Category: Statistics

Hum Brain Mapp. 2022 Feb 15. doi: 10.1002/hbm.25774. Online ahead of print.

ABSTRACT

This study sought to identify a reference tissue-based quantification approach for improving the statistical power in detecting changes in brain glucose metabolism, amyloid, and tau deposition in Alzheimer’s disease studies. A total of 794, 906, and 903 scans were included for ¹⁸ F-FDG, ¹⁸ F-florbetapir, and ¹⁸ F-flortaucipir, respectively. Positron emission tomography (PET) and T1-weighted images of participants were collected from the Alzheimer’s disease Neuroimaging Initiative database, followed by partial volume correction. The standardized uptake value ratios (SUVRs) calculated from the cerebellum gray matter, centrum semiovale, and pons were evaluated at both region of interest (ROI) and voxelwise levels. The statistical power of reference tissues in detecting longitudinal SUVR changes was assessed via paired t-test. In cross-sectional analysis, the impact of reference tissue-based SUVR differences between cognitively normal and cognitively impaired groups was evaluated by effect sizes Cohen’s d and two sample t-test adjusted by age, sex, and education levels. The average ROI t values of pons were 86.62 and 38.40% higher than that of centrum semiovale and cerebellum gray matter in detecting glucose metabolism decreases, while the centrum semiovale reference tissue-based SUVR provided higher t values for the detection of amyloid and tau deposition increases. The three reference tissues generated comparable d images for ¹⁸ F-FDG, ¹⁸ F-florbetapir, and ¹⁸ F-flortaucipir and comparable t maps for ¹⁸ F-florbetapir and ¹⁸ F-flortaucipir, but pons-based t map showed superior performance in ¹⁸ F-FDG. In conclusion, the tracer-specific reference tissue improved the detection of ¹⁸ F-FDG, ¹⁸ F-florbetapir, and ¹⁸ F-flortaucipir PET SUVR changes, which helps the early diagnosis, monitoring of disease progression, and therapeutic response in Alzheimer’s disease.

PMID:35165964 | DOI:10.1002/hbm.25774

Hum Brain Mapp. 2022 Feb 15. doi: 10.1002/hbm.25723. Online ahead of print.

ABSTRACT

Assessing and improving test-retest reliability is critical to efforts to address concerns about replicability of task-based functional magnetic resonance imaging. The current study uses two statistical approaches to examine how scanner and task-related factors influence reliability of neural response to face-emotion viewing. Forty healthy adult participants completed two face-emotion paradigms at up to three scanning sessions across two scanners of the same build over approximately 2 months. We examined reliability across the main task contrasts using Bayesian linear mixed-effects models performed voxel-wise across the brain. We also used a novel Bayesian hierarchical model across a predefined whole-brain parcellation scheme and subcortical anatomical regions. Scanner differences accounted for minimal variance in temporal signal-to-noise ratio and task contrast maps. Regions activated during task at the group level showed higher reliability relative to regions not activated significantly at the group level. Greater reliability was found for contrasts involving conditions with clearly distinct visual stimuli and associated cognitive demands (e.g., face vs. nonface discrimination) compared to conditions with more similar demands (e.g., angry vs. happy face discrimination). Voxel-wise reliability estimates tended to be higher than those based on predefined anatomical regions. This work informs attempts to improve reliability in the context of task activation patterns and specific task contrasts. Our study provides a new method to estimate reliability across a large number of regions of interest and can inform researchers’ selection of task conditions and analytic contrasts.

PMID:35165974 | DOI:10.1002/hbm.25723

Adv Mater. 2022 Feb 14:e2109107. doi: 10.1002/adma.202109107. Online ahead of print.

ABSTRACT

Fluorescent proteins (FPs) have recently emerged as a serious contender for realizing ultra-low threshold room temperature exciton-polariton condensation and lasing. Our contribution investigates the thermalization of FP microcavity exciton-polaritons upon optical pumping under ambient conditions. We realize polariton cooling using a new FP molecule, called mScarlet, coupled strongly to the optical modes in a Fabry-Pérot cavity. Interestingly, at the threshold excitation energy (fluence) of ∼9 nJ/pulse (15.6 mJ/cm² ), we observe an effective temperature, T_eff ∼350 ± 35 K close to the lattice temperature indicative of strongly thermalized exciton-polaritons at equilibrium. This efficient thermalization results from the interplay of radiative pumping facilitated by the energetics of the lower polariton branch and the cavity Q-factor. Direct evidence for dramatic switching from an equilibrium state into a metastable state is observed for the organic cavity polariton device at room temperature via deviation from the Maxwell-Boltzmann statistics at k_‖ = 0 above the threshold. Thermalized polariton gases in organic systems at equilibrium hold substantial promise for designing room temperature polaritonic circuits, switches, and lattices for analog simulation. This article is protected by copyright. All rights reserved.

