Covariate adjustment and estimation of difference in proportions in randomized clinical trials.

Difference in proportions is frequently used to measure treatment effect for binary outcomes in randomized clinical trials. The estimation of difference in proportions can be assisted by adjusting for prognostic baseline covariates to enhance precision and bolster statistical power. Standardization or g-computation is a widely used method for covariate adjustment in estimating unconditional difference in proportions, because of its robustness to model misspecification. Various inference methods have been proposed to quantify the uncertainty and confidence intervals based on large-sample theories. However, their performances under small sample sizes and model misspecification have not been comprehensively evaluated. We propose an alternative approach to estimate the unconditional variance of the standardization estimator based on the robust sandwich estimator to further enhance the finite sample performance. Extensive simulations are provided to demonstrate the performances of the proposed method, spanning a wide range of sample sizes, randomization ratios, and model specification. We apply the proposed method in a real data example to illustrate the practical utility.

Asymmetric magnetic levitation for density-based measurement and analysis.

BACKGROUND: Magnetic levitation (MagLev) based on negative magnetophoresis represents a promising technology for density-based analysis and manipulation of nonmagnetic objects. This approach has garnered considerable interest across multiple fields, such as chemistry, materials science, and biochemistry, primarily due to its inherent simplicity, precision, and cost-effectiveness. However, it is essential to recognize that frequently used MagLev configurations, including standard MagLev and axial MagLev, are not without their limitations. These configurations often struggle to strike a balance between levitation performance, ease of operation, and visibility. Therefore, it is necessary to develop a new MagLev configuration to address the aforementioned issue. RESULTS: This work describes the development of an innovative MagLev, termed "asymmetric MagLev", achieved by combining a ring magnet and a cylinder magnet as up-down asymmetric magnetic field sources. The asymmetric design overcomes the physical obstacles along the centerline of the standard MagLev, offering unique open-structure advantages, including easy handling of samples, the ability to observe samples from the top or bottom, and no restrictions on the container height. Meanwhile, comparative analysis reveals a considerable enhancement in the working distance of the asymmetric MagLev without significantly sacrificing the measurement range compared to the axial MagLev. Notably, the asymmetric MagLev achieves a remarkable sensitivity of up to about 1.8 × 104 mm (g cm-3)-1, surpassing the axial MagLev by approximately 30 times. Furthermore, experimental results validate the successful application of the asymmetric MagLev in density measurement and quality detection of small-sized objects. SIGNIFICANCE: This pioneering configuration represents the first utilization of up-down asymmetric magnets in the field of MagLev. Through the integration of an axially magnetized ring magnet and a cylinder magnet, the asymmetric MagLev design overcomes the limitations associated with conventional MagLev configurations. This innovative design exhibits outstanding operational capabilities and levitation performance, making it suitable for a wide range of applications in density-based measurement and analysis.

Radial Magnetic Levitation and Its Application to Density Measurement, Separation, and Detection of Microplastics.

This work describes the development of radial magnetic levitation (MagLev) using two radially magnetized ring magnets to solve the problem of limited operational spaces in standard MagLev and the major shortcoming of a short working distance in axial MagLev. Interestingly and importantly, we demonstrate that for the same magnet size, this new configuration of MagLev doubles the working distance over the axial MagLev without significantly sacrificing the density measurement range, whether for linear or nonlinear analysis. Meanwhile, we develop a magnetic assembly method to fabricate the magnets for the radial MagLev, where multiple magnetic tiles with single-direction magnetization are used as assembly elements. On this basis, we experimentally demonstrate that the radial MagLev has good applicability in density-based measurement, separation, and detection and show its advantages in improving separation performance compared with the axial MagLev. The open structure of two-ring magnets and good levitation characteristics make the radial MagLev have great application potential, and the performance improvement brought by adjusting the magnetization direction of magnets provides a new perspective for the magnet design in the field of MagLev.

Neighborhood deprivation and residential property values do not affect weight loss at 1 or 3 years after bariatric surgery.

