Is the Comparator in Your Diagnostic Cost-Effectiveness Model "Standard of Care"? Recommendations from Literature Reviews and Expert Interviews on How to Identify and Operationalize It

OBJECTIVES

This research aimed to develop best-practice recommendations for identifying the "standard of care" (SoC) and integrate it when it is the comparator in diagnostic economic models (SoC comparator).

METHODS

A multi-methods approach comprising 2 pragmatic literature reviews and 9 expert interviews was used. Experts rated their agreement with draft recommendations based on the authors' analysis of the reviews. These were refined iteratively to produce final recommendations.

RESULTS

Fourteen best-practice recommendations are provided. Care pathway mapping (using quantitative, qualitative, or mixed-methods approaches) should be used for identifying the SoC comparator. Guidelines analysis can be integrated with expert opinion to identify pathway variability and discrepancies from clinical practice. For integrating the SoC comparator into the model, recommendations around structure, input sourcing, data aggregation and reporting, input uncertainty, and model variability are presented. For example, modelers should consider that the reference standard is not synonymous with the SoC, and the SoC may not be the only comparator. The comparator limitations should be discussed with clinical experts, but elicitation of its diagnostic accuracy is not recommended. Probabilistic sensitivity analysis is recommended when evaluating the overall input uncertainty, and deterministic sensitivity analysis is useful when there is high model uncertainty or SoC variability. Consensus could not be reached for some topics (eg, the role of real-world data, model averaging, and alternative model structures), but the reported discussions provide points for consideration.

CONCLUSIONS

To our knowledge, this is the first guidance to support modelers when identifying and operationalizing the SoC comparator in diagnostic cost-effectiveness models.

Evidence Synthesis and Linkage for Modelling the Cost-Effectiveness of Diagnostic Tests: Preliminary Good Practice Recommendations

OBJECTIVES

To develop preliminary good practice recommendations for synthesising and linking evidence of treatment effectiveness when modelling the cost-effectiveness of diagnostic tests.

METHODS

We conducted a targeted review of guidance from key Health Technology Assessment (HTA) bodies to summarise current recommendations on synthesis and linkage of treatment effectiveness evidence within economic evaluations of diagnostic tests. We then focused on a specific case study, the cost-effectiveness of troponin for the diagnosis of myocardial infarction, and reviewed the approach taken to synthesise and link treatment effectiveness evidence in different modelling studies.

RESULTS

The Australian and UK HTA bodies provided advice for synthesising and linking treatment effectiveness in diagnostic models, acknowledging that linking test results to treatment options and their outcomes is common. Across all reviewed models for the case study, uniform test-directed treatment decision making was assumed, i.e., all those who tested positive were treated. Treatment outcome data from a variety of sources, including expert opinion, were utilised for linked clinical outcomes. Preliminary good practice recommendations for data identification, integration and description are proposed.

CONCLUSION

Modelling the cost-effectiveness of diagnostic tests poses unique challenges in linking evidence on test accuracy to treatment effectiveness data to understand how a test impacts patient outcomes and costs. Upfront consideration of how a test and its results will likely be incorporated into patient diagnostic pathways is key to exploring the optimal design of such models. We propose some preliminary good practice recommendations to improve the quality of cost-effectiveness evaluations of diagnostics tests going forward.

The cost-effectiveness of NT-proBNP for assessment of suspected acute heart failure in the emergency department

AIMS

When relying on clinical assessment alone, an estimated 22% of acute heart failure (AHF) patients are missed, so clinical guidelines recommend the use of N-terminal pro-B-type natriuretic peptide (NT-proBNP) for AHF diagnosis. Since publication of these guidelines, there has been poor uptake of NT-proBNP testing in part due to concerns over excessive false positive referrals resulting from the low specificity of a single 'rule-out' threshold of <300 pg/mL. Low specificity can be mitigated by the addition of age-specific 'rule-in' NT-proBNP thresholds.

METHODS AND RESULTS

A theoretical hybrid decision tree/semi-Markov model was developed, combining global trial and audit data to evaluate the cost-effectiveness of NT-proBNP testing using age-specific rule-in/rule-out (RI/RO) thresholds, compared with NT-proBNP RO only and with clinical decision alone (CDA). Cost-effectiveness was measured as the incremental cost per quality-adjusted life year (QALY) gained and incremental net health benefit. In the base case, using UK-specific inputs, NT-proBNP RI/RO was associated with both greater QALYs and lower costs than CDA. At a willingness-to-pay threshold of £20 000/QALY, NT-proBNP RO was also cost-effective compared with CDA [incremental cost-effectiveness ratio (ICER) of £8322/QALY], but not cost-effective vs. RI/RO (ICER of £64 518/QALY). Overall, NT-proBNP RI/RO was the most cost-effective strategy. Sensitivity and scenario analyses were undertaken; the conclusions were not impacted by plausible variations in parameters, and similar conclusions were obtained for the Netherlands and Spain.

CONCLUSIONS

An NT-proBNP strategy that combines an RO threshold with age-specific RI thresholds provides a cost-effective alternative to the currently recommended NT-proBNP RO only strategy, achieving greater diagnostic specificity with minimal reduction in sensitivity and thus reducing unnecessary echocardiograms and hospital admissions.

Clinical Efficacy and Safety of Once-Weekly Fractionation in Stereotactic Body Radiotherapy for Pulmonary Oligometastatic Lesions

PURPOSE/OBJECTIVE(S)

As the oligometastatic disease paradigm has become more widely accepted, further investigation is needed to risk-stratify patients within this spectrum of disease and define optimal treatment methods. Stereotactic Body Radiotherapy (SBRT) has emerged as an efficacious and safe modality to control individual lesions and improve clinical outcomes in the setting of oligometastatic disease. There is scant literature describing ideal SBRT inter-fraction time intervals or their impact on clinical outcomes, especially for treating pulmonary oligometastases. Most institutions appear to offer treatments on consecutive days or every other day. In this abstract, we sought to evaluate the efficacy and safety of delivering SBRT treatments in a once-weekly fractionation scheme.

MATERIALS/METHODS

The study was undertaken via retrospective review at a single institution. We included patients with pulmonary metastatic lesions treated with SBRT at our institution between 2015 and 2019. Patients with oligometastatic disease were included, defined as patients with 5 or fewer total metastatic lesions. Treatments were delivered between 3 and 5 fractions and using at least 5 Gy per fraction. Per institutional protocol, all treatments were delivered 7 days apart.

RESULTS

From a single institution, 204 lesions from 111 patients were included. Median follow-up was 16.5 months [IQR 7 - 36.3]. Median dose was 40 Gy [IQR 30 - 50], median BED was 80 Gy [IQR 60-100], median dose per fraction was 10 Gy [IQR 8-11]. Median internal target volume (ITV) was 18.5 cc [IQR 9.3 - 45.8]. The most common tumor histologies were lung adenocarcinoma (38.2%), colorectal adenocarcinoma (15.6%), lung squamous cell carcinoma (12.7%), renal cell carcinoma (5.9%), breast invasive ductal carcinoma (5.4%), small cell lung cancer (3.9%), and melanoma (2.9%). 2-year local control (LC) rate was 85.7% and 5-year LC rate was 84.3%. 2-year regional control (RC) rate was 53.9% and 5-year RC was 49%. Median overall survival (OS) was 20 months [IQR 9 - 37.3]. Cox regression analysis revealed biologically effective dose (BED) (HR 0.99 [0.98 - 0.99] p = 0.001) as well as dose per fraction (HR 0.92 [0.86 - 0.97] p = 0.003) were both associated with improved OS. Longest tumor dimension was associated with worse OS independent of BED and dose per fraction (HR 1.26 [1.1 - 1.4] p = 0.001). Total toxicity incidence was 7.3%, which consisted only of G1-G2 cough, dyspnea, and fatigue.

CONCLUSION

Treatment of pulmonary oligometastatic lesions with SBRT delivered via once-weekly fractionation is associated with excellent local control and minimal toxicity. Larger studies are warranted to directly compare clinical outcomes of weekly SBRT fractionation to other conventional SBRT treatment schedules.

A Precision Medicine Navigator Can Mitigate Inequities Associated with Utilization of Genomic Tests in Black Men with Prostate Cancer

PURPOSE/OBJECTIVE(S)

Black men with prostate cancer in the United States experience disproportionately worse clinical outcomes compared to other racial groups. Identifying more reliable prognosticators to address these inequities has thus been the subject of considerable research scrutiny. However, prognostic genomic tools and genomic biorepositories suffer from an even greater lack of racial diversity. Strategies to mitigate these amplifying developments in inequities are desperately needed. We hypothesized that the presence of a precision medicine navigator (PMN) may mitigate inequities with standard of care (SOC) genomic test utilization among Black men with prostate cancer.

