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.

Screening for Atrial Fibrillation

Approximately 10% of ischemic strokes are associated with atrial fibrillation (AF) first diagnosed at the time of stroke. Detecting asymptomatic AF would provide an opportunity to prevent these strokes by instituting appropriate anticoagulation. The AF-SCREEN international collaboration was formed in September 2015 to promote discussion and research about AF screening as a strategy to reduce stroke and death and to provide advocacy for implementation of country-specific AF screening programs. During 2016, 60 expert members of AF-SCREEN, including physicians, nurses, allied health professionals, health economists, and patient advocates, were invited to prepare sections of a draft document. In August 2016, 51 members met in Rome to discuss the draft document and consider the key points arising from it using a Delphi process. These key points emphasize that screen-detected AF found at a single timepoint or by intermittent ECG recordings over 2 weeks is not a benign condition and, with additional stroke factors, carries sufficient risk of stroke to justify consideration of anticoagulation. With regard to the methods of mass screening, handheld ECG devices have the advantage of providing a verifiable ECG trace that guidelines require for AF diagnosis and would therefore be preferred as screening tools. Certain patient groups, such as those with recent embolic stroke of uncertain source (ESUS), require more intensive monitoring for AF. Settings for screening include various venues in both the community and the clinic, but they must be linked to a pathway for appropriate diagnosis and management for screening to be effective. It is recognized that health resources vary widely between countries and health systems, so the setting for AF screening should be both country- and health system-specific. Based on current knowledge, this white paper provides a strong case for AF screening now while recognizing that large randomized outcomes studies would be helpful to strengthen the evidence base.

Post-viraemic detection of bovine ephemeral fever virus by use of autogenous lymphoid tissue-derived bovine primary cell cultures

BACKGROUND

The potential tissue replication sites and specific cell types that support in vivo virus survival beyond the acute phase of bovine ephemeral fever virus (BEFV) infection have not been fully defined in cattle. To clarify the knowledge gap, tissue specimens were tested after collection from an adult steer necropsied 1 week after acute BEF.

CASE REPORT

Significant necropsy findings included fibrinoproliferative synovitis in the stifle joints and fibrin clot-laden fluid in serous body cavities. Moderate numbers of infiltrating neutrophils were demonstrated in sections of the prefemoral lymph nodes and haemal node, and lymphoid hyperplasia in the spleen, haemal node and prefemoral lymph nodes. Viral RNA was detected by qRT-PCR in fresh spleen, haemal node, prefemoral lymph node, synovial fluid and in several spleen-derived cell cultures. BEFV was isolated from autogenously derived splenic primary cell cultures 6 days after cessation of viraemia, and characteristic bullet-shaped virions were confirmed by electron microscopy of an ultrathin haemal node section. In sections of the spleen, haemal node and other tissues, immunohistochemistry demonstrated BEFV antigens that were intracellularly associated with probable histiocytic cells.

CONCLUSION

BEFV has preferential tropism for bovine lymphoid tissues and the spleen and haemal node may be potential sites for post-viraemic virus replication.

Ensemble-free configurational temperature for spin systems

An estimator for the dynamical temperature in an arbitrary ensemble is derived in the framework of the conjugate variables theorem. We prove directly that its average indeed gives the inverse temperature and that it is independent of the ensemble. We test this estimator numerically by a simulation of the two-dimensional XY model in the canonical ensemble. As this model is critical in the whole region of temperatures below the Berezinski-Kosterlitz-Thouless critical temperature T_{BKT}, we use a generalization of Wolff's unicluster algorithm. The numerical results allow us to confirm the robustness of the analytical expression for the microscopic estimator of the temperature. This microscopic estimator has also the advantage that it gives a direct measure of the thermalization process and can be used to compute absolute errors associated with statistical fluctuations. In consequence, this estimator allows for a direct, absolute, and stringent test of the ergodicity of the underlying Markov process, which encodes the algorithm used in a numerical simulation.

