Flora C. Gosch

Nutritional Therapy for High Blood Pressure: Final Report of a Four-Year Randomized Controlled Trial— The Hypertension Control Program

A four-year trial assessed whether less severe hypertensives could discontinue antihypertensive drug therapy, using nutritional means to control blood pressure. Randomization was to three groups: group 1--discontinue drug therapy and reduce overweight, excess salt, and alcohol; group 2--discontinue drug therapy, with no nutritional program; or group 3--continue drug therapy, with no nutritional program. In groups 1 and 2 patients resumed drug therapy if pressure rose to hypertensive levels. Loss of at least 4.5 kg (10 + lb) was maintained by 30% of group 1, with a group mean loss of 1.8 kg (4 lb); sodium intake fell 36% and modest alcohol intake reduction was reported. At four years, 39% in group 1 remained normotensive without drug therapy, compared with 5% in group 2. Study findings demonstrated that nutritional therapy may substitute for drugs in a sizable proportion of hypertensives or, if drugs are still needed, can lessen some unwanted biochemical effects of drug treatment.

Do hypertensive patients have a different diurnal pattern of electrolyte excretion

Studies generally indicate that excretion of sodium, potassium, and water is greater during the day than during the night. To determine whether hypertensive patients exhibit this same pattern of excretion, diurnal variations in excretion of sodium, potassium, creatinine, and water were examined in 107 hypertensive men and women from a clinical trial on control of hypertension by nonpharmacological means--the Hypertension Control Program. Each participant provided two carefully timed 24-hour urine collections divided into daytime and overnight specimens. The median ratios of 24-hour to 8-hour overnight excretion were 2.84, 3.95, 2.99, and 2.77 for sodium, potassium, creatinine, and water, respectively. Thus, more than half of this hypertensive group exhibited a greater rate of sodium and water excretion during sleep than during daytime hours, a reversal of the usual pattern. When the group was subdivided based on age, sex, race, trial randomization group, use of diuretics, and hypertension severity, women had significantly lower ratios of 24-hour to overnight excretion for sodium and water than men and blacks had significantly lower 24-hour to overnight ratios for water and potassium than whites. When the 24-hour to overnight ratios for these hypertensive patients were compared with those for a group of 30 men and women with high-normal blood pressure, those with high-normal blood pressure had significantly larger ratios for sodium and water excretion than the hypertensive group. The results of this study suggest that hypertensive patients may have a different diurnal pattern of sodium and water excretion than normotensive subjects and that further research is needed to clarify this issue.

ADHERENCE AND BLOOD-PRESSURE RESPONSE TO HYPERTENSION TREATMENT

2 years of experience in the first phase of a large cooperative national hypertension programme yielded data indicating that a good level of patient adherence can be achieved and that satisfactory blood-pressure control can be maintained long term. For 116 participants, all employed persons, dropout in the first year was 20% but only 3% dropped out in the second year. At the second annual examination, 82% of those still in the programme had diastolic pressures under 90 mm Hg, with an average reduction of 18 mm Hg. Thus, nearly two-thirds (64%) of all patients originally enrolled were both active and with normal levels of blood-pressure after two years. Only 18% of active programme-treated patients had diastolic pressure 90 mm Hg or higher at the second anniversary in contrast with 33% of patients referred to their own doctors. In programme-treated patients, standard medication was used; diuretics effectively lowered blood-pressure in a third of patients, and diuretics plus reserpine were effective for another 20%. Special features of the programme included assistance to physicians by health counsellor therapists. Methods for achieving a high adherence-rate and satisfactory blood-pressure control probably have wider applicability.

