Keeping Older people healthy, deSigning and evaluating effective HEalth Services to maintain functional AbIlity (KOSHESAI); study protocol for a multimethod, prospective, hybrid implementation-effectiveness study 

Strengths

The study builds on the WHO ICOPE approach to offer a pragmatic community-based intervention delivered by non-specialists to promote healthy ageing in both urban and rural settings.

A prospective hybrid type 2 implementation-effectiveness study design will be complemented by a detailed process and cost evaluation.

The intervention incorporates community-based, ageing-focused peer support groups to enable self-management, promote healthy behaviours, physical activity and combat loneliness for older adults.

Limitations

Implementation is in part dependent upon existing public healthcare provision; effectiveness may be constrained by widespread health system resource limitations, as well as the financial constraints of the participant, affecting access to referrals and further specialized care.

The intervention focuses on the seven intrinsic capacity domains thought to have the greatest impact on functional ability, meaning other prevalent health conditions not directly related to these domains may be overlooked by the intervention.

The healthy ageing intervention

The Keeping Older people healthy, deSigning and evaluating effective HEalth Services to maintain functional AbIlity; KOSHESAI study provides a novel ‘healthy ageing’ clinic assessment, for older adults. Older adults in Zimbabwe are defined by the Old Persons’ Act as “a citizen of Zimbabwe aged sixty-five years or above, who is ordinarily resident”.¹⁰ Older adults will be screened for impairments in the seven intrinsic capacity domains, as set out by WHO ICOPE.³ If indicated, the team will provide immediate on-the-spot care, advice and/or referral.³ They will provide health promotion information and materials to support the adoption of healthy ageing behaviours and lifestyles. CHAPS groups will be developed, to which participants can be referred if eligible. The Healthy Ageing intervention is designed to be embedded within the current public healthcare system, being locally accessible, affordable, as well as clinically effective, so that should it prove effective, wider roll-out is feasible. Figure 1 presents a logic framework to underpin the design of the intervention. Table 1 applies the Template for Intervention Description and Replication (TIDieR) checklist to describe details of the intervention.²³ Of note this healthy ageing assessment represents a significant departure from the prevalent disease-specific screening and treatment paradigms common in many LMIC primary care settings, such as for HIV, diabetes, and hypertension. While these conditions are important, established albeit siloed healthcare pathways already exist for these, thus the current intervention takes a holistic approach to assess intrinsic capacities specifically, aligning with the WHO ICOPE framework.

Figure 1. A logic framework to underpin the design of the intervention and the causal pathways through which the intervention is expected to mediate its effect.

Patient and public involvement

Patients and members of the public were involved in the development of the KOSHESAI study from the earliest stages of project conceptualisation. Their input has been instrumental in ensuring the study is culturally appropriate, feasible, and addresses the actual priorities of older people in Zimbabwe. Older people and caregivers were consulted prior to securing funding for this study, and subsequently in the design of study conduct, the assessments and proposed interventions.

In consultation with older adults, their caregivers, community gatekeepers in the study sites, and stakeholders (health professions, community-based organizations) working with older adults, we adapted the WHO ICOPE screening tools to ensure their relevance to our context, ensuring that the language is culturally sensitive. Consultative workshops also influenced the structure and content of the peer-to-peer support groups. The choice of primary and secondary outcomes was refined following consultation with the health professions of what would be clinically relevant, and feasible based on their daily practices.

To ensure inclusive recruitment and participation in the study, we asked older adults and stakeholders who had participated in workshops to spread the word of the study. Going forward, to enhance community engagement, eligible workshop participants—older adults and caregivers—will work alongside CHAPS facilitators to lead recruitment efforts within their own communities. The public also recommended that peer-to-peer support groups take place during times that do not conflict with local agricultural cycles or community events.

A key output of the study—the community engagement handbooks—will be distributed during community sensitisation days. These events will serve as a platform to promote health awareness. To ensure accessibility for all community members, we will provide health information in the form of short, visual fliers and pamphlets, translated into local languages. This approach ensures that dissemination is not just a one-way report, but a continuing conversation with the communities involved.

