Linear Model Analysis Research Articles

Identifying multilevel factors on student mathematics performance for Singapore, Korea, Finland, and Denmark in PISA 2022: considering individualistic versus collectivistic cultures

Employing a two-level hierarchical linear modelling (HLM) analysis, the current study comparatively explored the effects of student- and school-level factors on student mathematics performance for Singapore, Korea, Finland, and Denmark in the 2022 Programme for International Student Assessment (PISA). The results showed that (a) economic, social and cultural status (ESCS), school average ESCS, mathematics self-efficacy, and mathematics anxiety are significantly associated with mathematics performance for Singapore, Korea, Finland, and Denmark; (b) mathematics teacher support has a significantly positive effect on mathematics performance for Finland and Denmark, while ability grouping for mathematics classes and student disruptive behaviours have a significantly negative impact on mathematics performance for Singapore and Korea; (c) the relationship between time in mathematics homework and mathematics performance is positive in Singapore and Korea but negative in Finland and Denmark; as well, (d) curiosity is positively related to mathematics performance for Korea, Finland, and Denmark, while the influence of mathematics motivation on mathematics performance is only significant for Finland and the influence of mathematics extra-curricular activities on mathematics performance is merely significant for Korea. In essence, the different effects may be associated with intrinsic discrepancies regarding educationally tight versus loose systems, as well as comparatively, regarding philosophically social versus individual orientations, which represent Eastern and Western cultures, respectively. The findings were discussed from a cross-cultural perspective in terms of individualism-collectivism.

Comparative Analysis of the Impact of Instructional Models on Students’ Attitudes towards physics: Exploring the Cognitivist and Constructivist Perspectives

This study analyses the effectiveness of directed vs. minimally directed inquiry-based instructional approaches in improving students’ attitudes toward physics. It specifically compares the impacts of cognitively guided instructional strategy (CGIS) and Cubing instructional strategy (CIS) on student attitudes. Using a pretest–post-test quasi-experimental design, the study collected data through the Students’ Attitude to physics (SAPQ) instrument. The study involved 160 students aged 14 to 20 across three schools. A multilevel linear model analysis accounted for the nested data structure at the classroom and school levels. The results showed that both CGIS and CIS enhanced students’ attitudes, with post-attitude mean scores notably higher in the CIS group than in the CGIS group. This indicates that the constructivist approach led to greater improvements in attitudes toward physics. The study underscores the importance of instructional strategies that offer minimal teacher involvement, as they actively engage students and significantly enhance their attitudes toward the subject.

Association between physical activity energy expenditure and bone mineral density in U.S. adults: A cross-sectional analysis of NHANES 2011-2018.

Osteoporosis is a global disease characterized by decreased bone mineral density (BMD) and impaired bone metabolism. The Physical Activity Metabolic Equivalent of Task (PA-MET) quantifies energy expenditure during physical activities. This study aims to investigate the relationship between energy expenditure, BMD, and the risk of developing osteoporosis. By exploring how varying levels of physical activity impact BMD, we seek to better understand the role of energy expenditure in osteoporosis prevention and management. Cross-sectional study. This was a cross-sectional study that included 6599 adult participants who took part in the National Health and Nutrition Examination Survey (NHANES) from 2011 to March 2018. We used multivariate weighted linear model analysis to reveal the association between PA-MET levels and BMD. Multivariable weighted linear model analysis showed a positive correlation between PA-MET and total BMD. Compared to the lower PA-MET group, the fourth quartile of the PA-MET group had a β=0.02 (95% CI, 0.01 to 0.03). Similarly, in the analysis with thoracic spine BMD as the outcome, the fourth quartile of the PA-MET group had a β=0.02 (95% CI, 0.01 to 0.02) compared to the lower PA-MET group. For lumbar spine BMD, the fourth quartile of the PA-MET group had a β=0.02 (95% CI, 0.01 to 0.03). In the analysis with trunk BMD as the outcome, the fourth quartile of the PA-MET group had a β=0.02 (95% CI, 0.02 to 0.03) compared to the lower PA-MET group. Our results show that the energy expenditure from physical activity has a positive relationship with BMD, which serves as a protective factor against the risk of osteoporosis.