METACOHORTS for the study of vascular disease and its contribution to cognitive decline and neurodegeneration: An initiative of the Joint Programme for Neurodegenerative Disease Research

Dementia is a global problem and major target for health care providers. Although up to 45% of cases are primarily or partly due to cerebrovascular disease, little is known of these mechanisms or treatments because most dementia research still focuses on pure Alzheimer's disease. An improved understanding of the vascular contributions to neurodegeneration and dementia, particularly by small vessel disease, is hampered by imprecise data, including the incidence and prevalence of symptomatic and clinically "silent" cerebrovascular disease, long-term outcomes (cognitive, stroke, or functional), and risk factors. New large collaborative studies with long follow-up are expensive and time consuming, yet substantial data to advance the field are available. In an initiative funded by the Joint Programme for Neurodegenerative Disease Research, 55 international experts surveyed and assessed available data, starting with European cohorts, to promote data sharing to advance understanding of how vascular disease affects brain structure and function, optimize methods for cerebrovascular disease in neurodegeneration research, and focus future research on gaps in knowledge. Here, we summarize the results and recommendations from this initiative. We identified data from over 90 studies, including over 660,000 participants, many being additional to neurodegeneration data initiatives. The enthusiastic response means that cohorts from North America, Australasia, and the Asia Pacific Region are included, creating a truly global, collaborative, data sharing platform, linked to major national dementia initiatives. Furthermore, the revised World Health Organization International Classification of Diseases version 11 should facilitate recognition of vascular-related brain damage by creating one category for all cerebrovascular disease presentations and thus accelerate identification of targets for dementia prevention.

Clinical Significance of Pretransplant Donor-Specific Antibodies in the Setting of Negative Cell-Based Flow Cytometry Crossmatching in Kidney Transplant Recipients

Antibodies to donor-specific HLA antigens (donor-specific antibodies [DSA]) detected by single-antigen bead (SAB) analysis prior to kidney transplant have been associated with inferior graft outcomes. However, studies of pretransplant DSA, specifically in the setting of a negative flow cytometry crossmatch (FCXM) without desensitization therapy, are limited. Six hundred and sixty kidney and kidney-pancreas recipients with a negative pretransplant FCXM from September 2007 to August 2012 without desensitization therapy were analyzed with a median follow-up of 4.2 years. All patients underwent cell-based FCXM and SAB analysis on current and historic sera prior to transplantation. One hundred and sixty-two patients (24.5%) had DSA detected prior to transplant. One-year acute rejection rates were similar in DSA-positive versus DSA-negative patients (15.4% vs. 11.4%, respectively; p = 0.18) and were higher in those with DSA mean fluorescence intensity (MFI) greater than or equal to 3000 in multivariable analysis (p = 0.046). The estimated glomerular filtration rate (eGFR) at 3 and 4 years was lower in the DSA(+) versus the DSA(-) group (p = 0.050 at 3 years) without an impact on 5-year death-censored graft survival (89.0% vs. 90.6%, respectively; p = 0.53). Timing (current or historic) of DSA detection did not alter these findings. In conclusion, pretransplant DSA in the setting of a negative FCXM confers minimal immunologic risk in the intermediate term, does not necessitate desensitization therapy and should not represent a barrier to renal transplant.

Thrombolysis and thrombectomy in patients treated with dabigatran with acute ischemic stroke: Expert opinion

Systemic thrombolysis with rt-PA is contraindicated in patients with acute ischemic stroke anticoagulated with dabigatran. This expert opinion provides guidance on the use of the specific reversal agent idarucizumab followed by rt-PA and/or thrombectomy in patients with ischemic stroke pre-treated with dabigatran. The use of idarucizumab followed by rt-PA is covered by the label of both drugs.