Aims

To develop, implement and evaluate an evidence-based, potentially sustainable, clinical framework for community-based non-specialist assessment and management of chronic impairments of ageing which impact intrinsic capacity and through this functional ability, to improve health and wellbeing of older people living in Zimbabwe.

Objectives

The study protocol is described following all recommendations established by 2025 Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT).²⁴

Community and stakeholder engagement and involvement

Community members and stakeholders were involved in the design of this research protocol. Using the 2019 WHO ICOPE framework as a starting point,⁹ the intervention was designed and contextualised following formative research conducted between December 2023 and December 2024 with a range of older people and their caregivers from the planned study settings, as well as key stakeholders, ageing-orientated non-governmental organisations (NGOs), and community-based organisations (CBOs). All community gatekeepers and leaders in the study communities were mapped and a network was established of KOSHESAI “champions”, constituting older people with and without recent health care experience(s), and key community leaders focused on older adult wellbeing. This formative work demonstrated that the planned healthy ageing assessments are highly desired by older people, likely to be feasible to implement, acceptable to stakeholders, and complementary to existing services. In urban Zimbabwe, it is expected that there is a substantial burden of unmet needs from previously untreated yet treatable intrinsic capacity impairments.²⁵

The stakeholder engagement contributed not only to the adaptation of clinic assessments but also shaped the design of the components of the community intervention, and the development of information materials. Stakeholders provided valuable advice and emphasized the need for culturally appropriate nutritional guidance, advocating for the incorporation of locally sourced foods and traditional dietary practices to improve dietary behaviours. Stakeholders highlighted the importance of promoting physical activities that are both accessible and acceptable to older adults within the Zimbabwean context, with suggestions aimed at mitigating potential barriers to accessing services, e.g., clinic and community hall renovations to enable access for those living with disability. For mental health support, stakeholders stressed the need for integrated approaches that combine the Friendship Bench community-based support model²² with strengthened referral pathways to the Mental Health Gap (MhGAP) services²⁶ embedded in the public health facilities. Key recommendations were to ensure the availability of appropriate and affordable assistive devices, such as walking sticks and reading glasses, to enhance mobility and sensory function.

Participatory workshops with older people and their caregivers found that older people were keen to learn more about their mental and physical health and about how they could improve their health over time. A CHAPS group intervention was co-designed with the older adults and stakeholders. CHAPS are designed to promote and maintain functional ability by facilitating self-management among older people. Older people, especially older men, were particularly interested in bladder health. Findings from workshops were used to co-create CHAPS facilitator handbooks, and the easy-to-understand information booklets on “healthy ageing” and bladder health (male and female specific versions). All booklets and handbooks were written in English and then translated into Shona, (additional Ndebele translation will follow). Booklets and handbooks were refined through focus group discussions (FGDs) with purposively selected men and women to ensure all relevant topics were covered and all information and images were understandable, appropriate, and acceptable.

To widely disseminate co-developed health information and promote healthy ageing, community education events were planned to be conducted in local community halls, during and after the recruitment period. These events will be open to the public and cover key topics relevant to older adult health, such as dementia and mental health, continence and sexual health, nutrition and physical activity, and abuse and neglect. Furthermore, outreach events will be organized at the one old age residential home in the study communities to maximise the reach of the intervention and evaluate it within an institutionalised care setting.

Logic model

We hypothesize that a routine healthy ageing assessment and intervention addressing the seven core intrinsic capacity domains will have an immediate positive impact on the health and wellbeing of older people in Zimbabwe. This KOSHESAI intervention is underpinned by a logic model ( Figure 1) that outlines the causal pathways through which the intervention is expected to mediate its effect. This model delineates the intervention’s activities, outputs, and intermediate outcomes, while also considering contextual factors that may influence its implementation and effectiveness. The logic model was developed collaboratively, drawing on the expertise of the research staff, and individuals with in-depth knowledge of the Zimbabwean context. During participant recruitment, a ‘Theory of Change’ will be developed to make explicit the granular causal pathways leading to the outcomes of the healthy ageing intervention.

