Knowledge of heart attack symptoms in a population survey in the United States: The REACT Trial. Rapid Early Action for Coronary Treatment.

BACKGROUND: Greater use of thrombolysis for patients with myocardial infarction has been limited by patient delay in seeking care for heart attack symptoms. Deficiencies in knowledge of symptoms may contribute to delay and could be a target for intervention. We sought to characterize symptom knowledge. METHODS: Rapid Early Action for Coronary Treatment is a community trial designed to reduce this delay. At baseline, a random-digit dialed survey was conducted among 1294 adult respondents in the 20 study communities. Two open-ended questions were asked about heart attack symptom knowledge. RESULTS: Chest pain or discomfort was reported as a symptom by 89.7% of respondents and was thought to be the most important symptom by 56.6%. Knowledge of arm pain or numbness (67.3%), shortness of breath (50.8%), sweating (21.3%), and other heart attack symptoms was less common. The median number of correct symptoms reported was 3 (of 11). In a multivariable-adjusted model, significantly higher mean numbers of correct symptoms were reported by non-Hispanic whites than by other racial or ethnic groups, by middle-aged persons than by older and younger persons, by persons with higher socioeconomic status than by those with lower, and by persons with previous experience with heart attack than by those without. CONCLUSIONS: Knowledge of chest pain as an important heart attack symptom is high and relatively uniform; however, knowledge of the complex constellation of heart attack symptoms is deficient in the US population, especially in low socioeconomic and racial or ethnic minority groups. Efforts to reduce delay in seeking medical care among persons with heart attack symptoms should address these deficiencies in knowledge.

Angiotensinogen genotype, sodium reduction, weight loss, and prevention of hypertension: trials of hypertension prevention, phase II.

The angiotensinogen gene has been linked to essential hypertension and increased blood pressure. A functional variant believed to be responsible for hypertension susceptibility occurs at position -6 in the promoter region of the gene in which an A for G base pair substitution is associated with higher angiotensinogen levels. To test whether an allele within the angiotensinogen gene is related to subsequent incidence of hypertension and blood pressure response to sustained sodium reduction, 1509 white male and female subjects participating in phase II of the Trials of Hypertension Prevention were genotyped at the angiotensinogen locus. Participants had diastolic blood pressures between 83 and 89 mm Hg and were randomized in a 2x2 factorial design to sodium reduction, weight loss, combined intervention, or usual care groups. Persons in the usual care group with the AA genotype at nucleotide position -6 had a higher 3-year incidence rate of hypertension (44.6%) compared with those with the GG genotype (31.5%), with a relative risk of 1.4 (95% confidence interval [0.87, 2.34], test for trend across all 3 genotypes, P=0.10). In contrast, the incidence of hypertension was significantly lower after sodium reduction for persons with the AA genotype (relative risk=0.57 [0.34, 0.98] versus usual care) but not for persons with the GG genotype (relative risk=1.2 [0.79, 1.81], test for trend P=0.02). Decreases of diastolic blood pressure at 36 months in the sodium reduction group versus usual care showed a significant trend across all 3 genotypes (P=0.01), with greater net blood pressure reduction in those with the AA genotype (-2.2 mm Hg) than those with the GG genotype (+1.1 mm Hg). A similar trend across the 3 genotypes for net systolic blood pressure reduction (-2.7 for AA versus -0.2 mm Hg for GG) was not significant (P=0.17). Trends across genotypes for the effects of weight loss on hypertension incidence and decreases in blood pressure were similar to those for sodium reduction. We conclude that the angiotensinogen genotype may affect blood pressure response to sodium or weight reduction and the development of hypertension.

Prevention and Treatment of Hypertension Study (PATHS): effects of an alcohol treatment program on blood pressure.

OBJECTIVE: To determine whether blood pressure is reduced for at least 6 months with an intervention to lower alcohol intake in moderate to heavy drinkers with above optimal to slightly elevated diastolic blood pressure, and whether reduction of alcohol intake can be maintained for 2 years. DESIGN: A randomized controlled trial. METHODS: Six hundred forty-one outpatient veterans with an average intake of 3 or more alcoholic drinks per day in the 6 months before entry into the study and with diastolic blood pressure 80 to 99 mm Hg were randomly assigned to a cognitive-behavioral alcohol reduction intervention program or a control observation group for 15 to 24 months. The goal of the intervention was the lower of 2 or fewer drinks daily or a 50% reduction in intake. A subgroup with hypertension was defined as having a diastolic blood pressure of 90 to 99 mm Hg, or 80 to 99 mm Hg if recently taking medication for hypertension. RESULTS: Reduction in average weekly self-reported alcohol intake was significantly greater (P<.001) at every assessment from 3 to 24 months in the intervention group vs the control group: levels declined from 432 g/wk at baseline by 202 g/wk in the intervention group and from 445 g/wk by 78 g/wk in the control group in the first 6 months, with similar reductions after 24 months. The intervention group had a 1.2/0.7-mm Hg greater reduction in blood pressure than the control group (for each, P = .17 and P = .18) for the 6-month primary end point; for the hypertensive stratum the difference was 0.9/0.7 mm Hg (for each, P = .58 and P = .44). CONCLUSIONS: The 1.3 drinks per day average difference between changes in self-reported alcohol intake observed in this trial produced only small nonsignificant effects on blood pressure. The results from the Prevention and Treatment of Hypertension Study (PATHS) do not provide strong support for reducing alcohol consumption in nondependent moderate drinkers as a sole method for the prevention or treatment of hypertension.

