Disease activity trajectories in juvenile dermatomyositis from childhood to adulthood.

OBJECTIVES: To assess whether there are identifiable subgroups of disease activity trajectory in a population of juvenile dermatomyositis (JDM) patients-followed throughout childhood and into adulthood-and determine factors that predict those trajectory groupings. METHODS: This is a retrospective, longitudinal inception cohort of patients with idiopathic inflammatory myopathies, largely JDM. We sought to identify baseline factors that predict membership into different groups (latent classes) of disease activity trajectory. RESULTS: A total of 172 patients (64% females), with median age at diagnosis of 7.7 years, were analyzed. We studied 4,725 visits (1,471 patient-years). We identified 3 latent classes of longitudinal disease activity, as measured by the modified disease activity score (DASm), with distinct class trajectories predicted by DASm at baseline, and by the changes of DASm from either baseline to 3 months or baseline to 6 months (early response to therapy). In the analysis in which DASm at baseline and the changes of DASm from baseline to 6 months are included as predictors, Class 1 (10%) has persistently high disease activity, Class 2 (34%) is characterized by moderate disease activity, and Class 3 (56%) is characterized by individuals with a high early disease activity but an apparently good response to treatment and long-term low disease activity. CONCLUSION: High early disease activity, and treatment resistance in the first few months, predict a more chronic longitudinal course of JDM.

A direct comparison between discrete choice with duration and composite time trade-off methods: do they produce similar results?

OBJECTIVES: Discrete Choice Experiments (DCE) including a duration attribute (DCEd) represent a promising candidate method for valuing health-related quality-of-life instruments. However, it has not been established that DCEd can produce similar results as composite Time-Trade-Off (cTTO) or EuroQol Valuation Technology (EQ-VT) valuations of the EQ-5D-5L instrument. This study provides a direct comparison between cTTO and EQ-VT, and DCEd valuation methods. METHODS: An EQ-VT study was conducted in Trinidad and Tobago to value the EQ-5D-5L. 1079 respondents each completed 10 cTTO tasks and 12 DCE tasks without a duration attribute. A separate sample of 970 respondents each completed 18 split-triplet DCEd tasks. Several regression models were applied to the EQ-VT data, and the DCEd data were analysed using mixed logit models with an exponential discount rate. The estimated values were compared using scatterplots and Bland-Altman plots. RESULTS: The ordering of dimensions was identical in level 5 for cTTO/EQ-VT and DCEd models, with pain/discomfort being the most important dimension and usual activities being least important. cTTO/EQ-VT models produced a value for state 55555 ranging between -0.52 and -0.69, while this was -0.543 for the non-linear mixed logit model for the DCEd data. Scatterplots and Bland-Altman plots suggested excellent agreement between cTTO/EQ-VT and DCEd-based estimates. CONCLUSIONS: CTTO/EQ-VT and DCEd valuations produce similar results when correcting DCEd for non-linear time preferences. The ordering of importance of the dimensions and scale are identical, suggesting that the two methods measure the same construct and produce similar results.

The EQ-5D-5L valuation study for Trinidad and Tobago.

PURPOSE: The 2016 EQ-5D-3L value set for Trinidad and Tobago (T&T) allows for the calculation of EQ-5D-5L values via the crosswalk algorithm. The 2016 value set was based on methods predating the EQ-VT protocol, now considered the gold standard for developing EQ-5D value sets. Furthermore, direct elicitation of EQ-5D-5L is preferred over crosswalked values. This study aimed to produce an EQ-5D-5L value set for T&T. METHODS: A representative sample (age, sex, geography) of adults each completed 10 composite Time Trade-Off (cTTO) tasks and 12 Discrete Choice Experiment (DCE) tasks in face-to-face interviews. The cTTO data were analyzed using a Tobit model that corrects for heteroskedasticity. DCE data were analyzed using a mixed logit model. The cTTO and DCE data were combined in hybrid models. RESULTS: One thousand and seventy-nine adults completed the valuation interviews. Among the modelling approaches that were explored, the hybrid heteroskedastic Tobit model produced all internally consistent, statistically significant coefficients, and performed best in terms of out-of-sample predictivity for single states. Compared to the existing EQ-5D-5L crosswalk set, the new value set had a higher number of negative values (236 or 7.6% versus 21 or 0.7%). The mean absolute difference was 0.157 and the correlation coefficient between the two sets was 0.879. CONCLUSION: This study provides a value set for the EQ-5D-5L for T&T using the EQ-VT protocol. We recommend this value set for QALY computations relating to T&T.