Study design and setting

A prospective hybrid type 2 implementation-effectiveness study will recruit older adults age ≥65 years and follow them up for four months. The intervention will be delivered in local primary healthcare clinics (community-based public healthcare facilities providing a range of routine outpatient medical services) within urban and rural settings. This setting facilitates the integration of the intervention within the established primary care system, offering a local location for intervention delivery, aiming to enhance accessibility and convenience for participants. Older adults residing within two urban settings in Harare (Mufakose and Highfield) will be recruited in 2025. In 2026 recruitment will expand to four rural settings in Murehwa district (potential clinics include Nyamatumbu, Kadzere, Chitate, Munamba, and Murehwa) (see Figure 2 for locations of study sites). Study findings and the process evaluation from the urban setting, together with further community and stakeholder engagement and involvement in the rural setting, will inform intervention refinement ready for rural intervention in 2026.

Figure 2. Shows the locations of study sites in both the urban setting (Harare) and rural setting (Murehwa).

Inclusion and Exclusion criteria

Adults aged ≥65 years based on photo identification, residing in the study areas will be included. Those with plans to relocate outside of the study area in the forthcoming four months, or with circumstances that would prevent them from returning for a 4-month follow-up appointment, will be excluded from the study.

Community sensitization

To enable participant recruitment a programme of community sensitization will be conducted in study communities using diverse approaches. A community team (research nurse and research assistants) will distribute study flyers, visit homes of potentially eligible individuals identified from the local offices of social welfare. Primary healthcare clinic staff will be able to refer older patients to the study team. Further methods will include community word-of-mouth, door-to-door house visits, and direct engagement at older adults’ social gathering points such as churches, beerhalls and betting halls. Participant identification will further involve referrals from CHAPS facilitators, community-based organizations, and previous study participants consenting to future contact for future studies.

Intervention implementation

The study clinic

Clinics have been renovated to ensure they offer an age-friendly environment, with improvements including ramps, grab bars in toilets, clearer signage (to toilets and study clinic assessment rooms), brighter lighting, and non-slip floor-proofing. Sanitation has been significantly improved by ensuring running water in toilets and the provision of cleaning detergents.

Consenting older adults will be screened for impairments in the seven intrinsic capacity domains, to identify the need for domain-specific interventions ( Table 2). Where needed, immediate on-the-spot interventions will be provided (e.g., ear syringing, fitting of walking sticks and/or reading glasses). Bespoke patient-specific health advice will be provided by trained nurses, relevant to the deficits identified, tailored to the participant’s specific health profile and risk factors, to promote healthy behaviours, self-management and health autonomy. All participants will be provided with a colour copy of the co-produced Healthy Ageing Booklet, designed to provide accessible and culturally relevant information on healthy ageing practices, which can be read by the older person and/or their caregiver(s) ( Figure 3).

Figure 3. The Healthy Ageing Booklet, designed to provide accessible and culturally relevant information on healthy ageing practices, which can be read by the older person and/or their caregiver(s).

Community healthy ageing peer-to-peer support groups (CHAPS)

Depending upon the deficits identified in the clinic, participants may be offered the opportunity to join a CHAPS group, either ‘Healthy Minds’ CHAPS if cognitive impairment is identified, or ‘Healthy Ageing’ if not. The CHAPS aim to promote and maintain functional ability by facilitating health promotion and self-management for older people. The two different types of CHAPS groups will be run to meet older people’s varying health needs: Healthy Minds CHAPS with focus on cognition and dementia, Healthy Ageing CHAPS with focus on improving mobility, nutrition, bladder health, and mental health. Healthy Ageing CHAPS, with 10-12 people in each group, will be split by gender as these groups will engage in sensitive discussions and exercises when addressing bladder health. Healthy Minds CHAPS groups, with five to eight people, will include both men and women. Each will be led by two community ‘champions’ (an older adult volunteer [age approximately ≥60 years], plus a younger adult volunteer [age 30-60 years]) who will be trained and supported by the multi-disciplinary project team. Where possible, champion pairings of an older and younger person are planned to harness diverse skill sets, relatability and organisational skills. Healthy Minds CHAPS champion pairings will have one man and one woman to represent the two genders in the groups. ‘How-to’ guides and manuals will guide the implementation of the CHAPS groups.

