Effect of Hibiscus Sabdariffa on Blood Pressure in a University Population

January 14, 2019 updated by: Sulaiman AlRajhi Colleges
Hypertension, also known as high blood pressure, is a very common disease and is considered "the silent killer". Hypertension is responsible for at least 45% of deaths due to heart disease, and 51% of deaths due to stroke. Hypertension plays a part in the worry of heart disease, stroke and kidney failure and premature mortality and disability. If hypertension goes uncontrolled, in the long term, it will cause serious complications, most of which will necessitate costly interventions to be solved and managed. Apparently, these interventions may include cardiac bypass surgery, carotid artery surgery and dialysis, draining individual and government budgets. Recent studies show that hibiscus (Hibiscus sabdariffa) tea can lower blood pressure as effectively as some standard anti-hypertensive drugs can. Hibiscus is widely consumed around the world as a ruby-colored, lemony beverage. Hibiscus is safe and, unlike most blood pressure drugs, rarely causes side effects. All of the studies the investigators found in the literature were either underpowered or inconclusive. All of these studies recommended further studies with bigger samples to accurately assess the effect of hibiscus sabdariffa on blood pressure in hypertensive patients. The aim of this study is to assess the feasibility of a large-scale study assessing the effectiveness of Hibiscus sabdariffa on lowering blood pressure in individuals with elevated blood pressure.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Unknown

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Research Question:

Will daily consumption of 240 ml of Hibiscus sabdariffa reduce blood pressure in individuals with elevated blood pressure?

Research Objectives:

Primary: To conduct a feasibility study investigating the effect of daily consumption of 240 ml of Hibiscus sabdariffa on blood pressure in individuals with elevated blood pressure

Secondary: To investigate the effect of daily consumption of 240 ml of Hibiscus sabdariffa on low-density lipoprotein (LDL) levels

Secondary: To investigate the effect of daily consumption of 240 ml of Hibiscus sabdariffa on sleep quality

Secondary: To investigate the effect of daily consumption of 240 ml of Hibiscus sabdariffa on stress levels

Trial Design:

This study is an open-label randomized controlled trial. The intervention arm is going to receive a 240 ml serving of hibiscus sabdariffa (sour tea) 1 time a day. The control arm will not have a placebo; hence, "open-label".

Allocation:

The investigators will use simple randomization in this trial. Each participant will have an assigned code number, which will be generated by a computer program, and then these numbers will randomly be placed into one of the two study arms by the same computer program. The participants will know to which study arm they belong to once the trial is officially started.

Study Setting:

This study will be conducted in Sulaiman Al-Rajhi Colleges (SRC) in Al-Qassim Region, Kingdom of Saudi Arabia

Interventions:

Participants will drink hibiscus sabdariffa 1 time a day for 3 months. Hibiscus sabdariffa will be given to the participants in the form of boxes filled with small paper bags filled with the herb (just like teabags). The participant will immerse the teabag in 240 milliliters of cold drinking water (the same volume as in a regular paper cup used for tea) and let it settle for 2-3 minutes before drinking it. This will be done 1 time a day for 3 whole months.

The participant will be given a month's supply on the first day of the trial, and additional supply will be given during the follow-up visits. Reminder text messages (SMS) will be sent regularly (every 2-3 days) to the participant to remind the participants of drinking the hibiscus. Regarding the study outcomes, the participant's blood pressure will be measured using a standardized manual sphygmomanometer at the times of measurement. Regarding the blood LDL levels, the participant will have a blood sample withdrawn and analyzed for LDL levels at the times of measurement. Regarding sleep quality and stress levels, the participant will fill out the respective questionnaires at the times of measurement.

Before initiating the trial, each participant will have the details of the trial, the benefits and risks of the intervention, and the possible outcome of the trial explained to the participants by one of the study investigators. To insure adherence to the intervention, participants in the intervention group will be sent either a text message (SMS) or an e-mail reminding the participants to take the hibiscus tea. The option of either SMS or e-mail depends upon the participant's preference. Any questions or concerns from the side of the participants will be cleared up before initiating the trial and during upcoming follow-up visits.

Multiple randomized controlled trials showed that ingestion of hibiscus tea significantly lowered blood pressure in hypertensive patients. Moreover, some studies showed that ingestion of hibiscus tea lowered LDL levels in addition to other positive changes in blood lipid profiles of patients. The investigators also want to assess if there is an effect of ingestion of hibiscus tea on sleep quality and stress levels.

