The effect of different statistical approaches on image quality data obtained from radiological examinations.

INTRODUCTION: Selection of optimal image acquisition protocols in medical imaging remains a grey area, the superimposed use of the Likert scale in radiological image quality evaluations creates an additional challenge for the statistical analysis of image quality data. Using a simulation study, we have trialled a novel approach to analysing radiological image quality Likert scale data. METHODS: A simulation study was undertaken where simulated datasets were generated based on the distribution of Likert scale values according to varying image acquisition protocols from a real dataset. Simulated Likert scale values were pooled in four different ways; the mean, median, mode and the summation of patient Likert scale values of which the total was assigned a categorical Likert scale value. Estimates of bias, MAPE and RMSPE were then calculated for all four pooling approaches to determine which method most accurately represented an expert's opinion. RESULTS: When compared to an expert's opinion, the method of summation and categorisation of Likert scale values was most accurate 49 times out of the 114 (43.0%) tests. The mean 28 times out of 114 (24.6%), the median 23 times out of 114 (20.2%) and the mode 17 times out of 114 (14.9%). CONCLUSION: We conclude that our method of summation and categorisation of Likert scale values is most often the best representation of the simulated data compared to the expert's opinion. IMPLICATIONS FOR PRACTICE: There is scope to reproduce this simulation study with multiple observers to reflect clinical reality more accurately with the dynamic nature of multiple observers. This also prompts future investigation into other anatomical areas, to see if the same methods produce similar results.

Using routinely recorded data in a UK RCT: a comparison to standard prospective data collection methods.

BACKGROUND: Routinely recorded data held in electronic health records can be used to inform the conduct of randomised controlled trials (RCTs). However, limitations with access and accuracy have been identified. OBJECTIVE: Using epilepsy as an exemplar condition, we assessed the attributes and agreement of routinely recorded data compared to data collected using case report forms in a UK RCT assessing antiepileptic drug treatments for individuals newly diagnosed with epilepsy. METHODS: The case study RCT is the Standard and New Antiepileptic Drugs II (SANAD II) trial, a pragmatic, UK multicentre RCT assessing the clinical and cost-effectiveness of antiepileptic drugs as treatments for epilepsy. Ninety-eight of 470 eligible participants provided consent for access to routinely recorded secondary care data that were retrieved from NHS Digital Hospital Episode Statistics (N=71) and primary and secondary care data from The Secure Anonymised Information Linkage Databank (N=27). We assessed data items relevant to the identification of individuals eligible for inclusion in SANAD II, baseline and follow-up visits. The attributes of routinely recorded data were assessed including the degree of missing data. The agreement between routinely recorded data and data collected on case report forms in SANAD II was assessed using calculation of Cohen's kappa for categorical data and construction of Bland-Altman plots for continuous data. RESULTS: There was a significant degree of missing data in the routine record for 15 of the 20 variables assessed, including all clinical variables. Agreement was poor for the majority of comparisons, including the assessments of seizure occurrence and adverse events. For example, only 23/62 (37%) participants had a date of first-ever seizure identified in routine datasets. Agreement was satisfactory for the date of prescription of antiepileptic drugs and episodes of healthcare resource use. CONCLUSIONS: There are currently significant limitations preventing the use of routinely recorded data for participant identification and assessment of clinical outcomes in epilepsy, and potentially other chronic conditions. Further research is urgently required to assess the attributes, agreement, additional benefits, cost-effectiveness and 'optimal mix' of routinely recorded data compared to data collected using standard methods such as case report forms at clinic visits for people with epilepsy. TRIAL REGISTRATION: Standard and New Antiepileptic Drugs II (SANAD II (EudraCT No: 2012-001884-64, registered 05/09/2012; ISRCTN Number: ISRCTN30294119 , registered 03/07/2012)).

Development and internal validation of clinical prediction models for outcomes of complicated intra-abdominal infection.