MATERIALS/METHODS

We retrospectively reviewed prostate cancer consults within one healthcare system from 11/2/2021 to 1/2/2022. We compared the frequency of patients who received SOC Decipher or Tempus genomic testing in the 7 months prior to the PMN start (pre-PMN) to the 7 months afterward (post-PMN). Chi square analysis was used to compare subgroups. Binary logistic regression was used to calculate the odds of receiving genomic testing.

RESULTS

The sample included 693 patients, 44.9% (311/693) pre-PMN and 55.1% (382/693) post-PMN, with a median age of 68 in both groups. Pre- and post-PMN racial distributions were similar with 60.1% and 60.2% White, 35.1% and 34% Black, 3.2% and 3.7% Asian/Pacific Islander, and 1.3% and 2.1% Latino, respectively. Pre- and post-PMN NCCN risk category distribution was 15.2% and 10.4% low risk, 46.8% and 49.9% intermediate risk, and 38.1% and 39.7% high risk, respectively. Pre- and post-PMN groups had 14.5% and 17% distant metastases, 77.2% and 76.9% localized disease, 10.3% and 10% prior prostatectomy, 47% and 51% income below sample median, 51% and 52% with Medicare/Medicaid, and 47% and 48% seen at community hospitals, respectively. There were no statistically significant differences for these variables pre- and post-PMN. However, from pre- to post-PMN, the proportion of Black patients receiving genomic testing increased from 19% to 58%. Black patients seen post-PMN were six times more likely to receive testing (p<0.001). Significant increases in SOC genomic testing post-PMN also occurred among lower median income patients, patients with Medicare/Medicaid, and community hospital patients.

CONCLUSION

The presence of a PMN may improve disparate rates of Black patients receiving SOC genomic tests for prostate cancer compared to other racial groups and may alleviate genomic testing inequities among other demographics.

Bayesian sample size determination for diagnostic accuracy studies

The development of a new diagnostic test ideally follows a sequence of stages which, among other aims, evaluate technical performance. This includes an analytical validity study, a diagnostic accuracy study, and an interventional clinical utility study. In this article, we propose a novel Bayesian approach to sample size determination for the diagnostic accuracy study, which takes advantage of information available from the analytical validity stage. We utilize assurance to calculate the required sample size based on the target width of a posterior probability interval and can choose to use or disregard the data from the analytical validity study when subsequently inferring measures of test accuracy. Sensitivity analyses are performed to assess the robustness of the proposed sample size to the choice of prior, and prior‐data conflict is evaluated by comparing the data to the prior predictive distributions. We illustrate the proposed approach using a motivating real‐life application involving a diagnostic test for ventilator associated pneumonia. Finally, we compare the properties of the approach against commonly used alternatives. The results show that, when suitable prior information is available, the assurance‐based approach can reduce the required sample size when compared to alternative approaches.

Diagnosing ventilator-associated pneumonia (VAP) in UK NHS ICUs: the perceived value and role of a novel optical technology

BACKGROUND

Diagnosing ventilator-associated pneumonia (VAP) in an intensive care unit (ICU) is a complex process. Our aim was to collect, evaluate and represent the information relating to current clinical practice for the diagnosis of VAP in UK NHS ICUs, and to explore the potential value and role of a novel diagnostic for VAP, which uses optical molecular alveoscopy to visualise the alveolar space.

METHODS

Qualitative study performing semi-structured interviews with clinical experts. Interviews were recorded, transcribed, and thematically analysed. A flow diagram of the VAP patient pathway was elicited and validated with the expert interviewees. Fourteen clinicians were interviewed from a range of UK NHS hospitals: 12 ICU consultants, 1 professor of respiratory medicine and 1 professor of critical care.

RESULTS

Five themes were identified, relating to [1] current practice for the diagnosis of VAP, [2] current clinical need in VAP diagnostics, [3] the potential value and role of the technology, [4] the barriers to adoption and [5] the evidence requirements for the technology, to help facilitate a successful adoption. These themes indicated that diagnosis of VAP is extremely difficult, as is the decision to stop antibiotic treatment. The analysis revealed that there is a clinical need for a diagnostic that provides an accurate and timely diagnosis of the causative pathogen, without the long delays associated with return of culture results, and which is not dangerous to the patient. It was determined that the technology would satisfy important aspects of this clinical need for diagnosing VAP (and pneumonia, more generally), but would require further evidence on safety and efficacy in the patient population to facilitate adoption.

CONCLUSIONS

Care pathway analysis performed in this study was deemed accurate and representative of current practice for diagnosing VAP in a UK ICU as determined by relevant clinical experts, and explored the value and role of a novel diagnostic, which uses optical technology, and could streamline the diagnostic pathway for VAP and other pneumonias.

Strategies to implement SARS-CoV-2 point-of-care testing into primary care settings: a qualitative secondary analysis guided by the Behaviour Change Wheel

BACKGROUND

The purpose of this study is to develop a theory-driven understanding of the barriers and facilitators underpinning physicians' attitudes and capabilities to implementing SARS-CoV-2 point-of-care (POC) testing into primary care practices.

METHODS

We used a secondary qualitative analysis approach to re-analyse data from a qualitative, interview study of 22 primary care physicians from 21 primary care practices across three regions in England. We followed the three-step method based on the Behaviour Change Wheel to identify the barriers to implementing SARS-CoV-2 POC testing and identified strategies to address these challenges.

RESULTS

Several factors underpinned primary care physicians' attitudes and capabilities to implement SARS-CoV-2 POC testing into practice. First, limited knowledge of the SARS-CoV-2 POC testing landscape and a demanding workload affected physicians' willingness to use the tests. Second, there was scepticism about the insufficient evidence pertaining to the clinical efficacy and utility of POC tests, which affected physicians' confidence in the accuracy of tests. Third, physicians would adopt POC tests if they were prescribed and recommended by authorities. Fourth, physicians required professional education and training to increase their confidence in using POC tests but also suggested that healthcare assistants should administer the tests. Fifth, physicians expressed concerns about their limited workload capacity and that extra resources are needed to accommodate any anticipated changes. Sixth, information sharing across practices shaped perceptions of POC tests and the quality of information influenced physician perceptions. Seventh, financial incentives could motivate physicians and were also needed to cover the associated costs of testing. Eighth, physicians were worried that society will view primary care as an alternative to community testing centres, which would change perceptions around their professional identity. Ninth, physicians' perception of assurance/risk influenced their willingness to use POC testing if it could help identify infectious individuals, but they were also concerned about the risk of occupational exposure and potentially losing staff members who would need to self-isolate.

CONCLUSIONS

Improving primary care physicians' knowledgebase of SARS-CoV-2 POC tests, introducing policies to embed testing into practice, and providing resources to meet the anticipated demands of testing are critical to implementing testing into practice.

Point of care testing using rapid automated antigen testing for SARS-COV-2 in care homes – an exploratory safety, usability and diagnostic agreement evaluation

Introduction

Successful adoption of POCTs (Point-of-Care tests) for COVID-19 in care homes requires the identification of ideal use cases and a full understanding of the contextual and usability factors that affect test results and minimise biosafety risks. This paper presents a scoping-usability and test performance study of a microfluidic immunofluorescence assay for COVID-19 in care homes.

Methods

A mixed-methods evaluation was conducted in four UK care homes to scope usability and to assess the agreement with qRT-PCR. A dry run with luminescent dye was conducted to explore biosafety issues.

Results

The agreement analysis was conducted on 227 asymptomatic participants (159 staff and 68 residents) and 14 symptomatic participants (5 staff and 9 residents). Asymptomatic specimens showed 50% (95% CI:1.3%−98.7%) positive agreement and 96% (95% CI: 92.5%−98.1%) negative agreement with overall prevalence and bias-adjusted Kappa (PABAK) of 0.911 (95% CI: 0.857−0.965). Symptomatic specimens showed 83.3% (95% CI: 35.9%−99.6%) positive agreement and 100% (95% CI: 63.1%−100%) negative agreement with overall prevalence and bias-adjusted Kappa (PABAK) of 0.857 (95% CI: 0.549−1). The dry run highlighted four main sources of contamination that led to the modification of the standard operating procedures. Simulation post-modification showed no further evidence of contamination.

Conclusion

Careful consideration of biosafety issues and contextual factors associated with care home are mandatory for safe use the POCT. Whilst POCT may have some utility for ruling out COVID-19, further diagnostic accuracy evaluations are needed to promote effective adoption.

COVID-19 point-of-care testing in care homes: what are the lessons for policy and practice?

COVID-19 has devastated care homes. Point-of-care tests (POCTs), mainly using lateral flow devices (LFDs), have been deployed hurriedly without much consideration of their usability or impact on care workflow. Even after the pandemic, POCTs, particularly multiplex tests, may be an important control against spread of SARS-CoV-2 and other respiratory infections in care homes by enabling identification of cases. They should not, however, replace other infection control measures such as barrier methods and quarantine. Adherence to LFDs as implemented among care home staff is suboptimal. Other tests-such as point-of-care polymerase chain reaction and automated antigen tests-would also need to be accommodated into care home workflows to improve adherence. The up-front costs of POCTs are straightforward but additional costs, including staffing preparation and reporting processes and the impacts of false positive and negative tests on absence rates and infection days, are more complex and as yet unquantified. A detailed appraisal is needed as the future of testing in care homes is considered.