Referral to specialized services

Where indicated, research nurses will refer participants for further care, particularly for hearing impairment, visual impairment, depression and anxiety, and cognitive impairment ( Table 2). Referrals aim to link participants to specialized services for diagnosis, treatment, and ongoing management of identified health conditions. Transport costs incurred accessing referral services will be provided ($5 per older adult, +/- an additional $5 for a caregiver), addressing financial barriers to participation and promoting adherence to the intervention protocol. If a participant is found to be acutely unwell, they will be transferred to the local hospital emergency department.

Home visits

Adults unable to attend the primary healthcare clinic due to severe mobility impairments, or severe dementia will be seen at home. Home visits ensure all eligible participants can be assessed and receive the intervention, promoting inclusivity and addressing potential barriers to access. Assessments and interventions delivered during home visits will be adapted according to the individual health conditions and needs of the older adult.

Composition and training of the KOSHESAI study team

The KOSHESAI study constitutes a multi-disciplinary team to ensure effective implementation and evaluation of the intervention. Two clinic teams, each led by a research nurse and composed of two research assistants, will manage participant recruitment, assessments, and clinic flow and logistics. A community team, also led by a research nurse, will lead community engagement and conduct home-based assessments. A CHAPS coordination team will oversee the training, monitoring, and evaluation of CHAPS champions during intervention delivery. A process evaluation team will evaluate implementation, impact mechanisms, and contextual influences. Another researcher will collect cost data in real-time. This structure integrates clinical service, community support, and rigorous evaluation. All staff will undergo a month-long training program, including classroom learning, scenario role-plays, and clinic ‘dry-runs’, covering ethical practices, study procedures, community engagement, data collection, intervention delivery, and data management.

Piloting the intervention

Following training, a 15-day pilot phase will optimise assessment procedures and intervention delivery. Daily participant recruitment will gradually increase, allowing identification and mitigation of any logistical challenges and workflow inefficiencies in real-time. The process evaluation team will focus on key implementation parameters within the Medical Research Council (MRC) Process Evaluation framework.³⁵ They will provide iterative, constructive feedback to the study team regarding the degree to which the intervention is delivered as specified in the protocol and identified barriers and facilitators to optimal clinic operations. Clinic observations, including participant waiting times, age-friendly communication, participants’ attitudes and response to the intervention, and overall operational efficiency, will be undertaken. In addition, the process evaluation team will collect time-and-motion data to quantify staff time allocation across the various clinic components. Dynamic feedback will enable iterative refinement of intervention delivery. Data collected in this phase will be included in the main study dataset.

Consent procedures

All eligible participants will receive a clear verbal explanation and a Participant Information Sheet (PIS) in English or Shona, with time for questions before providing informed written or witnessed thumb-print consent, in line with the Declaration of Helsinki.³⁶ Consent will cover assessments, interventions, clinical photography, audio recordings, data archiving, and future research contact. Older people lacking decisional capacity due to cognitive impairment will be eligible to participate, with surrogate consent obtained from their caregiver (consultee/proxy). If capacity is regained, standard consent will be sought directly from the participant.

Data collection

Clinic

Data collection at baseline and 4-month follow-up visits will include researcher-administered questionnaires, and a series of physical assessments conducted in designated clinic rooms providing visual and auditory privacy. At baseline, the clinic flow will enable different researchers to conduct independent screening and validation assessments. All data will be captured directly into pre-programmed ‘off-line’ ODK forms, with data validation checks, on Samsung Galaxy tablets, which will be backed up at the end of each day.

