Comparison of imputation methods for missing production data of dairy cattle

Nowadays, vast amounts of data representing feed intake, growth, and environmental impact of individual animals are being recorded in on-farm settings. Despite their apparent use, data collected in real-world applications often have missing values in one or several variables, due to reasons including human error, machine error, or sampling frequency misalignment across multiple variables. Since incomplete datasets are less valuable for downstream data analysis, it is important to address the missing value problem properly. One option may be to reduce the dataset to a subset that contains only complete data, but considerable data may be lost via this process. The current study aimed to compare imputation methods for the estimation of missing values in a raw dataset of dairy cattle including 454 553 records collected from 629 cows between 2009 and 2020. The dataset was subjected to a cleaning process that reduced its size to 437 075 observations corresponding to 512 cows. Missing values were present in four variables: concentrate DM intake (CDMI, missing percentage = 2.30%), forage DM intake (FDMI, 8.05%), milk yield (MY, 15.12%), and BW (64.33%). After removing all missing values, the resulting dataset (n = 129 353) was randomly sampled five times to create five independent subsets that exhibit the same missing data percentages as the cleaned dataset. Four univariate and nine multivariate imputation methods (eight machine learning methods and the MissForest method) were applied and evaluated on the five repeats, and average imputation performance was reported for each repeat. The results showed that Random Forest was overall the best imputation method for this type of data and had a lower mean squared prediction error and higher concordance correlation coefficient than the other imputation methods for all imputed variables. Random Forest performed particularly well for imputing CDMI, MY, and BW, compared to imputing FDMI.

Review: When worlds collide - poultry modeling in the 'Big Data' era

Within poultry production systems, models have provided vital decision support, opportunity analysis, and performance optimization capabilities to nutritionists and producers for decades. In recent years, due to the advancement of digital and sensor technologies, 'Big Data' streams have emerged, optimally positioned to be analyzed by machine-learning (ML) modeling approaches, with strengths in forecasting and prediction. This review explores the evolution of empirical and mechanistic models in poultry production systems, and how these models may interact with new digital tools and technologies. This review will also examine the emergence of ML and Big Data in the poultry production sector, and the emergence of precision feeding and automation of poultry production systems. There are several promising directions for the field, including: (1) application of Big Data analytics (e.g., sensor-based technologies, precision feeding systems) and ML methodologies (e.g., unsupervised and supervised learning algorithms) to feed more precisely to production targets given a 'known' individual animal, and (2) combination and hybridization of data-driven and mechanistic modeling approaches to bridge decision support with improved forecasting capabilities.

Body mass index from the RE-LY trial: further evidence of the obesity paradox

Background

The obesity paradox has been reported in 3 post-hoc analyses evaluating the direct oral anticoagulants (DOAC) against warfarin (W): apixaban (ARISTOTLE), rivaroxaban (ROCKET), and edoxaban (ENGAGE-AF).

Purpose

To evaluate the obesity paradox in a post-hoc analysis of the RE-LY trial, comparing dabigatran 110 mg BID (D110), 150 mg BID (D150), and W by body mass index (BMI).

Methods

Baseline characteristics were evaluated using World Health Organization (WHO) criteria of overweight and obese (BMI ≥25 kg/m2) and under and normal weight (BMI <25 kg/m2). Stroke and systemic embolism, ischemic stroke, major bleeding, mortality, and intracranial hemorrhage were evaluated using BMI as a continuous variable and by the WHO criteria using a cox proportional hazard model.

Results

BMI was available in 99.9% of patients randomized; 74% had a BMI ≥25. At baseline, patients with a BMI ≥25 were younger (70.9 vs 73.1, p<0.001) and had fewer prior strokes (11.5% vs 15.6%, p<0.001), but higher mean creatinine clearance (78.3 vs 57.0, p<0.001) and rates of diabetes (25.8% vs 16.1%, p<0.001) (Table 1). Independent of drug assignment, patients with a BMI ≥25 had lower rates of stroke and systemic embolism (HR 0.65 [95% CI 0.54–0.79], p<0.001), ischemic stroke (0.75 [95% CI 0.60, 0.94], p=0.01), major bleeding (HR 0.79 [95% CI 0.69,0.89], p<0.001), mortality (HR 0.60 [95% CI 0.53, 0.67], p<0.001) and intracranial hemorrhage (HR 0.53 [95% CI 0.38, 0.73], p<0.001) compared to those with a BMI <25. Using BMI as a continuous variable combining all outcomes at 3 years, endpoint rates declined as BMI approached 25 in all 3 treatment groups. The exceptions were intracranial hemorrhage for D110 and D150 and stroke in D150 patients, where rates were low independent of BMI. No significant interaction between BMI and treatment was observed in individual outcomes except for the D110 vs. D150 comparison for major bleeding, in favor of D110 for patients with BMI ≥25 (HR 0.77 [95% CI 0.65, 0.91] and HR 1.12 [95% CI 0.86, 1.47], interaction p=0.0190).

