This study will use a phased, multimethod approach grounded in an equity-informed Experience-Based Co-Design (EBCD) methodology [65,66], informed by prior HIV and co-design work [67]. EBCD is a participatory action research approach that meaningfully engages patients, caregivers, and HCPs as cocreators of care innovations, ensuring that the resulting models are grounded in lived experience and aligned with principles of PFCC [32,65,66]. To structure the co-design process, we will apply the UK Design Council’s Double Diamond framework, which consists of 4 iterative phases: Discover, Define, Develop, and Deliver [33]. This framework provides a transparent and replicable structure for moving from problem identification to implementation readiness. The study was codeveloped with a pre-grant advisory committee [68]. The advisory committee includes knowledge users (3 nonprofit administrators), 2 older adults living with HIV, and 5 clinicians. Members have contributed to study conceptualization, methodological decisions, and recruitment strategies. The advisory committee will meet quarterly throughout the project to provide input on study processes, support the interpretation of findings through peer debriefing, and guide integrated knowledge translation activities [34].

As co-design guidelines are still being developed [35], this study will be reported in accordance with established reporting guidelines for qualitative and participatory research. Specifically, we will follow the Standards for Reporting Qualitative Research to guide comprehensive reporting of study design, data collection, and analysis [36]. Given the participatory and co-design nature of this study, we will additionally apply the Guidance for Reporting Involvement of Patients and the Public to ensure transparent reporting of patient and community engagement throughout all phases [37]. Completed checklists will be provided as supplementary materials in related publications.

An explicit equity lens guides all phases of the study to ensure inclusivity, cultural responsiveness, and attention to structural determinants of health [38,39,69-73]. Equity is operationalized using the CCRCMA (Culturally-Competent Research Criteria for Methodological Areas) framework, which informs problem formulation, recruitment, data collection, analysis, and dissemination [74]. Participant diversity will be monitored using the PROGRESS-Plus framework, capturing social determinants such as place of residence, race/ethnicity, occupation, gender, religion, education, socioeconomic status, social capital, plus additional factors [75].

Gender identity data will be collected using inclusive categories aligned with Rainbow Health Ontario recommendations [76], with options to self-describe or decline. Intersectional analysis will be applied during data interpretation to examine how overlapping social identities and systems of oppression shape caregiving experiences [77-81].

Across all study phases, we will recruit older adults living with HIV (aged ≥50 y), caregivers (including both biological/legal family and chosen family), and HCPs who provide care or support to older adults living with HIV in Ontario. Including older adults living with HIV ensures that the model is grounded in their lived experiences, needs, and priorities. To address the underrepresentation of chosen family caregivers, we will ensure that at least 50% of caregiver participants in each phase are drawn from chosen family networks. Recruiting both chosen and biological or legal family caregivers will allow us to capture a range of perspectives and examine both shared and distinct caregiving experiences, thereby strengthening the development of a PFCC model that is responsive to diverse caregiving contexts. HCPs will be included to provide insight into current care practices, challenges in supporting caregivers, and opportunities to enhance caregiver integration. Eligibility for HCP participants will require that at least 10% of their caseload consists of older adults living with HIV, ensuring adequate experience with this population.

We will use a purposive sampling matrix informed by a maximum variation strategy to ensure diversity across key characteristics [82]. Specifically, older adults living with HIV and caregivers will be recruited to reflect variation in (1) gender identity (with at least 50% male or gender-diverse participants); (2) geographic location (urban, suburban, rural, and remote regions); (3) socioeconomic status and lived experience (including low income and housing instability); (4) racial, ethnic, and linguistic backgrounds; (5) immigration and residency status (eg, newcomers); (6) sexual orientation (with at least 50% identifying as sexual minorities); and (7) age (≥50 y for older adults living with HIV). Our team has demonstrated success in recruiting across these groups in prior studies. For HCPs, in addition to gender and geographic diversity, we will ensure variation in (1) organizational setting (eg, hospitals, community-based organizations, nonprofits, and independent practices); (2) professional role (eg, frontline providers, managers, nurses, and physicians); and (3) years of experience (early-, mid-, and late-career).

Participant identification and recruitment will be conducted collaboratively with the research team, advisory committee members, community partners, and health care networks, enabling targeted outreach to underrepresented groups. Recruitment strategies will include partnerships with community organizations, outreach through social media, in-person engagement, rapport-building activities, and word-of-mouth referrals (snowball sampling). Flexible and tailored recruitment approaches will be used to enhance accessibility and inclusivity. All data collection phases and sessions will have translators available for non-English speakers.

We will implement multiple strategies to promote sustained engagement and reduce participation barriers among older adults living with HIV, caregivers, and HCPs. These include partnering with trusted community organizations, using relationship-based recruitment approaches, offering flexible scheduling (including evenings and weekends), and providing participants with a choice of interview modality (in person, by phone, or via secure virtual platforms). Participants will receive honoraria at each phase to recognize their time and contributions. We will also maintain ongoing communication (eg, reminders and check-ins) and create a supportive, inclusive study environment grounded in trauma-informed and culturally sensitive practices. To facilitate participation in virtual data collection, where applicable, participants will be offered brief, one-on-one orientation sessions on how to use the selected platform (eg, Zoom), including step-by-step guidance and troubleshooting support. Written and visual instructions will be provided in plain language. Where needed, we will offer telephone-based participation as an alternative to reduce digital access barriers. The research team has prior experience supporting participants with varying levels of digital literacy. Recognizing potential concerns related to stigma, confidentiality, and digital privacy, particularly among people living with HIV, we will use secure, institutionally approved platforms for virtual data collection and encrypted data storage. Participants will be informed about privacy safeguards, including the option to keep cameras off, use pseudonyms, and participate from a location of their choosing. Consent procedures will emphasize voluntary participation and the right to withdraw at any time. Collaboration with trusted community partners and advisory committee members will further support trust-building, cultural safety, and the acceptability of study procedures.