At baseline data will be collected concerning sociodemographic factors (e.g., educational attainment, household income, marital status, food insecurity, caring responsibility), medical history (e.g. comorbidities, falls, disability,^29,37 pain), medications, smoking and alcohol consumption, security and social support,³⁸ activities of daily living (ADLs) and instrumental ADLs (iADLs),³⁹ health-related quality of life (HRQoL) (using EQ 5D-5L which measures HRQoL over the previous two weeks⁴⁰), and health expenditure in the previous 4-months. Where available, hand-held medical records will be interrogated to augment responses and determine historic events. Screening and validation assessments will be performed for all seven intrinsic capacity domains (cognition, mental health, nutrition, vision, hearing, continence, and locomotion) ( Table 2). No blood tests will be performed.

At the end of the clinic appointment the nurse will review the assessment. Where a deficit has been identified in one or more intrinsic capacities, they will offer on-the-spot advice and/or intervention and discuss goals and appropriate referral(s) according to the preferences of the older person. Potential interventions were listed in Table 2. The nurse will complete a semi-automated care plan, populated by the results of the assessments.

At 4-month follow-up data will be collected to determine new medical diagnoses, medication changes, changes in health behaviours, pain, disability, security and social support,³⁸ ADLs and iADLs,³⁹ and HRQoL.⁴⁰ Data on out-of-pocket health-associated expenditure incurred by participants accessing the intervention, including any transport costs and opportunity costs, will be collected, as will data on referral uptake and experiences. The questionnaire will be refined during the intervention piloting phase and finalised before the 4-month follow-up. To minimise loss to follow-up, participants will receive a clinic reminder card with the follow-up date, and a reminder telephone call the day before their appointment date. In the case of missed appointments, visits will be rescheduled.

Process evaluation

We will conduct a mixed-methods process evaluation based on guidance from the MRC Process Evaluation framework.⁴¹ This evaluation aims to comprehensively assess the intervention’s implementation, mechanisms of impact, and the influence of contextual factors. The process evaluation will investigate intervention delivery, including acceptability, adoption, appropriateness, feasibility, fidelity, and intervention impact. Additionally, it will draw on implementation and behavioural science frameworks, including the Consolidated Framework for Implementation Research (CFIR),⁴² the Framework for Understanding Successful Interventions (FUSI), and the Capability, Opportunity, Motivation - Behaviour Change Model (COM-B).⁴³ These frameworks will provide a theoretical basis for understanding intervention implementation from service providers’ perspectives (CFIR) and the intervention’s acceptability, uptake, and behavioural changes from the end-users’ perspectives (FUSI and COM-B).

The process evaluation will investigate several key domains: programme implementation, mechanisms of impact and context ( Table 3). Data will be collected at multiple time points, using multiple methods and sources, and in various locations (e.g., homes, community places, clinics) to ensure triangulation. Data collection tools will be developed in response to findings from formative work and guided by the theoretical frameworks. The process evaluation will remain flexible and dynamic throughout the study to adapt to emerging findings.

Quantitative data will provide insight into the reach and impact of implementation of the KOSHESAI intervention. At all intervention sites, routine metrics on program activity will be collected throughout the study period. This will include observations of variability of daily activities, such as reach, and time and motion measurements. Data on the reported uptake and acceptability of health services and CHAPS groups will be obtained after the initial screening and intervention visit and at the 4-month participant follow-up visit. CHAPS programme data will be collected, including data on CHAPS group set-up, meeting timelines and locations, participant attendance, and method and duration of travel to the meetings. The process evaluation will encompass the collection of data pertaining to linkage to care. This will involve monitoring communication and referral processes. The process evaluation team will also track intervention changes through intervention adaptation tracking forms.