Conclusions

In RE-LY, independent of drug assignment, patients with a higher BMI had improved outcomes, demonstrating the obesity paradox. As BMI increased towards 25, outcome rates improved except for intracranial hemorrhage rates for both D110 and D150 and ischemic stroke rates for D150, which were low independent of BMI. Patients treated with D110 with a BMI ≥25 kg/m2 had significantly lower rates of bleeding compared to D150.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Sharpe Strumia Foundation

Interferon-β Decreases the Hypermetabolic State of Red Blood Cells from Patients with Multiple Sclerosis

Multiple sclerosis (MS) is an inflammatory disease characterized by damage to the myelin sheath surrounding axons in the central nervous system. While the exact mechanism of this destruction is unknown, excess nitric oxide (NO) and adenosine triphosphate (ATP) have been measured in tissues and fluids obtained from people with MS. Here, incubation of interferon-beta (IFN-β), an MS drug with an unknown mechanism of action, with red blood cells (RBCs) obtained from people with MS provide evidence of a potential hypermetabolic state in the MS RBC that is decreased with IFN-β intervention. Specifically, binding of all three components of an albumin/C-peptide/Zn²⁺ complex to MS RBCs was significantly increased in comparison to control RBCs. For example, the binding of C-peptide to MS RBCs was significantly increased (3.4 ± 0.1 nM) compared to control RBCs (1.6 ± 0.2 nM). However, C-peptide binding to MS RBCs was reduced to a value (1.6 ± 0.3 nM) statistically equal to that of control RBCs in the presence of 2 nM IFN-β. Similar trends were measured for albumin and Zn²⁺ binding to RBCs when in the presence of IFN-β. RBC function was also affected by incubation of cells with IFN-β. Specifically, RBC-derived ATP and measurable membrane GLUT1 were both significantly decreased (56 and 24%, respectively) in the presence of IFN-β. Collectively, our results suggest that IFN-β inhibits albumin binding to the RBC, thereby reducing its ability to deliver ligands such as C-peptide and Zn²⁺ to the cell and normalizing the basal hypermetabolic state.

ASAS-NANP SYMPOSIUM: MATHEMATICAL MODELING IN ANIMAL NUTRITION: Opportunities and Challenges of Confined and Extensive Precision Livestock Production

Modern animal scientists, industry, and managers have never faced a more complex world. Precision livestock technologies have altered management in confined operations to meet production, environmental, and consumer goals. Applications of precision technologies have been limited in extensive systems such as rangelands due to lack of infrastructure, electrical power, communication, and durability. However, advancements in technology have helped to overcome many of these challenges. Investment in precision technologies is growing within the livestock sector, requiring the need to assess opportunities and challenges associated with implementation to enhance livestock production systems. In this review, precision livestock farming and digital livestock farming are explained in the context of a logical and iterative five-step process to successfully integrate precision livestock measurement and management tools, emphasizing the need for precision system models (PSMs). This five-step process acts as a guide to realize anticipated benefits from precision technologies and avoid unintended consequences. Consequently, the synthesis of precision livestock and modeling examples and key case studies help highlight past challenges and current opportunities within confined and extensive systems. Successfully developing PSM requires appropriate model(s) selection that aligns with desired management goals and precision technology capabilities. Therefore, it is imperative to consider the entire system to ensure that precision technology integration achieves desired goals while remaining economically and managerially sustainable. Achieving long-term success using precision technology requires the next generation of animal scientists to obtain additional skills to keep up with the rapid pace of technology innovation. Building workforce capacity and synergistic relationships between research, industry, and managers will be critical. As the process of precision technology adoption continues in more challenging and harsh, extensive systems, it is likely that confined operations will benefit from required advances in precision technology and PSMs, ultimately strengthening the benefits from precision technology to achieve short- and long-term goals.