Randomized trials of sodium reduction: an overview.

We updated a previously published overview of randomized clinical trials testing the effects of reducing sodium intake. We excluded trials that had confounded designs, enrolled preadolescent study populations, tested intakes outside the usual range for the US population, or reported neither systolic nor diastolic blood pressure. Thirty-two trials with outcome data for 2635 subjects were included. Two reviewers abstracted information independently and differences were reconciled. Pooled blood pressure differences between treated and control groups were highly significant for all trials combined and for trials in hypertensive and normotensive subjects pooled separately. The effects on blood pressure of lowering sodium in hypertensive and normotensive subjects, respectively (each trial weighted according to sample size), were -4.8/-2.5 and -1.9/-1.1 mm Hg (systolic/diastolic). Median differences in sodium excretion between sodium-reduction and control groups in these subgroups were -77 and -76 mmol/24 h, respectively. Weighted linear-regression analyses across the trials showed dose responses, which were more consistent for trials in normotensive subjects. These associations were, per 100 mmol Na/24 h, -5.8/-2.5 and -2.3/-1.4 mm Hg in hypertensive and normotensive subjects, respectively. There is no evidence that sodium reduction as achieved in these trials presents any safety hazards. The blood pressure reduction that would result from a substantial lowering of dietary sodium in the US population could reduce cardiovascular morbidity and mortality.

Dietary calcium and blood pressure: a meta-analysis of randomized clinical trials.

PURPOSE: To assess the effect of dietary calcium supplementation on blood pressure. DATA SOURCES: Published reports of trials studying the effect of dietary calcium supplementation on blood pressure were identified by a search of previous reviews, a MEDLINE search, a manual review of journal articles, and a review of abstracts from scientific meetings. STUDY SELECTION: Randomized clinical trials in which dietary calcium intake varied by intervention group were selected. Multifactorial trials were not included. DATA SYNTHESIS: Data from 28 active treatment arms or strata from 22 randomized clinical trials were pooled using a weighted average method, with weights proportional to the inverse of the variance of the treatment effect. The total sample comprised 1231 persons. Because trials of both normotensive and hypertensive persons were included, subgroup analyses could be done. Pooled estimates of the effect of calcium supplementation on blood pressure were -0.18 mm Hg for diastolic blood pressure (95% CI, -0.75 to 0.40 mm Hg) and -0.89 mm Hg for systolic blood pressure (CI, -1.74 to -0.05 mm Hg). Pooled estimates for systolic blood pressure were -0.53 mm Hg (CI, -1.56 to 0.49 mm Hg) for trials of normotensive persons and -1.68 mm Hg (CI, -3.18 to -0.18 mm Hg) for trials of hypertensive persons. Diastolic blood pressure was not significantly affected in either subgroup. CONCLUSION: The pooled estimate shows a statistically significant decrease of systolic blood pressure with calcium supplementation, both for hypertensive persons and for the overall sample. However, the effect is too small to support the use of calcium supplementation for preventing or treating hypertension.

Epidemiologic association between dietary calcium intake and blood pressure: a meta-analysis of published data.

