Development of core outcome sets for people undergoing major lower limb amputation for complications of peripheral vascular disease

Objective Every year, thousands of patients with peripheral vascular disease undergo major lower limb amputation. Despite this, evidence for optimal management is weak. Core outcome sets capture consensus on the most important outcomes for a patient group to improve the consistency and quality of research. The aim was to define short and medium term core outcome sets for studies involving patients undergoing major lower limb amputation. Methods A systematic review of the literature and focus groups involving patients, carers, and healthcare professionals were used to derive a list of potential outcomes. Findings informed a three round online Delphi consensus process, where outcomes were rated for both short and medium term studies. The results of the Delphi process were discussed at a face to face consensus meeting, and recommendations were made for each core outcome set. Results A systematic review revealed 45 themes to cazrry forward to the consensus survey. These were supplemented by a further five from focus groups. The consensus survey received responses from 123 participants in round one, and 91 individuals completed all three rounds. In the final round, nine outcomes were rated as “core” for short term studies and a further nine for medium term studies. Wound infection and healing were rated as “core” for both short and medium term studies. Outcomes related to mortality, quality of life, communication, and additional healthcare needs were also rated as “core” for short term studies. In medium term studies, outcomes related to quality of life, mobility, and social integration/independence were rated as “core”. The face to face stakeholder meeting ratified inclusion of all outcomes from the Delphi and suggested that deterioration of the other leg and psychological morbidity should also be reported for both short and medium term studies. Conclusion Consensus was established on 11 core outcomes for short and medium term studies. It is recommended that all future studies involving patients undergoing major lower limb amputation should report these outcomes

Theoretical and computational study of high pressure structures in barium

Recent high pressure work has suggested that elemental barium forms a high pressure self-hosting structure (Ba IV) involving two `types' of barium atom. Uniquely among reported elemental structures it cannot be described by a single crystalline lattice, instead involving two interpenetrating incommensurate lattices. In this letter we report pseudopotential calculations demonstrating the stability and the potentially disordered nature of the `guest' structure. Using band structures and nearly-free electron theory we relate the appearance of Ba IV to an instability in the close-packed structure, demonstrate that it has a zero energy vibrational mode, and speculate about the structure's stability in other divalent elements.Comment: 4 pages and 5 figures. To appear in PR

Imaging in Vascular Access

This review examines four imaging modalities; ultrasound (US), digital subtraction angiography (DSA), magnetic resonance imaging (MRI) and computed tomography (CT), that have common or potential applications in vascular access (VA). The four modalities are reviewed under their primary uses, techniques, advantages and disadvantages, and future directions that are specific to VA. Currently, US is the most commonly used modality in VA because it is cheaper (relative to other modalities), accessible, non-ionising, and does not require the use of contrast agents. DSA is predominantly only performed when an intervention is indicated. MRI is limited by its cost and the time required for image acquisition that mainly confines it to the realm of research where high resolution is required. CT’s short acquisition times and high resolution make it useful as a problem-solving tool in complex cases, although accessibility can be an issue. All four imaging modalities have advantages and disadvantages that limit their use in this particular patient cohort. Current imaging in VA comprises an integrated approach with each modality providing particular uses dependent on their capabilities. MRI and CT, which currently have limited use, may have increasingly important future roles in complex cases where detailed analysis is required

Association between meniscal tears and the peak external knee adduction moment and foot rotation during level walking in postmenopausal women without knee osteoarthritis: a cross-sectional study

Introduction Meniscal injury is a risk factor for the development and progression of knee osteoarthritis, yet little is known about risk factors for meniscal pathology. Joint loading mediated via gait parameters may be associated with meniscal tears, and determining whether such an association exists was the aim of this study. Methods Three-dimensional Vicon gait analyses were performed on the dominant knee of 20 non-osteoarthritic women, and the peak external knee adduction moment during early and late stance was determined. The degree of foot rotation was also examined when the knee adductor moment peaked during early and late stance. Magnetic resonance imaging was used to determine the presence and severity of meniscal lesions in the dominant knee. Results The presence (P = 0.04) and severity (P = 0.01) of medial meniscal tears were positively associated with the peak external knee adduction moment during early stance while a trend for late stance was observed (P = 0.07). They were also associated with increasing degrees of internal foot rotation during late stance, independent of the magnitude of the peak external knee adduction moment occurring at that time (P = 0.03). During level walking among healthy women, the presence and severity of medial meniscal tears were positively associated with the peak external knee adduction moment. Moreover, the magnitude of internal foot rotation was associated with the presence and severity of medial meniscal lesions, independent of the peak knee adductor moment during late stance. Conclusion These data may suggest that gait parameters may be associated with meniscal damage, although longitudinal studies will be required to clarify whether gait abnormalities predate meniscal lesions, or vice versa, and therefore whether modification of gait patterns may be helpful

The impact of equilibrating hemispheric albedos on tropical performance in the HadGEM2-ES coupled climate model

