ABSTRACT
Rationale
Hypertension disproportionately affects populations in low- and middle-income countries (LMICs), especially in Latin America and the Caribbean, due to its high prevalence and low control rate.
Primary Hypothesis
To close the knowledge-practice gap for blood pressure (BP) control, we are assessing the effectiveness and implementation of a team-based care strategy for BP control in primary care clinics in Colombia and Jamaica.
Design
The Caribbean and South American Team-based Strategy to Control Hypertension (CATCH) study is a cluster randomized trial using an effectiveness–implementation hybrid type-2 design. Clinics were randomly assigned to a team-based strategy or a provider-training strategy to implement current hypertension guidelines. The team-based strategy includes healthcare team training, care coordination, task sharing, BP audit and feedback, home BP monitoring, health coaching, single-pill combination therapy, and increased medication access. The primary clinical effectiveness outcome is difference in mean change of systolic BP from baseline to 18 months between randomized groups. The primary implementation outcome is a composite fidelity score to key implementation strategy components.
Sites
CATCH is conducted in 40 primary care clinics in Jamaica and Colombia.
Enrollment
Between February 2023 and August 2024, we recruited 1,707 participants, exceeding our planned enrollment. The planned sample size of 1,680 (42 patients per each of 40 clinics) has 90% statistical power to detect a 6.0 mm Hg difference in mean systolic BP change assuming 85% follow-up and a 2-sided significance level of 0.05.
Current Status
In follow-up
Conclusions
CATCH will provide evidence on effectiveness and implementation of a team-based care strategy to improve hypertension control in real-world, primary care settings. If proven effective, this approach can be scaled up in primary care throughout low- and middle-income countries (LMICs).
Clinical Trial Registration
Clinicaltrials.gov , NCT05405920
https://clinicaltrials.gov/study/ NCT05405920.
Background
Hypertension disproportionately affects populations in low- and middle-income countries (LMICs) due to its high prevalence, poor control, and the resulting excess burden of cardiovascular disease (CVD). ,, In recent years, the burden of hypertension has shifted overwhelmingly to LMICs. ,, In 2010, an estimated 74.8% of adults with hypertension lived in LMICs, and only 8% of them had their blood pressure (BP) controlled. Latin America and the Caribbean (LAC) has a higher prevalence of hypertension compared to global estimates with an age-standardized prevalence of 36.7% in women and 40.4% in men compared to 31.7% in women and 34.5% in men, globally.
Jamaica and Colombia are LAC countries with distinct cultures and healthcare system characteristics but shared high hypertension prevalence and suboptimal BP control. , Jamaica’s healthcare system is a mix of public and private facilities with half of the population using public primary care services that are free of charge to patients. Primary care is delivered at community-based health centers with patients with complications referred to regional hospitals. Colombia’s healthcare system is predominantly in the private sector. Private sector healthcare providers are paid through health insurance plans that are employment- and government-based. Including these diverse LAC healthcare systems in the same trial implementing a BP reduction intervention will allow overall and county-specific estimations and improve scale-up and generalizability if proven effective.
In 2017, the American College of Cardiology (ACC) and the American Heart Association (AHA) released a clinical practice guideline for the prevention, detection, evaluation, and treatment of high BP in adults. Following that, the World Health Organization (WHO) Guideline for the Pharmacological Treatment of Hypertension in Adults was released in 2021 and aimed to provide the most current and relevant evidence-based guidance on pharmacological treatment with a focus on LMICs. , While some differences exist between the two guidelines, both recommend initiation of treatment at systolic BP ≥130 mm Hg and treatment to a systolic treatment target <130 mm Hg in patients at higher CVD risk or with clinical CVD. ,, Further, the guidelines also recommend use of single pill combination medications to improve adherence and persistence and team-based care approaches to hypertension care. ,, These recommendations are also consistent with those from the more recent 2025 AHA/ACC hypertension guidelines.
