Diet Intervention for Hypertension: Adaptation and Dissemination to Native Communities

For Goal 1, all participants complete 4 data collection visits at the clinic (in person
screening visit, baseline, week 8, and week 12). Participants will be randomized into either
the control group or the intervention group at the baseline visit.

All participants will receive 8 weekly credits for groceries and will be given equipment for
monitoring their BP at home. Study staff will help participants place their grocery orders
each week, and will collect readings from the home BP monitoring equipment at the same time.
This data will be used to understand whether the intervention is effective for controlling
BP.

All participants will be encouraged to maintain their regular levels of physical activity and
receive treatment as usual from their healthcare providers.

The control group participants will receive an American Heart Association printed brochure
about the health benefits of a low-salt diet. All foods will be available to purchase,
including those that do not meet the DASH diet guidelines.

The intervention group participants will receive 1 hour of in-person nutritional counseling
and a personalized prescription for the low-salt DASH diet based on estimated calorie needs
at baseline, followed by weekly 20-minute phone calls in weeks 1-8 to provide extra support.

The intervention group's food choices will be limited to fresh produce and a pre-determined
list of other foods included in the DASH diet. During weekly phone calls, the dietitian will
use a structured phone curriculum to discuss in more detail a different component of the DASH
diet, followed by goal setting related to that component. Through small goal setting each
week, participants will receive ongoing support to improve full adherence to the DASH diet by
the end of week 8.

The pilot study will provide preliminary evidence for natural attenuation of BP, and will
evaluate the added benefit of the additional telephone support that can be used to inform
design of future studies.

Beginning in Year 3, 100 intervention group participants (50 at each site) who attend the
Week 8 follow up research visit and who successfully completed 5 of the 8 weekly phone calls
will be randomized to:

- Pilot Control group -no additional support, weekly BP measurements only

- Pilot Intervention group - 6 extra weeks of 20-minute phone consultations with the
dietitian (enhanced intervention)

We will also recruit 100 control group participants (50 at each site) to the pilot study, who
will be automatically assigned to receive no additional support while providing weekly BP
measurements.

The enhanced intervention consultations will provide support for maintaining a low-sodium
DASH lifestyle after the weekly grocery credit ends. We will contact pilot study participants
by telephone 6 and 9 months after baseline and talk them through accessing BP readings from
their home BP monitor.

Inclusion Criteria:

Participants must:

- be at least 18 years old;

- have had diagnosed hypertension for at least 1 year;

- be on a stable routine of antihypertensive medications for at least 2 months OR not
currently medicated, without anticipated changes for the duration of the study;

- have systolic BP ≥ 130 mmHg at the past 2 clinic visits and at the in-person screening
visit;

- have access to regular medical care and permission from their primary care provider to
participate (study staff obtain verbal permission before recruiting participants);

- be physically and cognitively able to use the home BP monitoring device;

- be willing and able to follow all other study procedures.

Exclusion Criteria:

People are ineligible if they:

- experienced incident cardiovascular disease or stroke within the previous 6 months;

- have a known diagnosis of secondary hypertension (e.g., renal artery stenosis);

- have a recent history of high blood potassium due to certain medications that can
raise potassium levels;

- have diagnosed Stage 4 or 5 kidney disease;

- are currently or planning to become pregnant during the course of the study;

- are participating in another health research study involving hypertension;

- are receiving treatment for cancer or another serious or terminal medical condition.