Viral neurotropism, peripheral neuropathy and other morphological abnormalities in bovine ephemeral fever virus-infected downer cattle

OBJECTIVE

This study assessed the neurotropism of bovine ephemeral fever (BEF) virus (BEFV) and described histomorphological abnormalities of the brain, spinal cord and peripheral nerves that may causally contribute to paresis or paralysis in BEF.

METHODS

Four paralysed and six asymptomatic but virus-infected cattle were monitored, and blood and serum samples screened by qRT-PCR, virus isolation and neutralisation tests. Fresh brain, spinal cord, peripheral nerve and other tissues were qRT-PCR-tested for viral RNA, while formalin-fixed specimens were processed routinely and immunohistochemically evaluated for histomorphological abnormalities and viral antigen distribution, respectively.

RESULTS

The neurotropism of BEFV was immunohistochemically confirmed in the brain and peripheral nerves and peripheral neuropathy was demonstrated in three paralysed but not the six aneurological but virus-infected animals. Wallerian degeneration (WD) was present in the ventral funicular white matter of the lumbar spinal cord of a paralysed steer and in cervical and thoracic spinal cord segments of three paralysed animals. Although no spinal cord lesions were seen in the steer euthanased within 7 days of illness, peripheral neuropathy was present and more severe in nerves of the brachial plexuses than in the gluteal or fibular nerves. The only steer with WD in the lumbar spinal cord also showed intrahistiocytic cell viral antigen that was spatially distributed within areas of moderate brain stem encephalitis.

CONCLUSION

The data confirmed neurotropism of BEFV in cattle and documented histomorphological abnormalities in peripheral nerves and brain which, together with spinal cord lesions, may contribute to chronic paralysis in BEFV-infected downer cattle.

Gonadal function is associated with cardiometabolic health in pre-pubertal boys with Klinefelter syndrome

The most common sex chromosome aneuploidy, Klinefelter syndrome (KS), is associated with primary gonadal failure and increased morbidity and mortality from cardiometabolic disorders in adulthood. Children with KS also have a high prevalence of metabolic syndrome (MetS) features. To assess the relationship of gonadal and cardiometabolic function in children with KS, we evaluated serum hormones [gonadotropins, inhibin B (INHB), anti-mullerian hormone (AMH), total testosterone (TT)], and features of MetS (waist circumference, fasting lipid panel, fasting blood glucose (FBG), and blood pressure) in 93 pre-pubertal boys with KS age 4-12 years (mean 7.7 ± 2.5 years). The cohort was grouped by age and tanner stage, and biomarkers were compared to normal ranges. A total of 80% of this pre-pubertal cohort had ≥1 feature of metabolic syndrome (MetS) and 11% had ≥3 features of MetS. Risk of MetS was independent of age and body mass index. Sertoli cell dysfunction was common with 18% having an INHB below the normal range. A low INHB was associated with higher FBG, triglycerides, LDL, and lower HDL (p < 0.05). An INHB <50 ng/dL yielded a sensitivity of 83% and a specificity of 79% for having ≥3 features of MetS. INHB and AMH positively correlated with each other (p < 0.001), and high AMH was protective of MetS. TT was below the lower limit of normal in 49% of subjects, with mean values significantly lower than expected (3.3 ng/dL vs. 4.9 ng/dL, p < 0.0001), however, no convincing relationship between TT and MetS was seen. In conclusion, gonadal and cardiometabolic dysfunction are prevalent in pre-pubertal boys with KS. Although the relationship of testosterone deficiency and MetS is well-known, this study is the first to report an association between impaired Sertoli cell function and cardiometabolic risk.

Braid Effects on Contractile Range and Friction Modeling in Pneumatic Muscle Actuators

Within braided pneumatic Muscle Actuators (pMA) the braid structure is vital to the actuator's performance, preventing over-inflation, converting radial expansion into axial contraction and setting limits for both dilation and contraction. This paper seeks to explore the nature of the contractile limit and the hysteresis observed by researchers during the actuation cycle.