Understanding Canadian stakeholders' views on measuring and valuing health for children and adolescents: a qualitative study.

OBJECTIVE: Valuing child health is critical to assessing the value of healthcare interventions for children. However, there remain important methodological and normative issues. This qualitative study aimed to understand the views of Canadian stakeholders on these issues. METHODS: Stakeholders from health technology assessment (HTA) agencies, pharmaceutical industry representatives, healthcare providers, and academic researchers/scholars were invited to attend an online interview. Semi-structured interviews were designed to focus on: (1) comparing the 3-level and 5-level versions of the EQ-5D-Y; (2) source of preferences for valuation (adults vs. children); (3) perspective of valuation tasks; and (4) methods for valuation (discrete choice experiment [DCE] and its variants versus time trade-off [TTO]). Participants were probed to consider HTA guidelines, cognitive capacity, and potential ethical concerns. All interviews were recorded and transcribed verbatim. Framework analysis with the incidence density method was used to analyze the data. RESULTS: Fifteen interviews were conducted between May and September 2022. 66.7% (N = 10) of participants had experience with economic evaluations, and 86.7% (N = 13) were parents. Eleven participants preferred the EQ-5D-Y-5L. 12 participants suggested that adolescents should be directly involved in child health valuation from their own perspective. The participants were split on the ethical concerns. Eight participants did not think that there was ethical concern. 11 participants preferred DCE to TTO. Among the DCE variants, 6 participants preferred the DCE with duration to the DCE with death. CONCLUSIONS: Most Canadian stakeholders supported eliciting the preferences of adolescents directly from their own perspective for child health valuation. DCE was preferred if adolescents are directly involved.

Evaluating the Impact of Ex Vivo Lung Perfusion on Organ Transplantation: A Retrospective Cohort Study.

BACKGROUND: Ex vivo lung perfusion (EVLP) sustains and allows advanced assessment of potentially useable donor lungs before transplantation, potentially relieving resource constraints. OBJECTIVE: We sought to characterize the effect of EVLP on organ utilization and patient outcomes. METHODS: We performed a retrospective, before-after cohort study using linked institutional data sources of adults wait-listed for lung transplant and donor organs transplanted in Ontario, Canada between 2005 and 2019. We regressed the annual number of transplants against year, EVLP use, and organ characteristics. Time-to-transplant, waitlist mortality, primary graft dysfunction, tracheostomy insertion, in-hospital mortality, and chronic lung allograft dysfunction were evaluated using propensity score-weighted regression. RESULTS: EVLP availability ( P =0.01 for interaction) and EVLP use ( P <0.001 for interaction) were both associated with steeper increases in transplantation than expected by historical trends. EVLP was associated with more donation after circulatory death and extended-criteria donors transplanted, while the numbers of standard-criteria donors remained relatively stable. Significantly faster time-to-transplant was observed after EVLP was available (hazard ratio=1.64 [1.41-1.92]; P <0.001). Fewer patients died on the waitlist after EVLP was available, but no difference in the hazard of waitlist mortality was observed (HR=1.19 [0.81-1.74]; P =0.176). We observed no difference in the likelihood of chronic lung allograft dysfunction before versus after EVLP was available. CONCLUSIONS: We observed a significant increase in organ transplantation since EVLP was introduced into practice, predominantly from increased acceptance of donation after circulatory death and extended-criteria lungs. Our findings suggest that EVLP-associated increases in organ availability meaningfully alleviated some barriers to transplant.

Genetics of longitudinal kidney function in children and adults with systemic lupus erythematosus.