Barriers to hypertension control exist at the healthcare system, provider, community and patient levels hindering guideline implementation and uptake. Some key barriers include clinical inertia, insufficient provider time, lack of continuity of care, medication availability and cost, long clinic wait times, and poor adherence to medications and lifestyle modifications. Increasingly, strategies have been tested to overcome these barriers and lower BP. In a meta-analysis of 100 trials, we found that team-based care is the most effective strategy for BP reduction. Team-based care is defined as healthcare provision by a collaborative interprofessional team using an integrated care process and a patient-centered approach. This team-based care strategy aligns with the Pan American Health Organization (PAHO)’s chronic care model for noncommunicable diseases (NCDs) and can be cost-effective, increase patient-provider face time, enhance quality of care, and improve patient satisfaction and health outcomes. ,
During the planning phase of the Caribbean and South American Team-based Strategy to Control Hypertension (CATCH) trial, we conducted a mixed methods needs assessment among primary care clinic staff and patients with hypertension in Jamaica and Colombia. Focus groups identified 4 overarching recommendations: enhance communication between patients and providers, improve health coaching, facilitate access to hypertension-related care and antihypertensive medications, and improve support from family and social networks. A quantitative survey found that among patients with hypertension, misconceptions exist about the impact of lifestyle modifications on BP and the consequences of high BP. Significant proportions of patients in both Jamaica and Colombia reported a lack of communication from providers about their hypertension care plan and medications. Patients in both countries found all aspects of the proposed team-based care approach acceptable, appropriate, and feasible.
Based on these preliminary findings, we have developed and refined our intervention and implementation strategies for the CATCH trial. We have adapted the 2017 ACC/AHA and 2021 WHO hypertension guidelines for primary care settings in Jamaica and Colombia. We will use a team-based care approach compared to provider education only to implement the adapted guidelines in Jamaica and Colombia. If proven effective, this approach can be scaled up throughout LAC and in LMICs as a whole to improve BP control.
Methods
Objectives and specific aims
The overall objective of the CATCH trial is to test the implementation and effectiveness of a team-based care strategy implementing the current hypertension clinical guidelines for BP control in Colombia and Jamaica. In this cluster randomized, effectiveness-implementation hybrid type 2 trial, 40 primary care clinics (20 from Colombia and 20 from Jamaica) were randomly assigned to a team-based care strategy or a provider-training strategy to implement an evidenced-based BP reduction intervention adapted from the 2017 ACC/AHA clinical hypertension guideline and the 2021 WHO guideline on the pharmacological treatment of hypertension. ,, Teams of physicians, nurses, and community health workers (CHW) work collaboratively with patients to achieve shared BP treatment goals. The CATCH trial has 2 specific aims: (1) to test the effectiveness of a team-based care strategy on BP reduction and hypertension control in patients with uncontrolled hypertension and (2) to evaluate the fidelity of the intervention and other implementation outcomes, including acceptability, adoption, appropriateness, feasibility, implementation costs, penetrance, reach, satisfaction, and sustainability of team-based care at primary care clinics in Colombia and Jamaica.
Study setting and participants
We have recruited 40 primary care clinics and 1,707 individuals with uncontrolled hypertension from real-world primary care settings in Colombia and Jamaica. Predefined eligibility criteria are minimal for both clinics and study participants to ensure the generalizability of study findings ( Table 1 ).
Table 1
Eligibility criteria
| Clinic eligibility |
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BP, blood pressure; CKD, chronic kidney disease; CVD, cardiovascular disease.
Among the 32 geographic departments in Colombia, 7 were selected for CATCH with at least one from each of the 5 continental regions. We have randomly selected 20 clinics meeting eligibility criteria from a total of 98 primary care clinics within the 7 departments (4 from Santander, 4 from Norte de Santander, 4 from Cesar, 2 from Atlántico, 2 from Quindío, 2 from Cauca, and 2 from Nariño). In Jamaica, there are 83 public primary care clinics providing chronic disease care within the 4 regional health authorities. We have randomly selected 20 public primary care clinics from 3 parishes (4 from St. Thomas, 15 from Kingston, and 1 from St. Andrew) in one regional health authority for the CATCH trial.
The selected clinics were randomly assigned to the intervention or control group with an allocation ratio of 1:1 ( Figure 1 ). The randomization was stratified by Colombia vs Jamaica, urban vs rural, and geographic region (Caribbean region, Pacific region, Central-East region) in Colombia to reduce potential imbalance in baseline covariates.
Study design of the CATCH trial.
