Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

Aircraft and satellite observations reveal historical gap between top-down and bottom-up CO2 emissions from Canadian oil sands

Measurement-based estimates of greenhouse gas (GHG) emissions from complex industrial operations are challenging to obtain, but serve as an important, independent check on inventory-reported emissions. Such top-down estimates, while important for oil and gas (O&G) emissions globally, are particularly relevant for Canadian oil sands (OS) operations, which represent the largest O&G contributor to national GHG emissions. We present a multifaceted top-down approach for estimating CO₂ emissions that combines aircraft-measured CO₂/NO_x emission ratios (ERs) with inventory and satellite-derived NO_x emissions from Ozone Monitoring Instrument (OMI) and TROPOspheric Ozone Monitoring Instrument (TROPOMI) and apply it to the Athabasca Oil Sands Region (AOSR) in Alberta, Canada. Historical CO₂ emissions were reconstructed for the surface mining region, and average top-down estimates were found to be >65% higher than facility-reported, bottom-up estimates from 2005 to 2020. Higher top-down vs. bottom-up emissions estimates were also consistently obtained for individual surface mining and in situ extraction facilities, which represent a growing category of energy-intensive OS operations. Although the magnitudes of the measured discrepancies vary between facilities, they combine such that the observed reporting gap for total AOSR emissions is ≥(31 ± 8) Mt for each of the last 3 years (2018-2020). This potential underestimation is large and broadly highlights the importance of continued review and refinement of bottom-up estimation methodologies and inventories. The ER method herein offers a powerful approach for upscaling measured facility-level or regional fossil fuel CO₂ emissions by taking advantage of satellite remote sensing observations.

Quantifying the computational capability of a nanomagnetic reservoir computing platform with emergent magnetisation dynamics

Devices based on arrays of interconnected magnetic nano-rings with emergent magnetization dynamics have recently been proposed for use in reservoir computing applications, but for them to be computationally useful it must be possible to optimise their dynamical responses. Here, we use a phenomenological model to demonstrate that such reservoirs can be optimised for classification tasks by tuning hyperparameters that control the scaling and input-rate of data into the system using rotating magnetic fields. We use task-independent metrics to assess the rings' computational capabilities at each set of these hyperparameters and show how these metrics correlate directly to performance in spoken and written digit recognition tasks. We then show that these metrics, and performance in tasks, can be further improved by expanding the reservoir's output to include multiple, concurrent measures of the ring arrays' magnetic states.

Clinical characteristics with inflammation profiling of long COVID and association with 1-year recovery following hospitalisation in the UK: a prospective observational study

BACKGROUND

No effective pharmacological or non-pharmacological interventions exist for patients with long COVID. We aimed to describe recovery 1 year after hospital discharge for COVID-19, identify factors associated with patient-perceived recovery, and identify potential therapeutic targets by describing the underlying inflammatory profiles of the previously described recovery clusters at 5 months after hospital discharge.

METHODS

The Post-hospitalisation COVID-19 study (PHOSP-COVID) is a prospective, longitudinal cohort study recruiting adults (aged ≥18 years) discharged from hospital with COVID-19 across the UK. Recovery was assessed using patient-reported outcome measures, physical performance, and organ function at 5 months and 1 year after hospital discharge, and stratified by both patient-perceived recovery and recovery cluster. Hierarchical logistic regression modelling was performed for patient-perceived recovery at 1 year. Cluster analysis was done using the clustering large applications k-medoids approach using clinical outcomes at 5 months. Inflammatory protein profiling was analysed from plasma at the 5-month visit. This study is registered on the ISRCTN Registry, ISRCTN10980107, and recruitment is ongoing.

FINDINGS

2320 participants discharged from hospital between March 7, 2020, and April 18, 2021, were assessed at 5 months after discharge and 807 (32·7%) participants completed both the 5-month and 1-year visits. 279 (35·6%) of these 807 patients were women and 505 (64·4%) were men, with a mean age of 58·7 (SD 12·5) years, and 224 (27·8%) had received invasive mechanical ventilation (WHO class 7-9). The proportion of patients reporting full recovery was unchanged between 5 months (501 [25·5%] of 1965) and 1 year (232 [28·9%] of 804). Factors associated with being less likely to report full recovery at 1 year were female sex (odds ratio 0·68 [95% CI 0·46-0·99]), obesity (0·50 [0·34-0·74]) and invasive mechanical ventilation (0·42 [0·23-0·76]). Cluster analysis (n=1636) corroborated the previously reported four clusters: very severe, severe, moderate with cognitive impairment, and mild, relating to the severity of physical health, mental health, and cognitive impairment at 5 months. We found increased inflammatory mediators of tissue damage and repair in both the very severe and the moderate with cognitive impairment clusters compared with the mild cluster, including IL-6 concentration, which was increased in both comparisons (n=626 participants). We found a substantial deficit in median EQ-5D-5L utility index from before COVID-19 (retrospective assessment; 0·88 [IQR 0·74-1·00]), at 5 months (0·74 [0·64-0·88]) to 1 year (0·75 [0·62-0·88]), with minimal improvements across all outcome measures at 1 year after discharge in the whole cohort and within each of the four clusters.