BACKGROUND: Complicated intra-abdominal infections (cIAIs) are associated with significant morbidity and mortality. The aim of this study was to describe the clinical characteristics of patients with cIAI in a multicentre study and to develop clinical prediction models (CPMs) to help identify patients at risk of mortality or relapse. METHODS: A multicentre observational study was conducted from August 2016 to February 2017 in the UK. Adult patients diagnosed with cIAI were included. Multivariable logistic regression was performed to develop CPMs for mortality and cIAI relapse. The c-statistic was used to test model discrimination. Model calibration was tested using calibration slopes and calibration in the large (CITL). The CPMs were then presented as point scoring systems and validated further. RESULTS: Overall, 417 patients from 31 surgical centres were included in the analysis. At 90 days after diagnosis, 17.3 per cent had a cIAI relapse and the mortality rate was 11.3 per cent. Predictors in the mortality model were age, cIAI aetiology, presence of a perforated viscus and source control procedure. Predictors of cIAI relapse included the presence of collections, outcome of initial management, and duration of antibiotic treatment. The c-statistic adjusted for model optimism was 0.79 (95 per cent c.i. 0.75 to 0.87) and 0.74 (0.73 to 0.85) for mortality and cIAI relapse CPMs. Adjusted calibration slopes were 0.88 (95 per cent c.i. 0.76 to 0.90) for the mortality model and 0.91 (0.88 to 0.94) for the relapse model; CITL was -0.19 (95 per cent c.i. -0.39 to -0.12) and - 0.01 (- 0.17 to -0.03) respectively. CONCLUSION: Relapse of infection and death after complicated intra-abdominal infections are common. Clinical prediction models were developed to identify patients at increased risk of relapse or death after treatment, these now require external validation.

Nonblanchable erythema for predicting pressure ulcer development: a systematic review with an individual participant data meta-analysis.

BACKGROUND: Empirical evidence is uncertain regarding the value of nonblanchable erythema in predicting the incidence of stage 2 (or more severe) pressure ulcers. OBJECTIVES: To investigate whether nonblanchable erythema is an independent prognostic factor for pressure ulcer incidence using individual patient data. METHODS: We performed an electronic database search in February 2017 to identify longitudinal studies that considered nonblanchable erythema for predicting pressure ulcer risk in any population. We collected individual participant data for the included studies, and assessed the risk of bias of these studies using the Quality In Prognosis Studies tool. We analysed individual participant data in Stata using mixed-effects logistic regression to investigate the association of interest. The certainty of evidence from individual participant data analysis was assessed using the Grades of Recommendation Assessment, Development and Evaluation. The study was registered with PROSPERO (CRD42017081151). RESULTS: From the 13 included studies (total 68 077 participants) we had access to individual participant data from four (n = 3223), and 11·9% of participants (383 of 3223) developed new pressure ulcers of stage 2 or above within 28 days. Mixed-effects logistic regression showed that participants with nonblanchable erythema had higher odds of developing new pressure ulcers of stage 2 or above within 28 days of follow-up than those without nonblanchable erythema (multivariable association: n = 2684; odds ratio 2·72, 95% confidence interval 2·02-3·69; τ2 = 0; moderate-certainty evidence). CONCLUSIONS: This first prognostic factor review with individual-level data analysis in patients with pressure ulcers suggests that people with nonblanchable erythema are more likely to develop new pressure ulcers of stage 2 or above within 28 days than people without nonblanchable erythema. It is important to identify nonblanchable erythema in practice and to intervene appropriately to prevent pressure ulceration. What's already known about this topic? Pressure ulcer reduction is a high priority for healthcare systems. Regularly inspecting skin to identify skin abnormalities is one key practice for preventing ulceration. Nonblanchable erythema - discoloration of the skin that does not turn white when pressed - is one clinically important skin abnormality. Empirical evidence synthesized using conventional meta-analysis is uncertain regarding the value of nonblanchable erythema for predicting open pressure ulcer incidence; this is partly because the conventional technique has weakness in terms of pooling prognostic effects of different multivariable analyses across studies. What does this study add? This prognostic factor review used individual-level data analysis to overcome the limitations of the conventional meta-analysis technique. For the first time there is confirmatory and moderate-certainty evidence on the association of nonblanchable erythema with pressure ulcer incidence. People with nonblanchable erythema are more likely to develop new pressure ulcers of stage 2 or more severe within 28 days than people without nonblanchable erythema, regardless of their age, baseline pressure ulcer risk or received support surfaces.