Is point-of-care testing feasible and safe in care homes in England? An exploratory usability and accuracy evaluation of a point-of-care polymerase chain reaction test for SARS-CoV-2

Introduction

Reliable rapid testing for COVID-19 is needed in care homes to reduce the risk of outbreaks and enable timely care. This study aimed to examine the usability and test performance of a point of care polymerase chain reaction (PCR) test for detection of SARS-CoV-2 (POCKIT^TM Central) in care homes.

Methods

POCKIT^TM Central was evaluated in a purposeful sample of four UK care homes. Test agreement with laboratory real-time PCR and usability and used errors were assessed.

Results

No significant usability-related hazards emerged, and the sources of error identified were found to be amendable with minor changes in training or test workflow. POCKIT^TM Central has acceptable sensitivity and specificity based on RT-PCR as the reference standard, especially for symptomatic cases.

Asymptomatic specimens showed 83.3% (95% confidence interval (CI): 35.9–99.6%) positive agreement and 98.7% negative agreement (95% CI: 96.2–99.7%), with overall prevalence and bias-adjusted kappa (PABAK) of 0.965 (95% CI: 0.932– 0.999). Symptomatic specimens showed 100% (95% CI: 2.5–100%) positive agreement and 100% negative agreement (95% CI: 85.8–100%), with overall PABAK of 1.

Recommendations are provided to mitigate the frequency of occurrence of the residual use errors observed. Integration pathways were discussed to identify opportunities and limitations of adopting POCKIT™ Central for screening and diagnostic testing purposes.

Conclusions

Point-of-care PCR testing in care homes can be considered with appropriate preparatory steps and safeguards. Further diagnostic accuracy evaluations and in-service evaluation studies should be conducted, if the test is to be implemented more widely, to build greater certainty on this initial exploratory analysis.

Systematic review of studies investigating ventilator associated pneumonia diagnostics in intensive care

Background

Ventilator-associated pneumonia (VAP) is an important diagnosis in critical care. VAP research is complicated by the lack of agreed diagnostic criteria and reference standard test criteria. Our aim was to review which reference standard tests are used to evaluate novel index tests for suspected VAP.

Methods

We conducted a comprehensive search using electronic databases and hand reference checks. The Cochrane Library, MEDLINE, CINHAL, EMBASE, and web of science were searched from 2008 until November 2018. All terms related to VAP diagnostics in the intensive treatment unit were used to conduct the search. We adopted a checklist from the critical appraisal skills programme checklist for diagnostic studies to assess the quality of the included studies.

Results

We identified 2441 records, of which 178 were selected for full-text review. Following methodological examination and quality assessment, 44 studies were included in narrative data synthesis. Thirty-two (72.7%) studies utilised a sole microbiological reference standard; the remaining 12 studies utilised a composite reference standard, nine of which included a mandatory microbiological criterion. Histopathological criteria were optional in four studies but mandatory in none.

Conclusions

Nearly all reference standards for VAP used in diagnostic test research required some microbiological confirmation of infection, with BAL culture being the most common reference standard used.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01560-0.

Care pathway and prioritization of rapid testing for COVID-19 in UK hospitals: a qualitative evaluation

OBJECTIVES

The second wave of the coronavirus pandemic is now established, occurring at a time of winter pressure on acute care in the NHS. This is likely to be more challenging then the first wave for the diagnosis of COVID-19 because of the similar symptomology with other respiratory conditions highly prevalent in winter. This study sought to understand the care pathways in place in UK NHS hospitals during the first wave (March-July 2020) for identification of patients with COVID-19 and to learn lessons to inform optimal testing strategies within the COVID-19 National Diagnostic Research and Evaluation Platform (CONDOR).

DESIGN, SETTING & PARTICIPANTS

Sixteen hospital-based clinicians from 12 UK NHS Trusts covering 10 different specialties were interviewed following a semi-structured topic guide. Data were coded soon after the interviews and analysed thematically.

RESULTS

We developed a diagrammatic, high-level visualisation of the care pathway describing the main clinical decisions associated with the diagnosis and management of patients with suspected COVID-19. COVID-19 testing influenced infection control considerations more so than treatment decisions. Two main features of service provision influenced the patient management significantly: access to rapid laboratory testing and the number of single occupancy rooms. If time to return of result was greater than 24 h, patients with a presumptive diagnosis would often be cohorted based on clinical suspicion alone. Undetected COVID-19 during this time could therefore lead to an increased risk of viral transmission.

CONCLUSIONS

During the winter months, priority for provision of rapid testing at admission should be given to hospitals with limited access to laboratory services and single room availability. Access to rapid testing is essential for urgent decisions related to emergency surgery, maternity services and organ transplant. The pathway and prioritization of need will inform the economic modelling, clinical evaluations, and implementation of new clinical tests in UK.

Conducting invasive urodynamics in primary care: qualitative interview study examining experiences of patients and healthcare professionals

BACKGROUND

Invasive urodynamics is used to investigate the causes of lower urinary tract symptoms; a procedure usually conducted in secondary care by specialist practitioners. No study has yet investigated the feasibility of carrying out this procedure in a non-specialist setting. Therefore, the aim of this study was to explore, using qualitative methodology, the feasibility and acceptability of conducting invasive urodynamic testing in primary care.

METHODS

Semi-structured interviews were conducted during the pilot phase of the PriMUS study, in which men experiencing bothersome lower urinary tract symptoms underwent invasive urodynamic testing along with a series of simple index tests in a primary care setting. Interviewees were 25 patients invited to take part in the PriMUS study and 18 healthcare professionals involved in study delivery. Interviews were audio-recorded, transcribed verbatim and analysed using a framework approach.

RESULTS

Patients generally found the urodynamic procedure acceptable and valued the primary care setting due to its increased accessibility and familiarity. Despite some logistical issues, facilitating invasive urodynamic testing in primary care was also a positive experience for urodynamic nurses. Initial issues with general practitioners receiving and utilising the results of urodynamic testing may have limited the potential benefit to some patients. Effective approaches to study recruitment included emphasising the benefits of the urodynamic test and maintaining contact with potential participants by telephone. Patients' relationship with their general practitioner was an important influence on study participation.

CONCLUSIONS

Conducting invasive urodynamics in primary care is feasible and acceptable and has the potential to benefit patients. Facilitating study procedures in a familiar primary care setting can impact positively on research recruitment. However, it is vital that there is a support network for urodynamic nurses and expertise available to help interpret urodynamic results.

COVID-19 testing in English care homes and implications for staff and residents

INTRODUCTION

Care home residents are at high risk of dying from coronavirus disease 2019 (COVID-19). Regular testing, producing rapid and reliable results is important in this population because infections spread quickly, and presentations are often atypical or asymptomatic. This study evaluated current testing pathways in care homes to explore the role of point-of-care tests (POCTs).

METHODS

A total of 10 staff from eight care homes, purposively sampled to reflect care organisational attributes that influence outbreak severity, underwent a semi-structured remote videoconference interview. Transcripts were analysed using process mapping tools and framework analysis focussing on perceptions about, gaps within and needs arising from current pathways.

RESULTS

Four main steps were identified in testing: infection prevention, preparatory steps, swabbing procedure and management of residents. Infection prevention was particularly challenging for mobile residents with cognitive impairment. Swabbing and preparatory steps were resource-intensive, requiring additional staff resource. Swabbing required flexibility and staff who were familiar to the resident. Frequent approaches to residents were needed to ensure they would participate at a suitable time. After-test management varied between sites. Several homes reported deviating from government guidance to take more cautious approaches, which they perceived to be more robust.

CONCLUSION

Swab-based testing is organisationally complex and resource-intensive in care homes. It needs to be flexible to meet the needs of residents and provide care homes with rapid information to support care decisions. POCT could help address gaps but the complexity of the setting means that each technology must be evaluated in context before widespread adoption in care homes.

Utility of Routine Laboratory Biomarkers to Detect COVID-19: A Systematic Review and Meta-Analysis

No routine laboratory biomarkers perform well enough in diagnosing COVID-19 in isolation for them to be used as a standalone diagnostic test or to help clinicians prioritize patients for treatment. Instead, other diagnostic tests are needed. The aim of this work was to statistically summarise routine laboratory biomarker measurements in COVID-19-positive and -negative patients to inform future work. A systematic literature review and meta-analysis were performed. The search included names of commonly used, routine laboratory tests in the UK NHS, and focused on research papers reporting laboratory results of patients diagnosed with COVID-19. A random effects meta-analysis of the standardized mean difference between COVID-19-positive and -negative groups was conducted for each biomarker. When comparing reported laboratory biomarker results, we identified decreased white blood cell, neutrophil, lymphocyte, eosinophil, and platelet counts; while lactate dehydrogenase, aspartate aminotransferase, and alanine aminotransferase were elevated in COVID-19-positive compared to COVID-19-negative patients. Differences were identified across a number of routine laboratory biomarkers between COVID-19-positive and -negative patients. Further research is required to identify whether routine laboratory biomarkers can be used in the development of a clinical scoring system to aid with triage of patients.