INTERPRETATION

The sequelae of a hospital admission with COVID-19 were substantial 1 year after discharge across a range of health domains, with the minority in our cohort feeling fully recovered. Patient-perceived health-related quality of life was reduced at 1 year compared with before hospital admission. Systematic inflammation and obesity are potential treatable traits that warrant further investigation in clinical trials.

FUNDING

UK Research and Innovation and National Institute for Health Research.

P-241 ‘Augmented intelligence’ to possibly shorten euploid identification time: A human-machine interaction study for euploid identification using ERICA, an Artificial Intelligence software to assist embryo ranking

Study question

What is the mean number of transfers needed to achieve a euploid transfer selected by embryologists plus ERICA’s assistance?

Summary answer

Augmented intelligence (ERICA plus human collaboration) outperforms both the embryologists and artificial intelligence's individual performance alone.

What is known already

Euploid embryos are more likely to implant successfully. Artificial intelligence (AI) could improve embryo selection over current techniques, but scepticism exists. Augmented intelligence (AuI) combines both the mathematical reproducibility of machine learning and the knowledge and experience of humans. This approach employs AI tools as an assistant, where the user shall learn to interpret the AI. A recent study suggested that embryologists assisted by AI improved the embryo selection of euploid transfers. ERICA (IVF2.0 Limited, UK) was designed to rank blastocysts according to their probability of euploidy.

Study design, size, duration

We prospectively studied embryo selection for ERICA alone, embryologists only and when interacting (embryologists and ERICA) in 150 synthetically generated (reconstructed on real-data) embryo transfer cycles. Embryos were ranked in order, and performance was assessed by time to identify a euploid embryo within each cycle cohort correctly. Embryologists were allowed to rank a maximum of 10 cycles per day for three weeks starting in January 2022, using a mobile phone application designed for this purpose.

Participants/materials, setting, methods

Using real-life cycle distributions of euploid/aneuploid blastocysts and the number of embryos in a cycle (according to ERICA’s database), we created 150 synthetic cycles, 30 for each age bracket (&lt; 35, 35-37, 38-40, 41-42, and &gt;42). These were randomly populated with blastocyst images preserving their actual ploidy status correspondingly. Each synthetic cycle contained between 2 to 6 authentic embryo images with at least one euploid and one aneuploid.

Main results and the role of chance

The total database had a euploid rate of 37.4% (n = 513), and by age brackets from 1 to 5 were 45.7% (n = 116), 43.8% (n = 105), 35.9% (n = 92), 31.2% (n = 96), and 28.8% (n = 104) respectively.

The mean number of cycles analysed by each participant was 113.5 (CI: 100.8-126.2). The mean time-to-euploid transfer for embryologists alone was 2.07 (CI:2.00-2.13); for the ERICA alone was 1.86 (CI:1.82-1.91); and for embryologists assisted by ERICA was 1.62 (CI:1.55-1.68). All study groups compared to each other were statistically significant using a paired two-tailed student’s t-test (p &lt; 0.001).

The proportion of euploid transfer at the first try for embryologists alone was 0.40 (CI:0.37-0.43), for ERICA alone was 0.54 (CI:0.53-0.54), and for embryologists assisted by ERICA was 0.47 (CI:0.44-0.50). All study groups compared with each other were statistically significant with a paired two-tailed student’s t-test (p &lt; 0.01).

Limitations, reasons for caution

Although our findings suggest that Aul outperforms both AI and humans alone, this study needs to be replicated with a larger cohort of embryologists with different experience levels in different countries to confirm these results.

Wider implications of the findings

Combining machine-human interaction through a well-designed process could improve embryo selection and reduce inter-operator variability amongst staff with different experience levels. It could also set a frame for adequate agency and accountability, and enhance trust and adoption.

Trial registration number

NA

P-085 Use of an artificial intelligence tool to assess single-sperm motility variables related to bias preference of ICSI sperm selection practice, normal fertilization, and blastocyst formation

Study question

Which single-sperm WHO motility variables are associated with ICSI sperm selection preference, normal fertilization, and blastocyst formation when assessed by an artificial intelligence platform?

Summary answer

Injected sperm had higher VSL, VAP, and LIN compared with non-injected. Higher STR was associated with fertilization and higher WOB and less HMP with blastulation.

What is known already

Sperm selection for intracytoplasmic sperm injection (ICSI) is key to its success. Currently, the procedure may be subjective although the embryologist selects rapidly from a small population of sperm. There is no consensus on specific motility variables for single-sperm selection.

SiD (IVF 2.0 Limited, UK) software is able to assess all sperm in a visual field and accurately compute the motility variables for each sperm in real-time. SiDTM could help to understand the association between motility variables related to ICSI success and to assess the differences in sperm selection practice between different clinics and operators.

Study design, size, duration

473 ICSI videos and their corresponding outcome were retrospectively analyzed using SiD software and assessed against normal fertilization (2PN), and blastocyst formation (BF), from four fertility clinics in different countries between July 2021 to December 2021. Ethical approval was obtained. This study was non-interventional. The study parameters were defined as sperm that were selected or non-selected, 2PN, and BF.

Participants/materials, setting, methods

Motility variables were computed from ICSI videos for VSL, VCL, LIN, VAP, ALH, WOB, STR as defined by the WHO manual for the examination and processing of human semen; and HMP, a metric associated with sperm-head movements. Injected sperm were manually identified and the injection was visually verified by a senior embryologist. Extracted motility variables were standardized according to each clinic and PVP concentration. Study groups were tested with a two-sided Mann-Whitney U test.

