Category: Statistics

Obesity (Silver Spring). 2021 Jul 7. doi: 10.1002/oby.23197. Online ahead of print.

ABSTRACT

OBJECTIVE: Classifying adiposity based on dual-energy x-ray absorptiometry (DXA) muscle and fat mass phenotypes has been proposed. Whether these phenotypes are more accurate in predicting cardiometabolic risk than BMI weight status is unknown.

METHODS: Data were from the National Health and Nutrition Examination Survey (NHANES; 1999-2006 cycles, n = 5,475). Weight status was defined by BMI. Phenotypes of adiposity and muscle were based on high (≥50th percentile) and low (<50th percentile) permutations of sex- and age-specific fat and muscle mass population curves. The area under the curves of receiver operating characteristic curves (ROC-AUCs), which predicted the presence of abnormal lipids, glucose, and blood pressure, were compared. All analyses were stratified by sex and incorporated the complex survey design and weighting of NHANES.

RESULTS: The ROC-AUCs from weight status models used to correctly identify cardiometabolic risk ranged from 0.57 to 0.68, indicating generally weak predictive power. However, the ROC-AUCs from DXA phenotypes were lower (ranging from 0.53-0.68), indicating weaker predictive power than weight status, and were statistically inferior for nearly all of the comparisons.

CONCLUSIONS: Despite DXA’s high cost and detailed output regarding body composition, its phenotype classification was inferior to weight status in predicting cardiometabolic risk. Further studies investigating the utility of the phenotypes are needed.

PMID:34231966 | DOI:10.1002/oby.23197

Pediatr Pulmonol. 2021 Jul 7. doi: 10.1002/ppul.25503. Online ahead of print.

ABSTRACT

OBJECTIVE: To provide a systematic review of the existing pediatric decannulation protocols, including the role of polysomnography, and their clinical outcomes.

METHODS: Five online databases were searched from database inception to May 29, 2020. Study inclusion was limited to publications that evaluated tracheostomy decannulation in children 18 years of age and younger. Data extracted included patient demographics and primary indication for tracheostomy. Methods used to assess readiness for decannulation were noted including the use of bronchoscopy, tracheostomy tube modifications, and gas exchange measurements. After decannulation, details regarding mode of ventilation, location, and length of observation period, and clinical outcomes were also collected. Descriptive statistical analyses were performed.

RESULTS: A total of 24 studies including 1395 children were reviewed. Tracheostomy indications included upper airway obstruction at a well-defined anatomic site (35%), upper airway obstruction not at a well-defined site (12%) and need for long-term ventilation and pulmonary care (53%). Bronchoscopy was routinely used in 23 of 24 (96%) protocols. Tracheostomy tube modifications in the protocols included capping (n = 20, 83%), downsizing (n = 14, 58%), and fenestrations (n = 2, 8%). Measurements of gas exchange included polysomnography (n = 13/18, 72%), oximetry (n = 10/18, 56%), blood gases (n = 3,17%), and capnography (n = 3, 17%). After decannulation, children in 92% of protocols were transitioned to room air. Observation period of 48 h or less was used in 76% of children.

CONCLUSIONS: There exists large variability in pediatric decannulation protocols. Polysomnography plays an integral role in assessing most children for tracheostomy removal. Evidence-based guidelines to standardize pediatric tracheostomy care remain an urgent priority.

PMID:34231976 | DOI:10.1002/ppul.25503

J Appl Clin Med Phys. 2021 Jul 7. doi: 10.1002/acm2.13331. Online ahead of print.

ABSTRACT

PURPOSE: Deep-learning-based segmentation models implicitly learn to predict the presence of a structure based on its overall prominence in the training dataset. This phenomenon is observed and accounted for in deep-learning applications such as natural language processing but is often neglected in segmentation literature. The purpose of this work is to demonstrate the significance of class imbalance in deep-learning-based segmentation and recommend tuning of the neural network optimization objective.

METHODS: An architecture and training procedure were chosen to represent common models in anatomical segmentation. A family of 5-block 2D U-Nets were independently trained to segment 10 structures from the Cancer Imaging Archive’s Head-Neck-Radiomics-HN1 dataset. We identify the optimal threshold for our models according to their Dice score on the validation datasets and consider perturbations about the optimum. A measure of structure prominence in segmentation datasets is defined, and its impact on the optimal threshold is analyzed. Finally, we consider the use of a 2D Dice objective in addition to binary cross entropy.

RESULTS: We observe significant decreases in perceived model performance with conventional 0.5-thresholding. Perturbations of as little as ±0.05 about the optimum threshold induce a median reduction in Dice score of 11.8% for our models. There is statistical evidence to suggest a weak correlation between training dataset prominence and optimal threshold (Pearson r=0.92 and p≈10–4 ). We find that network optimization with respect to the 2D Dice score itself significantly reduces variability due to thresholding but does not unequivocally create the best segmentation models when assessed with distance-based segmentation metrics.

CONCLUSION: Our results suggest that those practicing deep-learning-based contouring should consider their postprocessing procedures as a potential avenue for improved performance. For intensity-based postprocessing, we recommend a mixed objective function consisting of the traditional binary cross entropy along with the 2D Dice score.

PMID:34231950 | DOI:10.1002/acm2.13331

Eur J Heart Fail. 2021 Jul 7. doi: 10.1002/ejhf.2291. Online ahead of print.