Comparative diagnostic accuracy studies with an imperfect reference standard - a comparison of correction methods

BACKGROUND

Staquet et al. and Brenner both developed correction methods to estimate the sensitivity and specificity of a binary-response index test when the reference standard is imperfect and its sensitivity and specificity are known. However, to our knowledge, no study has compared the statistical properties of these methods, despite their long application in diagnostic accuracy studies.

AIM

To compare the correction methods developed by Staquet et al. and Brenner.

METHODS

Simulations techniques were employed to compare the methods under assumptions that the new test and the reference standard are conditionally independent or dependent given the true disease status of an individual. Three clinical datasets were analysed to understand the impact of using each method to inform clinical decision-making.

RESULTS

Under the assumption of conditional independence, the Staquet et al. correction method outperforms the Brenner correction method irrespective of the prevalence of disease and whether the performance of the reference standard is better or worse than the index test. However, when the prevalence of the disease is high (> 0.9) or low (< 0.1), the Staquet et al. correction method can produce illogical results (i.e. results outside [0,1]). Under the assumption of conditional dependence; both methods failed to estimate the sensitivity and specificity of the index test especially when the covariance terms between the index test and the reference standard is not close to zero.

CONCLUSION

When the new test and the imperfect reference standard are conditionally independent, and the sensitivity and specificity of the imperfect reference standard are known, the Staquet et al. correction method outperforms the Brenner method. However, where the prevalence of the target condition is very high or low or the two tests are conditionally dependent, other statistical methods such as latent class approaches should be considered.

Improving the identification of patients with a genetic diagnosis of familial hypercholesterolaemia in primary care: A strategy to achieve the NHS long term plan

BACKGROUND AND AIMS

We aimed to validate a nurse-led process using electronic health records to identify those at risk of familial hypercholesterolaemia (FH) for genetic diagnosis in primary care.

METHODS

Those at risk of FH were identified using searches developed and refined locally and implemented in primary care by a trained nurse; they were invited for further assessment and genetic testing if indicated. Family members at risk of FH were identified and invited for cascade testing.

RESULTS

In total 94,444 patient records were screened (expected prevalence of FH (1 in 250); 377). Of 176 records which already had a diagnostic for FH, 15 had been genetically confirmed and one was undergoing DNA testing. A further 572 (0.61%) were identified as high risk of FH. After desktop screening, 113 (15%) were invited for further assessment. Of these, 73 individuals attended the primary care clinic (64%) of whom 61 (54%) underwent proband genetic testing. Pathogenic variants were detected in 22 cases (36%) and variants of unknown significance in a further 4 cases; a total of 26 probands (43%) were therefore referred for family cascade testing.

CONCLUSIONS

An optimised FH identification pathway, based on the NICE CG71 recommendations for systematic searching of primary care electronic health records, can be deployed successfully in primary care settings.

Unmet clinical needs for COVID-19 tests in UK health and social care settings

There is an urgent requirement to identify which clinical settings are in most need of COVID-19 tests and the priority role(s) for tests in these settings to accelerate the development of tests fit for purpose in health and social care across the UK. This study sought to identify and prioritize unmet clinical needs for COVID-19 tests across different settings within the UK health and social care sector via an online survey of health and social care professionals and policymakers. Four hundred and forty-seven responses were received between 22nd May and 15th June 2020. Hospitals and care homes were recognized as the settings with the greatest unmet clinical need for COVID-19 diagnostics, despite reporting more access to laboratory molecular testing than other settings. Hospital staff identified a need for diagnostic tests for symptomatic workers and patients. In contrast, care home staff expressed an urgency for screening at the front door to protect high-risk residents and limit transmission. The length of time to test result was considered a widespread problem with current testing across all settings. Rapid tests for staff were regarded as an area of need across general practice and dental settings alongside tests to limit antibiotics use.

At what times during infection is SARS-CoV-2 detectable and no longer detectable using RT-PCR-based tests? A systematic review of individual participant data

BACKGROUND

Tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral ribonucleic acid (RNA) using reverse transcription polymerase chain reaction (RT-PCR) are pivotal to detecting current coronavirus disease (COVID-19) and duration of detectable virus indicating potential for infectivity.

METHODS

We conducted an individual participant data (IPD) systematic review of longitudinal studies of RT-PCR test results in symptomatic SARS-CoV-2. We searched PubMed, LitCOVID, medRxiv, and COVID-19 Living Evidence databases. We assessed risk of bias using a QUADAS-2 adaptation. Outcomes were the percentage of positive test results by time and the duration of detectable virus, by anatomical sampling sites.

RESULTS

Of 5078 studies screened, we included 32 studies with 1023 SARS-CoV-2 infected participants and 1619 test results, from - 6 to 66 days post-symptom onset and hospitalisation. The highest percentage virus detection was from nasopharyngeal sampling between 0 and 4 days post-symptom onset at 89% (95% confidence interval (CI) 83 to 93) dropping to 54% (95% CI 47 to 61) after 10 to 14 days. On average, duration of detectable virus was longer with lower respiratory tract (LRT) sampling than upper respiratory tract (URT). Duration of faecal and respiratory tract virus detection varied greatly within individual participants. In some participants, virus was still detectable at 46 days post-symptom onset.

CONCLUSIONS

RT-PCR misses detection of people with SARS-CoV-2 infection; early sampling minimises false negative diagnoses. Beyond 10 days post-symptom onset, lower RT or faecal testing may be preferred sampling sites. The included studies are open to substantial risk of bias, so the positivity rates are probably overestimated.

The Clinical Need for New Diagnostics in the Identification and Management of Patients with Suspected Sepsis in UK NHS Hospitals: A Survey of Healthcare Professionals

Development of a new diagnostic is ideally driven by an understanding of the clinical need that the test addresses and the optimal role the test will have within a care pathway. This survey aimed to understand the clinical need for new sepsis diagnostics and to identify specific clinical scenarios that could be improved by testing. An electronic, cross-sectional survey was circulated to UK National Health Service (NHS) doctors and nurses who care for patients with suspected sepsis in hospitals. Two hundred and sixty-five participants completed the survey, representing 64 NHS Trusts in England. Sixty-seven percent of respondents suggested that the major cause of delay was during the initial identification of sepsis and the subsequent recognition of patients who were deteriorating. Existing blood tests did not enhance the confidence of consultants making their diagnoses. Those surveyed identified a role for a near-patient test to "rule out" suspected sepsis and, thereby, stop or postpone use of antibiotics. Current diagnostic tests are slow, non-specific, and do not reliably identify patients with a high suspicion of sepsis. As a result, they have a limited use in patient management and antibiotic stewardship. Future development of sepsis diagnostics should focus on overcoming these limitations.

Diagnostic and economic evaluation of a point-of-care test for respiratory syncytial virus

Respiratory syncytial virus is a common cause of bronchiolitis. Historically, point-of-care tests have involved antigen detection technology with limited sensitivity. The aim of this study was to prospectively evaluate the diagnostic accuracy and model the economic impact of the Roche cobas® Liat® point-of-care influenza A/B and respiratory syncytial virus test.

The “DEC-RSV” study was a multi-centre, prospective, observational study in children under 2 years presenting with viral respiratory symptoms. A nasopharyngeal aspirate sample was tested using the point-of-care test and standard laboratory-based procedures. The primary outcome was accuracy of respiratory syncytial virus detection. The cost implications of adopting a point-of-care test were modelled using study data.

A total of 186 participants were recruited, with both tests performed on 177 samples. The point-of-care test was invalid for 16 samples (diagnostic yield 91%) leaving 161 available for primary analysis. After resolving discrepancies, the cobas® Liat® respiratory syncytial virus test had 100.00% (95% CI 96.07%–100.00%) sensitivity and 98.53% (95% CI 92.08%–99.96%) specificity. Median time to result was 0.6 h (interquartile range (IQR) 0.5–1) for point-of-care testing and 28.9 h (IQR 26.3–48.1) for standard laboratory testing. Estimated non-diagnostic cost savings for 1000 patients, based on isolation decision-making on point-of-care test result, were £57 010, which would increase to £94 847 when cohort nursing is used.

In young children the cobas® Liat® point-of-care respiratory syncytial virus test has high diagnostic accuracy using nasopharyngeal aspirates (currently an off-licence sample type). Time to result is clinically important and was favourable compared to laboratory-based testing. The potential exists for cost savings when adopting the point-of-care test.