Systemic IL-15 promotes allogeneic cell rejection in patients treated with natural killer cell adoptive therapy

Natural killer (NK) cells are a promising alternative to T cells for cancer immunotherapy. Adoptive therapies with allogeneic, cytokine-activated NK cells are being investigated in clinical trials. However, the optimal cytokine support after adoptive transfer to promote NK cell expansion, and persistence remains unclear. Correlative studies from 2 independent clinical trial cohorts treated with major histocompatibility complex-haploidentical NK cell therapy for relapsed/refractory acute myeloid leukemia revealed that cytokine support by systemic interleukin-15 (IL-15; N-803) resulted in reduced clinical activity, compared with IL-2. We hypothesized that the mechanism responsible was IL-15/N-803 promoting recipient CD8 T-cell activation that in turn accelerated donor NK cell rejection. This idea was supported by increased proliferating CD8+ T-cell numbers in patients treated with IL-15/N-803, compared with IL-2. Moreover, mixed lymphocyte reactions showed that IL-15/N-803 enhanced responder CD8 T-cell activation and proliferation, compared with IL-2 alone. Additionally, IL-15/N-803 accelerated the ability of responding T cells to kill stimulator-derived memory-like NK cells, demonstrating that additional IL-15 can hasten donor NK cell elimination. Thus, systemic IL-15 used to support allogeneic cell therapy may paradoxically limit their therapeutic window of opportunity and clinical activity. This study indicates that stimulating patient CD8 T-cell allo-rejection responses may critically limit allogeneic cellular therapy supported with IL-15. This trial was registered at www.clinicaltrials.gov as #NCT03050216 and #NCT01898793.

358 Ramucirumab in combination with pembrolizumab as first-line treatment for recurrent or metastatic head and neck squamous-cell carcinoma: a phase 1–2 trial

Background

VEGF, a key mediator of angiogenesis and resistance to immunotherapy, is overexpressed in head and neck squamous-cell carcinoma (HNSCC). The primary aims of this trial were to determine the recommended phase 2 dose (RP2D) of ramucirumab, a potent inhibitor of VEGF receptor-2, given with pembrolizumab, and the objective response rate (ORR) of this combination as first-line treatment for recurrent or metastatic (RM)-HNSCC.

Methods

Study participants provided written informed consent. Eligible patients had incurable HNSCC originating in the oral cavity, oropharynx, larynx, or hypopharynx. RM disease within 6 months of curative-intent systemic therapy and programmed death ligand (PD-L1) negative disease were permitted. In a dose de-escalation phase 1 design, patients received ramucirumab (level one: 10 mg/kg; then 8 and 6 mg/kg) and pembrolizumab (200 mg) on day 1 of each 21-day cycle until discontinuation criteria were met. Each dose level included three patients. The RP2D of ramucirumab was defined as the highest dose level at which one or fewer patients experienced a dose-limiting toxicity (DLT) during cycle one. In a Simon two-stage phase 2 design, patients with measurable, previously untreated RM-HNSCC received ramucirumab at the RP2D with pembrolizumab. Tumor response was assessed by RECIST1.1. When the trial was developed, the ORR of pembrolizumab given as first-line treatment wasn’t known; however, the ORR for platinum pre-treated disease was 13–18%. Therefore, an ORR of <13% was deemed unacceptable and an ORR of >32% was of clinical interest. In stage one, two or more responses among ten patients were required to enroll to stage two. Eight or more responses among 33 evaluable patients (those with at least one response assessment) was evidence for efficacy (80% power; one-sided α= 0.05).

Results

Three patients were treated in phase 1 and 37 in phase 2. Eleven patients (28%) had recurrent disease within 6 months of curative-intent systemic therapy. In phase 1, no DLT occurred at the starting dose of ramucirumab. Tumor response occurred in 2 of these 3 patients. In phase 2, tumor response occurred in 19 of 33 evaluable patients (ORR 57.6%, 95%CI: 39.2–74.5). Tumor response by PD-L1 CPS is shown in the table below (table 1). No unexpected safety concerns were identified.