OBJECTIVES: Genome-wide association studies (GWAS) have identified loci associated with estimated glomerular filtration rate (eGFR). Few LN risk loci have been identified to date. We tested the association of SLE and eGFR polygenic risk scores (PRS) with repeated eGFR measures from children and adults with SLE. METHODS: Patients from two tertiary care lupus clinics that met ≥4 ACR and/or SLICC criteria for SLE were genotyped on the Illumina MEGA or Omni1-Quad arrays. PRSs were calculated for SLE and eGFR, using published weighted GWA-significant alleles. eGFR was calculated using the CKD-EPI and Schwartz equations. We tested the effect of eGFR- and SLE-PRSs on eGFR mean and variance, adjusting for age at diagnosis, sex, ancestry, follow-up time, and clinical event flags. RESULTS: We included 1158 SLE patients (37% biopsy-confirmed LN) with 36 733 eGFR measures over a median of 7.6 years (IQR: 3.9-15.3). LN was associated with lower within-person mean eGFR [LN: 93.8 (s.d. 26.4) vs non-LN: 101.6 (s.d. 17.7) mL/min per 1.73 m2; P < 0.0001] and higher variance [LN median: 157.0 (IQR: 89.5, 268.9) vs non-LN median: 84.9 (IQR: 46.9, 138.2) (mL/min per 1.73 m2)2; P < 0.0001]. Increasing SLE-PRSs were associated with lower mean eGFR and greater variance, while increasing eGFR-PRS was associated with increased eGFR mean and variance. CONCLUSION: We observed significant associations between SLE and eGFR PRSs and repeated eGFR measurements, in a large cohort of children and adults with SLE. Longitudinal eGFR may serve as a powerful alternative outcome to LN categories for discovery of LN risk loci.

Causal inference with longitudinal data subject to irregular assessment times.

Data collected in the context of usual care present a rich source of longitudinal data for research, but often require analyses that simultaneously enable causal inferences from observational data while handling irregular and informative assessment times. An inverse-weighting approach to this was recently proposed, and handles the case where the assessment times are at random (ie, conditionally independent of the outcome process given the observed history). In this paper, we extend the inverse-weighting approach to handle a special case of assessment not at random, where assessment and outcome processes are conditionally independent given past observed covariates and random effects. We use multiple outputation to accomplish the same purpose as inverse-weighting, and apply it to the Liang semi-parametric joint model. Moreover, we develop an alternative joint model that does not require covariates for the outcome model to be known at times where there is no assessment of the outcome. We examine the performance of these methods through simulation and illustrate them through a study of the causal effect of wheezing on time spent playing outdoors among children aged 2-9 years and enrolled in the TargetKids! study.

Modifying the Composite Time Trade-Off Method to Improve Its Discriminatory Power.

OBJECTIVES: In cost-effectiveness analysis of health technologies, health state utilities are needed. They are often elicited with a composite time trade-off (cTTO) method, particularly for the widely used EQ-5D-5L. Unfortunately, cTTO discriminatory power is hindered by (1) respondents' nontrading (NT) of time for quality, (2) censoring of utilities at -1, and (3) poor correlation of negative utilities with state severity. We investigated whether modifying cTTO can mitigate these effects. METHODS: We interviewed online 478 students (February to April, 2021) who each valued the same 10 EQ-5D-5L health states in 1 of 3 arms. Arm A used a standard cTTO, expanded with 2 questions to explore reasons for NT and censoring. Arms B and C used a time trade-off with modified alternatives offered to overcome loss aversion, to unify the tasks for positive and negative utilities, and to enable eliciting utilities < -1. RESULTS: In arms B and C, we observed less NT than in A (respectively, 4% and 4% vs 10%), more strictly negative utilities (38% and 40% vs 25%), and more utilities ≤ -1 (18% and 30% vs 10%). The average utility of state 55555 dropped to -2.15 and -2.52 from -0.53. Enabling finer trades in arm A reduced NT by 70%. Arms B and C yielded an intuitive association between negative utilities and state severity. These arms were considered more difficult and resulted in more inconsistencies. CONCLUSIONS: The discriminatory power of cTTO can be improved, but it may require increasing the difficulty of the task. The standard cTTO may overestimate the utilities, especially of severe states.

