A diet low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) improves functional bowel symptoms and is a second-line dietary management strategy for the treatment of irritable bowel syndrome (IBS). The diet is complex and involves three stages: restriction, reintroduction and personalisation and clinical effectiveness is achieved with dietitian-led education; however, this is not always available. The aim of this review is to provide an update on the evidence for using the low FODMAP diet, with a focus on the impact of FODMAP restriction and reintroduction considering long-term management of IBS in a clinical setting. Randomised controlled trials have assessed symptom response, quality of life, dietary intake and changes to the gut microbiota during FODMAP restriction. Systematic reviews and meta-analyses consistently report that FODMAP restriction has a better symptom response compared with control diets and a network analysis reports the low FODMAP diet is superior to other dietary treatments for IBS. Research focused on FODMAP reintroduction and personalisation is limited and of lower quality, however common dietary triggers include wheat, onion, garlic, pulses and milk. Dietitian-led delivery of the low FODMAP diet is not always available and alternative education delivery methods, e.g. webinars, apps and leaflets, are available but remove the personalised approach and may be less acceptable to patients and may introduce safety concerns in terms of nutritional adequacy. Predicting response to the low FODMAP diet using symptom severity or a biomarker is of great interest. More evidence on less restrictive approaches and non-dietitian-led education delivery methods are needed.

The National Institute for Health and Care Excellence (NICE) is the UK's primary health care priority-setter, responsible for advising the National Health Service on its adoption of health technologies. The normative basis for NICE's advice has long been the subject of public and academic interest, but the existing literature does not include any comprehensive summary of the factors observed to have substantively shaped NICE's recommendations. The current review addresses this gap by bringing together 29 studies that have explored NICE decision-making from different disciplinary perspectives, using a range of quantitative and qualitative methods. It finds that although cost-effectiveness has historically played a central role in NICE decision-making, 10 other factors (uncertainty, budget impact, clinical need, innovation, rarity, age, cause of disease, wider societal impacts, stakeholder influence and process factors) are also demonstrably influential and interact with one another in ways that are not well understood. The review also highlights an over-representation in the literature of appraisals conducted prior to 2009, according to methods that have since been superseded. It suggests that this may present a misleading view of the importance of allocative efficiency to NICE's current approach and illustrates the need for further up-to-date research into the normative grounds for NICE's decisions.

The National Institute for Health and Care Excellence (NICE), the UK's primary health care priority-setting body, has traditionally described its decisions as being informed by ‘social value judgements’ about how resources should be allocated across society. This paper traces the intellectual history of this term and suggests that, in NICE's adoption of the idea of the ‘social value judgement’, we are hearing the echoes of welfare economics at a particular stage of its development, when logical positivism provided the basis for thinking about public policy choice. As such, it is argued that the term offers an overly simplistic conceptualisation of NICE's normative approach and contributes to a situation in which NICE finds itself without the necessary language fully and accurately to articulate its basis for decision-making. It is suggested that the notion of practical public reasoning, based on reflection about coherent principles of action, might provide a better characterisation of the enterprise in which NICE is, or hopes to be, engaged.

Dietary restriction of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) is clinically effective and a commonly utilised approach in the management of functional symptoms in irritable bowel syndrome. Despite this, the low FODMAP diet has a number of challenges: it can alter the gut microbiota; impact nutrient intake and diet quality; is complex to understand; requires the patient to be adequately supported to follow the diet accurately and safely; and lastly, not all patients respond to the diet. The current review highlights the evidence for the clinical effectiveness of the low FODMAP diet, but focusses on the challenges associated with the diet to the patient, health professionals and the wider healthcare service. Finally, the review discusses research findings and practical guidance for how these challenges can be minimised and mitigated. The low FODMAP diet is a useful management strategy for irritable bowel syndrome, with data from clinical trials suggesting a 50–80% response rate, and when administered appropriately, the challenges to implementing the diet can be overcome so that these outcomes can be realised effectively and safely in clinical practice.

Health technology assessment (HTA) recommendations informed by patient concerns are seen to ensure democracy and legitimacy. We explored how written and oral patient involvement in two HTAs was reported on in publicly available final recommendations and discussion summaries of appraisal committees from three HTA bodies. We aimed to gain insights into how patient input was utilized by appraisal committees to better understand the goals of patient involvement and how these are being achieved. In each of the three HTA bodies, templated submission questionnaires provide a formal process for seeking written patient group input. Additionally, the National Institute for Health and Care Excellence (NICE) selects patient experts to provide a templated submission and attend appraisal committee meetings. For Scottish Medicines Consortium (SMC), a patient advocate and clinician combined meeting (PACE) discussed the cancer drug, referred to in the final recommendation. The discussion summaries of all appraisal committees contained references to patient involvement. Where two mechanisms for patient involvement were provided, oral input from the expert patients and PACE were more clearly documented than information from written patient group submissions. NICE reports focused on the perspective of the patient expert. The SMC report highlighted feedback from the PACE throughout. We suggest that the lack of clear reporting on the use of patient group input in deliberations and therefore accountability to patient groups limits progress in patient involvement in HTA. Patient groups may therefore not have a clear understanding of what information they can best provide to inform deliberations, and in reporting back to members.

The National Institute for Health and Care Excellence (NICE) has acknowledged the value of waist-to-height ratio (WHtR) as an indicator for ‘early health risk’. We used recent UK data to explore whether classification based on WHtR identifies more adults at cardiometabolic risk than the ‘matrix’ based on BMI and waist circumference, currently used for screening. Data from the Health Survey for England (4112 adults aged 18+ years) were used to identify cardiometabolic risk, indicated by raised glycated Hb, dyslipidaemia and hypertension. HbA1c, total/HDL-cholesterol and systolic blood pressure (BP) were more strongly associated with WHtR than the ‘matrix’. In logistic regression models for HbA1c ≥ 48 mmol/mol, total/HDL-cholesterol > 4 and hypertension (BP > 140/90 mmHg or on medication), WHtR had a higher predictive value than the ‘matrix’. AUC was significantly greater for WHtR than the ‘matrix’ for raised HbA1c and hypertension. Of adults with raised HbA1c, 15 % would be judged as ‘no increased risk’ using the ‘matrix’ in contrast to 3 % using WHtR < 0·5. For hypertension, comparative values were 23 and 9 %, and for total/HDL-cholesterol > 4, 26 and 13 %. Nearly one-third of the ‘no increased risk’ group in the ‘matrix’ had WHtR ≥ 0·5 and hence could be underdiagnosed for cardiometabolic risk. WHtR has the potential to be a better indicator of cardiometabolic risks associated with central obesity than the current NICE ‘matrix’. The cut-off WHtR 0·5 in early screening translates to a simple message, ‘your waist should be less than half your height’, that allows individuals to be aware of their health risks.