Maximum actuator dilation occurs when adjacent braid strands are forced against one another. Within this work this is analyzed mathematically and it is shown that by halving the number of strands used to create the braided shell the actuator's contractile range can be increased by approximately 7%. This also results in a simultaneous peak contractile force increases of over 16%. These results are verified experimentally.

Hysteresis due to friction between braid strands during muscle operation is also explored. The paper will show how consideration of the deformation of the strands allows the contact area and therefore friction to be calculated without the need for experimentally obtained data as in previous research. A mathematical model is produced and verified experimentally.

A survey of factors affecting the capacity to work in patients with rheumatoid arthritis in South Wales

A survey was undertaken during 1992-93 to identify factors associated with the severity of rheumatoid arthritis and its management which might be modified to improve the patient's ability to continue to work. Two hundred and twenty patients taking part in a trial of second-line therapy were sent a postal questionnaire. Seventy-four per cent returned valid forms and these patients were subsequently medically examined. The unemployment rate in males was 71 % and in females 69%, compared to the average for the whole of Wales of 27% and 42% respectively in the same age range for the year in question. The data obtained suggested that improvements could be made with respect to disease control, organization of medical care and better use of rehabilitation services to optimize ability to work.

Preterm neonatal morbidity and mortality by gestational age: a contemporary cohort

BACKGROUND

Although preterm birth <37 weeks' gestation is the leading cause of neonatal morbidity and mortality in the United States, the majority of data regarding preterm neonatal outcomes come from older studies, and many reports have been limited to only very preterm neonates. Delineation of neonatal outcomes by delivery gestational age is needed to further clarify the continuum of mortality and morbidity frequencies among preterm neonates.

OBJECTIVE

We sought to describe the contemporary frequencies of neonatal death, neonatal morbidities, and neonatal length of stay across the spectrum of preterm gestational ages.

STUDY DESIGN

This was a secondary analysis of an obstetric cohort of 115,502 women and their neonates who were born in 25 hospitals nationwide, 2008 through 2011. All liveborn nonanomalous singleton preterm (23.0-36.9 weeks of gestation) neonates were included in this analysis. The frequency of neonatal death, major neonatal morbidity (intraventricular hemorrhage grade III/IV, seizures, hypoxic-ischemic encephalopathy, necrotizing enterocolitis stage II/III, bronchopulmonary dysplasia, persistent pulmonary hypertension), and minor neonatal morbidity (hypotension requiring treatment, intraventricular hemorrhage grade I/II, necrotizing enterocolitis stage I, respiratory distress syndrome, hyperbilirubinemia requiring treatment) were calculated by delivery gestational age; each neonate was classified once by the worst outcome for which criteria was met.

RESULTS

In all, 8334 deliveries met inclusion criteria. There were 119 (1.4%) neonatal deaths. In all, 657 (7.9%) neonates had major morbidity, 3136 (37.6%) had minor morbidity, and 4422 (53.1%) survived without any of the studied morbidities. Deaths declined rapidly with each advancing week of gestation. This decline in death was accompanied by an increase in major neonatal morbidity, which peaked at 54.8% at 25 weeks of gestation. As frequencies of death and major neonatal morbidity fell, minor neonatal morbidity increased, peaking at 81.7% at 31 weeks of gestation. The frequency of all morbidities fell >32 weeks. After 25 weeks, neonatal length of hospital stay decreased significantly with each additional completed week of pregnancy; among babies delivered from 26-32 weeks of gestation, each additional week in utero reduced the subsequent length of neonatal hospitalization by a minimum of 8 days. The median postmenstrual age at discharge nadired around 36 weeks' postmenstrual age for babies born at 31-35 weeks of gestation.

CONCLUSION

Our data show that there is a continuum of outcomes, with each additional week of gestation conferring survival benefit while reducing the length of initial hospitalization. These contemporary data can be useful for patient counseling regarding preterm outcomes.