Generic Health-Related Quality of Life Utility Measure for Preschool Children (Health Utilities Preschool): Design, Development, and Properties.

OBJECTIVES: Health Utilities Preschool (HuPS) was developed to fill the need for a generic preference-based measure (GPM) applicable in early childhood. A GPM has all the properties for higher-order summary measures, such as quality-adjusted life-years, required to inform important policy decisions regarding health and healthcare services. METHODS: Development was in accordance with published standards for a GPM, statistical procedures, and modeling. HuPS incorporates key components of 2 existing measurement systems: Health Status Classification System for Preschool Children and Health Utilities Index Mark 3 (HUI3). The study included a series of 4 measurement surveys: definitional, adaptational, quantificational, and evaluational health-related quality of life (HRQL). HuPS measurements were evaluated for reliability, validity, interpretability, and acceptability. RESULTS: Definitional measurements identified 8 Health Status Classification System for Preschool Children attributes in common with HUI3 (vision, hearing, speech, ambulation, dexterity, emotion, cognition, and pain and discomfort), making the HUI3 scoring equation commensurate with HuPS health states. Adaptational measurements informed the content of attribute-level descriptions (n = 35). Quantificational measurements determined level scoring coefficients. HRQL scoring inter-rater reliability (intraclass correlation coefficient = 0.79) was excellent. Continuity of HRQL scoring with HUI3 was reliable (intraclass correlation coefficient = 0.80, P < .001) and valid (mean absolute difference = 0.016, P = .396). CONCLUSIONS: HuPS is an acceptable, reliable, and valid GPM. HRQL scoring is continuous with HUI3. Continuity expands the applicability of GPM (HUI3) scoring to include subjects as young as 2 years of age. Widespread applications of HuPS would inform important health policy and management decisions as HUI3 does for older subjects.

Medical Masks Versus N95 Respirators for Preventing COVID-19 Among Health Care Workers : A Randomized Trial.

BACKGROUND: It is uncertain if medical masks offer similar protection against COVID-19 compared with N95 respirators. OBJECTIVE: To determine whether medical masks are noninferior to N95 respirators to prevent COVID-19 in health care workers providing routine care. DESIGN: Multicenter, randomized, noninferiority trial. (ClinicalTrials.gov: NCT04296643). SETTING: 29 health care facilities in Canada, Israel, Pakistan, and Egypt from 4 May 2020 to 29 March 2022. PARTICIPANTS: 1009 health care workers who provided direct care to patients with suspected or confirmed COVID-19. INTERVENTION: Use of medical masks versus fit-tested N95 respirators for 10 weeks, plus universal masking, which was the policy implemented at each site. MEASUREMENTS: The primary outcome was confirmed COVID-19 on reverse transcriptase polymerase chain reaction (RT-PCR) test. RESULTS: In the intention-to-treat analysis, RT-PCR-confirmed COVID-19 occurred in 52 of 497 (10.46%) participants in the medical mask group versus 47 of 507 (9.27%) in the N95 respirator group (hazard ratio [HR], 1.14 [95% CI, 0.77 to 1.69]). An unplanned subgroup analysis by country found that in the medical mask group versus the N95 respirator group RT-PCR-confirmed COVID-19 occurred in 8 of 131 (6.11%) versus 3 of 135 (2.22%) in Canada (HR, 2.83 [CI, 0.75 to 10.72]), 6 of 17 (35.29%) versus 4 of 17 (23.53%) in Israel (HR, 1.54 [CI, 0.43 to 5.49]), 3 of 92 (3.26%) versus 2 of 94 (2.13%) in Pakistan (HR, 1.50 [CI, 0.25 to 8.98]), and 35 of 257 (13.62%) versus 38 of 261 (14.56%) in Egypt (HR, 0.95 [CI, 0.60 to 1.50]). There were 47 (10.8%) adverse events related to the intervention reported in the medical mask group and 59 (13.6%) in the N95 respirator group. LIMITATION: Potential acquisition of SARS-CoV-2 through household and community exposure, heterogeneity between countries, uncertainty in the estimates of effect, differences in self-reported adherence, differences in baseline antibodies, and between-country differences in circulating variants and vaccination. CONCLUSION: Among health care workers who provided routine care to patients with COVID-19, the overall estimates rule out a doubling in hazard of RT-PCR-confirmed COVID-19 for medical masks when compared with HRs of RT-PCR-confirmed COVID-19 for N95 respirators. The subgroup results varied by country, and the overall estimates may not be applicable to individual countries because of treatment effect heterogeneity. PRIMARY FUNDING SOURCE: Canadian Institutes of Health Research, World Health Organization, and Juravinski Research Institute.

