Combining Early Ischemic Change and Collateral Extent for Functional Outcomes After Endovascular Therapy: An Analysis From AcT Trial.

BACKGROUND: Early ischemic change and collateral extent are colinear with ischemic core volume (ICV). We investigated the relationship between a combined score using the Alberta Stroke Program Early Computed Tomography Score and multiphase computed tomography angiography (mCTA) collateral extent, named mCTA-ACE score, on functional outcomes in endovascular therapy-treated patients. METHODS: We performed a post hoc analysis of a subset of endovascular therapy-treated patients from the Alteplase Compared to Tenecteplase trial which was conducted between December 2019 and January 2022 at 22 centers across Canada. Ten-point mCTA collateral corresponding to M2 to M6 regions of the Alberta Stroke Program Early Computed Tomography Score grid was evaluated as 0 (poor), 1 (moderate), or 2 (normal) and additively combined with the 10-point Alberta Stroke Program Early Computed Tomography Score to produce a 20-point mCTA-ACE score. We investigated the association of mCTA-ACE score with modified Rankin Scale score ≤2 and return to prestroke level of function at 90 to 120 days using mixed-effects logistic regression. In the subset of patients who underwent baseline computed tomography perfusion imaging, we compared the mCTA-ACE score and ICV for outcome prediction. RESULTS: Among 1577 intention-to-treat population in the trial, 368 (23%; 179 men; median age, 73 years) were included, with Alberta Stroke Program Early Computed Tomography Score, mCTA collateral, and combination of both (mCTA-ACE score: median [interquartile range], 8 [7-10], 9 [8-10], and 17 [16-19], respectively). The probability of modified Rankin Scale score ≤2 and return to prestroke level of function increased for each 1-point increase in mCTA-ACE score (odds ratio, 1.16 [95% CI, 1.06-1.28] and 1.22 [95% CI, 1.06-1.40], respectively). Among 173 patients in whom computed tomography perfusion data was assessable, the mCTA-ACE score was inversely correlated with ICV (ρ=-0.46; P<0.01). The mCTA-ACE score was comparable to ICV to predict a modified Rankin Scale score ≤2 and return to prestroke level of function (C statistics 0.71 versus 0.69 and 0.68 versus 0.64, respectively). CONCLUSIONS: The mCTA-ACE score had a significant positive association with functional outcomes after endovascular therapy and had a similar predictive performance as ICV.

Sex-Based Analysis of Workflow and Outcomes in Acute Ischemic Stroke Patients Treated With Alteplase Versus Tenecteplase.

BACKGROUND: Understanding sex differences in stroke care is important in reducing potential disparities. Our objective was to explore sex differences in workflow efficiency, treatment efficacy, and safety in the AcT trial (Alteplase Compared to Tenecteplase). METHODS: AcT was a multicenter, registry-linked randomized noninferiority trial comparing tenecteplase (0.25 mg/kg) with alteplase (0.9 mg/kg) in acute ischemic stroke within 4.5 hours of onset. In this post hoc analysis, baseline characteristics, workflow times, successful reperfusion (extended Thrombolysis in Cerebral Infarction score ≥2b), symptomatic intracerebral hemorrhage, 90-day functional independence (modified Rankin Scale score, 0-1), and 90-day mortality were compared by sex. Mixed-effects regression analysis was used adjusting for age, stroke severity, and occlusion site for outcomes. RESULTS: Of 1577 patients treated with intravenous thrombolysis (2019-2022), 755 (47.9%) were women. Women were older (median, 77 [68-86] years in women versus 70 [59-79] years in men) and had a higher proportion of severe strokes (National Institutes of Health Stroke Scale score >15; 32.4% versus 24.9%) and large vessel occlusions (28.7% versus 21.5%) compared with men. All workflow times were comparable between sexes. Women were less likely to achieve functional independence (31.7% versus 39.8%; unadjusted relative risk, 0.80 [95% CI, 0.70-0.91]) and had higher mortality (17.7% versus 13.3%; unadjusted relative risk, 1.33 [95% CI, 1.06-1.69]). Adjusted analysis showed no difference in outcomes between sexes. CONCLUSIONS: Differences in prognostic factors of age, stroke severity, and occlusion site largely accounted for higher functional dependence and mortality in women. No sex disparities were apparent in workflow quality indicators. Given the integration of the AcT trial into clinical practice, these results provide reassurance that no major sex biases are apparent in acute stroke management throughout participating Canadian centers. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03889249.