General health complaints and sleep associated with new injury within an endurance sporting population: A prospective study.

OBJECTIVES: To examine the association between subjective health complaints, sleep quantity and new injury within an endurance sport population. DESIGN: Prospective cohort study. METHODS: Ninety-five endurance sporting participants were recruited from running, triathlon, swimming, cycling and rowing disciplines. Over 52-week period participants submitted weekly data regarding subjective health complaints (SHCs) (cardiorespiratory, gastrointestinal and psychological/lifestyle), sleep quantity, training load and new injury episodes. Applying a 7- and 14-day lag period, a shared frailty model was used to explore new injury risk associations with total SHCs and sleep quantity. RESULTS: 92.6% of 95 participants completed all 52 weeks of data submission and the remainder of the participants completed ≥30 weeks. Seven-day lag psychological/lifestyle SHCs were significantly associated with new injury risk (Hazard ratio (HR)=1.32; CI 95%=1.01-1.72, p<0.04). In contrast, cardiorespiratory (HR=1.15; CI 95%=0.99-1.36, p=0.07) and gastrointestinal (HR=0.77; CI 95%=0.56-1.05, p=0.09) SHCs were not significantly associated with new injury risk. New injury risk had a significant increased association with 14-day lag <7h/day sleep quantity (HR=1.51; CI 95%=2.02-1.13, p<0.01) and a significant decreased association with >7h/day sleep quantity (HR=0.63, CI 95%=0.45-0.87, p<0.01. A secondary regression analysis demonstrated no significant association with total SHCs and training load factors (Relative Risk (RR)=0.08, CI 95%=0.04-0.21, p=0.20). CONCLUSIONS: To minimise an increased risk of new injuries within an endurance sporting population, this study demonstrates that psychological/lifestyle subjective health complaints and sleep quantity should be considered. The study also highlights a lag period between low sleep quantity and its subsequent impact on new injury risk. No association was demonstrated between subjective health complaints, sleep quantity and training load factors.

Variation in the length and structure of reports written by reporting radiographers: A retrospective study.

INTRODUCTION: The literature suggests that there is variation in various features of the written radiology report for a range of body areas and imaging modalities. The retrospective study presented here aims to determine if similar variation is demonstrated in a group of 5 reporting radiographers in a UK NHS Trust. METHODS: Full reports for 1530 knee radiographic examinations performed from accident and emergency referrals were extracted for a 12-month period from a Radiology Information System (RIS) into Excel. Copied into Word, the word count function was used for each report and the number of words and characters (without spaces) was returned into Excel. Average word count and word length per report, by radiographer, were calculated for the following sections of the report: report title, main body and signature. SPSS was used to perform inferential statistical analysis. RESULTS: A wide range in the maximum and minimum average report lengths (60.88 v 17.83 words) was demonstrated. Statistically significant differences (p < 0.05) were seen between all but one pair-wise comparison (Rad 2 v Rad 4; p = 0.98) for the overall report length; for the length of the findings section, four pair-wise comparisons did not reach significance. Average word length demonstrated less variation. 4 out of 5 radiographers always included a report title; 3 out of 5 never included a report signature. There was a strong negative correlation between experience and report length. CONCLUSION: Variation in report structure and length, as well as word length, was seen, comparable to studies of radiologist reports. Further research is required to investigate the drivers of this variation, and determine if there is any clinical significance.

Can acoustic radiation force imaging of the liver and spleen predict the presence of gastroesophageal varices?