Abstract 358 Table 1

Conclusions

The RP2D of ramucirumab given with pembrolizumab was 10 mg/kg on day 1 of each 21-day cycle. The primary hypothesis was accepted: the ORR with ramucirumab and pembrolizumab was higher than expected with pembrolizumab monotherapy when given as first-line treatment for RM-HNSCC.

Trial Registration

This trial is registered with ClinicalTrials.gov (NCT03650764).

Ethics Approval

This study was approved by Washington University’s Ethics Board; approval number 201809094.

Memory-like Differentiation Enhances NK Cell Responses to Melanoma

PURPOSE

Treatment of advanced melanoma is a clinical challenge. Natural killer (NK) cells are a promising cellular therapy for T cell-refractory cancers, but are frequently deficient or dysfunctional in patients with melanoma. Thus, new strategies are needed to enhance NK-cell antitumor responses. Cytokine-induced memory-like (ML) differentiation overcomes many barriers in the NK-cell therapeutics field, resulting in potent cytotoxicity and enhanced cytokine production against blood cancer targets. However, the preclinical activity of ML NK against solid tumors remains largely undefined.

EXPERIMENTAL DESIGN

Phenotypic and functional alterations of blood and advanced melanoma infiltrating NK cells were evaluated using mass cytometry. ML NK cells from healthy donors (HD) and patients with advanced melanoma were evaluated for their ability to produce IFNγ and kill melanoma targets in vitro and in vivo using a xenograft model.

RESULTS

NK cells in advanced melanoma exhibited a decreased cytotoxic potential compared with blood NK cells. ML NK cells differentiated from HD and patients with advanced melanoma displayed enhanced IFNγ production and cytotoxicity against melanoma targets. This included ML differentiation enhancing melanoma patients' NK-cell responses against autologous targets. The ML NK-cell response against melanoma was partially dependent on the NKG2D- and NKp46-activating receptors. Furthermore, in xenograft NSG mouse models, human ML NK cells demonstrated superior control of melanoma, compared with conventional NK cells.

CONCLUSIONS

Blood NK cells from allogeneic HD or patients with advanced melanoma can be differentiated into ML NK cells for use as a novel immunotherapeutic treatment for advanced melanoma, which warrants testing in early-phase clinical trials.

Outcome of older hip fracture patients on anticoagulation: a comparison of vitamin K-antagonists and Factor Xa inhibitors

INTRODUCTION

Older hip fracture patients are still challenging in daily clinical practice. Due to the high prevalence of osteoporosis and atrial fibrillation in this age group, the number of fragility fracture patients under oral anticoagulation (OAC) increases. The outcome is still disappointing, short- and long-term mortality and morbidity is high. The impact of pre-existing OAC is not yet clear, especially regarding new OAC drugs like Factor Xa inhibitors (FXa). The purpose of our study was to compare the short-term outcome of older hip fracture patients, without OAC (controls), on Vitamin K antagonists (VKA) and on FXa.

MATERIALS AND METHODS

The study is a retrospective case-control study including patients older than 70 years who sustained hip fractures caused by an inadequate trauma and treated at a level 1 trauma center from February 2017 to June 2018. Patient's information was taken from patient's charts. 102 cases were analysed, 61 controls, 41 on OAC (15 on VKA and 26 on FXa). As outcome parameter we defined mortality, perioperative complications, bleeding, need of blood supplements, delay of surgery, length of stay, and a combined outcome parameter (mortality, myocardial infarction, stroke, thromboembolic events, blood preservations, re-vision surgery, major bleeding and decline of hemoglobin).

RESULTS

Eight patients died during hospital stay, in-hospital mortality was 7.8%. The highest mortality rate was found in patients on VKA (20%), compared to patients on FXa (3.8%) and controls (6.6%). However, mortality rate did not differ significantly within the groups. The combined endpoint was significantly more frequently seen in patients on OAC compared to controls (p = 0.006). No difference was observed between patients on VKA or FXa. Mean time to surgery and LOS was significantly longer in patients on OAC compared to controls. No significant differences were seen between VKA and FXa.

CONCLUSIONS

In our study OAC was significantly associated with worse outcome compared to controls. Marginal differences were observed between patients on FXa or VKA. Further studies involving a higher number of patients are necessary to confirm our results. At that time, some our results have to interpreted carefully and need confirmation.