The Earth's hemispheric reflectances are equivalent to within ± 0.2 Wm-2, even though the Northern Hemisphere contains a greater proportion of higher reflectance land areas, because of greater cloud cover in the Southern Hemisphere. This equivalence is unlikely to be by chance, but the reasons are open to debate. Here we show that equilibrating hemispheric albedos in the Hadley Centre Global Environment Model version 2-Earth System coupled climate model significantly improves what have been considered longstanding and apparently intractable model biases. Monsoon precipitation biases over all continental land areas, the penetration of monsoon rainfall across the Sahel, the West African monsoon 'jump', and indicators of hurricane frequency are all significantly improved. Mechanistically, equilibrating hemispheric albedos improves the atmospheric cross-equatorial energy transport and increases the supply of tropical atmospheric moisture to the Hadley cell. We conclude that an accurate representation of the cross-equatorial energy transport appears to be critical if tropical performance is to be improved

Systematic review of economic evaluations and cost analyses of guideline implementation strategies

Objectives To appraise the quality of economic studies undertaken as part of evaluations of guideline implementation strategies; determine their resources use; and recommend methods to improve future studies. Methods Systematic review of economic studies undertaken alongside robust study designs of clinical guideline implementation strategies published (1966-1998). Studies assessed against the BMJ economic evaluations guidelines for each stage of the guideline process (guideline development, implementation and treatment). Results 235 studies were identified, 63 reported some information on cost. Only 3 studies provided evidence that their guideline was effective and efficient. 38 reported the treatment costs only, 12 implementation and treatment costs, 11 implementation costs alone, and two guideline development, implementation and treatment costs. No study gave reasonably complete information on costs. Conclusions Very few satisfactory economic evaluations of guideline implementation strategies have been performed. Current evaluations have numerous methodological defects and rarely consider all relevant costs and benefits. Future evaluations should focus on evaluating the implementation of evidence based guidelines. Keywords: Cost-effectiveness analysis, physician (or health care professional) behaviour, practice guidelines, quality improvement, systematic review.Peer reviewedAuthor versio

Optimal sampling of MRI slices for the assessment of knee cartilage volume for cross-sectional and longitudinal studies

BACKGROUND: MRI slices of 1.5 mm thickness have been used in both cross sectional and longitudinal studies of osteoarthritis, but is difficult to apply to large studies as most techniques used in measuring knee cartilage volumes require substantial post-image processing. The aim of this study was to determine the optimal sampling of 1.5 mm thick slices of MRI scans to estimate knee cartilage volume in males and females for cross-sectional and longitudinal studies. METHODS: A total of 150 subjects had a sagittal T1-weighted fat-suppressed MRI scan of the right knee at a partition thickness of 1.5 mm to determine their cartilage volume. Fifty subjects had both baseline and 2-year follow up MRI scans. Lateral, medial tibial and patellar cartilage volumes were calculated with different samples from 1.5 mm thick slices by extracting one in two, one in three, and one in four to compare to cartilage volume and its rate of change. Agreement was assessed by means of intraclass correlation coefficient (ICC) and Bland & Altman plots. RESULTS: Compared to the whole sample of 1.5 mm thick slices, measuring every second to fourth slice led to very little under or over estimation in cartilage volume and its annual change. At all sites and subgroups, measuring every second slice had less than 1% mean difference in cartilage volume and its annual rate of change with all ICCs ≥ 0.98. CONCLUSION: Sampling alternate 1.5 mm thick MRI slices is sufficient for knee cartilage volume measurement in cross-sectional and longitudinal epidemiological studies with little increase in measurement error. This approach will lead to a substantial decrease in post-scan processing time

The labels and models used to describe problematic substance use impact discrete elements of stigma: A Registered Report

Objectives: Problematic substance use is one of the most stigmatised health conditions leading research to examine how the labels and models used to describe it influence public stigma. Two recent studies examine whether beliefs in a disease model of addiction influence public stigma but result in equivocal findings – in line with the mixed-blessings model, Kelly et al. (2021) found that whilst the label ‘chronically relapsing brain disease’ reduced blame attribution, it decreased prognostic optimism and increased perceived danger and need for continued care; however, Rundle et al. (2021) conclude absence of evidence. This study isolates the different factors used in these two studies to assess whether health condition (drug use vs. health concern), aetiological label (brain disease vs. problem), and attributional judgement (low vs. high treatment stability) influence public stigma towards problematic substance use. Methods: 1613 participants were assigned randomly to one of eight vignette conditions that manipulated these factors. They completed self-report measures of discrete and general public stigma and an indirect measure of discrimination. Results: Greater social distance, danger, and public stigma but lower blame were ascribed to drug use relative to a health concern. Greater (genetic) blame was reported when drug use was labelled as a ‘chronically relapsing brain disease’ relative to a ‘problem’. Findings for attributional judgement were either inconclusive or statistically equivalent. Discussion: The labels used to describe problematic substance use appear to impact discrete elements of stigma. We suggest that addiction is a functional attribution, which may explain the mixed literature on the impact of aetiological labels on stigma to date