Modeling an Electrolyzer in a Graph-Based Framework

We propose a linear electrolyzer model for steady-state load flow analysis of multi-carrier energy networks, where the electrolyzer is capable of producing hydrogen gas and heat. For our electrolyzer model, we show that there are boundary conditions that lead to a well-posed problem. We derive these conditions for two cases, namely with a known and unknown heat efficiency parameter. Furthermore, the derived conditions are validated numerically. Moreover, we investigate the extensibility of our model by including nonlinear models from electricity, gas, and heat. In this setting, we derived boundary conditions based on our previous findings. Due to the involvement of nonlinearity, it is a challenge to prove that the boundary conditions lead to a well-posed problem. Therefore, we simulated the electrolyzer connected with an electricity, gas, and heat system. Additionally, we considered a known and unknown heat efficiency parameter. The numerical results support that the linear electrolyzer model is solvable in a multi-carrier energy network.

A Randomized Controlled Crossover Trial to Determine the Effects of Three Nostril Regulated Breathing Practices on Attention and Mood.

Previous studies on nostril regulated breathing have contrasting findings attributed to lack of controls or not taking into account baseline nostril patency. This randomized crossover study on the effects of three nostril regulated yoga breathing practices and two controls on mood states and attention attempted to address these issues. Forty-five participants between 20 and 45 years (group mean age ± SD; 24.3±3.8 years; M;F 23:22) were assessed in five sessions in random order on five separate days. Nostril patency recorded pre-interventions in 225 sessions showed right nostril dominant at rest (RNDR) in 136 and left nostril dominant at rest (LNDR) in 89 sessions. The sessions were: (i) SAV or right uninostril breathing, (ii) CAV or left unnostril breathing, (iii) (AV or alternate nostril yoga breathing, (iv) breath awareness (BAW), and (v) quiet seated rest (QS). The practices were for 15 min each. Nostril patency was recorded pre, Brief mood introspection scale (BMIS), Global Vigor and Affect Scale (GVA) and Six letter cancellation test (SLCT) were recorded pre and post each session. Data analysis used general linear mixed model analysis, with fixed effects of states (pre and post), sessions and baseline nostril dominance (right or left). A significant interaction of sessions, states and nostril dominance at baseline was observed for total global affect (GA) (F9,396.194=2.871, p=0.003) which increased after SAV, CAV, AV and QS in participants right nostril dominant at rest (NDR) (padj<0.05 in all cases). A significant main effect of states was observed followed by significant post-hoc pair wise comparison in right NDR for (i) pleasant mood after SAV, CAV, AV and QS, (ii) positive mood after SAV and AV, and (iii) global vigor after SAV, CAV, AV and QS, and (iv) a decrease in negative mood after CAV and AV. While the volunteers who had left NDR showed a significant increase in (i) PU after CAV, AV, and QR, (ii) PT after CAV, and (iii) GV after CAV and QS. Nostril dominance pre intervention appears to influence the effects of nostril regulated yoga breathing practices.

Inpatient dialectical behavior therapy combined with trauma-focused therapy for PTSD and borderline personality disorder symptoms: study design of the naturalistic trauma therapy study

