369 research outputs found

    Methodological standards for the development and evaluation of clinical prediction rules: A review of the literature

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    Clinical prediction rules (CPRs) that predict the absolute risk of a clinical condition or future outcome for individual patients are abundant in the medical literature, however systematic reviews have demonstrated shortcomings in the methodological quality and reporting of prediction studies. To maximize the potential and clinical usefulness of CPRs, they must be rigorously developed and validated, and their impact on clinical practice and patient outcomes must be evaluated. This review aims to present a comprehensive overview of the stages involved in the development, validation and evaluation of CPRs, and to describe in detail the methodological standards required at each stage, illustrated with examples where appropriate. Important features of the study design, statistical analysis, modelling strategy, data collection, performance assessment, CPR presentation, and reporting are discussed, in addition to other, often overlooked aspects such as the acceptability, cost-effectiveness and longer-term implementation of CPRs, and their comparison with clinical judgment. Although the development and evaluation of a robust, clinically useful CPR is anything but straightforward, adherence to the plethora of methodological standards, recommendations and frameworks at each stage will assist in the development of a rigorous CPR that has the potential to contribute usefully to clinical practice and decision-making and have a positive impact on patient car

    Reflections on qualitative data analysis training for PPI partners and its implementation into practice

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    Service users should be involved in every part of the research process, including analysis of qualitative research data such as interviews and focus groups. To enhance their participation, confidence and contributions, training and support for both the ‘professional’ researcher and lay member of public is essential. Historically this has taken a number of forms from short 1 day training sessions through to training spread out over several months. There currently is limited guidance on the quantity and content of such training sessions for Patient and Public Involvement (PPI) Partners. This paper discusses and explores the content and delivery of qualitative analysis training held over two sessions of 3 h duration to members of a University PPI group. The training was designed by experienced qualitative researchers and PPI partners based on available literature and research expertise. Training included the theory of qualitative research methods, and practical qualitative analysis coding skills. These skills were developed through the use of ‘mock’ interviews which participants practiced coding in supportive group sessions. Their feedback on the training is provided. One of the PPI partners subsequently went onto code data with a researcher working on a funded research study, and has reflected on both the training sessions and the subsequent analysis of the data. These reflections have been supplemented by reflections of the researcher who worked alongside the PPI partner, revealing that the process challenged perspectives and helped them view data through a service users eyes. A positive working relationship was central to this

    Letter to the editor

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    (3R,4R,5R)-5-(Acetamido­meth­yl)-N-benzyl-3,4-dihy­droxy­tetra­hydro­furan-3-carboxamide

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    X-ray crystallographic analysis with Cu Kα radiation established the relative configurations of the stereogenic centers in the title compound, C15H20N2O5, and clarified mechanistic ambiguities in the synthesis. The conformation of the five-membered ring approximates twisted, about a C—O bond. The absolute configuration of this carbon-branched dipeptide isostere was known based on the use of d-ribose as the starting material. Refinement of the Flack parameter gave an ambiguous result but the refined Hooft parameter is in agreement with the assumed (d-ribose) absolute structure. The crystal structure consists of N—H⋯O and O—H⋯O hydrogen-bonded bi-layers, with the terminal methyl and phenyl groups forming a hydro­phobic inter-layer inter­face. Some weak C—H⋯O inter­actions are also present

    Factors influencing child protection professionals' decision-making and multidisciplinary collaboration in suspected abusive head trauma cases: a qualitative study

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    Clinicians face unique challenges when assessing suspected child abuse cases. The majority of the literature exploring diagnostic decision-making in this field is anecdotal or survey-based and there is a lack of studies exploring decision-making around suspected abusive head trauma (AHT). We aimed to determine factors influencing decision-making and multidisciplinary collaboration in suspected AHT cases, amongst 56 child protection professionals. Semi-structured interviews were conducted with clinicians (25), child protection social workers (10), legal practitioners (9, including 4 judges), police officers (8), and pathologists (4), purposively sampled across southwest United Kingdom. Interviews were recorded, transcribed and imported into NVivo for thematic analysis (38% double-coded). We identified six themes influencing decision-making: ‘professional’, ‘medical’, ‘circumstantial’, ‘family’, ‘psychological’ and ‘legal’ factors. Participants diagnose AHT based on clinical features, the history, and the social history, after excluding potential differential diagnoses. Participants find these cases emotionally challenging but are aware of potential biases in their evaluations and strive to overcome these. Barriers to decision-making include lack of experience, uncertainty, the impact on the family, the pressure of making the correct diagnosis, and disagreements between professionals. Legal barriers include alternative theories of causation proposed in court. Facilitators include support from colleagues and knowledge of the evidence-base. Participants’ experiences with multidisciplinary collaboration are generally positive, however child protection social workers and police officers are heavily reliant on clinicians to guide their decision-making, suggesting the need for training on the medical aspects of physical abuse for these professionals and multidisciplinary training that provides knowledge about the roles of each agency