Developmental cascades between insistence on sameness behaviour and anxiety symptoms in autism spectrum disorder.

Autistic children experience high rates of anxiety. Insistence on sameness behaviour (IS) is a core feature of autism that appears correlated with anxiety severity. The objective of this study was to examine the longitudinal relations between anxiety and IS in autistic children using a developmental cascade model. A longitudinal cohort of 421 autistic children was followed between 4 and 11 years of age. Anxiety was quantified using items from the Anxiety Problems subscale of the Child Behavior Checklist; sameness behaviours were measured using the Repetitive Behavior Scale-Revised, Ritualistic/sameness subscale (both parent-report measures). Structural equation modelling was used to examine the longitudinal and directional associations between anxiety and IS at four time-points, through cross-lagged panel models (CLPM) with and without a random-intercepts component (RI-CLPM). Both the CLPM and the RI-CLPM had good fit. Significant directional associations were detected whereby elevated or increasing IS preceded elevated or increasing anxiety symptoms 1-2 years later, respectively. Stable baseline tendencies towards anxiety and IS as between-person traits (intercepts) were strongly associated (standardized estimate = 0.69, p < 0.001). The magnitude of the cross-sectional associations between anxiety and IS appeared to lessen with age. IS and anxiety symptoms in autism are closely related. They appear to be shared traits that mirror each other particularly in younger children. Increasing IS may be a sign of emerging future anxiety. Interventions that target IS to reduce or prevent anxiety amongst school-aged autistic children merit further study.

Randomized Trials With Repeatedly Measured Outcomes: Handling Irregular and Potentially Informative Assessment Times.

Randomized trials are often designed to collect outcomes at fixed points in time after randomization. In practice, the number and timing of outcome assessments can vary among participants (i.e., irregular assessment). In fact, the timing of assessments may be associated with the outcome of interest (i.e., informative assessment). For example, in a trial evaluating the effectiveness of treatments for major depressive disorder, not only did the timings of outcome assessments vary among participants but symptom scores were associated with assessment frequency. This type of informative observation requires appropriate statistical analysis. Although analytic methods have been developed, they are rarely used. In this article, we review the literature on irregular assessments with a view toward developing recommendations for analyzing trials with irregular and potentially informative assessment times. We show how the choice of analytic approach hinges on assumptions about the relationship between the assessment and outcome processes. We argue that irregular assessment should be treated with the same care as missing data, and we propose that trialists adopt strategies to minimize the extent of irregularity; describe the extent of irregularity in assessment times; make their assumptions about the relationships between assessment times and outcomes explicit; adopt analytic techniques that are appropriate to their assumptions; and assess the sensitivity of trial results to their assumptions.

The Clinician-reported Genetic testing Utility InDEx (C-GUIDE): Preliminary evidence of validity and reliability.