This prospective evaluation of the cobas Liat point-of-care RSV test in children demonstrated high diagnostic accuracy using nasopharyngeal aspirate samples, with favourable time to result compared to usual laboratory-based testing procedureshttps://bit.ly/2yKKmUB

PRImary care Management of lower Urinary tract Symptoms in men: protocol for development and validation of a diagnostic and clinical decision support tool (the PriMUS study)

INTRODUCTION

Lower urinary tract symptoms (LUTS) is a bothersome condition affecting older men which can lead to poor quality of life. General practitioners (GPs) currently have no easily available assessment tools to help effectively diagnose causes of LUTS and aid discussion of treatment with patients. Men are frequently referred to urology specialists who often recommend treatments that could have been initiated in primary care. GP access to simple, accurate tests and clinician decision tools are needed to facilitate accurate and effective patient management of LUTS in primary care.

METHODS AND ANALYSIS

PRImary care Management of lower Urinary tract Symptoms (PriMUS) is a prospective diagnostic accuracy study based in primary care. The study will determine which of a number of index tests used in combination best predict three urodynamic observations in men who present to their GP with LUTS. These are detrusor overactivity, bladder outlet obstruction and/or detrusor underactivity. Two cohorts of participants, one for development of the prototype diagnostic tool and other for validation, will undergo a series of simple index tests and the invasive reference standard (invasive urodynamics). We will develop and validate three diagnostic prediction models based on each condition and then combine them with management recommendations to form a clinical decision support tool.

ETHICS AND DISSEMINATION

Ethics approval is from the Wales Research Ethics Committee 6. Findings will be disseminated through peer-reviewed journals and conferences, and results will be of interest to professional and patient stakeholders.

TRIAL REGISTRATION NUMBER

ISRCTN10327305.

How to Ease the Pain of Taking a Diagnostic Point of Care Test to the Market: A Framework for Evidence Development

Bringing a diagnostic point of care test (POCT) to a healthcare market can be a painful experience as it requires the manufacturer to meet considerable technical, financial, managerial, and regulatory challenges. In this opinion article we propose a framework for developing the evidence needed to support product development, marketing, and adoption. We discuss each step in the evidence development pathway from the invention phase to the implementation of a new POCT in the healthcare system. We highlight the importance of articulating the value propositions and documenting the care pathway. We provide guidance on how to conduct care pathway analysis as little has been published on this. We summarize the clinical, economic and qualitative studies to be considered for developing evidence, and provide useful links to relevant software, on-line applications, websites, and give practical advice. We also provide advice on patient and public involvement and engagement (PPIE), and on product management. Our aim is to help device manufacturers to understand the concepts and terminology used in evaluation of in vitro diagnostics (IVDs) so that they can communicate effectively with evaluation methodologists, statisticians, and health economists. Manufacturers of medical tests and devices can use the proposed framework to plan their evidence development strategy in alignment with device development, applications for regulatory approval, and publication.

Biomarker-guided antibiotic stewardship in suspected ventilator-associated pneumonia (VAPrapid2): a randomised controlled trial and process evaluation

BACKGROUND

Ventilator-associated pneumonia is the most common intensive care unit (ICU)-acquired infection, yet accurate diagnosis remains difficult, leading to overuse of antibiotics. Low concentrations of IL-1β and IL-8 in bronchoalveolar lavage fluid have been validated as effective markers for exclusion of ventilator-associated pneumonia. The VAPrapid2 trial aimed to determine whether measurement of bronchoalveolar lavage fluid IL-1β and IL-8 could effectively and safely improve antibiotic stewardship in patients with clinically suspected ventilator-associated pneumonia.

METHODS

VAPrapid2 was a multicentre, randomised controlled trial in patients admitted to 24 ICUs from 17 National Health Service hospital trusts across England, Scotland, and Northern Ireland. Patients were screened for eligibility and included if they were 18 years or older, intubated and mechanically ventilated for at least 48 h, and had suspected ventilator-associated pneumonia. Patients were randomly assigned (1:1) to biomarker-guided recommendation on antibiotics (intervention group) or routine use of antibiotics (control group) using a web-based randomisation service hosted by Newcastle Clinical Trials Unit. Patients were randomised using randomly permuted blocks of size four and six and stratified by site, with allocation concealment. Clinicians were masked to patient assignment for an initial period until biomarker results were reported. Bronchoalveolar lavage was done in all patients, with concentrations of IL-1β and IL-8 rapidly determined in bronchoalveolar lavage fluid from patients randomised to the biomarker-based antibiotic recommendation group. If concentrations were below a previously validated cutoff, clinicians were advised that ventilator-associated pneumonia was unlikely and to consider discontinuing antibiotics. Patients in the routine use of antibiotics group received antibiotics according to usual practice at sites. Microbiology was done on bronchoalveolar lavage fluid from all patients and ventilator-associated pneumonia was confirmed by at least 104 colony forming units per mL of bronchoalveolar lavage fluid. The primary outcome was the distribution of antibiotic-free days in the 7 days following bronchoalveolar lavage. Data were analysed on an intention-to-treat basis, with an additional per-protocol analysis that excluded patients randomly assigned to the intervention group who defaulted to routine use of antibiotics because of failure to return an adequate biomarker result. An embedded process evaluation assessed factors influencing trial adoption, recruitment, and decision making. This study is registered with ISRCTN, ISRCTN65937227, and ClinicalTrials.gov, NCT01972425.

FINDINGS

Between Nov 6, 2013, and Sept 13, 2016, 360 patients were screened for inclusion in the study. 146 patients were ineligible, leaving 214 who were recruited to the study. Four patients were excluded before randomisation, meaning that 210 patients were randomly assigned to biomarker-guided recommendation on antibiotics (n=104) or routine use of antibiotics (n=106). One patient in the biomarker-guided recommendation group was withdrawn by the clinical team before bronchoscopy and so was excluded from the intention-to-treat analysis. We found no significant difference in the primary outcome of the distribution of antibiotic-free days in the 7 days following bronchoalveolar lavage in the intention-to-treat analysis (p=0·58). Bronchoalveolar lavage was associated with a small and transient increase in oxygen requirements. Established prescribing practices, reluctance for bronchoalveolar lavage, and dependence on a chain of trial-related procedures emerged as factors that impaired trial processes.

INTERPRETATION

Antibiotic use remains high in patients with suspected ventilator-associated pneumonia. Antibiotic stewardship was not improved by a rapid, highly sensitive rule-out test. Prescribing culture, rather than poor test performance, might explain this absence of effect.

FUNDING

UK Department of Health and the Wellcome Trust.

Diagnostic test evaluation methodology: A systematic review of methods employed to evaluate diagnostic tests in the absence of gold standard - An update

OBJECTIVE

To systematically review methods developed and employed to evaluate the diagnostic accuracy of medical test when there is a missing or no gold standard.

STUDY DESIGN AND SETTINGS

Articles that proposed or applied any methods to evaluate the diagnostic accuracy of medical test(s) in the absence of gold standard were reviewed. The protocol for this review was registered in PROSPERO (CRD42018089349).

RESULTS

Identified methods were classified into four main groups: methods employed when there is a missing gold standard; correction methods (which make adjustment for an imperfect reference standard with known diagnostic accuracy measures); methods employed to evaluate a medical test using multiple imperfect reference standards; and other methods, like agreement studies, and a mixed group of alternative study designs. Fifty-one statistical methods were identified from the review that were developed to evaluate medical test(s) when the true disease status of some participants is unverified with the gold standard. Seven correction methods were identified and four methods were identified to evaluate medical test(s) using multiple imperfect reference standards. Flow-diagrams were developed to guide the selection of appropriate methods.

CONCLUSION

Various methods have been proposed to evaluate medical test(s) in the absence of a gold standard for some or all participants in a diagnostic accuracy study. These methods depend on the availability of the gold standard, its' application to the participants in the study and the availability of alternative reference standard(s). The clinical application of some of these methods, especially methods developed when there is missing gold standard is however limited. This may be due to the complexity of these methods and/or a disconnection between the fields of expertise of those who develop (e.g. mathematicians) and those who employ the methods (e.g. clinical researchers). This review aims to help close this gap with our classification and guidance tools.

Early Economic Evaluation of Diagnostic Technologies: Experiences of the NIHR Diagnostic Evidence Co-operatives

Diagnostic tests are expensive and time-consuming to develop. Early economic evaluation using decision modeling can reduce commercial risk by providing early evidence on cost-effectiveness. The National Institute for Health Research Diagnostic Evidence Co-operatives (DECs) was established to catalyze evidence generation for diagnostic tests by collaborating with commercial developers; DEC researchers have consequently made extensive use of early modeling. The aim of this article is to summarize the experiences of the DECs using early modeling for diagnostics. We draw on 8 case studies to illustrate the methods, highlight methodological strengths and weaknesses particular to diagnostics, and provide advice. The case studies covered diagnosis, screening, and treatment stratification. Treatment effectiveness was a crucial determinant of cost-effectiveness in all cases, but robust evidence to inform this parameter was sparse. This risked limiting the usability of the results, although characterization of this uncertainty in turn highlighted the value of further evidence generation. Researchers evaluating early models must be aware of the importance of treatment effect evidence when reviewing the cost-effectiveness of diagnostics. Researchers planning to develop an early model of a test should also 1) consult widely with clinicians to ensure the model reflects real-world patient care; 2) develop comprehensive models that can be updated as the technology develops, rather than taking a “quick and dirty” approach that may risk producing misleading results; and 3) use flexible methods of reviewing evidence and evaluating model results, to fit the needs of multiple decision makers. Decision models can provide vital information for developers at an early stage, although limited evidence mean researchers should proceed with caution.