IntroductionChildhood traumatization can result in physical and mental health problems in adulthood, such as post-traumatic stress disorder (PTSD), which negatively influences quality of life and social functioning. Although evidence based trauma treatments benefit clients with PTSD after childhood abuse and comorbid personality disorders, they are less effective than in clients who were traumatized in adulthood, and drop-out is substantial. The current study aims to assess the effects of inpatient dialectical behavior therapy combined with prolonged exposure (DBT-PTSD) on severity of PTSD, dissociation, parasuicidal behavior and borderline personality disorder (BPD) in clients with severe PTSD and comorbid psychiatric disorders. Secondary outcomes are social functioning, quality of life, borderline and cluster C personality disorder symptoms as treatment predictors, treatment trajectories, clients’ experiences and health economic consequences.MethodsThe naturalistic, longitudinal Trauma Therapy Study is conducted from January 2019 until May 2025 in a mental healthcare center in the Netherlands. Clients with severe PTSD and comorbid conditions who are referred to inpatient DBT-PTSD are included into the study. Based on power analyses a total sample size of N=56 is needed. Measurements take place before the waiting list period, at pre- and posttreatment and at six- and twelve-months follow-up. Clients fill in a daily DBT-PTSD diary, which gives insight into individual symptom trajectories.ResultsStatistical analyses include two-sided paired samples t-tests, linear mixed model analyses and cost-effectiveness analyses. Qualitative interviews are conducted within two years posttreatment and analyzed using a phenomenological approach. We correct for chance capitalization by using a conservative α-level of.01. Multiple imputation is used to handle missing data.DiscussionResearch on the effects of integrated treatment programs for clients with severe PTSD and co-morbid conditions is scarce. This study extends current knowledge on the effects of inpatient DBT-PTSD on PTSD and BPD symptoms, clients’ social functioning and quality of life. In addition, it provides insight into individual symptom trajectories and experiences, inspiring future treatment improvements for clients with severe psychopathology.Trial registrationMedical Ethical Committee approval (NL669060018, RTPO1044/01.10.2018). Preregistration: Dutch registration database Centrale Commissie Mensgebonden Onderzoek and International Clinical Trials Registry Platform (NL-OMON46167/01.10.2018/https://trialsearch.who.int/Trial2.aspx?TrialID=NL-OMON46167).

Regional hippocampal thinning and gyrification abnormalities and associated cognition in children with prenatal alcohol exposure.

Prenatal alcohol exposure (PAE) impacts hippocampal structure and function, contributing to deficits in memory and decision-making in affected individuals. Here, we evaluate hippocampal anomalies in children with PAE and an unexposed comparison group using advanced MRI methods that characterize hippocampal curvature and thickness. Participants, ages 8 to 16years, included children with PAE (n = 48) and an unexposed comparison group (n = 46) who underwent a dysmorphology exam, neuropsychological assessment, and an MRI scan. Height, weight, head circumference, and dysmorphic facial features were evaluated. Of those with PAE, 4.2% had fetal alcohol syndrome (FAS), 22.9% had partial FAS, and 72.9% had alcohol-related neurodevelopmental disorder. Neuropsychological testing included measures of intelligence and memory functioning. T1-weighted anatomical data were processed with the Hippunfold pipeline, which "unfolds" the complex hippocampal structure onto a template surface and provides measures of thickness and gyrification/curvature at each vertex. Permutation Analysis of Linear Models (PALM) was used to test for group differences (PAE vs. comparison) in hippocampal thickness and gyrification at each vertex and also to assess correlations with cognitive functioning. There were significant regional differences in thickness and gyrification across bilateral hippocampi, with the PAE group showing substantially thinner tissue and less curvature than the comparison group, especially in CA1 and subiculum regions. For those with PAE, thinner subicular tissue (bilateral) was associated with lower IQ. Also in the PAE group, lower episodic memory performance was associated with thinness in the right hippocampus, especially in the subiculum region. There were no significant regional hippocampal patterns that were associated with cognitive functioning for individuals in the unexposed comparison group. We used a novel MRI method to evaluate hippocampal structure in children with PAE and an unexposed comparison group. The data suggest that PAE disrupts hippocampal development, impacting both the early-stage folding of the structure and its ultimate thickness. The data also demonstrate that these developmental anomalies have functional consequences in terms of core memory functions as well as global intellectual functioning in children with PAE.

Association between vertebral fractures and brain volume: insights from a community cohort study.