    Potential impact of the validated Predicting Abusive Head Trauma (PredAHT) clinical prediction tool: A clinical vignette study

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    Background The validated Predicting Abusive Head Trauma (PredAHT) tool estimates the probability of abusive head trauma (AHT) in children <3 years old with intracranial injury. Objective To explore the impact of PredAHT on clinicians’ AHT probability estimates and child protection (CP) actions, and assess inter-rater agreement between their estimates and between their CP actions, before and after PredAHT. Participants and Setting Twenty-nine clinicians from different specialties, at teaching and community hospitals. Methods Clinicians estimated the probability of AHT and indicated their CP actions in six clinical vignettes. One vignette described a child with AHT, another described a child with non-AHT, and four represented “gray” cases, where the diagnosis was uncertain. Clinicians calculated the PredAHT score, and reported whether this altered their estimate/actions. The ‘think-aloud’ method was used to capture the reasoning behind their responses. Analysis included linear modelling, linear mixed-effects modelling, chi-square tests, Fisher’s exact tests, intraclass correlation, Gwet’s AC1 coefficient and thematic analysis. Results Overall, PredAHT significantly influenced clinicians’ probability estimates in all vignettes (p < 0.001), although the impact on individual clinicians varied. However, the influence of PredAHT on clinicians’ CP actions was limited; after using PredAHT, 9/29 clinicians changed their CP actions in only 11/174 instances. Clinicians’ AHT probability estimates and CP actions varied somewhat both before and after PredAHT. Qualitative data suggested that PredAHT may increase clinicians’ confidence in their decisions when considered alongside other associated clinical, historical and social factors. Conclusions PredAHT significantly influenced clinicians’ AHT probability estimates, but had minimal impact on their CP actions

    Bayesian parameter estimation for characterising mobile ion vacancies in perovskite solar cells

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    To overcome the challenges associated with poor temporal stability of perovskite solar cells, methods are required that allow for fast iteration of fabrication and characterisation, such that optimal device performance and stability may be actively pursued. Currently, establishing the causes of underperformance is both complex and time-consuming, and optimisation of device fabrication thus inherently slow. Here, we present a means of computational device characterisation of mobile halide ion parameters from room temperature current-voltage (J-V) measurements only, requiring 2\sim 2 hours of computation on basic computing resources. With our approach, the physical parameters of the device may be reverse modelled from experimental J-V measurements. In a drift-diffusion model, the set of coupled drift-diffusion partial differential equations cannot be inverted explicitly, so a method for inverting the drift-diffusion simulation is required. We show how Bayesian Parameter Estimation (BPE) coupled with a drift-diffusion perovskite solar cell model can determine the extent to which device parameters affect performance measured by J-V characteristics. Our method is demonstrated by investigating the extent to which device performance is influenced by mobile halide ions for a specific fabricated device. The ion vacancy density N0N_0 and diffusion coefficient DID_I were found to be precisely characterised for both simulated and fabricated devices. This result opens up the possibility of pinpointing origins of degradation by finding which parameters most influence device J-V curves as the cell degrades

    Acceptability of the Predicting Abusive Head Trauma (PredAHT) clinical prediction tool: A qualitative study with child protection professionals

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    The validated Predicting Abusive Head Trauma (PredAHT) tool estimates the probability of abusive head trauma (AHT) based on combinations of six clinical features: head/neck bruising; apnea; seizures; rib/long-bone fractures; retinal hemorrhages. We aimed to determine the acceptability of PredAHT to child protection professionals. We conducted qualitative semi-structured interviews with 56 participants: clinicians (25), child protection social workers (10), legal practitioners (9, including 4 judges), police officers (8), and pathologists (4), purposively sampled across southwest United Kingdom. Interviews were recorded, transcribed and imported into NVivo for thematic analysis (38% double-coded). We explored participants’ evaluations of PredAHT, their opinions about the optimal way to present the calculated probabilities, and their interpretation of probabilities in the context of suspected AHT. Clinicians, child protection social workers and police thought PredAHT would be beneficial as an objective adjunct to their professional judgment, to give them greater confidence in their decisions. Lawyers and pathologists appreciated its value for prompting multidisciplinary investigations, but were uncertain of its usefulness in court. Perceived disadvantages included: possible over-reliance and false reassurance from a low score. Interpretations regarding which percentages equate to ‘low’, ‘medium’ or ‘high’ likelihood of AHT varied; participants preferred a precise % probability over these general terms. Participants would use PredAHT with provisos: if they received multi-agency training to define accepted risk thresholds for consistent interpretation; with knowledge of its development; if it was accepted by colleagues. PredAHT may therefore increase professionals’ confidence in their decision-making when investigating suspected AHT, but may be of less value in court
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