Between a ROC and a hard place: Teaching prevalence plots to understand real world biomarker performance in the clinic

The Receiver Operating Characteristic (ROC) curve and the Area Under the Curve (AUC) of the ROC curve are widely used in discovery to compare the performance of diagnostic and prognostic assays. The ROC curve has the advantage that it is independent of disease prevalence. However, in this note, we remind scientists and clinicians that the performance of an assay upon translation to the clinic is critically dependent upon that very same prevalence. Without an understanding of prevalence in the test population, even robust bioassays with excellent ROC characteristics may perform poorly in the clinic. While the exact prevalence in the target population is not always known, simple plots of candidate assay performance as a function of prevalence rate give a better understanding of the likely real-world performance and a greater understanding of the likely impact of variation in that prevalence on translation to the clinic.

Epidermal autophagy and beclin 1 regulator 1 and loricrin: a paradigm shift in the prognostication and stratification of the American Joint Committee on Cancer stage I melanomas

BACKGROUND

The updated American Joint Committee on Cancer (AJCC) staging criteria for melanoma remain unable to identify high-risk stage I tumour subsets.

OBJECTIVES

To determine the utility of epidermal autophagy and beclin 1 regulator 1 (AMBRA1)/loricrin (AMLo) expression as a prognostic biomarker for AJCC stage I cutaneous melanoma.

METHODS

Peritumoral AMBRA1 expression was evaluated in a retrospective discovery cohort of 76 AJCC stage I melanomas. AMLo expression was correlated with clinical outcomes up to 12 years in two independent powered, retrospective validation and qualification cohorts comprising 379 AJCC stage I melanomas.

RESULTS

Decreased AMBRA1 expression in the epidermis overlying primary melanomas in a discovery cohort of 76 AJCC stage I tumours was associated with a 7-year disease-free survival (DFS) rate of 81·5% vs. 100% survival with maintained AMBRA1 (P < 0·081). Following an immunohistochemistry protocol for semi-quantitative analysis of AMLo, analysis was undertaken in validation (n = 218) and qualification cohorts (n = 161) of AJCC stage I melanomas. Combined cohort analysis revealed a DFS rate of 98·3% in the AMLo low-risk group (n = 239) vs. 85·4% in the AMLo high-risk cohort (n = 140; P < 0·001). Subcohort multivariate analysis revealed that an AMLo hazard ratio (HR) of 4·04 [95% confidence interval (CI) 1·69-9·66; P = 0·002] is a stronger predictor of DFS than Breslow depth (HR 2·97, 95% CI 0·93-9·56; P = 0·068) in stage IB patients.

CONCLUSIONS

Loss of AMLo expression in the epidermis overlying primary AJCC stage I melanomas identifies high-risk tumour subsets independently of Breslow depth. What's already known about this topic? There is an unmet clinical need for biomarkers of early-stage melanoma. Autophagy and beclin 1 regulator 1 (AMBRA1) is a proautophagy regulatory protein with known roles in cell proliferation and differentiation, and is a known tumour suppressor. Loricrin is a marker of epidermal terminal differentiation. What does this study add? AMBRA1 has a functional role in keratinocyte/epidermal proliferation and differentiation. The combined decrease/loss of peritumoral AMBRA1 and loricrin is associated with a significantly increased risk of metastatic spread in American Joint Committee on Cancer (AJCC) stage I tumours vs. melanomas, in which peritumoral AMBRA1 and loricrin are maintained, independently of Breslow depth. What is the translational message? The integration of peritumoral epidermal AMBRA1/loricrin biomarker expression into melanoma care guidelines will facilitate more accurate, personalized risk stratification for patients with AJCC stage I melanomas, thereby facilitating stratification for appropriate follow-up and informing postdiagnostic investigations, including sentinel lymph node biopsy, ultimately resulting in improved disease outcomes and rationalization of healthcare costs.

Efficiency and Health Economic Evaluations of BD OneFlow™ Flow Cytometry Reagents for Diagnosing Chronic Lymphoid Leukemia

Reason for the study

To standardize the use of flow cytometry for classifying hematological malignancies and make the results reliable and reproducible across laboratories, the EuroFlow™ Consortium published a comprehensive specification of antibody‐fluorochrome conjugates, standard protocols, and algorithms for analysis. The BD OneFlow™ system builds on, and further standardizes, the EuroFlow protocols. We aimed to assess the effects on safety, efficiency, and costs for laboratories of adopting the BD OneFlow reagent tubes (LST and B‐CLPD T1) for diagnosing chronic lymphocytic leukemia.

Methods

We compared in‐house laboratory processes and results with those using the LST and B‐CLPD T1 reagent tubes with, and without, blood film morphology. Outcome measures included concordance in classification results, and efficiency within the laboratory, that is, resource usage, staff time, unwanted events, and cost‐consequences.

Results

There was 100% concordance between the classifications made with in‐house flow cytometry and those with the BD OneFlow reagent tubes. Using BD OneFlow tubes required 13 hours less staff time per month (i.e. for 100 samples) than the in‐house process. Sensitivity analyses explored the effects of uncertainties in the price of the BD OneFlow tubes and the prevalence of CLL and identified the thresholds at which laboratories might expect cost‐savings from adopting the BD OneFlow system. Laboratory and clinical staff considered the BD OneFlow system to be safe and effective.

Conclusions

Laboratories adopting the BD OneFlow system for classifying patients with suspected CLL can expect safe, efficient processes that can be cost saving if the discount on the list price, and prevalence of CLL (which will both vary between sites and countries), is within the thresholds suggested by the health economics sensitivity analysis. © 2019 International Clinical Cytometry Society

Can mid-regional pro-adrenomedullin (MR-proADM) increase the prognostic accuracy of NEWS in predicting deterioration in patients admitted to hospital with mild to moderately severe illness? A prospective single-centre observational study

OBJECTIVE

To assess the value added to the National Early Warning Score (NEWS) by mid-regional pro-adrenomedullin (MR-proADM) blood level in predicting deterioration in mild to moderately ill people.

DESIGN

Prospective observational study.

SETTING

The Medical Admissions Suite of the Royal Victoria Infirmary, Newcastle.

PARTICIPANTS

300 adults with NEWS between 2 and 5 on admission. Exclusion criteria included receiving palliative care, or admitted for social reasons or self-harming. Patients were enrolled between September and December 2015, and followed up for 30 days after discharge.

OUTCOME MEASURE

The primary outcome measure was the proportion of patients who, within 72 hours, had an acuity increase, defined as any combination of an increase of at least 2 in the NEWS; transfer to a higher-dependency bed or monitored area; death; or for those discharged from hospital, readmission for medical reasons.

RESULTS

NEWS and MR-proADM together predicted acuity increase more accurately than NEWS alone, increasing the area under the curve (AUC) to 0.61 (95% CI 0.54 to 0.69) from 0.55 (95% CI 0.48 to 0.62). When the confounding effects of presence of chronic obstructive pulmonary disease or heart failure and interaction with MR-proADM were included, the prognostic accuracy further increased the AUC to 0.69 (95% CI 0.63 to 0.76).

CONCLUSIONS

MR-proADM is potentially a clinically useful biomarker for deterioration in patients admitted to hospital with a mild to moderately severe acute illness, that is, with NEWS between 2 and 5. As a growing number of National Health Service hospitals are routinely recording the NEWS on their clinical information systems, further research should assess the practicality and use of developing a decision aid based on admission NEWS, MR-proADM level, and possibly other clinical data and other biomarkers that could further improve prognostic accuracy.

A PCR-based diagnostic testing strategy to identify carbapenemase-producing Enterobacteriaceae carriers upon admission to UK hospitals: early economic modelling to assess costs and consequences

BACKGROUND

Carbapenemase-producing Enterobacteriaceae (CPE), bacteria which are resistant to the carbapenem class of antibiotics, present an urgent public health risk. The objective of this study was to assess the potential costs and consequences of implementing a testing strategy involving a polymerase chain reaction (PCR)-based diagnostic test for CPE amongst high risk patients upon admission to UK hospitals, to replace the current culture-based testing strategy.

METHODS

A decision-analytic model was developed to estimate the expected medical care costs associated with a PCR testing strategy for CPE compared with the current culture testing strategy, and to consider the consequences, in terms of the diagnostic accuracy and associated cost implications, of each approach. The modelled population were patients admitted to hospital at high risk of colonisation with CPE, with model pathways for current practice based on those described in the Public Health England (PHE) toolkit for CPE testing. Costs were estimated from a UK National Health Service (NHS) perspective, with outcomes presented in terms of percentage of samples identified as true positive, false positive, true negative and false negative following each method of testing.