PURPOSE: Demonstrating the clinical utility of genetic testing is fundamental to clinical adoption and reimbursement, but standardized definitions and measurement strategies for this construct do not exist. The Clinician-reported Genetic testing Utility InDEx (C-GUIDE) offers a novel measure to fill this gap. This study assessed its validity and inter-rater reliability. METHODS: Genetics professionals completed C-GUIDE after disclosure of test results to patients. Construct validity was assessed using regression analysis to measure associations between C-GUIDE and global item scores as well as potentially explanatory variables. Inter-rater reliability was assessed by administering a vignette-based survey to genetics professionals and calculating Krippendorff's α. RESULTS: On average, a 1-point increase in the global item score was associated with an increase of 3.0 in the C-GUIDE score (P < .001). Compared with diagnostic results, partially/potentially diagnostic and nondiagnostic results were associated with a reduction in C-GUIDE score of 9.5 (P < .001) and 10.2 (P < .001), respectively. Across 19 vignettes, Krippendorff's α was 0.68 (95% CI: 0.63-0.72). CONCLUSION: C-GUIDE showed acceptable validity and inter-rater reliability. Although further evaluation is required, C-GUIDE version 1.2 can be useful as a standardized approach to assess the clinical utility of genetic testing.

Factors Associated with Surgery and Imaging Characteristics in Severe Orbital Infections.

OBJECTIVES: To evaluate risk factors associated with surgical intervention and subperiosteal/orbital abscess in hospitalized children with severe orbital infections. STUDY DESIGN: We conducted a multicenter cohort study of children 2 months to 18 years hospitalized with periorbital or orbital cellulitis from 2009 to 2018 at 10 hospitals in Canada. Clinical details were extracted, and patients were categorized as undergoing surgical or medical-only management. Primary outcome was surgical intervention and the main secondary outcome was clinically important imaging. Logistic regression was used to identify predictors. RESULTS: Of 1579 patients entered, median age was 5.4 years, 409 (25.9%) had an orbital/subperiosteal abscess, and 189 (12.0%) underwent surgery. In the adjusted analysis, the risk of surgical intervention was associated with older age (age 9 to <14: aOR 3.9, 95% CI 2.3-6.6; and age 14 to ≤18 years: aOR 7.0, 95% CI 3.4-14.1), elevated C-reactive protein >120 mg/L (aOR 2.8, 95% CI 1.3-5.9), elevated white blood cell count of 12-20 000/µL (aOR 1.7, 95% CI 1.1-2.6), proptosis (aOR 2.6, 95% CI 1.7-4.0), and subperiosteal/orbital abscess (aOR 5.3, 95% CI 3.6-7.9). There was no association with antibiotic use before hospital admission, sex, presence of a chronic disease, temperature greater than 38.0°C, and eye swollen shut. Complications were identified in 4.7% of patients, including vision loss (0.6%), intracranial extension (1.6%), and meningitis (0.8%). CONCLUSIONS: In children hospitalized with severe orbital infections, older age, elevated C-reactive protein, elevated white blood cell count, proptosis, and subperiosteal/orbital abscess were predictors of surgical intervention.

Characterizing the ASD-ADHD phenotype: measurement structure and invariance in a clinical sample.

BACKGROUND: Autism Spectrum Disorder (ASD) and Attention Deficit Hyperactivity Disorder (ADHD) have considerable overlap, supporting the need for a dimensional framework that examines neurodevelopmental domains which cross traditional diagnostic boundaries. In the following study, we use factor analysis to deconstruct the ASD-ADHD phenotype into its underlying phenotypic domains and test for measurement invariance across adaptive functioning, age, gender and ASD/ADHD clinical diagnoses. METHODS: Participants included children and youth (aged 3-20 years) with a clinical diagnosis of ASD (n = 727) or ADHD (n = 770) for a total of 1,497 participants. Parents of these children completed the Social Communication Questionnaire (SCQ), a measure of autism symptoms, and the Strengths and Weaknesses of ADHD and Normal Behaviour (SWAN) questionnaire, a measure of ADHD symptoms. An exploratory factor analysis (EFA) was performed on combined SCQ and SWAN items. This was followed by a confirmatory factor analysis (CFA) and tests of measurement invariance. RESULTS: EFA revealed a four-factor solution (inattention, hyperactivity/impulsivity, social-communication, and restricted, repetitive, behaviours and interests (RRBI)) and a CFA confirmed good model fit. This solution also showed good model fit across subgroups of interest. CONCLUSIONS: Our study shows that a combined ASD-ADHD phenotype is characterized by two latent ASD domains (social communication and RRBIs) and two latent ADHD domains (inattention and hyperactivity/impulsivity). We established measurement invariance of the derived measurement model across adaptive functioning, age, gender and ASD/ADHD diagnoses.

