated with modest blood pressure decreases of roughly 3 mm Hg systolic and diastolic. Weight-reducing diets may decrease dosage requirements of persons taking antihypertensive medications.

Objective: To estimate morbidity and mortality benefits of drug therapy for hypertensive elderly subjects, compare these benefits with effects in younger subjects, and provide a framework for generalizing results derived from trials to actual patients., Data Sources: A literature search using MEDLINE from 1966 to 1993, references from reviews and trial articles, and experts., Study Selection: Randomized trials lasting at least 1 year that evaluated effects of drug treatment on morbidity and mortality outcomes in hypertensive persons., Data Extraction: Four independent reviewers appraised protocol characteristics and quality of selected trials., Data Synthesis: There were 13 trials involving 16,564 elderly persons (age 60 years and older). The prevalence of cardiovascular risk factors, cardiovascular disease, and competing comorbid diseases was lower among trial participants than the general population of hypertensive elderly persons. When the six large high-quality trials were combined, trial results showed 43 subjects (95% confidence interval [CI], 31 to 69) and 61 subjects (95% CI, 39 to 141) needed to be treated for 5 years to prevent one cerebrovascular event and one coronary heart disease event, respectively. Including the other seven trials did not change the results significantly. Only 18 subjects (95% CI, 14 to 25) needed to be treated to prevent one cardiovascular event (cerebrovascular or cardiac). Twelve trials in primarily younger and middle-aged adults involved approximately 33,000 persons. For all outcomes except cardiac mortality, two to four times as many of the younger subjects as the older subjects needed to be treated for 5 years to prevent morbid and mortal events. No significant effect on cardiac mortality was seen among younger subjects, while 78 older subjects (95% CI, 50 to 180) needed to be treated to prevent a fatal cardiac event., Conclusions: Randomized trials demonstrate that treating healthy older persons with hypertension is highly efficacious. Five-year morbidity and mortality benefits derived from trials are greater for older than younger subjects. Extrapolating benefits from trials to individual patients is difficult, but should take into account multiple issues including the patient's risk factors, preexisting cardiovascular disease, and competing comorbid illnesses.

We critically appraised the medical literature to evaluate whether there is a point beyond which blood pressure reduction in hypertensive subjects is no longer beneficial and possibly even deleterious. Thirteen studies that stratified cardiovascular outcomes by level of achieved blood pressure in treated hypertensive subjects who had been followed up for at least 1 year were critiqued by four independent reviewers. Data addressing population, protocol, and methodological characteristics were evaluated. Studies did not show a consistent J-shaped relationship between treated blood pressure and stroke, but they did demonstrate a consistent J-shaped relationship for cardiac events and diastolic blood pressure. The beneficial therapeutic threshold point was 85 mm Hg. We conclude that low treated diastolic blood pressure levels, ie, below 85 mm Hg, are associated with increased risk of cardiac events.