RESULTS

Results indicated that the PCR testing strategy led to an estimated cost saving of £462 per patient for a 5-day hospital stay. For all sensitivity analyses conducted, PCR testing resulted in an expected cost saving. Potential cost savings approached £850 per patient for the sensitivity analysis assuming a 15-day hospital stay, indicating that PCR testing results in greater cost savings as length of stay increases. Fewer false positive, and more true negative, cases were identified with the PCR testing strategy in all analyses conducted.

CONCLUSIONS

This economic analysis gives an insight into the potential cost savings that could be made by the UK NHS through the introduction of a PCR-based diagnostic testing strategy to replace current recommended culture-based methods for the detection of CPE. Savings are due primarily to a faster time to result with PCR, meaning that CPE-free patients are not isolated unnecessarily. Therefore, a PCR-based diagnostic may aid appropriate use of isolation resource.

Simulation of TTT Curves for Additively Manufactured Inconel 625

The ability to use common computational thermodynamic and kinetic tools to study the microstructure evolution in Inconel 625 (IN625) manufactured using the additive manufacturing (AM) technique of laser powder-bed fusion is evaluated. Solidification simulations indicate that laser melting and re-melting during printing produce highly segregated interdendritic regions. Precipitation simulations for different degrees of segregation show that the larger the segregation, i.e., the richer the interdendritic regions are in Nb and Mo, the faster the δ-phase (Ni₃Nb) precipitation. This is in accordance with the accelerated d precipitation observed experimentally during post-build heat treatments of AM IN625 compared to wrought IN625. The δ-phase may be undesirable since it can lead to detrimental effects on the mechanical properties. The results are presented in the form of a TTT diagram and agreement between the simulated diagram and the experimental TTT diagram demonstrate how these computational tools can be used to guide and optimize post-build treatments of AM materials.

Diagnostic accuracy and cost analysis of the Alere™ i Influenza A&B near-patient test using throat swabs

BACKGROUND

Clinical diagnostic sensitivity alone is inadequate in the diagnosis of influenza. Polymerase chain reaction (PCR) testing is sensitive but the inherent delays in result availability potentially prolong time to isolation and treatment. Until recently no near-patient test (NPT) has demonstrated adequate sensitivity for routine clinical use.

AIM

To evaluate diagnostic accuracy, time to result availability, clinical impact, and cost consequences of Alere™ i Influenza A&B NPT (Alere Inc., Waltham, MA, USA) using off-label throat swabs.

METHODS

Prospective, multi-centre [four UK National Health Service (NHS) hospitals], diagnostic accuracy cohort study with cost modelling. Throat swab samples from suspected influenza patients were tested for influenza using the reference standard of PCR; a second throat swab was tested using NPT.

FINDINGS

A total of 827 participants were recruited; 589 were suitable for analysis: sensitivity was 75.8% [95% confidence interval (CI): 67.0-84.6]; specificity was 96.8% (95% CI: 95.2-98.3). Sensitivity varied between Sheffield (Northern General Hospital: 82.1%; Royal Hallamshire Hospital: 83.3%) and other sites (Doncaster Royal Infirmary: 71.4%; Newcastle's Royal Victoria Infirmary: 50.0%) whereas specificity was high (92-100%). Positive predictive value (PPV) was 81.2% (95% CI: 72.9-89.5) with negative predictive value 95.6% (95% CI: 93.9-97.4) with observed prevalence of 15.4%. Median time to result for PCR was 1.1 days (on-site laboratories) and 5.2 days (remote laboratories). Isolation findings: 75% influenza positive not isolated; 69% of isolated participants did not have influenza. For a cohort of 1000 participants, annual estimated non-diagnostic cost savings with NPT are £215,040.

CONCLUSION

This first prospective study of the Alere i NPT using throat swabs demonstrates high specificity, high PPV during seasonal epidemics, and rapid result availability which could lead to substantial cost savings.

Depletion of CD4 T lymphocytes at the time of infection with M. avium subsp. paratuberculosis does not accelerate disease progression

A calf model was used to determine if the depletion of CD4 T cells prior to inoculation of Mycobacterium avium subsp. paratuberculosis (Map) would delay development of an immune response to Map and accelerate disease progression. Ileal cannulas were surgically implanted in 5 bull calves at 2 months of age. Two calves were depleted of CD4 T cells by intravenous injection of anti-bovine CD4 antibody administered 24h prior to inoculation with Map. The two CD4-depleted calves and one non-depleted calf were inoculated via ileal cannula with 1 × 10(8)cfu live Map every 3 days for a total of 4 inoculations. Two additional calves served as non-depleted and uninfected controls. Injection with the anti-CD4 mAb reduced the frequency of CD4 T cells from a pre-depletion average of 15% to less than 1% in PBMC at 24h. However, a consistent proliferative response dominated by CD4 T cells, developed in both treated and untreated calves over the course of the 6-month study period. Recovery of Map from serial biopsies obtained from the CD4-depleted and non-depleted calves after Map infection did not differ. In addition, CD4 depletion did not increase the level of Map shed in the feces over the non-depleted animal.

Dynamics of bovine spleen cell populations during the acute response to Babesia bovis infection: an immunohistological study

The spleen is a critical organ in defence against haemoparasitic diseases like babesiosis. Many in vitro and ex vivo studies have identified splenic cells working in concert to activate mechanisms required for successful resolution of infection. The techniques used in those studies, however, remove cells from the anatomical context in which cell interaction and trafficking take place. In this study, an immunohistological approach was used to monitor the splenic distribution of defined cells during the acute response of naïve calves to Babesia bovis infection. Splenomegaly was characterized by disproportionate hyperplasia of large versus small leucocytes and altered distribution of several cell types thought to be important in mounting an effective immune response. In particular, the results suggest that the initial crosstalk between NK cells and immature dendritic cells occurs within the marginal zone and that immature dendritic cells are first redirected to encounter pathogens as they enter the spleen and then mature as they process antigen and migrate to T-cell-rich areas. The results of this study are remarkably similar to those observed in a mouse model of malarial infection, suggesting these dynamic events may be central to the acute response of naïve animals to haemoparasitic infection.

Atomoxetine treatment in children and adolescents with ADHD and comorbid tic disorders

OBJECTIVE

To test the hypothesis that atomoxetine does not significantly worsen tic severity relative to placebo in children and adolescents with attention deficit/hyperactivity disorder (ADHD) and comorbid tic disorders.

METHODS

Study subjects were 7 to 17 years old, met Diagnostic and Statistical Manual of Mental Disorders-IV criteria for ADHD, and had concurrent Tourette syndrome or chronic motor tic disorder. Patients were randomly assigned to double-blind treatment with placebo (n = 72) or atomoxetine (0.5 to 1.5 mg/kg/day, n = 76) for up to 18 weeks.

RESULTS

Atomoxetine treatment was associated with greater reduction of tic severity at endpoint relative to placebo, approaching significance on the Yale Global Tic Severity Scale total score (-5.5 +/- 6.9 vs -3.0 +/- 8.7, p = 0.063) and Tic Symptom Self-Report total score (-4.7 +/- 6.5 vs -2.9 +/- 5.2, p = 0.095) and achieving significance on the Clinical Global Impressions (CGI) tic/neurologic severity scale score (-0.7 +/- 1.2 vs -0.1 +/- 1.0, p = 0.002). Atomoxetine patients also showed greater improvement on the ADHD Rating Scale total score (-10.9 +/- 10.9 vs -4.9 +/- 10.3, p < 0.001) and CGI severity of ADHD/psychiatric symptoms scale score (-0.8 +/- 1.1 vs -0.3 +/- 1.0, p = 0.015). Discontinuation rates were not significantly different between treatment groups. Atomoxetine patients had greater increases in heart rate and decreases of body weight, and rates of treatment-emergent decreased appetite and nausea were higher. No other clinically relevant treatment differences were seen in any other vital sign, adverse event, or electrocardiographic or laboratory measures.

CONCLUSIONS

Atomoxetine did not exacerbate tic symptoms. Rather, there was some evidence of reduction in tic severity with a significant reduction of attention deficit/hyperactivity disorder symptoms. Atomoxetine treatment appeared safe and well tolerated.

Biosecurity and biocontainment in alpaca operations

Biosecurity on South American camelid operations involves both external and internal measures to prevent the introduction and spread of disease. External biosecurity involves practices and techniques directed at the prevention of entry of new diseases into a group of animals. Internal biosecurity or biocontainment, involves practices and techniques that are directed at the prevention or spread of disease within an existing group of animals. External biosecurity is particularly important in North America camelid operations due to the extensive movement of animals for breeding or show purposes. Internal biosecurity typically involves this the prevention and treatment of failure of passive transfer, maintenance of proper nutrition and housing, and the implementation of an appropriate vaccination program for endemic or relevant diseases. Attention to appropriate cleaning and disinfection procedures related to housing, feeding, and treatment equipment is important for the maintenance of both internal and external biosecurity practices. This paper discusses various risk factors associated with the control of infectious disease in the context of external and internal biosecurity measures in camelids operations.