Quality of Life After Intravenous Thrombolysis for Acute Ischemic Stroke: Results From the AcT Randomized Controlled Trial.

BACKGROUND: Recent evidence from thrombolysis trials indicates the noninferiority of intravenous tenecteplase to intravenous alteplase with respect to good functional outcomes in patients with acute stroke. We examined whether the health-related quality of life (HRQOL) of patients with acute stroke differs by the type of thrombolysis treatment received. In addition, we examined the association between the modified Rankin Scale score 0 to 1 and HRQOL and patient-reported return to prebaseline stroke functioning at 90 days. METHODS: Data were from all patients included in the AcT trial (Alteplase Compared to Tenecteplase), a pragmatic, registry-linked randomized trial comparing tenecteplase with alteplase. HRQOL at 90-day post-randomization was assessed using the 5-item EuroQOL questionnaire (EQ5D), which consists of 5 items and a visual analog scale (VAS). EQ5D index values were estimated from the EQ5D items using the time tradeoff approach based on Canadian norms. Tobit regression and quantile regression models were used to evaluate the adjusted effect of tenecteplase versus alteplase treatment on the EQ5D index values and VAS score, respectively. The association between return to prebaseline stroke functioning and the modified Rankin Scale score 0 to 1 and HRQOL was quantified using correlation coefficient (r) with 95% CI. RESULTS: Of 1577 included in the intention-to-treat analysis patients, 1503 (95.3%) had complete data on the EQ5D. Of this, 769 (51.2%) were administered tenecteplase and 717 (47.7%) were female. The mean EQ5D VAS score and EQ5D index values were not significantly higher for those who received intravenous tenecteplase compared with those who received intravenous alteplase (P=0.10). Older age (P<0.01), more severe stroke assessed using the National Institutes of Health Stroke Scale (P<0.01), and longer stroke onset-to-needle time (P=0.004) were associated with lower EQ5D index and VAS scores. There was a strong association (r, 0.85 [95% CI, 0.81-0.89]) between patient-reported return to prebaseline functioning and modified Rankin Scale score 0 to 1 Similarly, there was a moderate association between return to prebaseline functioning and EQ5D index (r, 0.45 [95% CI, 0.40-0.49]) and EQ5D VAS scores (r, 0.42 [95% CI, 0.37-0.46]). CONCLUSIONS: Although there is no differential effect of thrombolysis type on patient-reported global HRQOL and EQ 5D-5L index values in patients with acute stroke, sex- and age-related differences in HRQOL were noted in this study. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03889249.

Response shift results of quantitative research using patient-reported outcome measures: a descriptive systematic review.

PURPOSE: The objective of this systematic review was to describe the prevalence and magnitude of response shift effects, for different response shift methods, populations, study designs, and patient-reported outcome measures (PROM)s. METHODS: A literature search was performed in MEDLINE, PSYCINFO, CINAHL, EMBASE, Social Science Citation Index, and Dissertations & Theses Global to identify longitudinal quantitative studies that examined response shift using PROMs, published before 2021. The magnitude of each response shift effect (effect sizes, R-squared or percentage of respondents with response shift) was ascertained based on reported statistical information or as stated in the manuscript. Prevalence and magnitudes of response shift effects were summarized at two levels of analysis (study and effect levels), for recalibration and reprioritization/reconceptualization separately, and for different response shift methods, and population, study design, and PROM characteristics. Analyses were conducted twice: (a) including all studies and samples, and (b) including only unrelated studies and independent samples. RESULTS: Of the 150 included studies, 130 (86.7%) detected response shift effects. Of the 4868 effects investigated, 793 (16.3%) revealed response shift. Effect sizes could be determined for 105 (70.0%) of the studies for a total of 1130 effects, of which 537 (47.5%) resulted in detection of response shift. Whereas effect sizes varied widely, most median recalibration effect sizes (Cohen's d) were between 0.20 and 0.30 and median reprioritization/reconceptualization effect sizes rarely exceeded 0.15, across the characteristics. Similar results were obtained from unrelated studies. CONCLUSION: The results draw attention to the need to focus on understanding variability in response shift results: Who experience response shifts, to what extent, and under which circumstances?

Unsupervised item response theory models for assessing sample heterogeneity in patient-reported outcomes measures.