PMID:35165941 | DOI:10.1002/adma.202109107

Echocardiography. 2022 Feb 14. doi: 10.1111/echo.15315. Online ahead of print.

ABSTRACT

BACKGROUND: Recurrence of any atrial arrhythmia after surgical ablation is known as a negative predictor of cardiovascular events and total mortality. However, there have been no focused studies for atrial fibrillation (AF) recurrence prediction in patients with significant tricuspid regurgitation (TR), and the risk-benefit estimation of surgical ablation in tricuspid valve (TV) surgery is not fully established.

METHOD: We screened 385 patients who underwent a TV operation between 2001 and 2017. After excluding patients who did not undergo a maze operation, 158 patients were enrolled. Enrolled patients were divided by recurrence of AF. We analyzed the difference between the AF recurrence group and no AF recurrence group, and AF recurrence factors in terms of clinical risk factors and echocardiographic risk factors. The hazard ratio (HR) and 95% confidence intervals (CIs) were presented using a Cox proportional hazard model.

RESULTS: Among 158 patients, AF recurred in 65 patients within 10 years. For AF prediction, age was most the important clinical factor and right atrium (RA) diameter was the most important echocardiographic parameters. In patients with a larger RA diameter over 49.2 mm, the prevalence of AF recurrence was higher (HR 4.322, 95% CI [2.185-8.549], log rank p value < .001). In clinical outcome, there was no significant difference between the AF recurrence group and the no recurrence group in terms of death, TR recurrence, heart failure, and stroke. However, the risk of permanent pacemaker (PPM) insertion was higher in the AF recurrence group (HR 10.240, 95% CI [1.257-83.480], log rank p value .007) compared to the no recurrence group.

CONCLUSION: Age and RA enlargement are key predictors of AF recurrence after TV operation with the CM procedure in patients with significant TR.

PMID:35165935 | DOI:10.1111/echo.15315

Stat Med. 2022 Feb 14. doi: 10.1002/sim.9335. Online ahead of print.

ABSTRACT

Civil registration vital statistics (CRVS) systems provide data on maternal mortality that can be used for monitoring trends and to inform policies and programs. However, CRVS maternal mortality data may be subject to substantial reporting errors due to misclassification of maternal deaths. Information on misclassification is available for selected countries and periods only. We developed a Bayesian hierarchical bivariate random walk model to estimate sensitivity and specificity for multiple populations and years and used the model to estimate misclassification errors in the reporting of maternal mortality in CRVS systems. The proposed Bayesian misclassification (BMis) model captures differences in sensitivity and specificity across populations and over time, allows for extrapolations to periods with missing data, and includes an exact likelihood function for data provided in aggregated form. Validation exercises using maternal mortality data suggest that BMis is reasonably well calibrated and improves upon the CRVS-adjustment approach used until 2018 by the UN Maternal Mortality Inter-Agency Group (UN-MMEIG) to account for bias in CRVS data resulting from misclassification error. Since 2019, BMis is used by the UN-MMEIG to account for misclassification errors when estimating maternal mortality using CRVS data.

PMID:35165916 | DOI:10.1002/sim.9335

Br J Clin Pharmacol. 2022 Feb 14. doi: 10.1111/bcp.15276. Online ahead of print.

ABSTRACT

AIMS: Proton pump inhibitors (PPIs) are often prescribed to prevent or treat gastrointestinal disease. Whether the combination of systemic anti-tumor therapy and PPIs leads to poor outcomes in patients with advanced non-small cell lung cancer (NSCLC) is unclear. This systematic review explored the relationship between PPIs and survival outcomes of patients with advanced NSCLC who are receiving systemic anti-tumor therapy.

METHODS: We searched studies reporting the overall survival (OS) and/or progression-free survival (PFS) of advanced NSCLC patients who are receiving systemic anti-tumor therapy with or without PPIs on PubMed, EMBASE, and the Cochrane Library for literature published prior to 31 August 2021. The meta-analysis used a random effects model to estimate the risk ratio (HR) with 95% confidence intervals (CI) and I² to assess statistical heterogeneity. Publication bias and sensitivity analysis were performed.

RESULTS: Fourteen retrospective studies comprising 13,709 advanced NSCLC patients were identified. Subgroup analyses showed that the use of PPI was correlated with the OS or PFS of patients receiving chemotherapy, targeted therapy, and immunotherapy (PPI users’ group versus non-users’ group: HR for OS = 1.35, 95% CI = 1.21-1.51, P < 0.00001; HR for PFS = 1.50, 95% CI = 1.25-1.80, P < 0.0001). Publication bias and sensitivity analyses confirmed that the results were robust.