Vertebral fractures (VF) due to osteoporosis impact morbidity and quality of life in the elderly. The relationship between VF and changes in brain structure remains underexplored. This study aimed to investigate the association between VF and gray matter volume (GMV) reductions in specific brain regions and to explore potential sex differences. Data from 1,751 participants (571 males, 1,180 females; mean age 64.9, range 18-97) in the fourth survey of the population-based Research on Osteoarthritis/Osteoporosis Against Disability study (2015-2016) were used. Participants were classified into those with and without VF (VF + and VF - groups) based on Genant's semiquantitative method, assessed by spine radiographs. Voxel-based morphometry was applied to MRI images to measure GMV, and a general linear model analysis was performed to compare GMV between groups, adjusting for age, sex, total brain volume, and Mini-Mental State Examination scores as covariates. Additionally, a two-way analysis of variance was conducted on the significant GMV cluster, with sex and VF presence as independent variables, to explore interaction effects. The VF+ group consisted of 113 participants, while the VF- group included 1,638 participants.The analysis identified a significant cluster with reduced GMV in the VF + group compared to the VF - group. This cluster included the right hippocampus, right amygdala, and right parahippocampal gyrus. Further analysis revealed that males in the VF + group exhibited more pronounced GMV reductions in the significant cluster compared to females. These findings suggest that VF is associated with significant reductions in brain regions critical for memory, emotional processing, and visuospatial memory, with more severe effects observed in males.

Effects of Radiation Dose of Photon and Electron Beam Energies and Angles in Radiation Therapy

This study explores the effects of varying radiation beam energy levels and angles on the doses administered to adjacent healthy tissues and tumors during cancer treatment. While electron beams are best suited for superficial tumors because of their shallow penetration depth, photon beams produced by linear accelerators are useful for deep-seated tumors. Radiation doses were measured at different angles with 6 MV and 15 MV photon beams at 0° and 60° and with 6 MeV, 12 MeV, and 15 MeV electron beams at 0° and 15°. The findings demonstrate that larger angles and higher energy produce higher doses at different positions in photon therapy. Energy levels in electron therapy have a greater effect on dose distribution than angles. Our linear regression model analysis found that energy level angles and dose measurements in photon therapy strongly correlate with high R2 scores (above 0.8). Substantial and inconsistent correlations were observed with electron therapy. Despite these variations, a positive correlation was seen between various dose measurements for both treatments. These results emphasize the significance of choosing the right angles and energy levels to maximize treatment efficacy and minimize harm to healthy tissues. The use of these treatment protocols in clinical settings is supported by comparing our results with international standards which guarantee safety and efficacy.

Characterisation of nocturnal arrhythmia avalanche dynamics: Insights from generalised linear model analysis.

Nocturnal arrhythmia avalanche (NAA) episodes, characterised by transient non-sustained cardiac arrhythmias during sleep, have been demonstrated as a predictor of adverse cardiovascular events. However, their dynamics and association with sleep architecture and events remain unclear. While generalised linear models (GLM) have captured sleep-disordered breathing (SDB) dynamics, their application to NAA remains underexplored. This study explored whether changes in sleep architecture contribute to nocturnal arrhythmias and if the impact of sleep stages, SDB, and arousal events on these arrhythmias varies by demographic factors. We analysed 7341 ECG recordings from the multi-ethnic study of atherosclerosis (MESA) and the sleep heart health study (SHHS) datasets. R-R intervals were divided into 10-min periods to detect NAA, defined as a 30% drop from baseline followed by recovery to 90% of baseline. A GLM framework was developed to characterise NAA episodes as functions of SDB, sleep arousal events, sleep stages, and prior NAA episodes. The GLM analysis revealed that NAA occurrence was 18% and 30% higher during non-rapid eye movement (NREM) light sleep compared with deep sleep in SHHS (p < 0.001) and MESA (p < 0.001), respectively. SDB events increased the NAA risk in 34% of participants, and arousals in 29%. In SHHS, the impact of SDB on NAA was 5% greater in men (p = 0.018), while the arousal effects were more pronounced in those over 75, highlighting the role of demographic factors in modulating arrhythmia risk. These findings demonstrate the utility of the GLM framework in modelling the dynamics of nocturnal arrhythmias and their associations with sleep disruptions and architecture.

Using N2pc variability to probe functionality: Linear mixed modelling of trial EEG and behaviour.