Eligibility criteria for trial participants are designed to include clinic patients aged 18 years or older with uncontrolled hypertension according to the 2017 ACC/AHA and 2021 WHO hypertension clinical guidelines ( Table 1 ). ,, Recruitment was done using in-clinic recruitment and patient identification through health records. In Colombia, where electronic health records (EHR) are available, we performed EHR searches to identify patients with hypertension. In Jamaica, only paper health records are available. Therefore, patients were approached by project staff in waiting areas, and eligibility was confirmed by clinic staff paper record review. Prescreening was conducted either in person at the clinic or by phone. Patients who met eligibility criteria during prescreening were invited to attend clinical screening visits. BP eligibility was determined based on the average of 6 measurements obtained from 2 screening/baseline visits.
Intervention and implementation strategies
BP control intervention
Primary care providers and patients work collaboratively to establish individualized treatment plans to achieve BP goals. We target a systolic BP <130 mm Hg and a diastolic BP <80 mm Hg in all hypertensive patients. This target is based on recommendations from the 2017 ACC/AHA guideline and more recent data indicating more intensive BP lowering results in further reductions in CVD and all-cause mortality. ,,,,
A stepped-care protocol based on the 2017 ACC/AHA Clinical Practice Guideline for High Blood Pressure and the 2021 WHO Hypertension Guideline is being implemented ( Figure 2 ). ,, The CATCH intervention is also consistent with recommendations for the more recent 2025 ACC/AHA Guideline for the Prevention, Detection, Evaluation and Management of High Blood Pressure in Adults. In accordance with the 2021 WHO guideline, first-line agents for initial treatment should be from the following 3 classes of antihypertensive medications: thiazide and thiazidelike agents, ACEIs/ARBs, and long-acting dihydropyridine CCBs. , For individuals with untreated systolic BP 130 to 139 or diastolic BP 80 to 89 mm Hg, monotherapy or half-dose of a single-pill double combination is used. For individuals with untreated BP ≥140/90 mm Hg or treated BP ≥130/80 mm Hg, combination therapy, preferably with a single-pill double combination from the above 3 classes, is used.
Treatment algorithm for blood pressure control. ACEI, angiotensin converting enzyme inhibitor; ARB, angiotensin receptor blocker; BP, blood pressure; CCB, calcium channel blocker.
Initiation of antihypertensive medications occurs at the second baseline visit in untreated patients, and those on treatment are given the option of single pill combination medications based on physician’s assessment. Patients are provided with a 1-month supply of antihypertensive medications. Study participants return to the clinic for BP checks 1 month after baseline. If a patient’s average BP is <130/80 mm Hg, he/she is instructed to continue current antihypertensive treatment and is scheduled for a follow up appointment in 3 months. If a participant’s average BP is ≥130/80 mm Hg, adherence to antihypertensive medication is assessed. If appropriate, the dosage of antihypertensive medication(s) is titrated up. Participants are scheduled for monthly clinic visits until BP is controlled to <130/80 mm Hg, and then are scheduled for quarterly clinic visits. If a participant’s BP is still >130/80 mm Hg at the 6-month clinic visit, a new class of antihypertensive medications is added, preferring a single-pill triple combination.
All study participants are encouraged to make lifestyle changes and adhere to medications. Proven-effective lifestyle interventions for BP reduction include weight loss, a heart-healthy diet (eg, the DASH diet), sodium reduction, potassium supplementation, increased physical activity, and reduced alcohol consumption. ,,
Side effects of antihypertensive medications and approaches to minimize them are discussed at clinic visits. Providers provide suggestions to minimize side effects. Classes and dosages of medications are adjusted to address side effects.
Implementation framework
We have used the Exploration, Preparation, Implementation, Sustainment (EPIS) framework to guide the planning phase to identify barriers and facilitators to implementation, adapt the evidence-based intervention, and develop implementation strategies ( Figure 3 ). Key factors in the inner context that influence implementation are characteristics of the clinics, providers, administrators, and staff. Government agencies, communities, pharmacies, insurance companies/providers, and patient characteristics are important outer context factors. We will continue to use EPIS as a guide to understand important contextual factors and interactions between factors throughout the CATCH trial. An Implementation Research Logic Model summarizing key study components and processes is available in Supplementary Figure 1.