AIM: To determine whether acoustic radiation force imaging (ARFI) of the liver/spleen could be used in patients with cirrhosis to predict the presence of gastroesophageal varices (GOVs). MATERIALS AND METHODS: Fifty-eight patients with cirrhosis who were undergoing 6-monthly ultrasound examinations for hepatoma surveillance and who were due to have oesophagogastroduodenoscopy (OGD) within 6 months of their ultrasound were recruited. During routine ultrasound, the patient's liver and spleen were also assessed using ARFI. Other clinical parameters (platelet count, spleen size, and transient elastography measurements) were also collected. Logistic regression was used to determine which variables were significantly associated with presence or absence of varices univariably and multivariably RESULTS: Fourteen patients (24%) had GOVs. Patients with GOVs had higher ARFI measurements in the liver and spleen than patients without GOVs (liver: 2.39 versus 2.13, spleen: 2.89 versus 2.82), but these results were not statistically significant (odds ratio=1.75, 95% confidence interval [CI]=0.82, 3.91 and odds ratio=1.12, 95% CI=0.33, 3.97, respectively). The platelet/splenic ratio, in comparison, was associated with the presence or absence of GOVs in multivariate analysis (odds ratio=0.32, 95% CI=0.008, 0.91). CONCLUSION: Although patients with GOVs had overall higher ARFI liver and spleen results, this was not statistically significant. As such, ARFI cannot yet replace OGD in predicting GOVs in this patient group.

Using routinely recorded data in the UK to assess outcomes in a randomised controlled trial: The Trials of Access.

BACKGROUND: In the UK, routinely recorded data may benefit prospective studies including randomised controlled trials (RCTs). In an on-going study, we aim to assess the feasibility of access and agreement of routinely recorded clinical and non-clinical data compared to data collected during a RCT using standard prospective methods. This paper will summarise available UK routinely recorded data sources and discuss our experience with the feasibility of accessing routinely recorded data for participants of a RCT before finally proposing recommendations for improving the access and implementation of routinely recorded data in RCTs. METHODS: Setting: the case study RCT is the Standard and New Antiepileptic Drugs II (SANAD II) trial, a pragmatic, UK, multicentre, phase IV RCT assessing the clinical and cost-effectiveness of antiepileptic drug treatments for newly diagnosed epilepsy. PARTICIPANTS: 98 participants have provided written consent to permit the request of routinely recorded data. Study procedures: routinely recorded clinical and non-clinical data were identified and data requested through formal applications from available data holders for the duration that participants have been recruited into SANAD II. The feasibility of accessing routinely recorded data during a RCT is assessed and recommendations for improving access proposed. RESULTS: Secondary-care clinical and socioeconomic data is recorded on a national basis and can be accessed, although there are limitations in the application process. Primary-care data are recorded by a number of organisations on a de-identified basis but access for specific individuals has not been feasible. Access to data recorded by non-clinical sources, including The Department for Work and Pensions and The Driving and Vehicle Licensing Agency, was not successful. CONCLUSIONS: Recommendations discussed include further research to assess the attributes of routinely recorded data, an assessment of public perceptions and the development of strategies to collaboratively improve access to routinely recorded data for research. TRIAL REGISTRATION: International Standard Randomised Controlled Trials, ISRCTN30294119 . Registered on 3 July 2012. EudraCT No: 2012-001884-64. Registered on 9 May 2012.

The Influence of Cytomegalovirus on Expression of HLA-G and its Ligand KIR2DL4 by Human Peripheral Blood Leucocyte Subsets.

HLA-G is a non-classical class I HLA antigen, normally expressed in high levels only on extravillous cytotrophoblast. It has immunosuppressive properties in pregnancy and has also been found to be upregulated on leucocytes in viral infection. In this study, proportions of all leucocyte subsets expressing HLA-G were found to be low in healthy subjects positive or negative for cytomegalovirus (CMV). Significantly greater proportions of CD4+ CD69+ and CD56+ T cells expressed HLA-G compared to other T cells. However, following stimulation with CMV antigens or intact CMV, proportions of CD4+, CD8+, CD69+ and CD56+ T cells, and also B cells expressing HLA-G, were significantly increased in CMV+ subjects. Despite some subjects having alleles of HLA-G associated with high levels of expression, no relationship was found between HLA-G genotype and expression levels. Purified B cells from CMV+ subjects stimulated in mixed culture with CMV antigens showed significantly increased HLA-G mRNA expression by real-time polymerase chain reaction. Serum levels of soluble HLA-G were similar in CMV- and CMV+ subjects but levels in culture supernatants were significantly higher in cells from CMV+ than from CMV- subjects stimulated with CMV antigens. The HLA-G ligand KIR2DL4 was mainly expressed on NK cells and CD56+ T cells with no differences between CMV+ and CMV- subjects. Following stimulation with IL-2, an increase in the proportion of CD56+ T cells positive for KIR2DL4 was found, together with a significant decrease in CD56dimCD16+ NK cells. The results show that CMV influences HLA-G expression in healthy subjects and may contribute to viral immune evasion.