The objectives of the study were to assess whether the epidemiologic data support a relation between dietary calcium intake and blood pressure, to obtain a quantitative estimate of the difference in blood pressure for a given difference in dietary calcium intake, and to assess the public health implications. A meta-analysis of published data (January 1983 to November 1993) that investigated the association between dietary calcium intake and blood pressure in different populations around the world was performed. Of 63 population studies identified, 23 were suitable for a quantitative overview (total n = 38,950). Unadjusted regression coefficients (95% confidence intervals) were obtained. Pooled unadjusted regression coefficients (95% confidence intervals) were then computed weighting each individual study by the inverse of its variance. Tests of heterogeneity and sensitivity analysis were carried out, and the possibility of publication bias was assessed. The regression coefficients ranged between -9.40 and 1.63 mmHg/100 mg calcium for systolic blood pressure and between -4.90 and 0.47 for diastolic blood pressure. In men (11 studies, n = 7,271), the pooled regression coefficients were -0.010 and -0.009 mmHg/100 mg calcium for systolic and diastolic pressures, respectively (p < 0.001 and p < 0.05). In women (six studies, n = 8,507), they were -0.15 and -0.057 mmHg/100 mg calcium (p < 0.001 and p < 0.02), and in men and women combined (six studies, n = 23,172 for systolic pressure and four studies, n = 3,215 for diastolic pressure) they were -0.061 and -0.061 mmHg/100 mg calcium (p < 0.001 and p < 0.05). In those studies that used the 24-hour recall method, the pooled regression coefficients were -0.06 and -0.09 mmHg/100 mg calcium (p < 0.005 and p = 0.07), whereas in those that used the food frequency questionnaire, they were -0.15 and -0.05 mmhg/100 mg calcium (p < 0.001 and p < 0.03). These data are consistent with an inverse association between dietary calcium intake and blood pressure. However, the size of the estimate, the observed heterogeneity among studies, and the possibility of confounding and publication bias indicate that an increase in calcium intake above the Recommended Dietary Allowance is not recommended at population level for the prevention and treatment of high blood pressure.

Recruitment for phase II of the Trials of Hypertension Prevention. Effective strategies and predictors of randomization. Trials of Hypertension Prevention (TOHP) Collaborative Research Group.

Phase II of the Trials of Hypertension Prevention is a multicenter, randomized, controlled trial designed to determine the efficacy of weight loss and reduction of sodium intake for lowering blood pressure and incidence of hypertension among persons with high-normal levels of blood pressure. The 2 x 2 factorial study design includes weight loss alone, restricted sodium intake alone, the combination of weight loss and sodium restriction, and a control group. Nine clinical centers used a variety of recruitment strategies to enroll 2382 participants over 17 months, which exceeded the sample size goal of 2250. Among randomized participants, 21% were minorities and 34% were women. Overall, direct mail generated the most randomized participants (73%), followed by community screening (12%) and media advertisement (11%). Referrals from community health care providers yielded few participants. Prescreening improved overall efficiency and reduced costs. Participants who were more likely to drop out voluntarily during the three-visit screening regimen tended to be younger, single, male, smokers, and less educated.

Prevention and Treatment of Hypertension Study (PATHS). Rationale and design.

Alcohol consumption has been recognized as an important correlate of blood pressure in many epidemiologic studies, but few interventional studies have been conducted to examine the effect of a reduction in alcohol intake on blood pressure. Because these studies have usually included few subjects and been of short duration, the National Heart, Lung, and Blood Institute (NHLBI), the National Institute on Alcohol Abuse and Alcoholism (NIAAA), and the Veterans Affairs (VA) Cooperative Studies Program have initiated a randomized, controlled, multicenter trial to determine whether blood pressure and left ventricular mass are lowered over 6 months of alcohol moderation in non-dependent moderate to heavy drinkers (three or more drinks per day average but not alcohol dependent) with above-average normal (80 to 89 mm Hg) and mildly hypertensive (90 to 99 mm Hg) levels of diastolic blood pressure, and whether a reduction in alcohol intake can be maintained for 2 years. Eligible veterans are randomized to either an alcohol reduction intervention or a control observation group at seven clinical sites. The projected sample size is 580 participants. Alcohol intake is assessed by self-report using a retrospective diary (Chronological Drinking Record) and by various biochemical markers, including apolipoproteins, HDL cholesterol (and subfractions), and carbohydrate deficient transferrin, analyzed at a central laboratory. The alcohol intervention technique is a cognitive-behavioral program, the intensive phase of which consists of six counseling sessions over 3 months. Echocardiograms are obtained at baseline and 6 months after randomization. This trial has important implications for both the prevention and treatment of hypertension.

Hypertension treatment trials and stroke occurrence revisited. A quantitative overview.

To provide further understanding of the decline in stroke mortality in the United States, data from 16 randomized controlled trials of hypertension treatment and stroke published to date are pooled. The overall weighted average blood pressure reduction was 13/6 mm Hg. The pooled odds ratio was 0.61 (95% confidence interval: 0.55, 0.68), indicating approximately a 39% (32 to 45%) reduction in stroke occurrence. Percent reduction was somewhat higher in studies of mild-moderate hypertension (47%) and somewhat lower in studies of the elderly (35%). There was no differential effect by gender (reductions of 37% for women, 34% for men) or by race (32% for blacks, 37% for whites). The magnitudes of reductions for fatal (41%) and nonfatal (37%) strokes, and for diuretics and beta-blockers (odds ratio diuretic versus beta-blocker, 0.86; 95% CI: 0.69, 1.08) were similar. Implications for the decline in stroke mortality in the United States are discussed.