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Hypertension and diabetes are among the most common noncommunicable diseases in Zimbabwe. These 2 conditions are largely prevented and controlled by lifestyle modifications, such as healthy eating habits, physical activity, and avoiding the use of tobacco and alcohol.
This study aims to evaluate the effects of a community health worker (CHW)–led health literacy intervention on lifestyle modification among patients with diabetes and hypertension in the City of Harare, Zimbabwe, in terms of (1) adherence to recommended lifestyle changes, (2) blood pressure and blood glucose levels, and (3) medication adherence.
This is a 6-month–long cluster randomized controlled trial, which will be conducted in primary health care clinics in the city of Harare. A total of 14 clinics will be randomly allocated into either the intervention or control group. A total of 680 (49 participants per clinic) adult patients with hypertension and diabetes will be enrolled for the trial. Participants in the intervention arm will receive a simple health literacy intervention on lifestyle modification, which will be delivered by trained CHWs, while those in the control arm will receive usual care. The intervention consists of 4 face-to-face interactive educational sessions and monthly support visits by trained CHWs and will be carried out over a period of 6 months. The primary study outcomes will be blood pressure and blood glucose levels and levels of adherence to the recommended lifestyle modifications. Other outcomes will include adherence to medication. Data management and analysis will be done using Epi Info software, and the data will be analyzed using the intention-to-treat principle.
Recruitment of study participants commenced on June 1, 2023, and was completed on July 30, 2023. Baseline data are being collected after participants’ recruitment, and the final data collection will be completed by January 31, 2024.
There is an information dearth regarding the effectiveness of CHW-led interventions for the management and control of hypertension in Zimbabwe. Our study offers an opportunity to show the effectiveness of CHWs in addressing the gaps in the management of hypertension and diabetes. The findings from our study will provide crucial evidence on the effectiveness and feasibility of a simple intervention delivered by CHWs in resource-constrained areas.
PRR1-10.2196/47512
Hypertension and diabetes are among the leading causes of morbidity, disability, and premature death worldwide. In 2019, diabetes was the direct cause of 1.5 million deaths worldwide, and 48% of all deaths due to diabetes occurred before the age of 70 years [
Studies have shown links between hypertension and diabetes [
Lifestyle modification poses a challenge for patients with hypertension and diabetes, and several studies have demonstrated high noncompliance with the recommended lifestyle modifications worldwide [
CHWs are voluntary public health workers who are trusted members of the community they serve [
We have developed a simple CHW health literacy intervention on lifestyle modification, and we have designed a study to evaluate the effects of the intervention among patients with hypertension and diabetes in the city of Harare, Zimbabwe. This paper describes our research design and discusses the rationale of our study. We hypothesize that the intervention will have a positive effect on (1) adherence to recommended lifestyle modifications, (2) adherence to medication, as well as (3) blood glucose and blood pressure levels.
The study is a cluster randomized controlled trial, which will be conducted in the city of Harare in Zimbabwe from June 2023 to January 2024. The design, implementation, and reporting of the study are based on the recommendations from CONSORT (Consolidated Standards of Reporting Trials) statement on cluster randomized controlled trials [
The study will be conducted in 14 primary health care clinics in the city of Harare; these clinics were purposefully selected from a total of 39 health facilities (12 polyclinics, 6 family health services clinics, 15 satellite clinics, and 2 infectious diseases hospitals) in the city. The 14 facilities that have been selected for the study are the ones that offer comprehensive services, including curative services, chronic pain care, maternal and child health services, HIV prevention services, and community health services. These clinics are in the high-density suburbs of the city, with each clinic serving a population of 80,000-100,000 people, the majority of whom are socioeconomically disadvantaged. The 14 health facilities will be randomly allocated into either the intervention or the control arm. Thus, each study arm will comprise 7 health facilities.
The intervention arm will receive the CHW-led health literacy intervention, while the control arm will receive usual care.
The intervention was designed by the principal investigator (PI), and its development entailed two processes, as follows: (1) conducting a scoping review of the literature on CHW-based interventions for hypertension and diabetes and (2) validating the content through consultations with 10 experts (ie, 3 health promotion officers, 2 nutritionists, 2 medical doctors, 1 Diabetes Association of Zimbabwe official, 1 pharmacist, and 1 nurse). The intervention is based on the constructs of the Health Belief Model [
This intervention consists of face-to-face educational sessions and support visits to patients and will be delivered by trained CHWs. A total of 4 educational sessions will be conducted at either the patient’s home or the primary care clinic, through which the patient is routinely monitored. The first session will be held at the clinic on the day of recruitment. The second and the third sessions will be held at either the clinic or the patient’s home, as preferred by the patient. The fourth session will be a home visit, where the CHW will visit the patient in their home to provide support and follow-up. After the fourth educational session, the CHWs will continue to make monthly home visits to the patient.