PURPOSE: Unsupervised item-response theory (IRT) models such as polytomous IRT based on recursive partitioning (IRTrees) and mixture IRT (MixIRT) models can be used to assess differential item functioning (DIF) in patient-reported outcome measures (PROMs) when the covariates associated with DIF are unknown a priori. This study examines the consistency of results for IRTrees and MixIRT models. METHODS: Data were from 4478 individuals in the Alberta Provincial Project on Outcome Assessment in Coronary Heart Disease registry who received cardiac angiography in Alberta, Canada, and completed the Hospital Anxiety and Depression Scale (HADS) depression subscale items. The partial credit model (PCM) based on recursive partitioning (PCTree) and mixture PCM (MixPCM) were used to identify covariates associated with differential response patterns to HADS depression subscale items. Model covariates included demographic and clinical characteristics. RESULTS: The median (interquartile range) age was 64.5(15.7) years, and 3522(78.5%) patients were male. The PCTree identified 4 terminal nodes (subgroups) defined by smoking status, age, and body mass index. A 3-class PCM fits the data well. The MixPCM latent classes were defined by age, disease indication, smoking status, comorbid diabetes, congestive heart failure, and chronic obstructive pulmonary disease. CONCLUSION: PCTree and MixPCM were not consistent in detecting covariates associated with differential interpretations of PROM items. Future research will use computer simulations to assess these models' Type I error and statistical power for identifying covariates associated with DIF.

Response shift in coronary artery disease.

PURPOSE: Patients with coronary artery disease (CAD) experience significant angina symptoms and lifestyle changes. Revascularization procedures can result in better patient-reported outcomes (PROs) than optimal medical therapy (OMT) alone. This study evaluates the impact of response shift (RS) on changes in PROs of patients with CAD across treatment strategies. METHODS: Data were from patients with CAD in the Alberta Provincial Project on Outcome Assessment in Coronary Heart Disease (APPROACH) registry who completed the 16-item Canadian version of the Seattle Angina Questionnaire at 2 weeks and 1 year following a coronary angiogram. Multi-group confirmatory factor analysis (MG-CFA) was used to assess measurement invariance across treatment groups at week 2. Longitudinal MG-CFA was used to test for RS according to receipt of coronary artery bypass grafting (CABG), percutaneous coronary intervention (PCI), or optimal medical therapy (OMT) alone. RESULTS: Of the 3116 patients included in the analysis, 443 (14.2%) received CABG, 2049(65.8%) PCI, and the remainder OMT alone. The MG-CFA revealed a partial-strong invariance across the treatment groups at 2 weeks (CFI = 0.98, RMSEA [90% CI] = 0.05 [0.03, 0.06]). Recalibration RS was detected on the Angina Symptoms and Burden subscale and its magnitude in the OMT, PCI, and CABG groups were 0.32, 0.28, and 0.53, respectively. After adjusting for RS effects, the estimated target changes were largest in the CABG group and negligible in the OMT group. CONCLUSION: Adjusting for RS is recommended in studies that use SAQ-CAN to assess changes in patients with CAD who have received revascularization versus OMT alone.

Workflow and Outcome of Thrombectomy in Late Time Window: A Pooled Multicenter Analysis.

BACKGROUND: We investigated the impact of workflow times on the outcomes of patients treated with endovascular thrombectomy (EVT) in the late time window. METHODS: Individual patients' data who underwent EVT in the late time window (onset to imaging >6 hours) were pooled from seven registries and randomized clinical trials. Multiple time intervals were analyzed. Mixed-effects logistic regression was used to estimate the likelihood of functional independence at 90 days (modified Rankin Scale 0-2). Mixed-effects negative binomial regression was used to evaluate the relationship between patient characteristics and workflow time intervals. RESULTS: 608 patients were included. The median age was 70 years (IQR: 58-71), 307 (50.5%) were female, and 310 (53.2%) had wake-up strokes. Successful reperfusion was achieved in 493 (81.2%) patients, and 262 (44.9%) achieved 90-day mRS 0-2. The estimated odds of functional independence decreased by 13% for every 30 minute delay from emergency department (ED) arrival to imaging time and by 7% from ED arrival to the end of EVT in the entire cohort. Also, the estimated odds of functional independence decreased by 33% for every 30 minute delay in the interval from arterial puncture to end of EVT, 16% in the interval from arrival in ED to end of EVT and 6% in the interval from stroke onset to end of EVT among patients who had a wake-up stroke. CONCLUSION: Faster workflow from ED arrival to end of EVT is associated with improved functional independence among stroke patients treated in the late window.