Variable selection in semiparametric regression models for longitudinal data with informative observation times.

A common issue in longitudinal studies is that subjects' visits are irregular and may depend on observed outcome values which is known as longitudinal data with informative observation times (follow-up). Semiparametric regression modeling for this type of data has received much attention as it provides more flexibility in studying the association between regression factors and a longitudinal outcome. An important problem here is how to select relevant variables and estimate their coefficients in semiparametric regression models when the number of covariates at baseline is large. The current penalization procedures in semiparametric regression models for longitudinal data do not account for informative observation times. We propose a variable selection procedure that is suitable for the estimation methods based on pseudo-score functions. We investigate the asymptotic properties of penalized estimators and conduct simulation studies to illustrate the theoretical results. We also use the procedure for variable selection in semiparametric regression models for the STAR*D dataset from a multistage randomized clinical trial for treating major depressive disorder.

A Bayesian adaptive design for clinical trials of rare efficacy outcomes with multiple definitions.

INTRODUCTION: Bayesian adaptive designs for clinical trials have gained popularity in the recent years due to the flexibility and efficiency that they offer. We consider the scenario where the outcome of interest comprises events with relatively low risk of occurrence and different case definitions resulting in varying control group risk assumptions. This is a scenario that occurs frequently for infectious diseases in global health research. METHODS: We propose a Bayesian adaptive design that incorporates different case definitions of the outcome of interest that vary in stringency. A set of stopping rules are proposed where superiority and futility may be concluded with respect to different outcome definitions and therefore maintain a realistic probability of stopping in trials with low event rates. Through a simulation study, a variety of stopping rules and design configurations are compared. RESULTS: The simulation results are provided in an interactive web application that allows the user to explore and compare the design operating characteristics for a variety of assumptions and design parameters with respect to different outcome definitions. The results for select simulation scenarios are provided in the article. DISCUSSION: Bayesian adaptive designs offer the potential for maximizing the information learned from the data collected through clinical trials. The proposed design enables monitoring and utilizing multiple composite outcomes based on rare events to optimize the trial design operating characteristics.

Liver enzymes after short-term acetaminophen error in critically ill children: a cohort study.

Drug-associated harm is common but difficult to detect in the hospital setting. In critically ill children, we sought to evaluate drug-associated hepatic injury following enteral acetaminophen error, defined as acetaminophen dosing that exceeds daily maximum recommendations. This retrospective cohort study took place in two pediatric intensive care units within a pediatric hospital center. The included patients are children (< 18 years of age) admitted to the pediatric and cardiac intensive care unit between January 2008 and January 2018, and receiving enteral acetaminophen. We defined acetaminophen dosing error as exceeding daily acetaminophen dosing by > 10% the upper limit of maximum recommended dose for weight and age (> 82.5 mg/kg/day or > 4400 mg/day). We included 14,146 admissions, who received 147,485 doses of acetaminophen. Acetaminophen dosing errors occurred 1 in every 9.5 patient-days on acetaminophen. ALT and AST decreased significantly over the course of ICU admission (p < 0.0001). In patients with acetaminophen errors, ALT and AST measured in the 24 to 96 h post error were not significantly different than when measured outside this window. A sensitivity analysis using > 100 mg/kg/day as the upper daily acetaminophen error cut-off did not reveal any subsequent significant increase in ALT or ALT in the 24 to 96-h post-error window, compared to measurements taken outside the window. CONCLUSION: Although the administration of acetaminophen in critically ill children frequently exceeds the daily recommended limit and vigilance is needed, we did not find any associated increase in liver transaminases following acetaminophen errors. WHAT IS KNOWN: • Acetaminophen dosing errors are common in pediatric outpatients. • Excessive acetaminophen dosing can be associated with harm, including hepatic injury. WHAT IS NEW: • Exceeding daily acetaminophen dosing limit occurs 1 in every 9.5 patient-days in children admitted to the critical care unit. • In patients with daily dose excess of acetaminophen, we did not find a significant increase in the measured liver enzymes in the 24 to 96 h following the overdosing.