Qualitative data collection for the KOSHESAI process evaluation will employ a range of methods to capture diverse perspectives and in-depth insights. Purposive and theoretically informed sampling will guide qualitative data collection, with consideration of service provider and participant characteristics (e.g., age, sex, engagement with the intervention). These methods will include observations of implementation activities, such as staff skills training, clinic screening and assessments, and CHAPS implementation, to provide contextual understanding of intervention delivery. In-depth interviews (IDIs) will be conducted with CHAPS facilitators, KOSHESAI implementation team members, service providers at referral points, and community stakeholders to explore their experiences and perceptions of service delivery. Focus group discussions (FGDs) and participatory workshops will be conducted with older adults and caregivers to understand their experiences and views of clinic screening and assessments, and their experiences of attending CHAPS groups. In-depth case studies will also be carried out with older adults and their family members to provide an in-depth understanding of pathways through care, including barriers and facilitators to access, acceptability, and behaviour change. These diverse qualitative methods will allow for a comprehensive exploration of the determinants of implementation, the intervention’s implementation outcomes, and mechanisms of impacts.

Economic evaluation

An economic evaluation will quantify resource use in developing, adapting, and delivering interventions across different care domains and determine participant out-of-pocket costs. Project expenditure data will be gathered during the start-up and implementation phases and used to estimate health system costs, including staff salaries, consumables, equipment, and transportation. In the absence of a Zimbabwean guide on discounting rates for costs and outcomes, all capital costs and any costs with a lifespan greater than the project life will be annualised using a 3-5% discount rate. Total costs will be allocated to different care domains using process evaluation data such as direct allocation based on information obtained from the finance department and time spent by staff on each domain, which will be collected using staff-time surveys. Research-specific costs will be identified and excluded from the analysis. Data on costs incurred by participants to access the healthcare services will be collected using a bespoke interviewer administered questionnaire. Participant costs will focus on both direct medical and non-medical costs. Medical costs will include healthcare services costs, such as hospital and clinic visits, medications, and diagnostic tests, while non-medical costs will encompass transportation, lost income for caregivers and food expenses during visits. This information will be combined to estimate unit costs per older person screened, condition identified, and person managed using both a health system and participant perspective. Key drivers of costs will be assessed; understanding will help inform the scale-up and financial sustainability of the Healthy Ageing assessment and intervention.

Baseline and follow-up measurements of HRQoL (using the digital, interviewer-administered, EQ 5D-5L⁴⁰ - Shona or English versions) will be used to estimate quality-adjusted life years (QALYs), using the value set for Zimbabwe.⁴⁴ The QALYs will be used as the economic evaluation outcome measure in the cost-effectiveness of the intervention as the cost per improvement in older persons’ HRQoL. Cost and cost-effectiveness estimates will be compared to similar programmes in the region and will inform programme replication, scalability, and financial sustainability for different implementing partners.

Study outcomes

The primary outcome is the proportion of older adults identified as having a deficit in one or more of the seven domains of intrinsic capacity who receive appropriate on-the-spot care and/or complete appropriate referral to CHAPS and/or a health facility for treatment by follow-up at 4 months.

Secondary outcomes will include:

Sample size

To have 3.5% precision to detect a 70% successful provision of appropriate on-the-spot care or complete appropriate referral to peer-to-peer community healthy ageing group support and/or a health facility for treatment, 659 older adults will need to be followed-up at 4-months. If 80% of older people screen positive in one of more intrinsic capacity domains and are therefore in need of an intervention, then 824 older people will need to be screened. This falls to 732 older people if 90% screen positive in one of more intrinsic capacity domains. Thus, each of the two urban primary healthcare clinics will recruit and screen to identify 363 older people with one or more intrinsic capacity impairments, to follow-up 330 participants at four months and allow for 10% loss to follow up.

A similar approach will be taken in the rural study, although refinement will be informed by the proportion screening positive for impairments, and who are lost to follow-up in the urban setting.

Data analysis

A mixed-methods approach will be utilized for data analysis, systematically processing collected data and drawing insights from both statistical and qualitative examinations. The subsections below detail the specific methodologies that will be applied to assess the intervention’s effectiveness and its operational aspects.