Validating the Ontario Child Health Study Emotional Behavioural Scales-Brief Version (OCHS-EBS-B) in children with chronic physical illness.

BACKGROUND: A substantial proportion of children have a physical illness; these children commonly experience physical-mental comorbidity. To assess child mental health, brief scales that can be used in clinical and research settings are needed. This study assessed the validity and reliability of parent-reported Ontario Child Health Study Emotional Behavioural Scale-Brief Version (OCHS-EBS-B) scores. METHODS: Data come from a longitudinal study of children aged 2-16 years with a physical illness recruited from outpatient clinics at a pediatric hospital. Confirmatory factor analysis and McDonald's coefficient assessed the factor structure and internal consistency reliability of the OCHS-EBS-B, respectively. Point biserial correlations assessed agreement between the OCHS-EBS-B and Mini International Neuropsychiatric Interview for Children and Adolescents (MINI-KID), a structured diagnostic interview. The Wilcoxon rank sum test compared OCHS-EBS-B scores between children with versus without physical-mental comorbidity (known-group validity). RESULTS: The three-factor structure of the OCHS-EBS-B was replicated in this sample of children with physical illness (χ2 = 196.23(272), p < 0.001; CFI = 0.98; TLI = 0.98; SRMR = 0.06; RMSEA [90% CI] = 0.034 [0.027, 0.044]). It had excellent internal consistency reliability (ω = 0.86-0.92) and was moderately correlated with the MINI-KID (baseline: rpb = 0.43-0.51; 6 months: rpb = 0.55-0.65). OCHS-EBS-B scores were significantly higher among children with versus without physical-mental comorbidity. CONCLUSIONS: Findings confirm psychometric evidence that the OCHS-EBS-B is a valid and reliable measure of mental health in children with chronic physical illness. Its brevity and robust psychometric properties make the OCHS-EBS-B a strong candidate for routine use in integrated pediatric physical and mental health services.

Effect of Time to Thrombolysis on Clinical Outcomes in Patients With Acute Ischemic Stroke Treated With Tenecteplase Compared to Alteplase: Analysis From the AcT Randomized Controlled Trial.

BACKGROUND: The AcT (Alteplase Compared to Tenecteplase) randomized controlled trial showed that tenecteplase is noninferior to alteplase in treating patients with acute ischemic stroke within 4.5 hours of symptom onset. The effect of time to treatment on clinical outcomes with alteplase is well known; however, the nature of this relationship is yet to be described with tenecteplase. We assessed whether the association of time to thrombolysis treatment with clinical outcomes in patients with acute ischemic stroke differs by whether they receive intravenous tenecteplase versus alteplase. METHODS: Patients included were from AcT, a pragmatic, registry-linked, phase 3 randomized controlled trial comparing intravenous tenecteplase to alteplase in patients with acute ischemic stroke. Eligible patients were >18 years old, with disabling neurological deficits, presenting within 4.5 hours of symptom onset, and eligible for thrombolysis. Primary outcome was modified Rankin Scale score 0 to 1 at 90 days. Safety outcomes included 24-hour symptomatic intracerebral hemorrhage and 90-day mortality rates. Mixed-effects logistic regression was used to assess the following: (a) the association of stroke symptom onset to needle time; (b) door (hospital arrival) to needle time with outcomes; and (c) if these associations were modified by type of thrombolytic administered (tenecteplase versus alteplase), after adjusting for age, sex, baseline stroke severity, and site of intracranial occlusion. RESULTS: Of the 1538 patients included in this analysis, 1146 (74.5%; 591 tenecteplase and 555 alteplase) presented within 3 hours versus 392 (25.5%; 196: TNK and 196 alteplase) who presented within 3 to 4.5 hours of symptom onset. Baseline patient characteristics in the 0 to 3 hours versus 3- to 4.5-hour time window were similar, except patients in the 3- to 4.5-hour window had lower median baseline National Institutes of Health Stroke Severity Scale (10 versus 7, respectively) and lower proportion of patients with large vessel occlusion on baseline CT angiography (26.9% versus 18.7%, respectively). Type of thrombolytic agent (tenecteplase versus alteplase) did not modify the association between continuous onset to needle time (Pinteraction=0.161) or door-to-needle time (Pinteraction=0.972) and primary clinical outcome. Irrespective of the thrombolytic agent used, each 30-minute reduction in onset to needle time was associated with a 1.8% increase while every 10 minutes reduction in door-to-needle time was associated with a 0.2% increase in the probability of achieving 90-day modified Rankin Scale score 0 to 1, respectively. CONCLUSIONS: The effect of time to tenecteplase administration on clinical outcomes is like that of alteplase, with faster administration resulting in better clinical outcomes. REGISTRATION: URL: https://classic. CLINICALTRIALS: gov; Unique identifier: NCT03889249.