Main results and the role of chance

Video analysis identified 304 selected and 9543 non-selected sperm. 2PN and BF status was known for 302 and 301 injected oocytes respectively (2PN rate: 79%, BF rate: 53%).

Embryologists used VSL, VAP, and LIN as the preferred motility criteria to select sperm (p &lt; 0.001). Using data from all clinics, we found a tendency for STR (p = 0.12) and LIN (p = 0.14) for 2PN and WOB (p = 0.11) and VAP (p = 0.18) for BF.

There was partial consistency on sperm selection criteria amongst clinics: Clinic1 selected VSL, VAP, and LIN as the main variables to select sperm; Clinic2 VSL, WOB, and LIN; Clinic3 VSL, VAP, and VCL; and Clinic4 ALH, VCL, and VAP (p &lt; 0.001).

For Clinic1 higher HMP showed a correlation (p = 0.06, n = 21) to 2PN, while higher WOB (p = 0.12, n = 21) did for BF. Clinic2 showed a limited association to higher STR and 2PN (p = 0.12, n = 120), and a significant association between higher WOB and BF (p &lt; 0.05, n = 120). Clinic3’s data suggested that higher STR was associated with 2PN (p &lt; 0.05, n = 97) and low HMP with BF (p &lt; 0.05, n = 97).

Limitations, reasons for caution

This retrospective study needs to be repeated prospectively with larger numbers in more locations using embryologists with different levels of ICSI experience. Clinical outcome data such as clinical pregnancy, miscarriage, and live birth impact is still required.

Wider implications of the findings

SiD was able to track and extract motility features from single sperm. SiDTM could assist embryologists in real-time to select sperm during ICSI and could be used as a training tool to reduce variability among embryologists.

Trial registration number

RPA-2021-03

Airborne Emission Rate Measurements Validate Remote Sensing Observations and Emission Inventories of Western U.S. Wildfires

Carbonaceous emissions from wildfires are a dynamic mixture of gases and particles that have important impacts on air quality and climate. Emissions that feed atmospheric models are estimated using burned area and fire radiative power (FRP) methods that rely on satellite products. These approaches show wide variability and have large uncertainties, and their accuracy is challenging to evaluate due to limited aircraft and ground measurements. Here, we present a novel method to estimate fire plume-integrated total carbon and speciated emission rates using a unique combination of lidar remote sensing aerosol extinction profiles and in situ measured carbon constituents. We show strong agreement between these aircraft-derived emission rates of total carbon and a detailed burned area-based inventory that distributes carbon emissions in time using Geostationary Operational Environmental Satellite FRP observations (Fuel2Fire inventory, slope = 1.33 ± 0.04, r² = 0.93, and RMSE = 0.27). Other more commonly used inventories strongly correlate with aircraft-derived emissions but have wide-ranging over- and under-predictions. A strong correlation is found between carbon monoxide emissions estimated in situ with those derived from the TROPOspheric Monitoring Instrument (TROPOMI) for five wildfires with coincident sampling windows (slope = 0.99 ± 0.18; bias = 28.5%). Smoke emission coefficients (g MJ^-1) enable direct estimations of primary gas and aerosol emissions from satellite FRP observations, and we derive these values for many compounds emitted by temperate forest fuels, including several previously unreported species.

Outcomes of Patients with a pH<7.0 Presenting to the Emergency Department (OPpHED Study)

Objectives The aim of this study was to assess the mortality and predictive factors in patients presenting with a pH<7.0 to the emergency department (ED). Methods A retrospective study of patients presenting to the ED of University Hospital Galway with a pH<7.0 from January 2014 to December 2017 was performed. A pH<7.0 on arrival to the ED from either an arterial or venous sample as measured by the blood gas analyser machine were assessed for inclusion. Results A total of 130 patients presented to ED over a 4-year period, with a mean age of 58 ±20 years. Eighty-one (63%) patients of the total cohort were male. In terms of aetiology of presentation, 66 (51%) cases were from cardiac arrest (CA), while the remaining 64 (49%) cases were non-cardiac arrest (NCA) related. Twenty-eight-day mortality was 69.5% overall, with significant mortality in the CA group (89%) compared to the NCA group (48%) (p<0.00). A modified early warning score (MEWS) (odds ratio [OR] 1.37, 95% CI: 1.18-1.59) and PCO2 ([OR] 1.35, 95% CI: 1.08-1.68.) were predictive of mortality. Conclusion In patients presenting to the ED with a pH of <7.0 the overall mortality was 69.5%, with survival more likely in NCA aetiologies. Mortality was associated with higher pCO2 and MEWS.

O-235 ERICA (Embryo Ranking Intelligent Classification Assistant) AI predicts miscarriage in poorly ranked embryos from one static, non-invasive embryo image assessment

Study question

Does ERICA’s prognosis ranking based on ploidy, predict early miscarriage following positive biochemical pregnancy test?

Summary answer

The lower ERICA grades embryos, the higher the likelihood of early miscarriage, irrespective of age group.