In terms of content, in the first session, the CHW will educate the patient on the recommended lifestyle modifications and the consequences of nonadherence. In the second session, focus will be on the patient’s barriers to adopting recommended lifestyle modifications and ways to overcome them. At the end of this session, patients are expected to write down their own plan for lifestyle modifications on a card, which they will then place in a visible location in their home. This will serve as a cue to action. The second session will be highly interactive, compared to the first session. The third and fourth sessions will be supportive and evaluation sessions during which the CHW assesses whether the patient has been following the action plan established in the second session. In the fourth session, which will be conducted at home, available family members will be involved to support the patient, and this will serve as another cue to action for the patient and will also help to build the patient’s self-efficacy. Any deviations from the plan will be discussed and ways to correct will be explored. The monthly home visits conducted after the fourth educational session will serve as support visits, where the CHW will continue to reinforce the importance of adhering to lifestyle modifications.
In terms of timing, the first session will be conducted on the day of recruitment, and the second session will be scheduled a week after the first session. The third session will be conducted 2 weeks after the second session, and the fourth session will also be conducted 2 weeks after the third session. A month after the fourth session, the patients will receive monthly home visits at a date and time convenient for them. Each educational session will last 45-60 minutes, while the monthly support visits will last 10-15 minutes.
To ensure that the intervention adheres to the protocol and maintains study fidelity, the CHWs who will deliver educational sessions will undergo a 1-day training; this training will be conducted by the PI, 1 nurse, and 1 health promotion officer from the city of Harare. The CHWs will be given notes on the recommended lifestyle modifications, to which they will refer when conducting educational sessions. All the CHWs participating in the study have been working as CHWs for periods ranging from 5 to 30 years, and upon their initial recruitment as CHWs, they underwent an 8-week training program. They will also receive refresher trainings as needed, in accordance with the guidelines for CHWs in Zimbabwe [
The usual care for patients with diabetes and hypertension in the city of Harare involves patients coming to the clinic for monthly reviews and medication collection. Patients also receive counseling on medication adherence and recommended lifestyle modifications, particularly on the day when they are diagnosed and start their medication. Although there is no formalized CHW intervention, CHWs are involved in the continuum of care when patients fail to report for their monthly reviews for 3 consecutive months. Additionally, patients may seek consultation with CHWs in their communities, as needed.
Summary of study interventions.
| Component | Control arm (usual care) | Intervention arm (community health worker–led health literacy intervention) |
| Main components | Health education session on the importance of adhering to medication and lifestyle modifications on the day medication is initiated by a nurse or doctor and monthly drug pickups at local health facilities | Usual care and 4 interactive educational sessions and monthly home visits by community health workers |
| Theoretical background of educational sessions | None | Health Belief Model [ |
| Role of community health workers | Follow-up when the patient misses clinic appointments for 3 consecutive months | Continuous support in the management and control of diabetes and hypertension |
All 14 targeted health facilities will be randomly allocated to either the intervention or the control arm. Each arm will consist of 7 clinics. The randomization process will be conducted by an official from the city of Harare, from the City Health Department, who will not be part of the study staff. The randomization process will be done using the simple randomization technique, based on computer-generated random numbers. To reduce bias and improve study fidelity, group allocation will be concealed to the data collectors until the completion of baseline data collection.
All adults aged 18 years and older, with a confirmed diagnosis of hypertension and diabetes, residing within the targeted health facility’s catchment area, and capable of providing written informed consent will be eligible for enrollment.
Exclusion criteria will include the following: (1) individuals having hypertension- and diabetes-related complications that cannot be managed in a primary care setting, (2) individuals who are pregnant or planning to become pregnant during the course of the trial, (3) individuals who will not be able to stay within the catchment area of the clinic where they are enrolled for the duration of the trial, and (4) individuals who will not be able to give consent for any reason, such as severe mental health disorders.
Participants will be recruited by trained research assistants every day of the 1-week recruitment period. The recruitment process will be done concurrently at control and intervention sites. Baseline data will be collected on the day of the recruitment, and research assistants will not be aware of group allocations during the recruitment and the baseline data collection periods.