OBJECTIVE: This study examined the association between individual- and neighborhood-level sociodemographic factors and surgical weight loss at 1 year (short term) and 3 years (long term). METHODS: Data were obtained from the baseline survey of the BELONG (Bariatric Experience Long Term) prospective longitudinal cohort study. Individual-level self-reported data on sex, race and ethnicity, education, and household income were obtained by survey. Data from the 2010 US Census were used to calculate area Neighborhood Deprivation Index score and median value of owner-occupied housing units at the census tract level. RESULTS: Patients (N = 1341) had a mean age of 43.4 (SD 11.3) years, were mostly female (86%), were mostly Black or Hispanic (52%), had some college education (83%), and had annual household incomes ≥$51,000 (55%). Percentage total weight loss was 25.8% (SD 9.0%) at year 1 and 22.2% (SD 10.5%) at year 3. Race and ethnicity and age were significant predictors of weight loss at 1 and 3 years with a small effect of self-reported household income at year 1. There were no significant associations between census tract-level Neighborhood Deprivation Index score or value of owner-occupied housing units and weight loss at either time point. CONCLUSIONS: Health systems could improve the chances of weight-loss maintenance after surgery by addressing factors related to racial and ethnic disparities and to income disparities.

Performance of Noninvasive Tests of Fibrosis Among Asians, Hispanic, and non-Hispanic Whites in the STELLAR Trials.

BACKGROUND & AIMS: The effect of race on routinely available noninvasive tests of fibrosis is incompletely understood. This study evaluated the performance of noninvasive tests among white and Asian patients in the STELLAR trials (NCT03053050 and NCT03053063), which evaluated selonsertib in patients with advanced (F3-F4) fibrosis due to nonalcoholic steatohepatitis (NASH). METHODS: Baseline liver biopsies were centrally read using the NASH Clinical Research Network system, and 4 noninvasive tests (Nonalcoholic fatty liver disease fibrosis score [NFS], Fibrosis-4 index [FIB-4], Enhanced Liver Fibrosis test [ELF], and liver stiffness by vibration-controlled transient elastography) were measured. The performance of these tests to discriminate advanced fibrosis was evaluated using areas under the receiver operating characteristics curves with 5-fold cross-validation repeated 100 times. RESULTS: Among 3207 patients screened with evaluable liver histology, 2281 were whites and 762 were Asians. Seventy-two percent of whites and 67% of Asians had advanced fibrosis. The areas under the receiver operating characteristics curves of the noninvasive tests for advanced fibrosis were similar in whites and Asians: 0.73 and 0.75 for NFS, 0.78 and 0.80 for FIB-4, 0.79 and 0.81 for ELF, and 0.80 and 0.83 for liver stiffness, respectively. At the published cutoffs, the tests had similar sensitivities and specificities in the 2 groups. However, the sensitivities of NFS, FIB-4, and ELF were low in both white and Asian patients younger than 40 years. CONCLUSIONS: In the global phase III STELLAR trials, the diagnostic performance of routinely available noninvasive tests for the detection of advanced fibrosis due to NASH was acceptable and similar between white and Asian patients.

Assessment of Screening for Adverse Childhood Experiences and Receipt of Behavioral Health Services Among Children and Adolescents.

Importance: Screening for adverse childhood experiences (ACEs) in primary care settings has been increasing as a response to the overwhelming and consistent evidence of the deleterious associations between ACEs and later physical and mental health. However, there is little empirical guidance on the appropriate implementation of ACEs screening in pediatric primary care. Objective: To test the use of a pilot intervention for ACEs screening and referral on the receipt of behavioral health care for children and adolescents within a large integrated health care delivery system. Design, Setting, and Participants: A retrospective cohort study was conducted in a large integrated health care system serving Southern California. Child and adolescent members of the target health care system younger than 18 years between July 1, 2018, and November 30, 2021, who received a positive screening for ACEs at the pilot clinic were included. This pilot clinic implemented an intervention that included additional screening questions and incorporated social workers into the process of evaluation and referral for behavioral health needs following ACEs screening. Exposures: ACEs screening. Main Outcomes and Measures: Visit to a behavioral health care service within 90 days of a positive ACEs screen determined as a score of 1 or higher and behavioral symptoms. Results: The cohort consisted of 4030 children (mean [SD] age, 9.94 [4.55] years) with positive ACEs screening, 48% adolescents (11-17.99 years), approximately equal gender (51% females), 73% Hispanic, and 33% with Medicaid insurance. After the intervention, children were more likely to have a behavioral health services visit within 90 days of the screening than before the intervention (from 4.33% to 32.48%; incidence rate ratio, 7.50; 95% CI, 1.55-36.2). Conclusions and Relevance: In this cohort study, the implementation of a new ACEs screening and referral process was associated with increased receipt of behavioral health services among children with a positive ACEs screening. This could be useful strategy for other health care systems responding to state and local mandates to screen and provide care for children with ACEs.