Statistical analysis

The primary analysis will be conducted separately, first for urban and second for rural settings. Secondary analyses will assess urban-rural differences. In the study settings a contemporaneous comparison group is not available as no routine screening is taking place, hence baseline assessments will provide the counterfactual for internal comparisons. Similarly, a before-after comparison is appropriate; since there is no treatment targeting healthy ageing in these settings, any reductions in prevalence of intrinsic capacity impairments between baseline and 4-month follow-up can be attributed to the healthy ageing intervention.

Counts and percentages, means and standard deviations (SD), medians and inter-quartile ranges (IQR) will be used to describe quantitative data. The ICOPE screening tools will be validated against assessment tools ( Table 2), calculating sensitivity, specificity, positive predictive value, and negative predictive value. Screening test results will be reported, as will the services delivered, and referrals made, overall and stratified by age, sex, and location. We will use descriptive analysis to describe clinic-level characteristics at each of the polyclinics.

The primary outcome is a single proportion which will be presented with a 95% confidence interval. Secondary outcomes which are measured at a single time point will be presented in a similar way. For outcomes which are measured at two or more time-points, a before-after analysis will be conducted comparing differences in measures between the two time-points. The unit of analysis will be the individual. For clinical outcomes which are measured at two or more time-points, the initial baseline visit will give the prevalence of undiagnosed and untreated intrinsic capacity impairments and chronic conditions which will represent the counterfactual. The proportion of undiagnosed and untreated intrinsic capacity impairments and chronic conditions at the 4-month follow-up visit will be formally compared to this counterfactual to estimate the effectiveness of the intervention in improving these clinical outcomes. We will assess health service and older-person-specific determinants of correct management of conditions at 4-months using multivariable linear and logistic regression.

Quantitative data collected as part of the process evaluation (e.g., program data, monitoring forms) will be analysed using descriptive statistics to assess intervention delivery, reach, and fidelity. The cost-effectiveness of community-based health checks will be evaluated from a health system and patient perspective by comparing both costs and health outcomes (measured in quality-adjusted life years, QALYs) against a counterfactual scenario of no health checks. The cost-effectiveness of various screening, assessment and treatment/referral scenarios will be modelled considering the underlying epidemiology, sensitivity and specificity of screening tests, and effectiveness of condition-specific interventions.

Qualitative Analysis

Qualitative data will be analysed using an inductive thematic analysis.⁴⁵ Given the study’s focus on applied health research and the need for a structured approach to analyze data across cases and sites, we will also incorporate elements of the Framework Method⁴⁶ to aid in data management and comparison. Analysis will be informed by the CFIR and FUSI frameworks to understand service provider and user perspectives on implementation; and the COM-B model to identify factors influencing behaviour change in older adults.

Integration of findings

Qualitative and quantitative data will be triangulated using a convergent parallel study design.⁴⁷ Findings will be integrated at the level of interpretation using a narrative approach.⁴⁷ This will provide a richer, more nuanced understanding of how the intervention is being experienced and delivered. The findings will provide evidence to support development of the Healthy Ageing Intervention Toolkit and inform potential future sustainable and scalable implementation by health care providers should the intervention prove successful.

Ethical and governance approvals

Ethical approval for this study was obtained from the ethics committee of the Medical Research Council of Zimbabwe (reference MRCZ/A/3077;15 December 2023).

Data protection and management

Data protection will be strictly observed. After the study completion, data will be stored at data.bris following General Data Protection Regulations (GDPR). Third party researchers wishing to access individual data records will be able to apply following processes outlined at http://www.bristol.ac.uk/staff/researchers/data/accessing-research-data/, subject to a data transfer agreement and informed consent procedures regarding use of anonymised data by other researchers. Data for sharing will be anonymised so that they contain no information that could directly identify any of the participants. Data users will need to acknowledge data sources and ensure regulatory requirements are met: The Medical Research Council of Zimbabwe (MRCZ), expects that a Zimbabwean co-author be included in all publications resulting from data collected on Zimbabwean human subjects.