SAT0422 FIRST-LINE CSDMARD MONOTHERAPY RETENTION IN PSORIATIC ARTHRITIS: METHOTREXATE OUTPERFORMS SULFASALAZINE

Background:

Conventional synthetic disease modifying anti-rheumatic drugs (csDMARDs) are the first-line treatment for psoriatic arthritis (PsA), but there is conflicting data regarding their efficacy and scarce reports describing the duration of use (drug retention) of csDMARD in this population. Their position in treatment recommendations is a matter of growing debate due the availability of alternative treatment options with higher levels of evidence.

Objectives:

To study drug retention and predictors for drug retention among PsA patients receiving first-line csDMARD monotherapy.

Methods:

Retrospective cohort study in DMARD-naïve adult PsA patients in whom a first csDMARD was prescribed as monotherapy primarily to treat PsA-related symptoms. Main outcome was time to failure of the csDMARD (i.e stopping the csDMARD or adding another DMARD).

Results:

187 patients were included, who were mainly prescribed methotrexate (MTX) (n=163) or sulfasalazine (SSZ) (n=21) (Table 1). The pooled median time to failure was 31.8 months (IQR 9.04-110). Drug retention was significantly higher in MTX (median 34.5 months; IQR 9.60-123) as compared to SSZ treated patients (median 12.0 months; IQR 4.80-55.7)(p=0.016, log-rank test) (Figure 1). In multivariable cox-regression the use of MTX and older age were associated with increased retention. The main reasons for treatment failure were inefficacy (52%) and side-effects (28%) (Figure 2). Upon failure, MTX treated patients were more commonly, subsequently treated with a biologic DMARD compared to SSZ (p<0.05).

Table 1.

Main demographic and clinical characteristics of the study population at baseline. The total cohort (n=187) included 3 patients treated with leflunomide (data not shown separately). Psoriasis area and severity scores were unavailable for most cases and not shown. Descriptive data show the mean ± SD, median (IQR) or N (%).

Total, N = 187MTX, N = 163SSZ, N = 21Male, N (%)128 (31.6)115 (71)12 (57) Age (years), mean ± SD*48.3 ± 13.349.1 ± 12.739.5 ± 13.4 Body mass index, mean ± SD*26.7 ± 4.527.4 ± 4.425.3 ± 3.5 Smoker, N (%)34/150 (18.2)31/129 (19.0)3/18 (14.3)Disease duration (years), median (IQR) PsA0.4 (0.1 – 3.0)0.4 (0.1 – 2.9)0.3 (0.1 – 2.0) Psoriasis7.5 (2.1 – 18.4)7.5 (2.0 – 15.7)10.8 (3.1 – 26.7)Psoriasis phenotype, N (%)* Vulgaris only130/185 (69.5)117/161 (71.8)10/21 (47.6) Sine psoriasis31/185 (16.6)21/161 (12.9)10/21 (47.6) Other types124/185 (12.8)23/161 (14.1)1/21 (4.8)Nail disease present, N (%)81/121 (43.3)72/104 (44.2)9/17 (42.9)Swollen joint count, median (IQR)*4 (2 – 6)4 (2 – 6)2 (1 – 3)Tender joint count, median (IQR)*4 (1 – 6)4 (2 – 6)1 (0 – 3)Dactylitis present, N (%)18/161 (9.6)17/142 (10.4)1/17 (4.8)Axial disease present2, N (%)27/185 (14.4)24/161 (14.7)3/21 (14.3)CRP, median (IQR)8.0 (2.9 – 16.0)8.0 (3.0 – 15.0)10.0 (1.0 – 26.0)ESR, median (IQR)14.0 (6.0 – 27.5)14.0 (7.0 – 27.0)16.0 (6.0 – 31.0)Erosive disease, N (%)40/156 (21.4)37/140 (22.7)2/15 (9.5)

1Other psoriasis types included guttate, palmoplantaris, inverse, and mixed types.

2Presence/absence of axial disease was based on the clinical diagnosis from the treating physician.

* Clinical parameter is significantly different (P <0.05) between MTX and SSZ.