Acquired low immunoglobulin levels and risk of clinically relevant infection in adult patients with systemic lupus erythematosus: a cohort study.

OBJECTIVE: Infection is a leading cause of death in the SLE population. Low immunoglobulin levels might be a potential risk for infection. We aimed to assess whether acquired low levels of any type of immunoglobulin increase the risk of clinically relevant infection in adult patients with SLE. METHODS: We compared adult SLE patients who had acquired any low immunoglobulin levels (IgA, IgM or IgG) for 2 years with patients with normal or high levels with respect to clinically relevant infection (defined as infections requiring intravenous or oral antibiotics) in a prospective cohort study. Group balance was achieved using propensity score adjustment, matching and inverse probability weighting. Primary analysis was time to event using Cox-regression modelling adjusting for potential confounders. Sensitivity analyses were conducted to examine several exposure and outcome definitions. RESULTS: Patients with hypogammaglobulinaemia had longer disease duration, more lupus nephritis history, higher proteinuria and more accumulated damage. Low IgA level was associated with increased risk of clinically relevant infection [hazard ratio (HR): 2.24, 95% CI: 1.61, 3.12] while low IgG (HR: 1.15, 95% CI: 0.84, 1.59) or low IgM (HR: 0.95, 95% CI: 0.73, 1.23) was not. Low immunoglobulin recovery in the first year was 2.5% (11), second year 8.2% (36), third year 10.1% (44) and fourth year 18.4% (80), and 60% (263) of acquired hypogammaglobulinaemia recovered over 4 years. CONCLUSION: The majority of acquired hypogammaglobulinaemia in adult patients with SLE is transient. Only low acquired IgA was associated with increased risk of infection among adult patients with SLE. Whether immunoglobulin replacement provides additional protective effect requires further investigation.

Co-occurring trajectories of anxiety and insistence on sameness behaviour in autism spectrum disorder.

BACKGROUND: Children with autism spectrum disorder (ASD) have increased susceptibility to anxiety disorders. Variation in a common ASD symptom, insistence on sameness behaviour, may predict future anxiety symptoms. AIMS: To describe the joint heterogeneous longitudinal trajectories of insistence on sameness and anxiety in children with ASD and to characterise subgroups at higher risk for anxiety. METHOD: In a longitudinal ASD cohort (n = 421), insistence on sameness behaviour was measured using the Autism Diagnostic Interview-Revised at approximately ages 3, 6 and 11 years. Anxiety was quantified at 8 time points between ages 3 and 11 years using the Child Behavior Checklist (CBCL) (parent report). Clusters of participants following similar trajectories were identified using group-based and joint trajectory modelling. RESULTS: Three insistence on sameness trajectories were identified: (a) 'low-stable' (41.7% of participants), (b) 'moderate-increasing' (52.0%) and (c) 'high-peaking' (i.e. increasing then stabilising/decreasing behaviour) (6.3%). Four anxiety trajectories were identified: (a) 'low-increasing' (51.0%), (b) 'moderate-decreasing' (16.2%), (c) 'moderate-increasing' (19.6%) and (d) 'high-stable' (13.1%). Of those assigned to the 'high-peaking' insistence on sameness trajectory, 95% jointly followed an anxiety trajectory that surpassed the threshold for clinical concern (T-score >65) by middle childhood (anxiety trajectories 3 or 4). Insistence on sameness and anxiety trajectories were similar in severity and direction for 64% of the sample; for 36%, incongruous patterns were seen (e.g. decreasing anxiety and increasing insistence on sameness). CONCLUSIONS: The concurrent assessment of insistence on sameness behaviour and anxiety in ASD may help in understanding current symptom profiles and anticipating future trajectories. High preschool insistence on sameness in particular may be associated with elevated current or future anxiety symptoms.