Rapid hematopoietic engraftment following fractionated TBI conditioning and transplantation with CD34(+) enriched hematopoietic progenitor cells from partially mismatched related donors

Nineteen adult patients with poor-risk hematologic malignancy received T cell-depleted (TCD) hematopoietic progenitor cell (HPC) transplant from partially mismatched related donors (PMRD). The preparative regimen (FITFA) included fractionated TBI, thiotepa, fludarabine, and horse (n = 3) or rabbit (n = 16) anti-thymocyte anti-sera (ATG). GVHD prophylaxis consisted of TCD by positive/negative selection using the Isolex 300i system and pre-transplant ATG with no post-transplant immunosuppression. The mean number (+/-s.d.) of transplanted CD34(+) and CD3(+) cells were 8.9 x 10(6)/kg +/-4.3 (range 2.6-19.3) and 1.4 x 10(4)/kg +/-1.2 (range 0.3-4.6) respectively. Seventeen patients evaluable for neutrophil engraftment achieved an ANC >0.5 x 10(9)/l at a median of 12 days (range 9-27), with evidence of full donor chimerism. Thirteen patients died of the following causes: relapse (n = 6), infections (n = 5), interstitial pneumonia (n = 1), and unknown causes (n = 1) None of the recipients of rabbit ATG required therapy for acute or chronic GVHD. Five patients are alive and disease-free at a median time of 303 days post transplant (range 100-660). The FITFA preparative regimen using fractionated TBI is well tolerated and is sufficiently immunosuppressive to allow rapid and stable donor origin hematopoietic engraftment without 'mega' doses of CD34(+) cells. Combination of stringent ex vivo TCD and pre-transplant ATG is effective GVHD prophylaxis.

Lack of pathogenic mutations in the 5'-untranslated region of the thrombopoietin gene in patients with non-familial essential thrombocythaemia

Thrombopoietin (TPO) is thought to be the major physiological regulator of thrombopoiesis, and, in general, circulating levels are inversely proportional to megakaryocyte and platelet mass. However, normal or elevated TPO levels are found in patients with essential thrombocythaemia (ET) and the reason for this is not fully understood. Recent studies have shown that four kindreds with hereditary thrombocythaemia (HT) have point mutations in the 5'-untranslated region (UTR) of the TPO gene which lead to increased TPO translation. In order to determine whether similar mutations are present in apparently acquired ET, in particular in those patients with polyclonal myelopoiesis, we have studied this region in 50 ET patients using neutrophil DNA. The known HT mutations were investigated using polymerase chain reaction with mismatch primers and restriction enzyme digestion; only wild-type alleles were detected. Single-stranded conformation polymorphism (SSCP) analysis of exons 1-4 identified a C-->T substitution at nucleotide 3767. However, this appears to be a common polymorphism, as it was present at the same frequency in haematologically normal controls and is unlikely to be of pathological significance. These results demonstrate that mutations in the 5' UTR of the TPO gene are not the cause of the normal or elevated TPO levels in acquired ET.

The role of ERp57 in disulfide bond formation during the assembly of major histocompatibility complex class I in a synchronized semipermeabilized cell translation system

We have established a semipermeabilized cell system that reproduces the folding and assembly of a major histocompatibility complex (MHC) class I complex as it would occur in the intact cell. The translation of the MHC class I heavy chain (HLA-B27) in this system was synchronized allowing the folding and assembly of polypeptide chains synthesized within a short time frame to be analyzed. This has enabled us to dissect the time course of interaction of both disulfide and nondisulfide-bonded heavy chain with various molecular chaperones during its assembly in a functionally intact endoplasmic reticulum. The results demonstrate that unassembled, nondisulfide-bonded forms of heavy chain interact initially with calnexin. A later and more prolonged interaction of calreticulin, specifically with assembled, disulfide-bonded heavy chain, highlights distinct differences in the roles of these two proteins in the assembly of MHC class I molecules. We also demonstrate that the thiol-dependent reductase ERp57 initially interacts with nondisulfide-bonded heavy chain, but this rapidly becomes disulfide-bonded and indicates that heavy chain folding occurs during its interaction with ERp57. In addition, we also confirm a direct interaction between MHC class I heavy chain and tapasin, emphasizing the role that this protein plays in the later stages of MHC class I assembly.

A pilot study of penicillin prophylaxis for neuropsychiatric exacerbations triggered by streptococcal infections

BACKGROUND

Some children with obsessive-compulsive disorder (OCD) and tic disorders appear to have symptom exacerbations triggered by group A beta-hemolytic streptococcal infections in a manner that is similar to rheumatic fever and its neurologic variant, Sydenham's chorea. Because penicillin prophylaxis has proven to be effective in preventing recurrences of rheumatic fever, it was postulated that it might also prevent streptococcal-triggered neuropsychiatric symptom exacerbations in children with Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections (PANDAS). These children are identified by five clinical characteristics: presence of OCD or tic disorder, prepubertal onset, episodic symptom course, neurologic abnormalities (i.e., choreiform movements) and streptococcal-triggered symptom exacerbations.

METHODS

Thirty-seven children with PANDAS were enrolled in an 8 month, double-blind, balanced cross-over study. Patients were randomized to receive either 4 months of the active compound (twice daily oral 250 mg penicillin V) followed by 4 months of placebo, or placebo followed by penicillin V. Tic, OCD, and other psychiatric symptoms were monitored monthly. Throat cultures and streptococcal antibody titers were also obtained.

RESULTS

There were an equal number of infections in both the active and placebo phases of the study. There was no significant change seen in either the obsessive-compulsive or tic symptom severity between the two phases.

CONCLUSIONS

Because of the failure to achieve an acceptable level of streptococcal prophylaxis, no conclusions can be drawn from this study regarding the efficacy of penicillin prophylaxis in preventing tic or OCD symptom exacerbations. Future studies should employ a more effective prophylactic agent, and include a larger sample size.

Pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections: clinical description of the first 50 cases

OBJECTIVE

The purpose of this study was to describe the clinical characteristics of a novel group of patients with obsessive-compulsive disorder (OCD) and tic disorders, designated as pediatric autoimmune neuropsychiatric disorders associated with streptococcal (group A beta-hemolytic streptococcal [GABHS]) infections (PANDAS).

METHOD

The authors conducted a systematic clinical evaluation of 50 children who met all of the following five working diagnostic criteria: presence of OCD and/or a tic disorder, prepubertal symptom onset, episodic course of symptom severity, association with GABHS infections, and association with neurological abnormalities.

RESULTS

The children's symptom onset was acute and dramatic, typically triggered by GABHS infections at a very early age (mean = 6.3 years, SD = 2.7, for tics; mean = 7.4 years, SD = 2.7, for OCD). The PANDAS clinical course was characterized by a relapsing-remitting symptom pattern with significant psychiatric comorbidity accompanying the exacerbations; emotional lability, separation anxiety, nighttime fears and bedtime rituals, cognitive deficits, oppositional behaviors, and motoric hyperactivity were particularly common. Symptom onset was triggered by GABHS infection for 22 (44%) of the children and by pharyngitis (no throat culture obtained) for 14 others (28%). Among the 50 children; there were 144 separate episodes of symptom exacerbation; 45 (31%) were associated with documented GABHS infection, 60 (42%) with symptoms of pharyngitis or upper respiratory infection (no throat culture obtained), and six (4%) with GABHS exposure.

CONCLUSIONS

The working diagnostic criteria appear to accurately characterize a homogeneous patient group in which symptom exacerbations are triggered by GABHS infections. The identification of such a subgroup will allow for testing of models of pathogenesis, as well as the development of novel treatment and prevention strategies.

Pharmacology of the selective serotonin reuptake inhibitors in children and adolescents

OBJECTIVE

To review the pharmacology of a new class of medications, the potent selective serotonin reuptake inhibitors (SSRIs), what is known about their metabolism in children and adolescents, and the practical clinical implications of such.

METHOD

Articles were retrieved through index Medicus searches for articles published during the past 10 years on the SSRIs and on pediatric pharmacology.

RESULTS

More than 300 articles were reviewed. Pharmacological data, derived from relevant adult literature, were summarized and extrapolated to children and from the limited pediatric literature. The SSRIs represent a new class of antidepressants with distinct advantages in their side effect profile and their broad therapeutic index over that seen with the tricyclic antidepressants. Their advantage of few anticholinergic side effects and limited cardiovascular toxicities are particularly relevant for the pediatric population. The SSRIs are metabolized via the hepatic cytochrome isoenzyme P450 system, and potential drug-drug interactions are reviewed.

CONCLUSIONS

The SSRIs appear to offer advantages over the tricyclic antidepressants. Unfortunately, pharmacokinetic data are lacking, and systematic studies of safety and efficacy in the pediatric age group are limited. Preliminary reports are encouraging, but further study is required.