CONCLUSION: Meta-analysis demonstrated that PPI use in advanced NSCLC patients who were undergoing systemic anti-tumor therapy was correlated with increased mortality risk. Until results are further confirmed, caution should be applied when administering PPIs and systemic anti-tumor therapy to advanced NSCLC patients.

PMID:35165922 | DOI:10.1111/bcp.15276

Community Dent Oral Epidemiol. 2022 Feb 14. doi: 10.1111/cdoe.12733. Online ahead of print.

ABSTRACT

OBJECTIVES: This study aimed to perform a systematic review and meta-analysis regarding the prevalence of traumatic dental injuries (TDI) in emergency dental services.

METHODS: Seven electronic and two grey literature databases were searched, up to December 2021, for studies that reported the TDI prevalence among dental emergencies. The Joanna Briggs Institute critical appraisal checklist for prevalence studies, and The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach were used to assess the risk of bias and quality of evidence respectively. The R software was used to perform a proportion meta-analysis on a random-effects model to estimate the pooled prevalence and respective 95% CI.

RESULTS: From a total of 1476 studies identified after excluding duplicates, 38 met the inclusion criteria, and another five were identified through hand searching, summing 43 included observational studies with a total sample of 209099 individuals searching for emergency dental care. The overall pooled prevalence of TDI was 15.4% (95% CI: 11%-21%, I² = 100%). Paediatric dental emergency services and age group from 0 to 21 years presented the highest prevalence, 29% (95% CI: 22%-38%, I² = 99.5%) and 24% (95% CI: 15%-35%, I² = 98%) respectively.

CONCLUSIONS: The overall pooled prevalence of TDI in emergency dental services was 15.4%, and 24% in the age group under 21 years. Considering the impact of prompt and correct emergency care in the long-term prognosis of TDI, such knowledge is relevant to organize emergency healthcare and support public policies in this area.

PMID:35165912 | DOI:10.1111/cdoe.12733

Stat Med. 2022 Feb 14. doi: 10.1002/sim.9344. Online ahead of print.

ABSTRACT

A rate ratio (RR) is an important metric for comparing cancer risks among different subpopulations. Inference for RR becomes complicated when populations used for calculating age-standardized cancer rates involve sampling errors, a situation that arises increasingly often when sample surveys must be used to obtain the population data. We compare a few strategies of estimating the standardized RR and propose bias-corrected ratio estimators as well as the corresponding variance estimators and confidence intervals that simultaneously consider the sampling error in estimating populations and the traditional Poisson error in the occurrence of cancer case or death. Performance of the proposed methods is evaluated empirically based on simulation studies. An application to immigration disparities in cancer mortality among Hispanic Americans is discussed. Our simulation studies show that a bias-corrected RR estimator performs the best in reducing the bias without increasing the coefficient of variation; the proposed variance estimators for the RR estimators and associated confidence intervals are fairly accurate. Finding of our application study are both interesting and consistent with the common sense as well as the results of our simulation studies.

PMID:35165903 | DOI:10.1002/sim.9344

Planta Med. 2022 Feb 14. doi: 10.1055/a-1770-7581. Online ahead of print.

ABSTRACT

Essential oils are often utilized for therapeutic purposes and are composed of complex structural molecules, including sesquiterpenes, with high molecular weight and potential for stereochemistry. A detailed study on the properties of selected sesquiterpenes was conducted as part of a broader investigation on the effects of sesquiterpenes on the central nervous system. A set of 18 sesquiterpenes, rigorously selected from an original list of 114, was divided into 2 groups i.e., the training and test sets, with each containing 9 compounds. The training set was evaluated for the sedative activity in mice through inhalation, and all compounds were sedatives at any dose in the range of 4 × 10-4-4 × 10-2 mg/cage, except for curzerene. Molecular determinants of the sedative activities of sesquiterpenes were evaluated using quantitative structure-activity relationship (QSAR) and structure-activity relationship (SAR) analyses. An additional test set of six compounds obtained from the literature was utilized for validating the QSAR model. The parental carbonyl cation and an oxygen-containing groups are possible determinants of sedative activity. The QSAR study using multiple regression models could reasonably predict the sedative activity of sesquiterpenes with statistical parameters such as the correlation coefficient r² = 0.82 > 0.6 and q²_LOO = 0.71 > 0.5 obtained using the leave-one-out cross-validation technique. Molar refractivity and the number of hydrogen bond acceptors were statistically important in predicting the activities. The present study could help predict the sedative activity of additional sesquiterpenes, thus accelerating the process of drug development.

PMID:35158383 | DOI:10.1055/a-1770-7581