Machine learning using multimodal clinical, electroencephalographic, and magnetic resonance imaging data can predict incident depression in adults with epilepsy: A pilot study.

OBJECTIVE: This study was undertaken to develop a multimodal machine learning (ML) approach for predicting incident depression in adults with epilepsy. METHODS: We randomly selected 200 patients from the Calgary Comprehensive Epilepsy Program registry and linked their registry-based clinical data to their first-available clinical electroencephalogram (EEG) and magnetic resonance imaging (MRI) study. We excluded patients with a clinical or Neurological Disorders Depression Inventory for Epilepsy (NDDI-E)-based diagnosis of major depression at baseline. The NDDI-E was used to detect incident depression over a median of 2.4 years of follow-up (interquartile range [IQR] = 1.5-3.3 years). A ReliefF algorithm was applied to clinical as well as quantitative EEG and MRI parameters for feature selection. Six ML algorithms were trained and tested using stratified threefold cross-validation. Multiple metrics were used to assess model performances. RESULTS: Of 200 patients, 150 had EEG and MRI data of sufficient quality for ML, of whom 59 were excluded due to prevalent depression. Therefore, 91 patients (41 women) were included, with a median age of 29 (IQR = 22-44) years. A total of 42 features were selected by ReliefF, none of which was a quantitative MRI or EEG variable. All models had a sensitivity > 80%, and five of six had an F1 score ≥ .72. A multilayer perceptron model had the highest F1 score (median = .74, IQR = .71-.78) and sensitivity (84.3%). Median area under the receiver operating characteristic curve and normalized Matthews correlation coefficient were .70 (IQR = .64-.78) and .57 (IQR = .50-.65), respectively. SIGNIFICANCE: Multimodal ML using baseline features can predict incident depression in this population. Our pilot models demonstrated high accuracy for depression prediction. However, overall performance and calibration can be improved. This model has promise for identifying those at risk for incident depression during follow-up, although efforts to refine it in larger populations along with external validation are required.

The contribution of modifiable risk factors to socioeconomic inequities in cardiovascular disease morbidity and mortality: A nationally representative population-based cohort study.

This study examined the individual and joint effects of modifiable risk factors mediating the associations between socioeconomic position (SEP) and morbidity and mortality from cardiovascular diseases (CVD) in a nationally representative sample of adults in Canada. Participants in the Canadian Community Health Survey (n = 289,800) were followed longitudinally for CVD morbidity and mortality using administrative health and mortality data. SEP was measured as a latent variable consisting of household income and individual educational attainment. Mediators included smoking, physical inactivity, obesity, diabetes and hypertension. The primary outcome was CVD morbidity and mortality, defined as the first fatal/nonfatal CVD event during follow-up (median 6.2 years). Generalized structural equation modeling tested the mediating effects of modifiable risk factors in associations between SEP and CVD in the total population and stratified by sex. Lower SEP was associated with 2.5 times increased odds of CVD morbidity and mortality (OR: 2.52, 95% CI: 2.28, 2.76). Modifiable risk factors mediated 74% of associations between SEP and CVD morbidity and mortality in the total population and were more important mediators of associations in females (83%) than males (62%). Smoking mediated these associations independently and jointly with other mediators. The mediating effects of physical inactivity were through joint mediating effects with obesity, diabetes or hypertension. There were additional joint mediating effects of obesity through diabetes or hypertension in females. Findings point to modifiable risk factors as important targets for interventions along with interventions that target structural determinants of health to reduce socioeconomic inequities in CVD.

Response shift in parent-reported psychopathology in children with chronic physical illness.