This paper has two concurrent goals. On one hand, we hope it will serve as a simple primer in the use of linear mixed modelling (LMM) for inferential statistical analysis of multimodal data. We describe how LMM can be easily adopted for the identification of trial-wise relationships between disparate measures and provide a brief cookbook for assessing the suitability of LMM in your analyses. On the other hand, this paper is an empirical report, probing how trial-wise variance in the N2pc, and specifically its sub-component the NT, can be predicted by manual reaction time (RT) and stimuli parameters. Extant work has identified a link between N2pc and RT that has been interpreted as evidence of a direct and causative relationship. However, results have left open the less-interesting possibility that the measures covary as a function of motivation or arousal. Using LMM, we demonstrate that the relationship only emerges when the NT is elicited by targets, not distractors, suggesting a discrete and functional relationship. In other analyses, we find that the target-elicited NT is sensitive to variance in distractor identity even when the distractor cannot itself elicit consistently lateralized brain activity. The NT thus appears closely linked to attentional target processing, supporting the propagation of target-related information to response preparation and execution. At the same time, we find that this component is sensitive to distractor interference, which leaves open the possibility that NT reflects brain activity responsible for the suppression of irrelevant distractor information.

Spatial and Habitat Determinants of Small-Mammal Biodiversity in Urban Green Areas: Lessons for Nature-Based Solutions

Spatial and Habitat Determinants of Small-Mammal Biodiversity in Urban Green Areas: Lessons for Nature-Based Solutions

The relationship between AutoNRT thresholds and subjective programming levels revisited

Objectives The aim of this study wasto systemically examine the relationship between AutoNRT thresholds and subjective programming levels by controlling for individual subject variation, and further, to propose an alternative way to calculate the AutoNRT threshold profile for programming purposes. Methods The study was a prospective observational study. AutoNRT thresholds, T- and C-levels were recorded at six and twelve months after activation. All subjects had received a CI24RE implant. Results Forty-one adults participated in the study. A linear mixed-effects model analysis of the relationship between the AutoNRT thresholds and the T-and C-levels resulted in a large unexplainable variation between subjects, the standard deviation was between 15.42 and 18.89 CL. However, the study showed that the profiles for the T- and C-levels could be predicted with an acceptable accuracy from AutoNRT. A model for calculating profiles from AutoNRT thresholds based on linear regression resulted in the lowest deviation from the subjective programming thresholds, with somewhat better results for C-levels than T-levels. Conclusion The results from this study showed that the predictability was reasonable when calculating the profiles for the T- and C-levels based on AutoNRT. And, further, that AutoNRT thresholds can be used when programming cochlear implants, to make global adjustments without predicting actual T- or C-levels.

A comic-based body image intervention for adolescents in semi-rural Indian schools: A randomised controlled trial.

Adolescents in India experience body dissatisfaction and its associated adverse impacts on physical and mental health and gender equality. However, evidence-based interventions are scarce. Mental health interventions worldwide have traditionally relied upon delivery by expert providers. However, this prevents scalability, particularly in rural settings, where resources are often lacking. Therefore, this study evaluated the efficacy of a low-resource teacher-delivered mixed-gender comic-based body image intervention among adolescents in semi-rural Indian schools. A randomised controlled trial was conducted among 2631 students (50 % girls; classes 6 to 8; Mage = 12.03 years, SD = 1.22) across 41 schools around the Jaipur district in Rajasthan. Each school was randomly allocated to receive six comic-based intervention sessions (n = 1347) or lessons-as-usual (n = 1284; control). The primary outcome of body esteem and related secondary and exploratory outcomes assessing mental health and gender stereotyping were assessed at baseline, 1 week-post-intervention, and 3-months follow-up (ClinicalTrials.gov, NCT04317755). Linear Mixed Model analyses revealed that compared to the control group, intervention students reported significantly higher body esteem and skin shade satisfaction, and significantly lower eating pathology, internalisation of appearance ideals, and gender stereotyping, with all effects maintained at follow-up. Compared to control group, boys in the intervention group also demonstrated significantly higher body image-related life engagement and body hair satisfaction at follow-up. Both students and teachers indicated high intervention acceptability via quantitative and qualitative findings. These findings present the first effective teacher-delivered school-based body image intervention in India, which can be implemented at scale using minimal resources, and thus indicates promise regarding broader dissemination across urban and rural settings.