Cohort profile: The Bariatric Experience Long Term (BELONG): a long-term prospective study to understand the psychosocial, environmental, health and behavioural predictors of weight loss and regain in patients who have bariatric surgery.

PURPOSE: The Bariatric Experience Long Term (BELONG) prospective study cohort was created to address limitations in the literature regarding the relationship between surgical weight loss and psychosocial, health, behaviour and environmental factors. The BELONG cohort is unique because it contains 70% gastric sleeve and 64% patients with non-white race/ethnicity and was developed with strong stakeholder engagement including patients and providers. PARTICIPANTS: The BELONG cohort study included 1975 patients preparing to have bariatric surgery who completed a baseline survey in a large integrated health system in Southern California. Patients were primarily women (84%), either black or Hispanic (59%), with a body mass index (BMI) of 45.1±7.4 kg/m2, age 43.3±11.5 years old, and 32% had at least one comorbidity. FINDINGS TO DATE: A total of 5552 patients were approached before surgery between February 2016 and May 2017, and 1975 (42%) completed a baseline survey. A total of 1203 (73%) patients completed the year 1 and 1033 (74%) patients completed the year 3 postoperative survey. Of these survey respondents, 1341 at baseline, 999 at year 1, and 951 at year 3 were included in the analyses of all survey and weight outcome data. A total of 803 (60% of eligible patients) had survey data for all time points. Data collected were self-reported constructs to support the proposed theoretical model. Height, weight and BMI were abstracted from the electronic medical record to obtain the main outcomes of the study: weight loss and regain. FUTURE PLANS: We will collect self-reported constructs and obtain height, weight and BMI from the electronic medical record 5 years after bariatric surgery between April 2022 and January 2023. We will also collect patient experiences using focus groups of 8-12 patients each throughout 2022.

A Roadmap for Institutionalizing Collaborative Care for Depression in a Large Integrated Healthcare System.

BACKGROUND: Collaborative models for depression have not been widely adopted throughout the USA, possibly because there are no successful roadmaps for implementing these types of models. OBJECTIVE: To provide such a roadmap through a case study of the institutionalization of a depression care management (DCM) initiative for adult depression in a large healthcare system serving over 300,000 adults with depression. DESIGN: A retrospective observational program evaluation. Program evaluation results are presented for those patients enrolled in the initiative from January 1, 2015, to December 31, 2018. PARTICIPANTS: Over a 4-year period, 17,052 patients were treated in the DCM program. In general, participants were women (76%), were Hispanic (47%), spoke English (84%), and were 51.1 ± 18.3 years old, the majority of whom were 30-64 years old (57%). INTERVENTION: The collaborative care portion of the DCM initiative (DCM program) was implemented by a collaborative care team containing a treatment specialist, an assessment specialist, administrative staff, a primary care physician, and a psychiatry physician. MAIN MEASURES: The main outcome measures were total score on the 9-item Patient Health Questionnaire (PHQ-9). Outcomes were improvement (defined as at least 50% reduction in symptoms) and remission (defined as a PHQ-9 less than 5) of depression symptoms. Follow-up of depression symptoms was also collected at 6 months following discharge. KEY RESULTS: The average course of treatment in 2018, after full implementation, was 4.6 ± 3.0 months; 62% of patients experienced improvement in symptoms, and 45% experienced remission of their depression at the time of discharge. These rates were maintained at the 6-month follow-up. CONCLUSIONS: Collaborative care for depression can be institutionalized in large healthcare systems and be sustained with a specific, detailed roadmap that includes workflows, training, treatment guidelines, and clear documentation standards that are linked to performance metrics. Extensive stakeholder engagement at every level is also critical for success.