PURPOSE: Because physical-mental comorbidity in children is relatively common, this study tested for response shift (RS) in children with chronic physical illness using a parent-reported measure of child psychopathology. METHODS: Data come from Multimorbidity in Children and Youth across Life-course (MY LIFE), a prospective study of n = 263 children aged 2-16 years with physical illness in Canada. Parents provided information on child psychopathology using the Ontario Child Health Study Emotional Behavioral Scales (OCHS-EBS) at baseline and 24 months. Oort's structural equation modeling was used to test for different forms of RS in parent-reported assessments between baseline and 24 months. Model fit was evaluated using root mean square error of approximation (RMSEA), comparative fit index (CFI), and standardized root mean residual (SRMR). RESULTS: There were n = 215 (81.7%) children with complete data and were included in this analysis. Of these, n = 105 (48.8%) were female and the mean (SD) age was 9.4 (4.2) years. A two-factor measurement model provided good fit to the data [RMSEA (90% CI) = 0.05 (0.01, 0.10); CFI = 0.99; SRMR = 0.03]. Non-uniform recalibration RS was detected on the conduct disorder subscale of the OCHS-EBS. This RS effect had negligible impact on the longitudinal change in externalizing and internalizing disorders construct over time. CONCLUSIONS: Response shift detected on the conduct disorder subscale of the OCHS-EBS, indicated that parents of children with physical illness may recalibrate their responses on child psychopathology over 24 months. Researchers and health professionals should be aware of RS when using the OCHS-EBS to assess child psychopathology over time.

Implications of the syntheses on definition, theory, and methods conducted by the Response Shift - in Sync Working Group.

PURPOSE: Our aim is to advance response shift research by explicating the implications of published syntheses by the Response Shift - in Sync Working Group in an integrative way and suggesting ways for improving the quality of future response shift studies. METHODS: Members of the Working Group further discussed the syntheses of the literature on definitions, theoretical underpinnings, operationalizations, and response shift methods. They outlined areas in need of further explication and refinement, and delineated additional implications for future research. RESULTS: First, the proposed response shift definition was further specified and its implications for the interpretation of results explicated in relation to former, published definitions. Second, the proposed theoretical model was further explained in relation to previous theoretical models and its implications for formulating research objectives highlighted. Third, ways to explore alternative explanations per response shift method and their implications for response shift detection and explanation were delineated. The implications of the diversity of the response shift methods for response shift research were presented. Fourth, the implications of the need to enhance the quality and reporting of the response shift studies for future research were sketched. CONCLUSION: With our work, we intend to contribute to a common language regarding response shift definitions, theory, and methods. By elucidating some of the major implications of earlier work, we hope to advance response shift research.

Unplanned Extubations Requiring Reintubation in Pediatric Critical Care: An Epidemiological Study.

OBJECTIVES: Unplanned extubations are an infrequent but life-threatening adverse event in pediatric critical care. Due to the rarity of these events, previous studies have been small, limiting the generalizability of findings and the ability to detect associations. Our objectives were to describe unplanned extubations and explore predictors of unplanned extubation requiring reintubation in PICUs. DESIGN: Retrospective observational study and multilevel regression model. SETTING: PICUs participating in Virtual Pediatric Systems (LLC). PATIENTS: Patients (≤ 18 yr) who had an unplanned extubation in PICU (2012-2020). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We developed and trained a multilevel least absolute shrinkage and selection operator (LASSO) logistic regression model in the 2012-2016 sample that accounted for between-PICU variations as a random effect to predict reintubation after unplanned extubation. The remaining sample (2017-2020) was used to externally validate the model. Predictors included age, weight, sex, primary diagnosis, admission type, and readmission status. Model calibration and discriminatory performance were evaluated using Hosmer-Lemeshow goodness-of-fit (HL-GOF) and area under the receiver operating characteristic curve (AUROC), respectively. Of the 5,703 patients included, 1,661 (29.1%) required reintubation. Variables associated with increased risk of reintubation were age (< 2 yr; odds ratio [OR], 1.5; 95% CI, 1.1-1.9) and diagnosis (respiratory; OR, 1.3; 95% CI, 1.1-1.6). Scheduled admission was associated with decreased risk of reintubation (OR, 0.7; 95% CI, 0.6-0.9). With LASSO (lambda = 0.011), remaining variables were age, weight, diagnosis, and scheduled admission. The predictors resulted in AUROC of 0.59 (95% CI, 0.57-0.61); HL-GOF showed the model was well calibrated (p = 0.88). The model performed similarly in external validation (AUROC, 0.58; 95% CI, 0.56-0.61). CONCLUSIONS: Predictors associated with increased risk of reintubation included age and respiratory primary diagnosis. Including clinical factors (e.g., oxygen and ventilatory requirements at the time of unplanned extubation) in the model may increase predictive ability.