Abbreviations: MTX = methotrexate. SSZ = sulfasalazine. CRP = C-reactive protein. ESR = erythrocyte sedimentation rate. PsA = psoriatic arthritis.

Conclusion:

MTX outperformed SSZ as first-line csDMARD monotherapy in DMARD-naïve PsA patients with respect to drug retention in daily clinical practice.

References:

n.a.

Disclosure of Interests:

Marleen Jacobs: None declared, Juliette Pouw: None declared, Paco Welsing: None declared, Timothy RDJ Radstake Employee of: TR currently is an employee of AbbVie. At the time of the work described he had no COIs., Emmerik Leijten: None declared

The GOLIATH Project: Towards an Internationally Harmonised Approach for Testing Metabolism Disrupting Compounds

The purpose of this project report is to introduce the European "GOLIATH" project, a new research project which addresses one of the most urgent regulatory needs in the testing of endocrine-disrupting chemicals (EDCs), namely the lack of methods for testing EDCs that disrupt metabolism and metabolic functions. These chemicals collectively referred to as "metabolism disrupting compounds" (MDCs) are natural and anthropogenic chemicals that can promote metabolic changes that can ultimately result in obesity, diabetes, and/or fatty liver in humans. This project report introduces the main approaches of the project and provides a focused review of the evidence of metabolic disruption for selected EDCs. GOLIATH will generate the world's first integrated approach to testing and assessment (IATA) specifically tailored to MDCs. GOLIATH will focus on the main cellular targets of metabolic disruption-hepatocytes, pancreatic endocrine cells, myocytes and adipocytes-and using an adverse outcome pathway (AOP) framework will provide key information on MDC-related mode of action by incorporating multi-omic analyses and translating results from in silico, in vitro, and in vivo models and assays to adverse metabolic health outcomes in humans at real-life exposures. Given the importance of international acceptance of the developed test methods for regulatory use, GOLIATH will link with ongoing initiatives of the Organisation for Economic Development (OECD) for test method (pre-)validation, IATA, and AOP development.

The Y-chromosome F haplogroup contributes to the development of Barrett's esophagus-associated esophageal adenocarcinoma in a white male population

Barrett's esophagus (BE) is a metaplastic condition of the distal esophagus, resulting from longstanding gastroesophageal reflux disease (GERD). BE predisposes for the highly malignant esophageal adenocarcinoma (EAC). Both BE and EAC have the highest frequencies in white males. Only a subset of patients with GERD develop BE, while <0.5% of BE will progress to EAC. Therefore, it is most likely that the development of BE and EAC is associated with underlying genetic factors. We hypothesized that in white males, Y-chromosomal haplogroups are associated with BE and EAC. To investigate this we conducted a multicenter study studying the frequencies of the Y-chromosomal haplogroups in GERD, BE, and EAC patients. We used genomic analysis by polymerase chain reaction and restriction fragment length polymorphism to determine the frequency of six Y-chromosomal haplogroups (DE, F(xJ,xK), K(xP), J, P(xR1a), and R1a) between GERD, BE, and EAC in a cohort of 1,365 white males, including 612 GERD, 753 BE patients, while 178 of the BE patients also had BE-associated EAC. Univariate logistic regression analysis was used to compare the outcomes. In this study, we found the R1a (6% vs. 9%, P = 0.04) and K (3% vs. 6%, P = 0.035) to be significantly underrepresented in BE patients as compared to GERD patients with an odds ratio (OR) of 0.63 (95% CI 0.42-0.95, P = 0.03) and of 0.56 (95% CI 0.33-0.96, P = 0.03), respectively, while the K haplogroup was protective against EAC (OR 0.30; 95% CI 0.07-0.86, P = 0.05). A significant overrepresentation of the F haplogroup was found in EAC compared to BE and GERD patients (34% vs. 27% and 23%, respectively). The F haplogroup was found to be a risk factor for EAC with an OR of 1.5 (95% CI 1.03-2.19, P = 0.03). We identified the R1a and K haplogroups as protective factors against development of BE. These haplogroups have low frequencies in white male populations. Of importance is that we could link the presence of the predominantly occurring F haplogroup in white males to EAC. It is possible that this F haplogroup is associated to genetic variants that predispose for the EAC development. In future, the haplogroups could be applied to improve stratification of BE and GERD patients with increased risk to develop BE and/or EAC.