Sample Size:

Sample size is based on feasibility trial, to test whether this can be done, not on sample size statistics. Also, the target population is pre-hypertensive individuals in a university setting (this includes students, teaching staff, administration staff, and workers). Since there is a definite effect of hibiscus on blood pressure, the investigators recognized that the investigators need a relatively small sample size for the investigators' trial. 40 subjects (randomized into two arms of 20 subjects each) is the required number of participants for the study in order to not comprise the statistical significance and power of the results.

Recruitment:

The principal investigators will invite subjects to participate in the study via sending e-mails to all university individuals. Individuals willing to participate in the trial will sign up to participate in the trial using an online registration form. The investigators used the definition of elevated blood pressure (pre-hypertension) given by the 2017 American Heart Association Guidelines: "Elevated blood pressure (pre-hypertension): Systolic blood pressure [SBP] between 120-129 mm Hg and diastolic blood pressure [DBP] less than 80 mm Hg." (15) The investigators also used the definition of essential hypertension given by the 2017 American Heart Association Guidelines: "Hypertension Stage I: Systolic blood pressure [SBP] 130 - 139 mm Hg OR diastolic blood pressure [DBP] 80 - 89 mm Hg. Hypertension Stage II: Systolic blood pressure [SBP] at least 140 mm Hg OR diastolic blood pressure [DBP] at least 90 mm Hg" (15) The target population is individuals with elevated or Stage I hypertensive levels of blood pressure. This means the investigators will be recruiting individuals with a systolic blood pressure of 120 - 139 mm Hg and a diastolic blood pressure of 80 - 89 mm Hg. After being recognized as eligible participants via the inclusion / exclusion criteria, these participants will be randomized into one of the two study arms.

Data Collection:

Blood pressure (the primary outcome) will be measured regularly during the trial; specifically, at the start of the trial, at 1 month after the official start, at 2 months after the official start, and at 3 months after the official start (at the end of the trial). Measurement will be done during curricular activity hours in the university clinic, on multiple days of each measurement week (to accommodate for the schedule differences of participants). The study investigators will measure each participant's blood pressure using a standardized sphygmomanometer.

Low-density lipoprotein [LDL] (a secondary outcome) will be measured twice during the trial; specifically, once at the official start of the trial, and once at 3 months after the official start (at the end of the trial). A blood sample will be drawn from the participant by the study investigators.

Sleep quality and stress levels (secondary outcomes) will be measured twice during the trial; specifically, once at the official start of the trial, and once at 3 months after the official start (at the end of the trial). The participant will fill out a validated questionnaire form regarding sleep quality (the Pittsburgh Sleep Quality Index [PSQI]) and another form regarding stress levels (the Depression, Anxiety, & Stress Scales [DASS] AND the Perceived Stress Scale [PSS]).

In addition, during each measurement point, the study investigators will inquire about the participants' adherence to the intervention and will ask about any possible adverse effects caused by the intervention. Time will be given to clear up any concerns or questions the participants may have regarding the trial or its details.

For follow-up, the participants will visit the study investigators at the official start of the trial, at 1 month after the official start, at 2 months after the official start, and at 3 months after the official start (at the end of the trial).

Statistical Methods:

The investigators will analyze the collected data using the IBM SPSS Statistics software. The investigators will use the latest version (Version 25).

The investigators will analyze the difference between the mean blood pressures of the intervention group prior to taking the hibiscus tea and the mean blood pressures of the intervention group after taking the hibiscus tea (at the end of the trial) using the paired t-tests. The investigators will analyze the difference between the mean blood pressures of the control group and the mean blood pressures of the intervention group (both before and after the intervention) using the unpaired t-tests.

Similarly, the difference between LDL levels of the control group and LDL levels of the intervention group will be analyzed via the unpaired t-tests.

The differences in sleep quality and stress levels between the control group and the intervention group will be analyzed using paired t-tests. The differences in sleep quality and stress levels in the intervention group before and after the intervention will be analyzed using paired t-tests as well.