What is known already

The vast majority of early miscarriages are due to aneuploidy, but preimplantation genetic testing for aneuploidy (PGTA) is potentially invasive, expensive, time-consuming and usually necessitates cryopreservation. Current methods for embryo selection based on morphology and morphokinetics are poorly correlated with ploidy. ERICA is a deep-learning non-invasive tool for embryo ranking, trained to identify ploidy, and has previously been shown to be similar or better than experienced embryologists in assessing implantation potential. AI-based tools capable of embryo ranking and assessment could help save laboratory time and costs, avoiding risk to embryos from invasive techniques.

Study design, size, duration

Retrospective analysis of 599 blastocysts transferred over 12 months in which ERICA was used to assist embryologists during the embryo selection process. ERICA’s prognosis based on ploidy potential is presented as groups labelled as “optimal”, “good”, “fair”, or “poor”. Embryo transfers (ET) reaching biochemical pregnancy (beta-hCG ≥ 20iu) were considered for the study. Early pregnancy loss (EPL) was defined as a biochemical pregnancy failing to develop a gestational sac and/or failure to show heartbeat (FHR).

Participants/materials, setting, methods

ETs resulting in biochemical pregnancies at two IVF clinics were followed-up to FHR till 8 weeks gestation. EPLs were divided into groups according to the presence or absence of a pregnancy sac. ERICA’s suggested prognosis during the embryo selection process was tested against pregnancy outcomes. Further analysis of pregnancy outcomes and their relation to ERICA’s labels was also performed based on age groups. Z-test for two proportions was used to assess statistical significance.

Main results and the role of chance

506 ETs were performed for 599 embryos (mean 1.2 embryos), from which 285 resulted in positive pregnancy tests (56.3%). Thirty-one (10.9%) EPLs happened before the identification of a gestational sac (GS). Ten pregnancies failed to develop FHR after initial GS identification (3.9%), for an overall EPL of 14.4%. The average age in this group was 35.4 years. When evaluated using ERICA’s labels “optimal”, “good”, “fair, and “poor”, chances of miscarriage before GS were 8.9% (8/89); 14.1% (11/78); 18.5% (5/27); and 18.7% (9/48) respectively, where denominator represents total number within a label (i.e. EPL/n). When including all EPLs, chances of miscarriage according to the same labels were 11.2%; 17.9%; 22.2%; and 22.9% respectively.

ERICA’s performance to anticipate the risk of EPL showed statistical significance when the optimal label was compared against all other labels (Z -1.786, p &lt; 0.05), and against the poor prognosis label (Z=-1.653, p &lt; 0.05). After stratifying the dataset according to age groups, increasing miscarriage rates were maintained as ERICA’s prognosis for an embryo worsened, regardless of age groups. The most notable performance was for ≤35-year-olds, where embryos ranked as optimal had an EPL rate of 14.3% in contrast to lowest ranked embryos having a 33.3% EPL rate.

Limitations, reasons for caution

The retrospective nature of this study along with its sample-size might limit the reach of our conclusions, in particular for older patients. The results we present must still be confirmed prospectively, and on a larger dataset.

Wider implications of the findings

Most EPLs are attributed to genetic factors, hence ERICA’s training for embryo ranking was based on ploidy. We conclude that ERICA’s AI is able to identify embryos at a higher risk of EPL non-invasively. Cytogenetic studies from products of miscarriage would help to confirm the hypothesis.

Trial registration number

Not applicable

P–111 Development of a flow cytometric assay for membrane lipid oxidation in human sperm

Study question

Is a commercially available lipid peroxidation assay sensitive enough to detect sperm lipid membrane damage and thus provide a novel indicator of male fertility status?

Summary answer

Provisional results demonstrate the novelty of creating a protocol to identify and quantify sperm lipid membrane damage and indicate possible insight into individual male fertility.

What is known already

Cytotoxic lipid aldehydes such as 4-hydroxynonenal (4HNE) created by the damaging effects of reactive oxygen species (ROS) have been studied extensively in sperm, as an indicator of male fertility. This is due to their connection with detrimental effects on sperm function such as morphology, acrosome reactions, motility and fertilization of the oocyte. Although literature states the mechanisms of damage caused to the lipid membrane of the sperm cell, there is no evidence of its quantification or usage as a commercial fertility indicator for human males.

Study design, size, duration

Since the assay is still being developed, there is no formal study size or duration. The goal of this pilot study is to determine whether a commercial lipid peroxidation assay can detect the difference between sperm with high levels of oxidative damage and control sperm cells. We used the remains of sperm samples initially collected for standard semen analysis, which were flash-frozen and then assayed with / without hydrogen peroxide treatment to induce oxidative damage.

Participants/materials, setting, methods

Frozen sperm from consenting donors (n = 21) were washed, optionally treated with hydrogen peroxide to induce oxidative damage, stained with a commercially available lipid peroxidation sensor (LPS, Abcam ab243377), and the resulting fluorescence quantitated by flow cytometry. Assay optimization varied the numbers of sperm input to the protocol, the concentration of the peroxidation sensor, the amount and duration of hydrogen peroxide treatment and the effect of paraformaldehyde (PFA) fixation of samples before or after staining.

Main results and the role of chance

Successful detection of lipid damage in control samples

We observed a significant difference at a p-value &lt; 0.05 between untreated samples and all positive controls with hydrogen peroxide concentrations stronger than 500uM (p &lt; 0.038) . This indicates that we can detect sperm bearing oxidative damage, and establishes the conditions required to make a positive control sample.