The study will be conducted in 3 phases.

This study involves human participants and has received ethical approval from the Sinai Health Research Ethics Board, Ontario, Canada (approval number 25-0043-E). All participants will provide informed consent prior to participation. Consent will be obtained in writing after participants have received detailed information about the study purpose, procedures, risks, benefits, and their rights, including the right to withdraw at any time without penalty. Ongoing assent will be sought during the co-design workshops. All data will be handled in accordance with institutional and provincial privacy standards. Interview recordings will be transcribed verbatim and deidentified, with all personally identifying information removed or replaced with pseudonyms. Data will be stored on secure, password-protected institutional servers, with access restricted to authorized research team members. For virtual data collection, secure, institutionally approved platforms will be used. Participants will be reminded to join from a private location and may choose to keep cameras off or use pseudonyms to further protect their identity. Participants will receive an honorarium in recognition of their time and contributions at each phase of the study. Compensation amounts will be appropriate to the level of participation and consistent with institutional and funding guidelines.

All study materials, including interview guides, demographic questionnaires, workshop facilitation guides, coding frameworks, and analytic protocols, will be provided as supplementary materials to enable replication and adaptation in subsequent manuscripts. All publications emerging from this study will be reported using established qualitative reporting standards and EBCD methodological guidance.

This study will provide novel insights into the experiences and support needs of older adults living with HIV and their diverse caregivers, highlighting both gaps in existing services and strategies to enhance PFCC. By co-designing a PFCC model with end users and health care providers, we anticipate producing a framework that is inclusive, culturally safe, and aligned with real-world care experiences. Our findings are expected to build on previous research showing that participatory approaches and tailored interventions improve health outcomes and reduce caregiver burden while supporting more efficient health care delivery [64]. The anticipated results will likely demonstrate that integrating chosen family caregivers alongside biological and legal caregivers strengthens care coordination, improves continuity of support, and addresses inequities in access to services.

The implications of this work could extend beyond the HIV context. A co-designed, equity-informed PFCC model can serve as a blueprint for addressing the complex needs of older adults with chronic or stigmatized conditions, guiding both practice and policy. Embedding implementation science strategies ensures the model’s feasibility, scalability, and sustainability in health care settings, offering actionable recommendations for clinicians, administrators, and policymakers. By systematically incorporating end-user perspectives and intersectional social determinants of health, this approach advances inclusive and responsive health care design.

Future research should evaluate the PFCC model’s effectiveness in improving caregiver and patient outcomes, its adaptability across different health care settings, and its potential for integration into broader policy frameworks. Longitudinal studies could examine how sustained implementation impacts health care utilization, caregiver well-being, and quality of life among older adults living with HIV. Ultimately, this work lays the foundation for a person- and family-centered approach that not only addresses current gaps in HIV care but also informs the development of inclusive caregiving policies and practices in diverse health care contexts.

Data collection has not yet begun but is planned to start in summer 2026. Data analysis will commence following completion of data collection. We anticipate that this study will identify key barriers and facilitators to supporting older adults living with HIV and their diverse caregivers, including systemic gaps, caregiver burden, and inequities in care access, as well as strategies that enable effective, person- and family-centered support. Co-design workshops are expected to yield a prototype PFCC model incorporating care coordination, inclusive recognition of chosen and biological caregivers, tailored education for caregivers and health care providers, and communication and policy supports. Focus groups on implementation will likely highlight practical strategies for adoption, scalability, and sustainability across Canadian care settings. Collectively, these findings will provide actionable guidance for developing equitable, culturally safe, and sustainable interventions; inform policy and practice; and offer a replicable methodological framework for researchers aiming to co-design PFCC models in diverse health care contexts.

This study has limitations. The research was conducted in Ontario, Canada, which may limit transferability to other jurisdictions with different health care systems or social contexts. Participation bias is possible, as individuals engaged with community networks or comfortable with virtual platforms may be overrepresented [96]. Recruitment may also be challenging due to differences in urban vs rural populations, which could also affect the representativeness of the sample. Additionally, while co-design workshops provide rich qualitative insights, translating these insights into widely adoptable interventions will require further feasibility testing.

The proposed project is rooted in existing participatory action research initiatives with older adults living with HIV [55,67,81,97-99]. A key area identified by this work is the need to center diverse caregivers (ie, biological, bio-legal, and chosen family) in future care initiatives. To build on this patient-identified gap in service and research, this project was codeveloped with a pre-grant advisory committee [67]. The research team will continue to work closely with this advisory committee throughout the duration of the project.

This study addresses a critical gap in HIV and aging care by centering the experiences of older adults living with HIV and their diverse caregivers, including chosen family members. Through an equity-informed, Experience-Based Co-Design approach, we developed a PFCC model that is grounded in lived experience and responsive to the complex, intersecting needs of this population. The resulting model provides actionable guidance for inclusive care coordination, caregiver recognition, tailored education, and supportive policies. By integrating implementation science principles, the study also produces a context-sensitive roadmap to support adoption, scalability, and sustainability of the PFCC model across diverse Canadian care settings. Ultimately, this work has the potential to improve caregiver support, enhance care experiences for older adults living with HIV, and advance equity in health and social care systems. Furthermore, the methodological framework outlined in this protocol offers a replicable approach for co-designing inclusive care models for other chronic or stigmatized conditions.