Risk of a seizure recurrence after a breakthrough seizure and the implications for driving: further analysis of the standard versus new antiepileptic drugs (SANAD) randomised controlled trial.

OBJECTIVES: A breakthrough seizure is one occurring after at least 12 months seizure freedom while on treatment. The Driver and Vehicle Licensing Agency (DVLA) allows an individual to return to driving once they have been seizure free for 12 months following a breakthrough seizure. This is based on the assumption that the risk of a further seizure in the next 12 months has dropped <20%. This analysis considers whether the prescribed 1 year off driving following a breakthrough seizure is sufficient for this and stratifies risk according to clinical characteristics. DESIGN, SETTING, PARTICIPANTS, INTERVENTIONS AND MAIN OUTCOME MEASURES: The multicentre UK-based Standard versus New Antiepileptic Drugs (SANAD) study was a randomised controlled trial assessing standard and new antiepileptic drugs for patients with newly diagnosed epilepsy. For participants aged at least 16 with a breakthrough seizure, data have been analysed to estimate the annual seizure recurrence risk following a period of 6, 9 and 12 months seizure freedom. Regression modelling was used to investigate how antiepileptic drug treatment and a number of clinical factors influence the risk of seizure recurrence. RESULTS: At 12 months following a breakthrough seizure, the overall unadjusted risk of a recurrence over the next 12 months is lower than 20%, risk 17% (95% CI 15% to 19%). However, some patient subgroups have been identified which have an annual recurrence risk significantly greater than 20% after an initial 12-month seizure-free period following a breakthrough seizure. CONCLUSIONS: This reanalysis of SANAD provides estimates of seizure recurrence risks following a breakthrough seizure that will inform policy and guidance about regaining an ordinary driving licence. Further guidance is needed as to how such data should be used. TRIAL REGISTRATION NUMBER: SANAD is registered with the International Standard Randomised Controlled Trial Number Register ISRCTN38354748.

A comprehensive functional and clinical analysis of ABCC2 and its impact on treatment response to carbamazepine.

At the blood-brain barrier, overexpression of the drug efflux transporter ABCC2 (also known as MRP2) has been proposed as a mechanism for impaired carbamazepine (CBZ) treatment response in epilepsy. However, investigation of the impact of ABCC2 polymorphisms on CBZ treatment efficacy has produced conflicting and inconclusive results. A series of in vitro cell efflux and plasma membrane vesicle uptake assays were undertaken to investigate whether CBZ was an ABCC2 substrate. In addition, the effect of three common ABCC2 polymorphisms, -24C>T, c.1249G>A and c.3972C>T, on the efficacy of CBZ in epilepsy (assessed using the clinical end points time to first seizure and time to 12-month remission from the SANAD (Standard and New Antiepileptic Drugs) trial) was determined. CBZ was found not to be a substrate for human ABCC2 in vitro. Clinically, no significant association was observed for the ABCC2 genetic variants and CBZ treatment outcomes. This comprehensive analysis does not support a role for ABCC2 in CBZ treatment efficacy.

Child development following in utero exposure: levetiracetam vs sodium valproate.