Establishment of assay parameters

Results indicate the concentration of sperm input to the protocol is not a significant factor for concentrations below 5 million/ml. Low concentration samples thus do not require further dilution before testing.

Correlation with DNA damage

A significant direct strong positive Pearson correlation coefficient (R = 0.93, p &lt; 0.023) was found between samples with low DNA fragmentation index (DFI (%), measured by flow cytometric staining with acridine orange) and the LPS flow cytometric data (%).

Limitations, reasons for caution

As yet our data only addresses high level lipid damage induced by peroxide treatment. It remains to be established whether it is possible to detect endogenous LPO damage due to oxidative stress in semen. Future work will correlate our data with motility information and oxidative stress data (measured by MiOXSYS).

Wider implications of the findings: If we are able to develop a direct assay for sperm LPO, this will allow an additional avenue for testing patients with unexplained male infertility, which could in turn affect treatment choices and ART methodology. Improved diagnosis and treatment will potentially improve the lives of families with their fertility matters.

Trial registration number

Not applicable

P–574 Examination of inter centre variation in PGT-A “no result rate” and efficacy of rebiopsy - Analysis of 22,833 samples 2015–2019

Study question

Are there significant differences in PGT-A “no result” rates and clinical outcomes following rebiopsy between ART clinics, and do rebiopsied embryos perform better than transferring with no result?

Summary answer

There is significant differences between clinics in terms of “no result rate” in PGT-A and utilisation of rebiopsy. What is known already: With any testing platform used in PGT-A, there is always a chance that a sample will not yield a result and rebiopsy may be considered to ascertain an embryos cytogenetic status. Studies have demonstrated rebiopsy yields results and adds to embryos genetically suitable for transfer. Clinical outcome data, however, remains scarce, leading to difficulty for clinics in benchmarking their performance when rebiopsied embryos are transferred.

Study design, size, duration

A retrospective analysis was performed of trophectoderm samples submitted for PGT-A via NGS over a 5yr period, 2015–2019. The no result (NR) rate was calculated per year and per clinic. Clinics were contacted for follow up data on NR embryos in terms of usage and clinical outcomes. Clinical outcomes from rebiopsied embryos were compared with those transferred as NR without rebiopsy.

Participants/materials, setting, methods

Data was collected on 22833 trophectoderm samples, submitted by 30 IVF laboratories. NR rate was analysed by year and by clinic. Clinics were asked if NR embryos had undergone rebiopsy, and if so if they had survived warming and rebiopsy. Clinics were asked if embryos selected for transfer had survived (re)warming, and to provide clinical follow-up including hCG test, clinical pregnancies, miscarriage and livebirth. The two tailed Fishers exact test was used for statistical analysis.

Main results and the role of chance

There was a wide range in sample numbers submitted by clinics over the time period, ranging from 9 samples through to 2633. In tclinics submitting over 500 samples the NR rate ranged from 0.6% to 7.4%, and in the those submitting 100–499 samples it ranged from 1.1% to 5.8%. Both these differences proved to be statistically significant (p &lt; 0.05) between the best and worst performing clinics, and shows that a gap in performance exists between clinics. Less than 50% of NR embryos underwent rebiopsy. While the majority of embryos undergoing rebiopsy yielded a result (92.3%) and 31.4% of these were euploid or mosaic, almost half still remain in storage. The rate of livebirth/ongoing implantation in the rebiopsy group is 35.5% and 17.1% in the non rebiopsy group, illustrating a non significant trend towards a higher chance of implantation and livebirth in the rebiopsy group. Of 58 patients undergoing rebiopsy without any euploids in their initial cycle, 18 had a euploid embryo identified for future use. The additional manipulations involved in rebiopsy do not impact on survival at warming for transfer, but clinical outcomes in rebiopsied embryos appear poorer than those where a result was generated at first biopsy.

Limitations, reasons for caution

Despite starting with 22833 samples, 1115 of which were classified as NR, there were only 31 rebiopsied and 42 NR embryos transferred. It was therefore not possible to analyse transfer data by clinic or by embryo quality.

Wider implications of the findings: Rebiopsy yields genetic results and embryos suitable for patient use, including for patients who produced no other euploid/mosaic embryos in their cycle. However, it is not offered/performed in many cases. Clinical outcome data must continue to be compiled and analysed to confirm performance exceeds transfer of NR embryos.

Trial registration number

Not applicable

Highly realistic cadaveric trauma simulation of the multiply injured battlefield casualty: an international, multidisciplinary exercise in far-forward surgical management

INTRODUCTION

We designed an ultra-high-fidelity military cadaveric surgical simulation course to train military medical teams for specific battlefield injuries. Our aim was to deliver a highly realistic, immersive simulation training experience, teaching both technical and non-technical skills necessary for the management of war-injuries in the austere environment of a far forward surgical facility. We designed an educational cohort study around the course to measure its learning impact.

METHODS

25 personnel participated in 15 non-continuous hours of simulation that included 12 patient scenarios. Participants were given previously piloted questionnaires pre- and post-simulation to assess their confidence with managing battlefield injuries by body area, their views on the realism of the simulation, and their perceptions of training benefit. All questions were assessed using a Likert scale of 1-10 (10=best).