Expert elicitation of risk factors for progression to dementia in individuals with mild cognitive impairment.

INTRODUCTION: This study assesses experts' beliefs about important predictors of developing dementia in persons with mild cognitive impairment (MCI). METHODS: Structured expert elicitation, a methodology to quantify expert knowledge, was used to elicit the most important risk factors for developing dementia. We recruited 11 experts (6 neurologists, 3 geriatricians, and 2 psychiatrists). Ten experts fully participated in introductory meetings, two rounds of surveys, and discussion meetings. The data from these ten experts were utilized for this study. RESULTS: The expert elicitation identified age, CSF analysis, fluorodeoxyglucose-positron emission tomography (FDG-PET) findings, hippocampal atrophy, MoCA (or MMSE) score, parkinsonism, apathy, psychosis, informant report of cognitive symptoms, and global atrophy as the ten most important predictors of progressing to dementia in persons with MCI. DISCUSSION: Several dementia predictors are not routinely collected in existing registries, observational studies, or usual care. This might partially explain the low uptake of existing published dementia risk scores in clinical practice.

Ethical Justification for Deferral of Consent in the AcT Trial for Acute Ischemic Stroke.

The AcT trial (Alteplase Compared to Tenecteplase) compares alteplase or tenecteplase for patients with acute ischemic stroke. All eligible patients are enrolled by deferral of consent. Although the use of deferral of consent in the AcT trial meets the requirements of Canadian policy, we sought to provide a more explicit and rigorous approach to the justification of deferral of consent organized around 3 questions. Ultimately, the approach we outline here could become the foundation for a general justification for deferral of consent.

Association between antiseizure medications and quality of life in epilepsy: A mediation analysis.

OBJECTIVE: The relationship between antiseizure medications (ASMs), which improve health outcomes by controlling seizures, and health-related quality of life (HRQOL) is poorly understood and may involve intermediate variables. We evaluated the potential mediators of the association between ASMs and HRQOL. METHODS: Data are from an outpatient registry of adult patients with epilepsy seen at the Foothills Medical Center, Calgary, Alberta, Canada. Quality of life was measured using the 10-item Quality of Life in Epilepsy, and depression was measured using the Neurological Disorders Depression Inventory for Epilepsy. Propensity score matching was used to adjust for covariate imbalance between patients who received a single ASM (monotherapy) and those who received two or more ASMs (polytherapy) due to confounding. Mediation analysis was used to estimate the mediating effects of depression and ASM side effects on the association between patients' ASM polytherapy and HRQOL. RESULTS: Of 778 patients included in this analysis, 274 (35.2%) were on two or more ASMs. Patient-reported depression and ASM side effects jointly mediated the association between ASMs and HRQOL; these mediators accounted for 42% of the total average effect of ASM polytherapy ( ß  = -13.6, 95% confidence interval = -18.2 to -8.6) on HRQOL. SIGNIFICANCE: These findings highlight the importance of managing depression and ASM side effects for improving health outcomes of patients requiring treatment with ASMs. Intervention programs aimed at improving HRQOL of patients with epilepsy need to target these potential mediators.

Validity and reliability of global ratings of satisfaction with epilepsy surgery.