Confidentiality:

Informed consent will be offered to every participant. The purpose of the study will be explained to all the participants and the investigators will ensure strict confidentiality and anonymity before proceeding with the study. The participants will be placed individually in the university clinic and only the investigators will record the results in order for the data collected to be totally confidential.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Anticipated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
40

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 4

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

14 years to 66 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Both sexes
  • Age 18 - 70 years
  • Abnormal blood pressure (SBP 120 - 139 mm Hg; DBP 80 - 89 mm Hg)
  • Sulaiman Al Rajhi Colleges affiliate (student, teaching staff member, administrative staff member, worker)
  • No regular medication

Exclusion Criteria:

  • Allergic to hibiscus sabdariffa
  • Normal blood pressure (SBP ≤ 120 mm Hg; DBP ≤ 80 mm Hg)
  • Essential hypertension Stage II or higher (SBP ≥ 140 mm Hg; DBP ≥ 90 mm Hg)
  • Hypertension due to secondary causes
  • Other comorbid conditions (diabetes mellitus, renal failure, coronary artery disease, heart failure, malignant hypertension [BP ≥ 180/110], etc.)
  • Regular hibiscus user
  • Pregnancy
  • Any metabolic or malabsorptive disease that may interfere with absorption of hibiscus sabdariffa (e.g. coeliac disease, chronic pancreatitis, etc.)
  • Diagnosis of a sleep disorder or use of medication that interferes with sleep (either causing drowsiness or wakefulness)
  • Diagnosis of a mood disorder or stress disorder
  • Taking psychiatric medication (mood stabilizers, antidepressants, anxiolytics, or antipsychotics)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Intervention Arm (or Group)
This arm will receive the intervention (Hibiscus Sabdariffa extract supplement)
Dietary supplement: Hibiscus Sabdariffa
The extract of the plant Hibiscus Sabdariffa, also known as sour or red tea
No Intervention: Control Arm (or Group)
This arm will receive no intervention whatsoever, not even placebo

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Blood Pressure (BP)
Time Frame: 3 months
The investigators want to see the effect of Hibiscus Sabdariffa on the blood pressure of participants in the intervention group.
3 months

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Low-density lipoprotein (LDL) levels
Time Frame: 3 months
The investigators want to see the effect of Hibiscus Sabdariffa on the low-density lipoprotein (LDL) levels of participants in the intervention group.
3 months
The Pittsburgh Sleep Quality Index (PSQI)
Time Frame: 3 months

The investigators want to see the effect of Hibiscus Sabdariffa on the sleep quality of participants in the intervention group.

The Pittsburgh Sleep Quality Index (PSQI) contains 19 self-rated questions and 5 questions rated by the bed partner or roommate (if one is available). Only self-rated questions are included in the scoring. The 19 self-rated items are combined to form seven "component" scores, each of which has a range of 0-3 points. In all cases, a score of "0" indicates no difficulty, while a score of "3" indicates severe difficulty. The seven component scores are then added to yield one "global" score, with a range of 0-21 points, "0" indicating no difficulty and "21" indicating severe difficulties in all areas.
3 months
The Depression, Anxiety, and Stress Scales (DASS)
Time Frame: 3 months

The investigators want to see the effect of Hibiscus Sabdariffa on the stress levels of participants in the intervention group.

The DASS is a set of three self-report scales designed to measure the negative emotional states of depression, anxiety and stress.

The DASS is composed of three 14-item subscales, for a total of 42 questions. DASS scores can be 0-42 on each subscale. Total score is calculated by summing the scores for each subscale.

For each of the three subscales, a higher score indicates a more severe negative emotional state.
3 months
The Perceived Stress Scale (PSS)
Time Frame: 3 months

The investigators want to see the effect of Hibiscus Sabdariffa on the stress levels of participants in the intervention group.

Individual scores on the PSS can range from 0 to 40 with higher scores indicating higher perceived stress.

  • Scores ranging from 0-13 would be considered low stress.
  • Scores ranging from 14-26 would be considered moderate stress.
  • Scores ranging from 27-40 would be considered high perceived stress.
3 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Sulaiman AlRajhi Colleges

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Anticipated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
February 1, 2019

Primary Completion (Anticipated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
April 1, 2019

Study Completion (Anticipated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
June 29, 2019

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
January 7, 2019

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 11, 2019

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
January 15, 2019

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
January 16, 2019

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 14, 2019

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
January 1, 2019

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • SulimanAC-Hibiscus

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Elevated Blood Pressure

Clinical Trials on Hibiscus Sabdariffa

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Cookie Settings

We use cookies to ensure that we give you the best experience on our website. For more details carefully read our Privacy and Cookies Policy. ...>>>You can change your preferences or withdraw your consent at any time by deleting the cookies from your website or computer as described in the policy. Please accept it and choose your preferences by ticking the corresponding boxes in the "Manage Settings" section below. Please carefully read our Terms of Service before you proceed with using any part of this website.
«Manage Settings