What helps or hinders intervention success in primary care? Qualitative findings with older adults and primary care practitioners during a feasibility study to address malnutrition risk.

Background: In the UK, about 14% of community-dwelling adults aged 65 and over are estimated to be at risk of malnutrition. Screening older adults in primary care and treating those identified as 'at risk' may help reduce malnutrition risk and associated healthcare use, and improve quality of life. The aim of this study is to explore how primary care practitioners (PCPs) and older adults perceive, use and respond to an intervention to support those identified as 'at risk'.

Methods: We developed and optimised an intervention (screen and treat protocol, online tools and printed materials) to support primary care practitioners to identify malnutrition risk among older adults, and intervene where necessary. We recruited older adults (described as 'patients' here) taking part in a feasibility study, and carried out semi-structured interviews to assess PCPs' and patients' engagement with the intervention, and identify any contextual issues that supported or undermined their engagement.

Results: Four themes were developed, encompassing patients' and PCPs' perceptions of undernutrition, study measures and appointments, constraints on PCPs' enthusiasm to make a difference, and patients' expectations of nutritional appointments. Key findings included patients commonly not accepting advice for undernutrition/malnutrition but welcoming support for their nutritional needs; checklists potentially distracting patients from recalling discussions about their nutritional needs; a tension between PCPs' desire to recruit less-well patients and logistical difficulties in doing so; and patients compromising their nutritional needs to suit others.

Conclusions: Diverse factors influence whether an intervention succeeds in primary care. PCPs learn about an intervention/study in different ways, vary in how they understand and accept its aims, and desire to make a difference to their patients. Patients bring perceptions and expectations about the study's aims, coloured by their habits and preferences, prior experience of research and healthcare, and pressure from social expectations. Each aspect must be considered when developing a successful primary care intervention that is viewed as relevant and meaningful, and presented using language that aligns with participants' values and goals. Our findings suggest that references to 'malnutrition risk' should be avoided in any patient-facing materials/interactions as participants do not accept or identify with this label.