Nonpharmacological control of hypertension

Ability to safely withdraw well-controlled mild hypertensives from drugs is being tested in a three-group randomized trial. Group I (intervention) was removed from drugs after the first 2 months of nutrition counseling. Counseling is continuing through the remaining years of the trial to achieve a minimum weight loss of 10 lb if overweight, reduction of sodium intake to less than 1,800 mg, and reduction of alcohol intake to not more than two drinks per day. Group II (the first control group) was also removed from drugs to see if previous long-term blood pressure control had a carryover effect without dietary change. Blood pressure is monitored frequently in both groups, with return to drug treatment in the event of specified blood pressure rise. Group III (the second control group) has remained on drugs for comparison of blood pressure and biochemical variables. In Group I mean 30-month weight loss was 8 lb, with 35% losing 10+ lb; sodium intake was reduced by 38%. Blood pressure control without drugs was maintained for 47% of Group I patients but only 16% of group II patients (P less than 0.05). These findings indicate it may be possible, after establishing good blood pressure control, to maintain control in a sizable proportion without medication, when reduction of weight, sodium, and alcohol intake is achieved.

Initial antihypertensive drug therapy: Alpha blocker or diuretic: Interim report of a randomized, controlled trial

A two-center, randomized, controlled trial designed to evaluate and compare an alpha blocker and a diuretic as initial antihypertensive drug treatment is currently in progress. Approximately 100 men and women, aged 30 to 69 years, are being randomly assigned to treatment with either of these two agents. If diastolic blood pressure is not reduced to its target level and is 85 mm Hg or higher, the alternate agent is added. The alternate agent is substituted if a patient does not tolerate the assigned agent. This preliminary report presents data concerning 62 patients who completed at least three of the planned 12 months of drug treatment. At that point, the alpha blocker prazosin and the diuretic hydrochlorothiazide were similar in their ability to lower the average diastolic blood pressure to normal levels. Serum total cholesterol and triglyceride levels declined in prazosin-treated patients but increased in hydrochlorothiazide-treated patients, a difference that was statistically significant. No significant weight change, a possible confounding variable, occurred in either group. More patients were unable to tolerate prazosin than were unable to tolerate hydrochlorothiazide (10 of 30 receiving prazosin, compared with three of 32 receiving hydrochlorothiazide). For those able to continue with prazosin, the favorable lipid response appears to be an asset in regard to reducing possible atherogenic effects of treatment.

Initial antihypertensive drug therapy. Final report of a randomized, controlled trial comparing alpha-blocker and diuretic.

We compared the effect on serum Upids of an α-blocker (prazosin) and a diuretic (hydrochlorothiazide) used as initial antihypertensive drug treatment for 102 men and women with less severe hypertension (average entry blood pressure, 148/97 mm Hg, with no major organ system damage). A two-center trial randomized patients to treatment with either prazosin or hydrochlorothiazide; the alternate drug was added if adequate blood pressure control was not achieved with the originally assigned drug, and patients were removed from any drug they were not able to tolerate. After an average of 40 weeks on the assigned drug regimen, a decline was observed in prazosin-treated patients in both serum total cholesterol (−9.3 mg/dl) and serum triglycerides (−33.9 mg/dl). In contrast, an increase in both these Upids was seen in hydrochlorothiazide-treated patients (+5.0 mg/dl for serum total cholesterol and + 18.6 mg/dl for serum triglycerides). The net trial differences between the groups were 14.3 mg/dl for total cholesterol and 52.5 mg/dl for triglycerides, in favor of prazosin (p < 0.001 for both comparisons). These differences in Upids between the two groups persisted into the second year of the trial (p < 0.05). There were no significant differences between the drug groups in regard to the level of high density Upoprotein cholesterol or its subtractions or low density Upoprotein cholesterol. In patients who required a combination of the two drugs to achieve blood pressure control, the a-blocker diminished or eliminated the Upid-raising effects of the diuretic. Both drugs were similar in their ability to control the elevation of diastoUc pressure. More patients were unable to tolerate prazosin than were unable to tolerate hydrochlorothiazide. For those able to continue with prazosin, either as the single initial treatment or in combination with hydrochlorothiazide, the lipki response appeared to be an asset in regard to avoiding possible atherogenic effects of treatment and thereby possibly reducing coronary risk.