Adapted exploration, preparation, implementation, sustainment (EPIS) framework for the CATCH trial.
Team-based care implementation strategy
Team-based care is the key, overarching implementation strategy and encompasses provider training, protocol-based treatment, health coaching, home BP monitoring, and increased medication access as substrategies. We have worked with each team-based care clinic to develop a provider team using a physician-nurse-CHW combination. In Colombia, auxiliary nurses serve in the role of the CHWs, and in Jamaica, community health aides perform CHW duties. Patients work collaboratively with physicians and nurses to establish a shared treatment plan. Physicians conducted a clinical evaluation of patients, choose initial BP medications, adjust medication based on patients’ responses and treatment protocol, and supervise nurses. Nurses meet with patients regularly to review clinic and home BP. They also track clinic BP readings for each participant and prepare a list of patients with uncontrolled BP for audit and feedback meetings with the healthcare team. CHWs, under the supervision of nurses, function as health coaches and care coordinators to facilitate all aspects of patient care, including scheduling appointments and obtaining medications. The entire team meets monthly to review patients’ BP data and treatment plan.
Physicians, nurses, and CHWs are trained in their roles and responsibilities as part of the healthcare team. Physicians are trained in antihypertensive medication titration based on a protocol adapted from the ACC/AHA and WHO hypertension guidelines and in effectively communicating with patients. ,, Nurses are trained to oversee and assist CHWs with patient care coordination. CHWs are trained to conduct health coaching on lifestyle modification and medication adherence. ,,, Physicians, nurses, and CHWs are also trained to measure BP using a standard method according to an AHA protocol. Continuing medical education credits are available from training sessions.
CHWs conduct monthly health coaching sessions during the first 6 months (approximately 60 minutes each) and quarterly during the remaining 12 months (approximately 45 minutes each). Sessions cover medication adherence, healthy eating, , engaging in physical activity, losing weight/maintaining a healthy weight, and talking to your healthcare provider. Sessions focus on identifying barriers to behavior change, setting specific goals, problem solving, and maintaining motivation during challenging situations. Coaching materials have been adapted to be culturally relevant, including use of traditional or herbal medicines, culturally appropriate food options, and the importance of social support and religion in BP control.
Each participant also receives a home BP monitor, and CHWs provide demonstration and instructions on how to use the monitor correctly. Patients are instructed to measure BP on at least 2 days each week (3 in the morning and 3 in the evening each day) according to a standard protocol. Patients record these measurements in a BP log, and bring BP logs to health coaching sessions.
Antihypertensive medications are provided at no cost to the participants and are available in the clinic or pharmacy for pick-up.
Provider training strategy
In clinics randomized to provider training, we train primary care physicians, nurses, and other clinic staff in performing standardized BP measurements. We offer physician education on clinical guidelines for hypertension management and issue continuing medical education credits. Patient educational materials are distributed. We do not conduct any other interventions in the provider training strategy clinics.
Clinical effectiveness and implementation outcomes
The primary clinical outcome is the difference in mean change of systolic BP from baseline to 18 months between intervention and control groups. Mean systolic BP levels at baseline and 18-month termination visits are the average of 6 readings from 2 separate days (3 from each day). Secondary outcomes include differences between intervention and control groups at 18 months in the proportion of patients with systolic BP <130 mm Hg and diastolic BP <80 mm Hg, the proportion of patients with systolic BP <120 mm Hg and diastolic BP <80 mm Hg, mean change of diastolic BP, change in quality of life assessed using the EQ-5D-5L , and SF-12, and side effects of antihypertensive medications and adverse events.
The primary implementation outcome is implementation fidelity, operationalized as a composite fidelity score (Supplementary Table 1). This includes: the proportion of provider visits completed, the proportion of clinic visits with less than 2 hours of waiting time, the proportion of health education/counseling sessions received, the proportion of treatment intensified, the proportion of high adherence to antihypertensive medications, and the proportion of home BP monitoring. Other implementation outcomes include acceptability, adoption, appropriateness, feasibility, implementation costs, penetrance, reach, satisfaction, and sustainability (Supplementary Table 1).
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