OBJECTIVE: Children born to women with epilepsy (WWE), exposed in utero to levetiracetam (LEV, n = 51), were assessed for early cognitive development and compared to children exposed to sodium valproate in utero (VPA, n = 44) and a group of children representative of the general population (n = 97). METHODS: Children were recruited prospectively from 2 cohorts in the United Kingdom and assessed using the Griffiths Mental Development Scale (1996), aged <24 months. Information regarding maternal demographics were collected and controlled for. This is an observational study with researchers not involved in the clinical management of the WWE. RESULTS: On overall developmental ability, children exposed to LEV obtained higher developmental scores when compared to children exposed to VPA (p < 0.001). When compared, children exposed to LEV did not differ from control children (p = 0.62) on overall development. Eight percent of children exposed to LEV in utero fell within the below average range (DQ score of <84), compared with 40% of children exposed to VPA. After controlling for maternal epilepsy and demographic factors using linear regression analysis, exposure to LEV in utero was not associated with outcome (p = 0.67). Conversely, when compared with VPA exposure, LEV exposure was associated with higher scores for the overall developmental quotient (p < 0.001). CONCLUSION: Children exposed to LEV in utero are not at an increased risk of delayed early cognitive development under the age of 24 months. LEV may therefore be a preferable drug choice, where appropriate, for WWE prior to and of childbearing age.

Risk of recurrence after a first seizure and implications for driving: further analysis of the Multicentre study of early Epilepsy and Single Seizures.

OBJECTIVE: To determine for how long after a first unprovoked seizure a driver must be seizure-free before the risk of recurrence in the next 12 months falls below 20%, enabling them to regain their driving licence. DESIGN: Randomised controlled trial: Multicentre study of early Epilepsy and Single Seizures (MESS). SETTING: UK hospital outpatient clinics from 1 January 1993 to 31 December 2000. PARTICIPANTS: People entered MESS if they had had one or more unprovoked seizures and both the participant and the clinician were uncertain about the need to start antiepileptic drug treatment. The subset of people used for this analysis comprised participants aged at least 16 years with a single unprovoked seizure. MAIN OUTCOME MEASURE: Risk of seizure recurrence in the 12 months after a seizure-free period of 6, 12, 18, or 24 months from the date of the first (index) seizure. Regression modelling was used to investigate how antiepileptic treatment and several clinical factors influence the risk of seizure recurrence. RESULTS: At six months after the index seizure the risk of recurrence in the next 12 months for those who start antiepileptic drugs was significantly below 20% (unadjusted risk 14%, 95% confidence interval 10% to 18%). For patients who did not start treatment the risk estimate was less than 20% but the upper limit of the confidence interval was greater than 20% (18%, 13% to 23%). Multivariable analyses identified subgroups with a significantly greater than 20% risk of seizure recurrence in the 12 months after a six month seizure-free period, such as those with a remote symptomatic seizure with abnormal electroencephalogram results. CONCLUSION: After a single unprovoked seizure this reanalysis of MESS provides estimates of seizure recurrence risks that will inform policy and guidance about regaining an ordinary driving licence. Further guidance is needed as to how such data should be utilised; in particular, whether a population approach should be taken with a focus on the unadjusted results or whether attempts should be made to individualise risk. Guidance is also required as to whether the focus should be on risk estimates only or on the confidence interval as well. If the focus is on the estimate only our unadjusted estimates suggest that treated and untreated patients are eligible to drive after being seizure-free for six months. If the focus is also on confidence intervals, direction is needed as to whether a conservative or liberal approach should be taken. TRIAL REGISTRATION: Current Controlled Trials ISRCTN98767960.

Isolation and Cell-free Translation of Total Messenger RNA from Germinating Castor Bean Endosperm.

Polyadenylated RNA was isolated from the total RNA fraction extracted from the endosperm tissue of 3-day-old castor bean seedlings by affinity chromatography on oligo(dT)-cellulose. This polyadenylated RNA was efficiently translated into protein when added to a messenger RNA-dependent cell-free system derived from rabbit reticulocytes. Characterization of the translational products by electrophoresis followed by autoradiography established that numerous discrete polypeptides were formed with molecular weights ranging from 10,000 to over 100,000. Immunoprecipitation in the presence of antiserum raised in rabbits against the total glyoxysomal matrix proteins showed that these proteins accounted for 15 to 20% of the total translational products.Attempts to reconstitute rough endoplasmic reticulum by the addition of washed castor bean microsomal membranes to the translational system were unsuccessful, these membranes severely inhibiting protein synthesis. Canine pancreatic microsomes could be added to endosperm messenger RNA-dependent reticulocyte lysates at relatively high concentrations while still allowing significant protein synthesis.