The outcome evaluation for this study will be based on data collected both at baseline and during the postintervention follow-up (after 6 months). Data collection tools will be identical for data collection at both periods and include information on patient’s demographics, disease history, lifestyle behaviors, medication use, primary use of health care services, and hospitalizations. Height, weight, waist circumference, glycosylated blood glucose levels, and blood pressure will also be measured.
The primary study outcomes will be blood pressure and blood glucose levels as well as levels of adherence to recommended lifestyle modifications. Other outcomes will include changes in medication adherence and additional health-related outcomes, such as frequency of hospitalization or the occurrence of complications.
A consolidated interviewer-administered questioner comprising of all measures (as detailed in
Patients’ levels of adherence to recommended lifestyle modifications will be assessed using self-reported questions adapted from the Hypertension Self-Care Activity Level Effects Scale (H-SCALE) questionnaire. The H-SCALE is a validated self-reported questionnaire for assessing self-care practices for hypertension prevention and control [
Assessment of lifestyle modifications using an interviewer-administered questionnaire adapted from the Hypertension Self-Care Activity Level Effects Scale (H-SCALE).
| Recommended lifestyle modification | The WHOa recommendation | Assessment method |
| Weight reduction and management | Maintain normal body weight (BMI 18.5-24.9 kg/m2) | First, the patient’s BMI will be assessed based on the patient’s height and weight. All patients with a BMI above 24.9 will be considered as overweight. |
| Reducing dietary salt intake | Reduce dietary salt intake to less than 2400 mg of sodium per day or less than 6000 mg sodium chloride per day. | A total of 6 questions will be used to assess practices related avoiding salt while cooking and avoiding foods high in salt content. Patients who answer yes to 3 or more questions will be considered as nonadherent to a low salt diet. |
| Reducing dietary fat intake | Avoid foods high in cholesterol and fat content | A total of 2 questions will be used to assess practices related to avoiding foods high in cholesterol and fat content. Patients who answer yes to any 1 question will be considered as nonadherent to a low fat or cholesterol diet. |
| Increasing fruit and vegetable consumption | Consume 5 servings (equivalent of 5 tablespoons) of vegetables and 3 servings (equivalent of to at least 3 fruits) of fruits every day. | A total of 2 questions will be asked to assess adherence to fruits and vegetables. Patients who answer yes to any 1 question will be considered as adherent to a high fruit and vegetable diet. |
| Smoking | Avoid smoking | Smoking status will be assessed by 1 question. All patients who answer yes to the question will be considered nonadherent to nonsmoking recommendations |
| Moderation in alcohol consumption | Limit alcohol consumption to no more than 2 drinks (eg, 24 oz of beer, 10 oz of wine, or 3 oz of 80-proof whiskey) per day in men and no more than 1 drink per day in women and lighter-weight persons. | Alcohol intake will be assessed using 2 questions. Participants who answer yes to any 1 of the questions will be considered nonadherent to the alcohol recommendation moderation. |
| Physical activity | Engage in regular aerobic exercises, such as brisk walking for at least 30 minutes per day, for at least 5 days a week. | Physical activity will be assessed by 1 question. Participants who answer yes to the question will be considered as being adherent to the physical activity recommendation. |
aWHO: World Health Organization.
Patient’s hypertension and diabetes control will be assessed by blood pressure and HbA1c measurements, respectively
Patients’ adherence to medication will be assessed using a widely used and validated tool, the 8-item Morisky Medication Adherence Scale (MMAS-8) [
Other health outcomes, such as hospitalization and the occurrence of diabetes and hypertension complications, will be assessed from the patients’ clinic records
Based on the recommendations for sample size calculation for cluster randomized controlled trials with a fixed number of clusters [
Recruitment of participants started in June 2023. Baseline data were collected during the recruitment of participants. Follow-up data will be collected after 6 months, in January 2024. Data will be collected using the research assistants’ smartphones. The questionnaire will be uploaded onto the phones and the REDCap platform will be used for storing and managing the data. The computer system that will be used for storing the data will be password protected so that the data will only be accessible to authorized individuals. Patients will be assigned unique identifying numbers at the beginning of the study and the same number will be used in the follow-up data collection period. Data will be managed according to the International Conference on Harmonisation Guidelines for Good Clinical Practices [
Data analysis will be performed using the Epi Info (Centers for Disease Control and Prevention) software. The primary analysis will be conducted under the intention-to-treat principle. For individual outcomes, proportions will be compared using the chi-square test, and continuous measures will be compared using 2-tailed
Permission to carry out the study in the city of Harare clinics was obtained from the City Health Services Director. Ethical clearance was obtained from the University of Zimbabwe’s institutional review board, the Joint Research and Ethics Committee (JREC/339/2022). Written informed consent will be obtained from all study participants. Confidentiality of the study participants will be maintained at all stages of the study.