Cardiovascular responses to exercise of participants in a trial on the primary prevention of hypertension.

The Chicago study on the Primary Prevention of Hypertension (PPH) is a long-term, randomized controlled trial to test the ability of nutritional-hygienic non-pharmacological methods to prevent high blood pressure in hypertension-prone persons aged 30-44 years at entry. In order to assess the effects of this programme on cardiovascular responses to exercise, graded submaximal treadmill exercise tests were done serially at baseline and during the trial. Eighty-five participants (48 intervention, 37 control) successfully finished baseline and 2- or 3-year follow-up tests. The exercise maximal double product (DP) [systolic blood pressure (SBP) X heart rate/100] was significantly lower for both groups at 2-3 years compared with baseline, and this reduction was greater for the intervention than for the control group (-27.1 versus -15.5; P = 0.055). Similarly, improvement in maximal increase in DP (maximal DP minus standing DP) was greater for the intervention than the control group (-22.1 versus -9.9, respectively; P = 0.068). The lowest DP during the 6-min recovery period and the debt DP (lowest recovery DP minus standing DP) fell significantly at 2-3 years compared with baseline in the intervention but not in the control group (-12.7 versus -4.8; P = 0.017 for the first index, and -7.7 versus +0.9; P = 0.029 for the second). These interim data from this trial indicate that its intervention procedures favourably influenced cardiovascular responses to graded submaximal exercise.

Dietary salt and blood pressure.

Abstract Research evidence on the role of dietary sodium in the etiology and pathogenesis of hypertension is briefly reviewed. This matter is assuming new importance at present, given new data on the efficacy of normalization of blood pressure for adults with so-called “mild” hypertension (average diastolic 90–104 mm Hg), hence the need for safe nutritional-hygienic alternatives to years-long drug treatment for millions of people with such hypertension. Two trials by the authors deal with some unresolved questions in this area. The first, a preliminary study, involved 21 lacto-ovo-vegetarian high school students living in a boarding school. With decrease in daily Na intake from 216 to 72 meq for the experimental compared with the control group, red blood cell Na concentration was significantly lower in the former; systolic pressure was slightly but not significantly lower. The second trial, the Primary Prevention of Hypertension, involves over 200 hypertension-prone persons aged 30–44, and explores the ability in the experimental group to reduce blood pressure and prevent development of hypertension by safe nutritional-hygienic means (weight reduction, dietary Na decrease, avoidance of excess alcohol, rhythmic exercise). Initial results at 6 months are presented. Trials on the prevention and control of hypertension by nonpharmacologic means, including reduced Na intake, and involving analyses of the interrelationships among dietary Na, other dietary factors, Na metabolism, and blood pressure in samples from different population strata, are an important present-day research need.

Sodium-lithium countertransport and systolic blood pressure response to exercise

This study examined the relationship between erythrocyte sodium-stimulated lithium countertransport (Na-Li CT) and systolic blood pressure (SBP) response to exercise in 22 white normotensive men (mean age 40.6 years) completing a submaximal (85% of target heart rate) graded exercise tolerance test. These men were assessed to be at risk of hypertension on the basis of a high normal diastolic blood pressure (DBP; 80-89 mmHg), being overweight and having a rapid resting pulse rate. Na-Li CT was positively and significantly associated with the maximal SBP reached during exercise (P less than 0.01) and the lowest SBP achieved during post-exercise supine rest (P less than 0.01). The relationship with resting blood pressure was not significant. Standing DBP was the only resting blood pressure measurement significantly associated with Na-Li CT (P less than 0.05). We found an association between Na-Li CT, a membrane sodium transport system associated with blood pressure and hypertension, and the maximal SBP reached during exercise, a blood pressure measurement predictive of future hypertension, in people with normotensive resting blood pressure. This suggests that altered membrane sodium transport may occur before the establishment of hypertension, and supports the possibility that Na-Li CT may be a risk factor for this disease.