RESULTS

The response rate for complete questionnaires was 95%. Baseline confidence scores were; abdomen (5.5), pelvis (5.7), chest (6.2), airway (6.3), extremity (7.3). Confidence gains following training were; abdomen (+1.7), pelvis (+ 1.6), chest (+1.6), airway (+1.2), extremity (+0.8). The most realistic aspects of the simulation were; injury replication (9.1), the cadaver as a multiply injured casualty (9.1) and the multidisciplinary team (9.2). The mean ratings for technical and non-technical skill acquisition were 9.1 and 9.0 respectively. Cadaveric simulation was reported to be ideal for learning military medical skills (9.3), and participants strongly recommended that provision should be increased (9.7).

CONCLUSION

We have demonstrated an ability to recreate highly realistic injuries in an ultra-high-fidelity simulation of a multiply injured military casualty. There was a measurable increase in confidence for both technical skills in all major body areas, and non-technical skills. Multinational and multidisciplinary working strongly enhanced learning.

Isolating the impact of COVID-19 lockdown measures on urban air quality in Canada

We have investigated the impact of reduced emissions due to COVID-19 lockdown measures in spring 2020 on air quality in Canada's four largest cities: Toronto, Montreal, Vancouver, and Calgary. Observed daily concentrations of NO₂, PM_2.5, and O₃ during a "pre-lockdown" period (15 February-14 March 2020) and a "lockdown" period (22 March-2 May 2020), when lockdown measures were in full force everywhere in Canada, were compared to the same periods in the previous decade (2010-2019). Higher-than-usual seasonal declines in mean daily NO₂ were observed for the pre-lockdown to lockdown periods in 2020. For PM_2.5, Montreal was the only city with a higher-than-usual seasonal decline, whereas for O₃ all four cities remained within the previous decadal range. In order to isolate the impact of lockdown-related emission changes from other factors such as seasonal changes in meteorology and emissions and meteorological variability, two emission scenarios were performed with the GEM-MACH air quality model. The first was a Business-As-Usual (BAU) scenario with baseline emissions and the second was a more realistic simulation with estimated COVID-19 lockdown emissions. NO₂ surface concentrations for the COVID-19 emission scenario decreased by 31 to 34% on average relative to the BAU scenario in the four metropolitan areas. Lower decreases ranging from 6 to 17% were predicted for PM_2.5. O₃ surface concentrations, on the other hand, showed increases up to a maximum of 21% close to city centers versus slight decreases over the suburbs, but O_x (odd oxygen), like NO₂ and PM_2.5, decreased as expected over these cities.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11869-021-01039-1.

Disentangling the Impact of the COVID-19 Lockdowns on Urban NO2 From Natural Variability

TROPOMI satellite data show substantial drops in nitrogen dioxide (NO₂) during COVID-19 physical distancing. To attribute NO₂ changes to NO _x emissions changes over short timescales, one must account for meteorology. We find that meteorological patterns were especially favorable for low NO₂ in much of the United States in spring 2020, complicating comparisons with spring 2019. Meteorological variations between years can cause column NO₂ differences of ~15% over monthly timescales. After accounting for solar angle and meteorological considerations, we calculate that NO₂ drops ranged between 9.2% and 43.4% among 20 cities in North America, with a median of 21.6%. Of the studied cities, largest NO₂ drops (>30%) were in San Jose, Los Angeles, and Toronto, and smallest drops (<12%) were in Miami, Minneapolis, and Dallas. These normalized NO₂ changes can be used to highlight locations with greater activity changes and better understand the sources contributing to adverse air quality in each city.

The AirTight Protocol for Mixed Criticality Wireless CPS

This article describes the motivation, design, analysis, and configuration of the criticality-aware multi-hop wireless communication protocol AirTight. Wireless communication has become a crucial part of the infrastructure of many cyber-physical applications. Many of these applications are real-time and also mixed-criticality, in that they have components/subsystems with different consequences of failure. Wireless communication is inevitably subject to levels of external interference. In this article, we represent this interference using a criticality-aware fault model; for each level of temporal interference in the fault model, we guarantee the timing behaviour of the protocol (i.e., we guarantee that packet deadlines are satisfied for certain levels of criticality). Although a new protocol, AirTight is built upon existing standards such as IEEE 802.15.4. A prototype implementation and protocol-accurate simulator have been produced. This article develops a series of schedulability analysis techniques for single-channel and multichannel wireless Cyber-Physical Systems (CPS). Heuristics are specified and evaluated as the starting point of design space exploration. Genetic algorithms are then defined and evaluated to assess their performance in developing schedule tables incorporating multichannel allocations in these systems.