Pregnant women’s lifestyles and exposure to endocrine-disrupting chemicals: a machine learning approach

Women have ubiquitous exposure to various endocrine disrupting chemicals (EDCs) present in personal care products, food packaging, and processing. Pregnancy is a phase of increased vulnerability to environmental stressors. Therefore, we aimed to identify questionnaire based variables of pregnant women's lifestyle factors affecting the prenatal concentrations of EDCs: bis-phenol A (BPA), triclosan (TCS), parabens, and phthalates. We also aimed to explore the association between these lifestyle factors and EDC exposure in pregnant women in South Korea. This study is a part of Korean CHildren's ENvironmental health Study (Ko-CHENS). The following lifestyle factors: usage of personal care products, eating habits, cooking practices, food storage practices, and chemical exposure were evaluated through questionnaire. We examined prenatal EDCs: phenols (BPA), TCS, parabens (MEP, ETP, and PRP), and phthalates (MEHHP, MEOHP, MECPP, MBZP, MCOP, MCPP, MCNP, and MNBP). The random forest and least absolute shrinkage and selection operator regression machine learning models were used to predict the important lifestyle factors affecting the prenatal EDC concentrations in pregnant women. Next, we calculated the lifestyle score and evaluated its association with prenatal EDCs, respectively. Our results show that pregnant women who used makeup [β: 1.01, 95% C.I.: 0.01,2.00] >6 times/week had a significant increase in early-pregnancy (EP) ΣParaben exposure. Using perfume up to 3 times/month was significantly associated with EP TCS exposure (β: 0.05, 95% C.I.: 0.01,0.23). While, using perfume >6 times/week was significantly associated to late-pregnancy (LP) ΣParaben exposure, and consuming cup noodles significantly increased LP ΣDEHP exposure. Linear model analysis showed that the lifestyle score significantly increased the EP (β: 0.24, 95% C.I.: 0.07,0.40) and LP (β:0.10, 95% C.I.: 0.01,0.20) ΣParaben exposure. Therefore, pregnant women's lifestyle factors, such as using makeup and perfume and eating habits (e.g., cup noodle consumption), were associated with prenatal EDC exposure.

Complete blood count and systemic inflammation indices in individuals with Alzheimer's disease: A case-control study.

Alzheimer's disease (AD) is the most common cause of dementia, characterized by progressive cognitive and functional decline and is associated with aging. Chronic inflammatory processes are also involved in its the etiology, as the consequence or cause of proteinopathy (amyloid and tau load in the brain). This study aimed to investigate the complete blood count and systemic inflammation indices in 61 individuals with AD, compared to 59 cognitively healthy individuals as controls. The diagnosis of AD dementia was based on the NIA-AA criteria and patients presented biomarkers in the cerebrospinal fluid compatible with the diagnosis of AD. The complete blood count (CBC) was conducted using an automated system. The neutrophil count (p=0.011), neutrophil-to-lymphocyte ratio (p=0.023), and Systemic Inflammation Response Index (SIRI) (p=0.044) were significantly higher, whereas the lymphocyte count (p=0.018) and platelet count (p=0.038) were significantly lower in the AD group compared to the control group. After a multivariategeneralized linear model analyses, neutrophils count and SIRI maintained significant difference between the groups, even after correcting for age, sex, body mass index and ApoE ε4 carrier status. The overall results suggest that AD is associated with a low-grade pro-inflammatory profile, characterized by alterations in blood inflammatory and immune cells, leading to a higher systemic inflammatory index. The CBC and its derived inflammatory indices, routinely obtained in clinical practice, have potential utility in the context of AD.

