Current issues of ACP Journal Club are published in Annals of Internal Medicine


Therapeutics

Weight reduction and sodium reduction caused small decreases in blood pressure in adults with high-normal blood pressure

ACP J Club. 1992 July-Aug;117:2. doi:10.7326/ACPJC-1992-117-1-002


Source Citation

The Trials of Hypertension Prevention Collaborative Research Group. The effects of nonpharmacologic interventions on blood pressure of persons with high normal levels. Results of the Trials of Hypertension Prevention, phase 1. JAMA. 1992 Mar 4;267:1213-20.


Abstract

Objective

To test the effect on blood pressure (BP) of nutritional supplements and lifestyle interventions in adults with high-normal BP levels.

Design

Randomized controlled trial of 7 interventions; the 4 nutritional supplements were masked and placebo controlled.

Setting

10 university clinics tested either 2, 4, or 6 interventions.

Patients

Men and women, aged 30 through 54 years with diastolic (D) BP from 80 to 89 mm Hg and who had not taken antihypertensive drugs for the previous 2 months, were eligible. Reasons for exclusion were cardiovascular or other disabling diseases; requirements for, or contraindications to, any of the interventions; and likelihood of poor compliance. 2182 of 16 821 persons who were screened entered the trial. 70% were men; 82%, white; and 15%, black. All patients were included in intention-to-treat analysis; 96% had ≥ 1 follow-up BP measurement.

Intervention

Lifestyle interventions, given for 18 months, comprised group education and individual counseling sessions on either weight reduction, dietary sodium restriction, or stress management; the control group received usual care. Dietary supplements or placebo were given for a period of 6 months. They were calcium, 25 mmol/d (l g/d), or magnesium, 15 mmol/d (360 mg/d), and, after a washout period, potassium chloride, 60 mmol/d, or fish oil, 6 g/d. Compliance was measured.

Main outcome measures

The mean change in DBP and systolic (S) BP from baseline between each group and its control. BP was measured by blinded observers on follow-up visits at 3 and 6 months for the dietary supplement groups and, in addition, at 12 and 18 months for the lifestyle change groups.

Main results

BP was reduced for the sodium restriction group by 1.7/0.9 (SBP/DBP in mm Hg) and, for the weight reduction groups, by 2.9/2.3 (P < 0.05 for all comparisons at the end of the study). BP changes in the stress management group and the nutritional supplement groups did not differ from their controls, except for an unsustained DBP reduction of 1.2 mm Hg for the potassium group at 3 months (P = 0.04).

Conclusion

Among 7 nonpharmacologic interventions, only weight reduction and reduced sodium intake lowered high-normal blood pressure in otherwise healthy adults.

Source of funding: National Heart, Lung, and Blood Institute.

Address for article reprint: Dr. J.A. Cutler, Room 604, Federal Building, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.


Commentary

Nonpharmacologic treatment of hypertension has clinical appeal because it potentially avoids the side effects and cost of medications. Many lifestyle changes and nutritional supplements have been proposed to lower BP; weight loss and dietary sodium restriction have reduced BP or medication requirements among patients with mild-to-moderate hypertension (1).

This well-designed study evaluates whether primary prevention of hypertension is possible in patients with high-normal BP. The answer is a qualified yes for 2 of the interventions studied: Those patients who received dietary counseling for 18 months lost weight (mean net reduction, 3.9 kg) and those who reduced sodium (mean, 44 mmol/d) reduced systolic and diastolic BP by 1 to 3 mm Hg. Further, patients in the weight-loss group were less likely to develop overt hypertension during the study. The other 5 interventions had little effect on BP despite reasonable compliance with clinically feasible regimens.

There are 2 limitations to the clinical usefulness of the study results. First, its findings are mostly applicable to motivated patients willing to participate in intensive educational efforts. Second, the duration of benefit and the costs of the programs require further evaluation. On the positive side, the ability of weight loss to prevent or defer the development of hypertension has important public health implications, and the potential benefit of combining nonpharmacologic measures represents a promising area for continued research. Finally, this study bolsters existing evidence that weight loss and, to a lesser extent, sodium restriction are important components of clinical efforts to prevent or control hypertension.

John F. Steiner, MD, MPH
University of ColoradoDenver, Colorado, USA

John F. Steiner, MD, MPH
University of Colorado
Denver, Colorado, USA


Reference

1. MacMahon S, Cutler J, Brittain E, Higgins M. Obesity and hypertension: epidemiological and clinical issues. Eur Heart J. 1987;8(Suppl B):57-70.