OBJECTIVE: We aimed to assess the reliability and validity of single-item global ratings (GR) of satisfaction with epilepsy surgery. METHODS: We recruited 240 patients from four centers in Canada and Sweden who underwent epilepsy surgery ≥1 year earlier. Participants completed a validated questionnaire on satisfaction with epilepsy surgery (the ESSQ-19), plus a single-item GR of satisfaction with epilepsy surgery twice, 4-6 weeks apart. They also completed validated questionnaires on quality of life, depression, health state utilities, epilepsy severity and disability, medical treatment satisfaction and social desirability. Test-retest reliability of the GR was assessed with the intra-class correlation coefficient (ICC). Construct and criterion validity were examined with polyserial correlations between the GR measure of satisfaction and validated questionnaires and with the ESSQ-19 summary score. Non-parametric rank tests evaluated levels of satisfaction, and ROC analysis assessed the ability of GRs to distinguish among clinically different patient groups. RESULTS: Median age and time since surgery were 42 years (IQR 32-54) and 5 years (IQR 2-8), respectively. The GR demonstrated good to excellent test-retest reliability (ICC = 0.76; 95% CI 0.67-0.84) and criterion validity (0.85; 95% CI 0.81-0.89), and moderate correlations in the expected direction with instruments assessing quality of life (0.59; 95% CI 0.51-0.63), health utilities (0.55; 95% CI 0.45-0.65), disability (-0.51; 95% CI -0.41, -0.61), depression (-0.48; 95% CI -0.38, -0.58), and epilepsy severity (-0.48; 95% CI -0.38, -0.58). As expected, correlations were lower for social desirability (0.40; 95% CI 0.28-0.52) and medical treatment satisfaction (0.33; 95% CI 0.21-0.45). The GR distinguished participants who were seizure-free (AUC 0.75; 95% CI 0.67-0.82), depressed (AUC 0.75; 95% CI 0.67-0.83), and self-rated as having more severe epilepsy (AUC 0.78; 95% CI 0.71-0.85) and being more disabled (AUC 0.82; 95% CI 0.74-0.90). SIGNIFICANCE: The GR of epilepsy surgery satisfaction showed good measurement properties, distinguished among clinically different patient groups, and appears well-suited for use in clinical practice and research.

Dementia risk prediction in individuals with mild cognitive impairment: a comparison of Cox regression and machine learning models.

BACKGROUND: Cox proportional hazards regression models and machine learning models are widely used for predicting the risk of dementia. Existing comparisons of these models have mostly been based on empirical datasets and have yielded mixed results. This study examines the accuracy of various machine learning and of the Cox regression models for predicting time-to-event outcomes using Monte Carlo simulation in people with mild cognitive impairment (MCI). METHODS: The predictive accuracy of nine time-to-event regression and machine learning models were investigated. These models include Cox regression, penalized Cox regression (with Ridge, LASSO, and elastic net penalties), survival trees, random survival forests, survival support vector machines, artificial neural networks, and extreme gradient boosting. Simulation data were generated using study design and data characteristics of a clinical registry and a large community-based registry of patients with MCI. The predictive performance of these models was evaluated based on three-fold cross-validation via Harrell's concordance index (c-index), integrated calibration index (ICI), and integrated brier score (IBS). RESULTS: Cox regression and machine learning model had comparable predictive accuracy across three different performance metrics and data-analytic conditions. The estimated c-index values for Cox regression, random survival forests, and extreme gradient boosting were 0.70, 0.69 and 0.70, respectively, when the data were generated from a Cox regression model in a large sample-size conditions. In contrast, the estimated c-index values for these models were 0.64, 0.64, and 0.65 when the data were generated from a random survival forest in a large sample size conditions. Both Cox regression and random survival forest had the lowest ICI values (0.12 for a large sample size and 0.18 for a small sample size) among all the investigated models regardless of sample size and data generating model. CONCLUSION: Cox regression models have comparable, and sometimes better predictive performance, than more complex machine learning models. We recommend that the choice among these models should be guided by important considerations for research hypotheses, model interpretability, and type of data.

Accuracy of mixture item response theory models for identifying sample heterogeneity in patient-reported outcomes: a simulation study.

PURPOSE: Mixture item response theory (MixIRT) models can be used to uncover heterogeneity in responses to items that comprise patient-reported outcome measures (PROMs). This is accomplished by identifying relatively homogenous latent subgroups in heterogeneous populations. Misspecification of the number of latent subgroups may affect model accuracy. This study evaluated the impact of specifying too many latent subgroups on the accuracy of MixIRT models. METHODS: Monte Carlo methods were used to assess MixIRT accuracy. Simulation conditions included number of items and latent classes, class size ratio, sample size, number of non-invariant items, and magnitude of between-class difference in item parameters. Bias and mean square error in item parameters and accuracy of latent class recovery were assessed. RESULTS: When the number of latent classes was correctly specified, the average bias and MSE in model parameters decreased as the number of items and latent classes increased, but specification of too many latent classes resulted in modest decrease (i.e., < 10%) in the accuracy of latent class recovery. CONCLUSION: The accuracy of MixIRT model is largely influenced by the overspecification of the number of latent classes. Appropriate choice of goodness-of-fit measures, study design considerations, and a priori contextual understanding of the degree of sample heterogeneity can guide model selection.