All participants will be treated fairly, and they will not be intentionally subjected to any harm. During the study, all participants who present with any other health education needs that do not result in contamination of the study will be assisted. Those with complications or any other needs beyond the scope of the research team will be referred to appropriate HCWs. The knowledge that will be generated from this study will be disseminated to all pertinent stakeholders using various strategies, such as publications and feedback meetings.
Recruitment of study participants commenced on June 1, 2023, and was completed on July 30, 2023. Baseline data are being collected after participant recruitment, and the final data collection will be completed by January 31, 2024.
Hypertension and diabetes are global health challenges that have placed significant burdens on health care systems in all nations [
Evidence-based national and international guidelines on managing hypertension and diabetes are well-established, cost-effective approaches, suitable for adoption in resource-constrained settings, but they have not been adequately investigated [
The strengths of our study include CHWs who are already integrated in the Zimbabwean primary health care system. The CHWs have prior experience in disseminating health education on various health topics, particularly prevention of diarrheal diseases and malaria, which are prevalent in the country. Additionally, the CHWs are routinely involved in follow-ups with patients who have hypertension and diabetes, ensuring they do not miss monthly checkups. Therefore, if successful, our intervention will modify and strengthen community-based management of hypertension and diabetes. Unlike most of the CHW-based interventions being implemented in other low- and middle-income countries, our intervention is based on a tested and tried health behavior model, the Health Belief Model [
Nonetheless, there are weaknesses in our study, mainly emanating from the cluster randomized controlled trial design. First, our study does not involve blinding of study participants. Lack of blinding is one of the weaknesses inherent in cluster randomized controlled trials that include behavioral interventions. However, to reduce bias associated with lack of blinding, there will be partial blinding of data collectors during the collection of baseline data. The data collectors will not know the arm to which each clinic will belong. In addition, there is a possibility of information sharing among participants in the intervention and control group, since the suburbs in Harare are within close proximities. To limit the sharing of information, participants in the intervention group will receive a detailed explanation of the study’s importance from the PI. There is also a possibility of social desirability bias in assessing lifestyle modifications. Participants may report what they perceive as the desired behavior rather than their actual behavior. However, the study will assess overall changes in blood glucose and hypertension levels as well as BMI, which are more objective outcome measures.
Our trial aims to evaluate the effects of a CHW-led health literacy intervention for lifestyle modifications among patients with diabetes and hypertension in Harare, Zimbabwe. Findings from our study will provide reliable evidence on the effectiveness of a simple community-based intervention in the management and control of the two most common NCDs in Zimbabwe. In summary, our study will contribute to the much-needed body of knowledge on the effectiveness of using CHWs in the management of chronic NCDs in resource-limited countries.
Interviewer-administered questionnaire for collecting data.
community health worker
Consolidated Standards of Reporting Trials
Hypertension Self-Care Activity Level Effects Scale
glycosylated hemoglobin
Morisky Medication Adherence Scale-8
noncommunicable disease
principal investigator
We would like to thank the city of Harare’s City Health Director for granting permission to carry out the study in the city of Harare’s health facilities. We would also like to thank our colleagues from the Family Medicine, Global and Public Health unit, for their peer review of the initial study proposal. We are grateful to all the participants who will be enrolled in this study.
Research reported in this publication was supported by the Fogarty International Center and National Institute of Dental and Craniofacial Research of the National Institutes of Health (award number D43 TW011968). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
NAK acquired a license to use the 8-item Morisky Medication Adherence Scale (MMAS-8) for this study from the scale developer, Dr Donald E Morisky. The MMAS-8 Scale, content, name, and trademarks are protected by US copyright and trademark laws. Permission for use of the scale and its coding is required. A license agreement is available from MMAR, LLC (http://www.moriskyscale.com).
All authors declared that they had insufficient or no funding to support open access publication of this manuscript, including from affiliated organizations or institutions, funding agencies, or other organizations. JMIR Publications provided article processing fee (APF) support for the publication of this article.
The consent and ethical approvals for this study do not have any restrictions on data sharing. Therefore, the data sets generated from this study will be made publicly available as supplementary files in all publications of the study results.
NAK conceptualized the study and was responsible for drafting the initial manuscript, and the subsequent drafts, leading to the final version; SR, SS, and GTF reviewed the study proposal as well as the initial manuscript and its subsequent drafts. All authors read and approved the final manuscript.
None declared.