Social Prescribing in Portugal: Study Protocol for a Primary Care Intervention Addressing Loneliness and Well-Being.

Loneliness is one of the most relevant social health determinants in the elderly population, associated with polypharmacy, increased use of health services, cognitive decline, and increased morbidity and mortality. In Portugal, the high prevalence of loneliness among older adults highlights the urgent need for innovative strategies that go beyond conventional responses based mainly on biomedical approaches. Social prescribing (SP) is a promising non-pharmacological intervention characterized by the formal, structured referral of patients to community activities tailored to their needs, interests, and life context. International experiences, particularly in the United Kingdom, have informed the development and implementation of social prescribing initiatives across healthcare settings. However, the literature identifies limitations, including heterogeneity in recruitment methodologies, a scarcity of long-term studies, limited integration of sociocultural variables, and the absence of robust frameworks for evaluating and monitoring results. In this context, this project aims to implement and evaluate a pilot model of SP in primary healthcare (PHC) for people aged 65 years or over, monitored in three family health units (FHUs) in central Portugal. The main objective is to evaluate the impact of the intervention on participants' perceptions of loneliness and well-being. Additionally, this study aims to identify individual and contextual factors that influence adherence, as well as barriers and facilitators, and to evaluate the implementation process in a real PHC setting. The design is prospective and longitudinal, and it integrates quantitative and qualitative assessments. The intervention involves recruiting users via the ALONE and Personal Well-Being Index (PWI) scales and SP appointments, during which, through shared decision-making, community-based cultural, recreational, sports, and/or social activities are prescribed. The evaluation and monitoring of outcomes will be based on validated scales (ALONE, PWI, UCLA, EQ-5D, and PHQ-4) administered at baseline and at three, six, 12, and 18 months. Additionally, the implementation will be evaluated by analyzing barriers and facilitators, as well as professionals' and participants' perceptions, using the RE-AIM framework. We plan to recruit 165 participants to ensure adequate statistical power, given possible follow-up losses. Expected results include a reduction in perceived loneliness, improved well-being and quality of life, characterization of adherence determinants, and recommendations for the sustainable integration of SP into PHC. This pilot study has the potential to generate innovative and transferable knowledge that supports the consolidation of the National Social Prescription Network and the formulation of person-centered health policies. By integrating health and community, it seeks to promote active aging, well-being, and social inclusion, reinforcing the PHC's role as a privileged space for innovative and cost-effective responses to the social determinants of health.