Exploiting OMI NO2 satellite observations to infer fossil-fuel CO2 emissions from U.S. megacities

Fossil-fuel CO₂ emissions and their trends in eight U.S. megacities during 2006-2017 are inferred by combining satellite-derived NO_X emissions with bottom-up city-specific NO_X-to-CO₂ emission ratios. A statistical model is fit to a collection NO₂ plumes observed from the Ozone Monitoring Instrument (OMI), and is used to calculate top-down NO_X emissions. Decreases in OMI-derived NO_X emissions are observed across the eight cities from 2006 to 2017 (-17% in Miami to -58% in Los Angeles), and are generally consistent with long-term trends of bottom-up inventories (-25% in Miami to -49% in Los Angeles), but there are some interannual discrepancies. City-specific NO_X-to-CO₂ emission ratios, used to calculate inferred CO₂, are estimated through annual bottom-up inventories of NO_X and CO₂ emissions disaggregated to 1 × 1 km² resolution. Over the study period, NO_X-to-CO₂ emission ratios have decreased by ~40% nationwide (-24% to -51% for our studied cities), which is attributed to a faster reduction in NO_X when compared to CO₂ due to policy regulations and fuel type shifts. Combining top-down NO_X emissions and bottom-up NO_X-to-CO₂ emission ratios, annual fossil-fuel CO₂ emissions are derived. Inferred OMI-based top-down CO₂ emissions trends vary between +7% in Dallas to -31% in Phoenix. For 2017, we report annual fossil-fuel CO₂ emissions to be: Los Angeles 113 ± 49 Tg/yr; New York City 144 ± 62 Tg/yr; and Chicago 55 ± 24 Tg/yr. A study in the Los Angeles area, using independent methods, reported a 2013-2016 average CO₂ emissions rate of 104 Tg/yr and 120 Tg/yr, which suggests that the CO₂ emissions from our method are in good agreement with other studies' top-down estimates. We anticipate future remote sensing instruments - with better spatial and temporal resolution - will better constrain the NO_X-to-CO₂ ratio and reduce the uncertainty in our method.

Sorting Beef Subprimals by Ribeye Size at the Packer Level to Maximize Utility and Product Uniformity in Foodservice and Retail Sectors

ObjectivesTo determine the impact of sorting beef carcasses at the packer level by ribeye area, instead of sorting subprimals by weight, to provide more consistent products for the end user via foodservice and retail channelsMaterials and MethodsInstrument grading technology was used to select 100 USDA Choice, yield grade 2 or 3 sides, and 100 USDA Select, yield grade 2 or 3 sides. Carcass sides were sorted into one of five ribeye area (REA) categories, as outlined in Tabsle 6.USDA Choice carcass sides were fabricated to remove beef rib, ribeye, lip-on (IMPS 112A) and beef loin, strip loin, boneless (IMPS 180) from each USDA Choice. Beef loin, tenderloin, full, side muscle on, partially defatted (IMPS 189B) subprimals were procured from each USDA Select side. Subprimals were weighed, trimmed to specification, and passed through a 3-D visual analysis portioning machine and to obtain scan data for a variety of portioning outcomes generated by simulation software.ResultsBased on input from our foodservice collaborators, 1.25 inches (3.18 cm) was identified, for ribeye and strip loin steaks, as the targeted optimal thickness to meet consumer expectations. After evaluation of multiple portioning outcomes, it was determined that a 14.00-ounce (396.89 g) portion, for each REA category, most consistently delivered the preferred steak thickness identified previously. REA categories 1 and 2 most frequently produced desirable thickness and portion weight outcomes in ribeye and strip loin steaks. Statistical analysis of number of portions per subprimal stratified by portion weight and portion thickness revealed differences (P < 0.05) across all REA area categories in both ribeyes and strip loins. As portion weight and thickness increased, steak portion number tended to decrease. In tenderloins, an optimal steak thickness of 1.75 to 2.00 in (4.45 to 5.08 cm) was identified as optimal. Most frequently, 8, 9, and 10-ounce (226.80, 255.15, and 283.50 g) portions met the targets for optimal portion weight and thickness parameters. For tenderloins, number of portions by portion weight showed significant differences (P < 0.05) in all ribeye area categories with the exception of 7-ounces (198.45 g) and showed no differences when stratified by portion thickness. In this investigation, USDA Choice carcasses (r = 0.76) and USDA Select carcasses (r = 0.56) expressed moderate correlation between REA area and hot carcass weight.ConclusionResults of the present study suggest strip loin, ribeye, and tenderloin subprimals from carcasses possessing a ribeye area ranging from 74.8 cm2 to 87.1 cm2 offered the greatest level of utility when portioned for use in foodservice and retail sectors. Further research is warranted to continue examining the merit of sorting carcasses by ribeye area at the packer level, but results of this study suggest that there is potential for improved consistency and utility of subprimals in the foodservice and retail sectors.Table 6.Ribeye area (REA) categories and associated acceptable REA ranges.

Enhanced Capabilities of TROPOMI NO2: Estimating NOX from North American Cities and Power Plants

The TROPOspheric Monitoring Instrument (TROPOMI) is used to derive top-down NO_X emissions for two large power plants and three megacities in North America. We first re-process the vertical column NO₂ with an improved air mass factor to correct for a known systematic low bias in the operational retrieval near urban centers. For the two power plants, top-down NO_X emissions agree to within 10% of the emissions reported by the power plants. We then derive top-down NO_X emissions rates for New York City, Chicago, and Toronto, and compare them to projected bottom-up emissions inventories. In this analysis of 2018 NO_X emissions, we find a +22% overestimate for New York City, a -21% underestimate in Toronto, and good agreement in Chicago in the projected bottom-up inventories when compared to the top-down emissions. Top-down NO_X emissions also capture intraseasonal variability, such as the weekday versus weekend effect (emissions are +45% larger on weekdays versus weekends in Chicago). Finally, we demonstrate the enhanced capabilities of TROPOMI, which allow us to derive a NO_X emissions rate for Chicago using a single overpass on July 7, 2018. The large signal-to-noise ratio of TROPOMI is well-suited for estimating NO_X emissions from relatively small sources and for sub-seasonal timeframes.