Tax knowledge and tax compliance of the small and medium enterprises in Vietnam

This research explored the motivations, behaviors, and consequences of tax non-compliance and aimed to provide empirical evidence to evaluate the impact of tax knowledge, perceived non-tax opportunity and felt tax loss on tax compliance in small and medium enterprises (SMEs). A quantitative approach on a panel of 326 SMEs through SEM linear structural model analysis using SmartPLS software. The hypotheses were tested in a parallel mediation model. The perceived non-tax opportunity and felt tax loss, in contrast to tax knowledge, negatively affect taxpayers’ behavior and tax-compliance level. The two mediators, i.e., perceived non-tax opportunity and felt tax loss, create an indirect relationship between tax knowledge and tax compliance. Without the two mediators, there is no relationship between tax knowledge and tax compliance. The study also added evidence in supporting the view that tax compliance behavior depends on both personal (economic) and social motivations. Furthermore, in the disadvantage case, prospect theory is more suitable to explain tax non-compliance behavior than deterrence theory and vice versa.

Quality of Life in Patients with Locally Advanced Pancreatic Cancer During Stereotactic Radiotherapy Combined with Heat-Killed Mycobacterium Obuense Vaccination.

Background: New treatment options for patients with locally advanced pancreatic cancer (LAPC) have proven to be safe but, in addition, may have an effect on the patient's quality of life. Objectives: To evaluate the effect of stereotactic body radiotherapy (SBRT) combined with intradermal heat-killed mycobacterium obuense (IMM-101) vaccination on health-related quality of life (HRQoL), pain, and sleep, in patients with LAPC. Design: Prospective cohort study. Setting/Participants: In total, 42 Dutch patients with LAPC were included after completion of at least four cycles of (m) leucovorin calcium (folinic acid), fluorouracil, irinotecan hydrochloride, and oxaliplatin (FOLFIRINOX). Measurements: Quality of life was assessed with the EORTC QLQ-C30. Patients completed the Richard Campbell Sleep Questionnaire (RCSQ) for five consecutive nights and wore simultaneously a GENEActiv tri-axial accelerometer, which registered sleep duration and sleep efficiency. The Numeric Rating Scale was used to assess pain intensity during treatment. Data were collected at the baseline visit [i.e., at inclusion in the study after (m)FOLFIRINOX treatment] and at week 8 (i.e., 6 weeks after start date of SBRT and after four IMM-101 vaccinations). Results: Univariable linear mixed model analysis revealed significant improvement for EORTC QLQ-C30 items "cognitive functioning" and "emotional functioning." Outcomes on RCSQ subscales and "RCSQ total score" did not significantly change. In the multivariable model, with "Global HRQoL scale" and "RCSQ total score" as outcomes, we did not find a significant change during treatment. Conclusion: In this prospective cohort study, we found that SBRT combined with IMM-101, in patients with LAPC, is well tolerated and does not negatively affect HRQoL, sleep quality, and pain.

P-1337. Analyzing SARS-CoV-2 Case Numbers and Clustering to Predict a Nursing Home Outbreak

