Practice-changing trials in blood pressure control
Researchers in four trials presented their findings in Sunday’s Late-Breaking Science session, “Practice-Changing Trials in Blood Pressure Control.” They found:
- Daily oral KCl supplementation reduced blood pressure with no salt or other dietary changes.
- Economic incentives improved medication adherence with similar effects on blood pressure compared to the control group.
- Healthy eating patterns can reduce blood pressure, LDL-C in urban food desert populations.
- At-home blood pressure monitoring reduced population-wide blood pressure in rural Chinese villages.
Oral KCl supplementation reduced blood pressure without cutting NaCl intake
Adding oral potassium supplements to the diet can reduce systolic blood pressure approximately 8 mmHg without altering dietary salt intake. Oral potassium chloride (KCl) supplements also reduced sodium concentrations in both blood and muscle tissue with no change in dietary sodium consumption.
Jens Marc Titze, MD
The See Sodium to Treat (SSTT) trial was designed in response to earlier results from a randomized controlled potassium substitution trial in the Salt Substitute and Stroke Study (SSaSS) in rural China. Using potassium-enriched table salt reduced the incidence of cardiovascular disease and mortality, but it was not clear whether the benefit was attributable to salt reduction, potassium enrichment or both. SSTT was designed to isolate potassium intake as a potential causative factor.
The prospective open label trial enrolled 40 patients in Singapore, said Hien Tran, MD, National University of Singapore. All had arterial hypertension, a combination of essential hypertension 42.5%) or hyperaldosteronism (57.5%). Patients received personalized oral KCl supplementation based on baseline serum K+ levels targeting >4 mmol/L. Personalized daily KCl dosage ranged from 1.2 g / day up to 9.0 g / day, depending on the participant’s blood K+ levels.
The primary endpoint was muscle Na+ content in patients with hyperaldosteronism compared to essential hypertension at baseline. Secondary endpoints included changes in muscle Na+ content, changes in blood Na+ and K+, and systolic blood pressure after six to nine weeks of oral KCl supplementation.
Hien Tran, MD
Oral KCl supplementation showed significant increases in blood and serum K+ concentration and urinary K+ excretion with no change in urinary Na+ in both groups. Blood Na+ concentration was reduced, and the Na+/K+ ratio fell in both groups, as did muscle Na+ content and blood pressure.
“Hypertension is a potassium-sodium redistribution disorder,” Hien said. “We can treat it by taking salt away or by adding potassium. Potassium supplementation is feasible and costs about US$30 per patient per year. We should be considering potassium supplementation for hypertension.”
Economic intervention improves blood pressure medication adherence but did not lead to better blood pressure control
One of the largest mobile behavioral health economic interventions in blood pressure doubled adherence to antihypertensive medications over six months. But improved adherence did not lead to better systolic blood pressure control.
John A. Dodson, MD, MPH
BETTER-BP randomized 400 participants with hypertension who were prescribed at least one antihypertensive medication at three safety net clinics in New York City. All had systolic blood pressure of >140 mmHg within the prior year and self-identified as missing at least two medication doses of the past seven. All participants had adherence monitoring via an electronic medication container that recorded each time the container was opened. Participants had a median age of 57 years, 60.5% were female, 61.5% Hispanic and 20.3% non-Hispanic Black.
Those in the intervention arm (265 participants) were enrolled in an incentive lottery using SMS messaging. The lottery included chances to win a variable dollar amount award daily for the six-month intervention period. The lottery included a “regret” component by which participants who would have won had they been adherent that day were notified of their loss.
Those in the control arm (135 participants) continued usual care.
The primary clinical endpoint was change in systolic blood pressure at six months, the primary process endpoint was antihypertensive medication adherence >80% at six months. Secondary endpoints included medication adherence at 12 months.
At six months, participants in the intervention arm were twice as likely to achieve adequate adherence, 71%, vs. 34% for the control arm, adjusted risk ratio (ARR) 2.04 (95% CI: 1.58 to 2.63). But there was no significant change in systolic blood pressure, -6.7 mmHg in the intervention arm vs. -5.8 mmHg control, p=0.62.
At 12 months, adherence was similar in both arms, 31% for intervention vs. 26% control, ARR 1.17 (95% CI: 0.83 to 1.65). Dodson noted the average winnings for those in the intervention arm were $212 over six months (range: $10 to $515).
“One of the take-home messages is that there has been a lot of enthusiasm in the literature about behavioral economics in health care,” he said. “To my knowledge, these approaches haven’t been adopted widely by health systems because they have been difficult to deploy these approaches at scale and be cost-effective.”
BETTER-BP was published simultaneously in JACC.