High resolution mapping of nitrogen dioxide with TROPOMI: First results and validation over the Canadian oil sands

TROPOMI, on-board the Sentinel-5 Precursor satellite is a nadir-viewing spectrometer measuring reflected sunlight in the ultraviolet, visible, near-infrared, and shortwave infrared spectral range. From these spectra several important air quality and climate-related atmospheric constituents are retrieved at an unprecedented high spatial resolution, including nitrogen dioxide (NO₂). We present the first retrievals of TROPOMI NO₂ over the Canadian Oil Sands, contrasting them with observations from the OMI satellite instrument, and demonstrate its ability to resolve individual plumes and highlight its potential for deriving emissions from individual mining facilities. Further, the first TROPOMI NO₂ validation is presented, consisting of aircraft and surface in-situ NO₂ observations, as well as ground-based remote-sensing measurements between March and May 2018. Our comparisons show that the TROPOMI NO₂ vertical column densities are highly correlated with the aircraft and surface in-situ NO₂ observations, and the ground-based remote-sensing measurements with a low bias (15-30 %) over the Canadian Oil Sands.

PLAIN LANGUAGE SUMMARY

Nitrogen dioxide (NO₂) is a pollutant that is linked to respiratory health issues and has negative environmental impacts such as soil and water acidification. Near the surface the most significant sources of NO₂ are fossil fuel combustion and biomass burning. With a recently launched satellite instrument (TROPOspheric Monitoring Instrument; TROPOMI) NO₂ can be measured with an unprecedented combination of accuracy, spatial coverage, and resolution. This work presents the first TROPOMI NO₂ measurements near the Canadian Oil Sands and shows that these measurements have an outstanding ability to detect NO₂ on a very high horizontal resolution that is unprecedented for satellite NO₂ observations. Further, these satellite measurements are in excellent agreement with aircraft and ground-based measurements.

The decision-making threshold and the factors that affect it: A qualitative study of patients' decision-making in knee replacement surgery

BACKGROUND

Osteoarthritis is a significant cause of burden to the ageing population and knee replacement is a common operation for treatment of end-stage disease. We aimed to explore these factors to help understand patients' decision-making, which is critical in informing patient-centred care. These can be used to enhance decision-making and dialogue between clinicians and patients, allowing a more informed choice.

METHODS

The study consisted of two focus groups, in a patient cohort after total knee replacement followed by more in-depth interviews to further test and explore themes from the focus groups, in patients in either the deliberation stage or the decision-making stage.

RESULTS

Using qualitative research methods (iterative thematic analysis) reviewing decision-making and deliberation phases of making informed choices we found nine key themes that emerged from the study groups.

CONCLUSIONS

An awareness of the deliberation phase, the factors that influence it, the stress associated with it, preferred models of care, and the influence of the decision-making threshold will aid useful communication between doctors and patients.

Vitamin D Deficiency and Insufficiency Prevalence in the West of Ireland - A Retrospective Study

OBJECTIVES

Vitamin D plays an important role in calcium homeostasis and is essential for normal bone growth and remodeling. Previous studies of acutely ill and institutionalized older women in Galway revealed that vitamin D insufficiency is extremely common. We aimed to evaluate age and gender-related rates of vitamin D insufficiency and deficiency in adult patients attending their General Practitioners in the same region.

DESIGN

A retrospective cohort study.

SETTING

General practices in Galway, a city located on the west coast of Ireland, latitude 53.17 North.

PARTICIPANTS

A total of 15,708 consecutive blood samples from adults attending their General Practitioners between January 2013 and December 2014 were sent to the Clinical Biochemistry Laboratory in the University Hospital Galway for vitamin D level testing. 73% were from women.

INTERVENTION

Data were collected and grouped according to age, sex and season. Vitamin D levels (25OHD) were categorised into deficiency (<25nmol/L), insufficiency (25-50nmol/L) and sufficiency ( >50nmol/L).

MEASUREMENTS

Median and interquartile range were reported as vitamin D levels were not normally distributed. Descriptive statistics were performed using STATA/MP 13.1 for Mac.

RESULTS

While vitamin D levels were sufficient in 56.4% (n=8,496), they were insufficient in 32.4% (n=4,891) and deficient in 11.2% (n=1,691). Of the deficient group, 19%( 325) had levels <15nmol/L consistent with profound deficiency. Men were more likely than women to be deficient (12% (n=489) vs. 10.9% (n=1,202)) and insufficient (38.0% (n=1,550) vs. 30.4% (n=3,341)) (p<0.01). Highest rates of deficiency were seen in those 81-97 years (19.4% (n=136)) and 18-40 years (13.8% (n=543)), the former group showing less seasonal variation.

CONCLUSION

Overall prevalence of insufficiency is similar to those in national and European studies published recently. However, there is a high possibility that those most vulnerable to vitamin D deficiency were underrepresented in this cohort, when results from previous studies in the same region are considered. Further prospective studies are needed to guide treatment with supplementation of vitamin D for appropriate subgroups.