P3599Minicare high sensitivity troponin: a novel point-of-care tool to improve ACS workflows

Background

Cardiac troponin (cTn) has been broadly accepted as the biomarker of choice in the diagnosis of patients presenting with Acute Coronary Syndrome (ACS). Point-of-care (POC) cTn testing, defined as testing near the patient with rapid availability of results, has attracted a strong interest in the emergency department (ED) setting. It offers the potential to improve workflows, expedite clinical decisions and to reduce the length of stay. Workflows could be further optimized when a first measurement can already be performed by the emergency medical services prior to admission to the hospital.

Advances in assay technology have led to high sensitive (HS) cTn assays that have a profound impact on clinical practice, providing early results at presentation and 1 hour after admission which speed up clinical decision-making. Here we evaluate the Minicare HS cTnI POC test under development, which has the potential to combine the benefits of HS-cTnI protocols with a POC workflow.

Objective

Evaluate the analytical and clinical capability of the Minicare HS-cTnI test under development to meet the criteria‡ for HS cTn of having a 10% CV <99th percentile and a percentage measurable (>LoD) of >50%.

Methods

The evaluation is based on the Clinical Laboratory Standards Institute (CLSI) guidelines. Li-heparin whole blood and Li-heparin plasma samples were used to establish LoB, LoD, and LoQ, sample matrix comparison and linearity in the low range. The clinical performance for Minicare HS-cTnI was assessed and compared to Abbott Architect high-sensitivity troponin using banked samples from patients with ACS and collected at t=2–4h after admission. The percentage measurable was assessed and compared to Abbott Architect high-sensitivity troponin in a healthy population of 165 individuals.

Results

With a time to result within 10 minutes, the LoB is determined at 1.0 ng/L and the LoD at 2.1 ng/L. Plasma and whole blood results correlated well and showed comparable results. The 10% and 20% CV LoQ are established at 7.9 ng/L and 3.1 ng/L, well below the anticipated 99th percentile of 26 ng/L. With a percentage measurable of 77%, the criteria for a HS-cTnI assay are met in a POC device. A sensitivity of 93% and an NPV of 99% are found for Minicare HS-cTnI for a t=2–4h protocol vs 90% and 98% for Abbott Architect high-sensitivity troponin. In this study the area under the curve is 0.98 for Minicare HS-cTnI and 0.97 for Architect HS-cTnI.

ROC curve t=2-4 h

Conclusions

With HS-cTnI capability on the Minicare platform, we show the potential to support a 0/1 h sampling protocol, combined with the speed of a POC workflow. This may enable even more rapid and safe rule-out of patients with ACS.

1202The incidence, treatment and mortality of new-onset atrial fibrillation patients at the intensive care unit

Background

Critically ill patients admitted to the intensive care unit (ICU) often develop atrial fibrillation (AF), with an incidence of around 5%. Stroke prevention in AF is well described in clinical guidelines. However, the extent to which stroke prevention is prescribed to ICU patients with AF is unknown.

Purpose

We aimed to determine the incidence of new-onset AF and describe the stroke prevention strategies that were initiated on the ICU of our teaching hospital. Also, we compared mortality in patients with new-onset AF to critically ill patients with previously diagnosed AF and patients without any AF.

Methods

This study was a retrospective cohort study including all admissions to the ICU of the our hospital in the period 2011–2016. Propensity score matching was used to compare the different patient groups. Survival analyses were performed using these real-world data.

Results

In total, 3334 patients were admitted to the ICU, of whom 213 patients (6.4%) developed new-onset AF. 583 patients (17.5%) had a previous diagnosis of AF, the other patients (76.1%) were in normal sinus rhythm. In-hospital mortality and one-year mortality after hospital discharge were significantly higher for new-onset AF patients compared to patients with no history of AF or previously diagnosed AF. At hospital discharge, only 50.4% of the new-onset AF-patients eligible for stroke prevention received an anticoagulant and anticoagulation was not dependent on CHA2DS2VASc score or other patient characteristics. An effect of anticoagulative status on mortality was not significant.

Conclusion

AF is associated with increased mortality in critically ill patients that were admitted to the ICU. More guidance is needed to optimize anticoagulant treatment in critically ill new-onset AF patients.

Acknowledgement/Funding

None