DASH-type diet reduces blood pressure, LDL-cholesterol in urban population
The GoFresh trial found that providing fresh, nutritious food choices to families living in food deserts reduced blood pressure and lipid levels in just three months. A six-month follow-up period found that the improvements in cardiovascular risk factors were not maintained without continued access to fresh foods.
Stephen P. Juraschek, MD, PhD
The prospective prevention study randomized adults in Boston communities to receive either free, home-delivered weekly groceries with the help of weekly counseling by a registered dietitian or $500 per month to spend as they wished with a nutrition handout. All households were in food deserts, areas with limited or poor access to grocery stores and other retail fresh food sellers.
Participants had systolic blood pressure 120 to <150 mmHg at baseline and lived in households with up to five additional individuals. Participants all self-identified as Black. Some were born in the U.S., some were immigrants from Caribbean countries, and others from various parts of Africa.
“Our goal was to have something feasible in the real world,” Juraschek said. “Cultural differences for different food types, different fruits and vegetables differed between groups and within groups. Having multiple grocery options allowed us to try to provide items that were important to people and their families and that were DASH-concordant.”
Nutrition recommendations were based on four DASH principles:
- Prepare food at home and avoid using salt as seasoning.
- Prepare a grocery list with a 2:1 potassium to sodium ratio.
- Restrict saturated fat to less than 7% of total calories.
- Balance foods in accordance with DASH: 60% fruits and vegetables; 20% whole grains; 8% nuts, seeds and legumes; and 12% low-fat dairy.
Lean animal protein was also allowed, but candies and other sweets could not be ordered.
The grocery intervention reduced systolic blood pressure by 5.7 mmHg, GoFresh also reduced LDL-cholesterol 8 mg/dL.
“This is a very clear strategy that can work for people in the real world,” Juraschek said. “We are looking to create tools that can be more accessible to patients and health care professionals. But encouraging people to follow these principles is something that can be done immediately. It provides a useful roadmap for people to follow.”
GO FRESH was published simultaneously in JAMA.
Family-based home blood pressure monitoring reduced blood pressure in rural China
A population-based study comparing at-home blood pressure monitoring with usual care reduced systolic blood pressure by a mean of 10 mmHg in 80 rural villages in Henan Province, China. Interventions included free low-sodium, potassium-enriched salt substitutes and group exercise recommendations, all coordinated by a local family health instructor.
“The Healthy Families Trial is the first time we have shown at the population level that the distribution of mean blood pressure can be shifted to the left and reduced,” said Jun Cai, MD, professor at Beijing Anzhen Hospital, Capital Medical University, in Beijing, China. “And the cost is not expensive. To provide a blood pressure monitor, low-sodium salt and a small incentive for the family health instructor costs about $12 to reduce systolic blood pressure 10 mmHg across an entire population.”
Healthy Families randomized 80 villages and 8,001 participants in rural China to usual care (40 villages, 4,000 participants) with individuals seeking medical care when they feel unwell, or a family-based cardiovascular intervention (40 villages, 4,001 participants). Families in intervention villages were given a home device to measure blood pressure for each member of the family. Readings were uploaded to WeChat, a video-based chat app popular in China.
One person in each family was charged with overseeing family blood pressure measurement. Repeat blood pressure measurements were performed as needed based on the previous reading.
Individuals with blood pressure <120 mmHg measured again in three months. Those with a blood pressure of 140–159/90–99 mmHg measured repeated blood pressure measurement within one week. Those with BP ≥160/110 mmHg re-measured blood pressure the following day.
“Blood pressure is poorly controlled, and the highest risk in rural villages is for stroke,” Cai said. “People don’t know they have hypertension because they have no symptoms, so they don’t seek medical advice. That is why we took action to find a family-based intervention to control blood pressure in the whole population instead of just those people with diagnosed hypertension. Healthy Families is unique because we involved all individuals regardless of their blood pressure compared to previous studies that look only at patients with hypertension or high-risk populations.”
Each intervention family was also provided with a low-sodium, potassium-enriched salt substitute to reduce dietary sodium. Families were also advised to engage in regular group physical activity such as group dancing in the village square.
The entire program was overseen by local family health instructors with basic health literacy instruction and basic medical training. The intervention lasted six months.
All families were followed an additional six months after the intervention period to assess the durability of effect. The primary endpoint was change in systolic blood pressure from baseline. The secondary endpoint was change in systolic blood pressure at 12 months.
The 10 mmHg decline in systolic blood pressure at six months fell to 3.7 mmHg at 12 months, Cai reported. A larger three-year trial across 1,000 villages will assess clinical endpoints including reduction in stroke, other cardiovascular events and all-cause mortality.