Abstract Background Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), can spread rapidly in nursing homes (NH). Intervening to reduce spread should follow a signal predicting an imminent "outbreak". Various thresholds for declaring a COVID-19 outbreak have considered local factors, viral variants, case identification timelines and vaccination rates. We evaluated the number and interval between initial SARS-CoV-2 infections (cases) most predictive of future cases using VA Community Living Centers (CLCs) as NH analogues. Methods We captured SARS-CoV-2 PCR test results from individual NH neighborhoods (specialized wards). After an initial index case, we evaluated for additional cases over the next 28 days by R² analysis and 14 days by Classification and Regression Trees (CART) analysis. We evaluated the R2 goodness-of-fit measure from separate linear models by neighborhood to measure the predictive power of various outbreak definitions, adjusted for the number of residents in the neighborhood. Also, we used CART creating a tree-like structure to predict continuous target variables to see the effect of census and time at only 14 days. Results We included 136 CLCs housing 16,339 Veterans, mean age of 74, mostly male (96%) and white (68%), in 490 neighborhoods, representing 1,252,037 Veteran exposure days from 12/18/2021 to 06/18/2022, and 1,765 SARS-CoV-2 infections. We divided neighborhoods by small [&amp;lt; 10 Veterans (n=30,390)], medium [10-15 veterans (n=25,349)], and large [ &amp;gt;15 veterans (n=31,899)]. The most predictive outbreak definition for future COVID-19 cases over the next 14 days for our linear model analysis was: 2 cases across all neighborhoods, 4 cases for large, 2 for medium and 1 for small size neighborhoods. Our preliminary CART analysis suggested the first case was predictive of another case in 5 days, but if ≥4 occurred in 5 consecutive days, it predicted a large-scale outbreak with 10 or more cases over the next 14 days if the neighborhood is large enough to have that many cases. Conclusion Our analysis suggests when 4 SARS-CoV-2 cases cluster in five days in a large neighborhood, a large outbreak is imminent, potentially warranting aggressive control measures. However further refinement of our methods is needed to confirm this conclusion. Disclosures Yasin Abul, MD, Moderna: Grant/Research Support|Moderna, Abt, CDC: Grant/Research Support Kevin McConeghy, Pharm.D., Genentech: Grant/Research Support|GlaxoSmithKline: Grant/Research Support|Moderna: Grant/Research Support|Sanofi-Pasteur: Grant/Research Support|Seqirus: Grant/Research Support Stefan Gravenstein, MD, MPH, CDC: Advisor/Consultant|CDC: Grant/Research Support|Genentech: Advisor/Consultant|Genentech: Grant/Research Support|Genentech: Honoraria|GlaxoSmithKline: Advisor/Consultant|GlaxoSmithKline: Grant/Research Support|GlaxoSmithKline: Honoraria|Janssen: Advisor/Consultant|Janssen: Grant/Research Support|Janssen: Honoraria|Moderna: Advisor/Consultant|Moderna: Grant/Research Support|Moderna: Honoraria|NIH: Grant/Research Support|Pfizer: Advisor/Consultant|Pfizer: Grant/Research Support|Pfizer: Honoraria|Sanofi: Advisor/Consultant|Sanofi: Grant/Research Support|Sanofi: Honoraria|Seqirus: Advisor/Consultant

Performance of spondyloarthritis-specific health utilities based on ASAS Health Index: an ancillary analysis from ASAS-HI validation study.

To compare the utility values of Spondyloarthritis (SpA)-specific ASAS Health Index (U-ASAS-HI) to generic utilities and to understand the contribution of health outcomes, personal- and country-level factors to the U-ASAS-HI. Ancillary analysis of the ASAS-HI international validation study. SpA patients who completed the ASAS-HI, 5-level EuroQol-5D (EQ-5D-5L) and Short Form-36 (SF-36) questionnaires were selected, and utilities calculated. Correlations between U-ASAS-HI and generic utility values were tested. Potential explanatory variables were evaluated in a linear multivariable mixed-effects model analysis with multilevel modeling fitted by country. 1425 patients were included, with a mean age of 42 (Standard Deviation, SD : 13.5) and 65% male. The mean utility scores were EQ-5D-5L 0.75 (SD : 0.11), SF-6D 0.72 (SD : 0.24), and U-ASAS-HI 0.42 (SD : 0.29). Correlation between U-ASAS-HI and EQ-5D-5L and SF-6D was strong (r = 0.75 and r = 0.72; p< 0.001, respectively). The linear mixed-effects model showed that worse disease activity (ASDAS) and lower physical function (BASFI) were associated with lower U-ASAS-HI. Additionally, younger age, female gender, higher comorbidity score, and symptoms of depression were associated with lower U-ASAS-HI. SpA subtype had no influence on health utility. The random effects model indicated an intercept SD : 0.045 with a 5.5% variance ratio between countries and the total U-ASAS-HI variation. The U-ASAS-HI captures the physical and mental impact of SpA, as well as personal contextual factors such as age, gender, and comorbidities. The influence of the country of residence seems negligible. The U-ASAS-HI algorithm has sufficient support to be used in health economic evaluations for SpA patients across different countries.