Identifying Barriers in the Prescription Pathway of Special Low-Protein Foods and Protein Substitutes for People with PKU in the UK: An Industry Perspective

Background/Objectives: Timely access to protein substitutes and special low-protein foods (SLPFs) is fundamental to maintaining dietary adherence and metabolic control in phenylketonuria (PKU). Disruptions within the prescription pathway may compromise the continuity of medical nutrition supply, with potential consequences for patient outcomes and health service efficiency. This study aimed to identify the most frequently reported prescription-related challenges from the perspective of UK industry stakeholders and to outline their implications for the care and dietetic practice of individuals with PKU. Methods: A structured questionnaire was distributed by the National Society for Phenylketonuria to industry representatives involved in supplying Advisory Committee on Borderline Substances (ACBS) approved protein substitutes and special low-protein foods (SPLFs). Anonymised responses were analysed descriptively to identify the types, frequency, and impact of prescription-related issues. Results: Forty-four prescribing and supply incidents were reported by specialist nutrition manufacturers and suppliers. Reported incidents affected both paediatric (54%) and adult (46%) patients, with protein substitutes accounting for the largest proportion of prescribing and supply issues (48%), followed by SLPFs (27%) and combined product issues (25%). Most reported barriers originated within primary care, particularly general practitioner (GP) practices (61%), followed by community pharmacies (21%). Thematic analysis identified five key areas of difficulty: GP prescribing barriers, prescribing errors, pharmacy and wholesaler procurement problems, supply chain and distribution challenges, and communication and care coordination failures. These challenges affected continuity of dietary treatment, increased the burden on patients, carers and healthcare professionals, generated additional financial costs, and highlighted wider inefficiencies within the prescribing and supply pathway. Fewer than half of the reported incidents were resolved (41%). Conclusions: Addressing these system-level barriers through improved prescribing processes, clearer communication pathways, and better coordination between stakeholders may enhance continuity of dietary treatment, reduce burden on patients and healthcare professionals, and support more efficient delivery of specialist nutritional care for individuals with PKU.