ABSTRACT

AIMS: Recent evidence points towards a distinct obese phenotype among patients with heart failure with preserved ejection fraction (HFpEF). We aimed to identify differentially expressed circulating biomarkers in obese HFpEF patients and link them to disease severity and outcomes.

METHODS AND RESULTS: From the LIFE-Heart study, 999 patients with HFpEF and 999 patients without heart failure (no-HF) were selected and 92 circulating serum biomarkers were measured using a proximity extension assay. Elevation of identified biomarkers was validated in 220 patients from the Aldo-DHF trial with diagnosed HFpEF. HFpEF patients were older and had more comorbidities including coronary artery disease and type 2 diabetes as compared to no-HF patients (p<0.05 for all). After adjusting for covariates, Adrenomedullin (ADM), Galectin-9 (Gal-9), Thrombospondin-2 (THBS-2), CD4, and TNF-related apoptosis-inducing ligand receptor 2 (TRAIL-R2) were significantly higher in obese HFpEF (BMI≥30 kg/m² , n=464) patients as compared to lean HFpEF (BMI<30 kg/m² , n=535) and obese no-HF patients (BMI≥30 kg/m² , n=387) (p<0.001 for both), those findings were verified in the Aldo-DHF validation cohort (p<0.001). Except for CD4 these proteins were associated with increased estimates of left atrial pressure in a linear fashion. Importantly, ADM, TRAIL-R2 and CD4 were associated with increased mortality in obese HFpEF patients after adjusting for covariates.

CONCLUSION: Obese HFpEF patients exhibit higher circulating biomarkers of volume expansion (ADM), myocardial fibrosis (THBS-2) and systemic inflammation (Gal-9, CD4) compared to obese non-HFpEF or lean HFpEF. These findings support the clinical definition of a distinct obese HFpEF phenotype and might merit further investigation. This article is protected by copyright. All rights reserved.

PMID:34231954 | DOI:10.1002/ejhf.2291

Pathol Int. 2021 Jul 7. doi: 10.1111/pin.13144. Online ahead of print.

ABSTRACT

CD163 is one of the scavenger receptors expressed on macrophages. However, several immunohistochemical studies have demonstrated that CD163 is also detected on cancer cells, and is associated with a poor prognosis. In the present study, we detected CD163 staining on cancer cells in lung adenocarcinoma and squamous cell carcinoma (SCC), and investigated the relationship between CD163 on cancer cells and the clinical prognosis. CD163 staining was seen in 128 of 342 adenocarcinoma cases and 35 of 103 SCC cases. Among the lung adenocarcinoma cases, the progression-free survival and overall survival were significantly shorter in the CD163 high group than the CD163 low group. A similar trend was observed among the SCC cases, but the difference was not statistically significant. Additionally, a higher number of macrophages was detected in areas with CD163-positive cancer cells when compared to areas with CD163-negative cancer cells. In summary, we found that CD163-positive cancer cells are a predictor of a worse clinical course in lung adenocarcinoma and SCC.

PMID:34231937 | DOI:10.1111/pin.13144

Helicobacter. 2021 Jul 7:e12832. doi: 10.1111/hel.12832. Online ahead of print.

ABSTRACT

OBJECTIVE: To evaluate the effectiveness of using WeChat platform to manage the patients with H. pylori infection.

METHODS: 566 patients were randomly divided into two groups: The control group was treated with traditional management method, and the experimental group established WeChat group and implemented the informatization management. The two groups were given a unified plan to eradicate H. pylori. After the treatment, the C14 breath test was reexamined. The follow-up rate and H. pylori eradication rate of the two groups were counted.

RESULTS: In the experimental group, 289 patients were enrolled and 271 patients were followed up. The follow-up rate was 93.8%. The number of H. pylori-negative patients was 244, and the eradication rate was 90.0%. In the control group, 277 patients were enrolled in the study, and 215 patients were followed up. The follow-up rate was 77.6%. 169 cases of H. pylori-negative conversion were found, and the eradication rate was 78.6%.

CONCLUSION: Through WeChat management, the medication adherence, regular follow-up, and H.pylori infection eradication rate of the patients with H.pylori infection in the experimental group were better than that in control group, during the treatment of eradicating H.pylori, and the difference was statistically significant.

PMID:34231948 | DOI:10.1111/hel.12832

J Appl Clin Med Phys. 2021 Jul 7. doi: 10.1002/acm2.13325. Online ahead of print.

ABSTRACT

PURPOSE: Eye plaques are widely used for ocular melanoma and provide an effective alternative to enucleation with adequate tumor control. A COMS plaque utilizes a Silastic insert for precise positioning of the radioactive seeds with respect to the scleral surface of the eye; however, due to manufacturing variability, the insert may unintentionally increase or decrease the distance between the sources and tumor. The purpose of this work is to provide guidance in measuring and identifying outliers in Silastic inserts. The importance of regular quality assurance (QA) is illustrated in an experience where a systematic problem was detected and the manufacturer’s 22-mm mold was corrected.

METHODS: A detailed description of the molds and manufacturing process used to produce Silastic inserts is provided, including photographs of the process steps. The variability in Silastic insert production was evaluated by measuring the thickness of 124 Silastic inserts. An estimate of how the observed Silastic thickness discrepancies impact the dose to the tumor and critical eye structures was performed using homogeneous dose calculations. A standard QA protocol was developed to guide the clinical user.

RESULTS: Thickness of the measured Silastic inserts ranged from 1.22 to 2.67 mm, demonstrating variation from the 2.25 mm standard. Six of the 22-mm inserts were outliers (Δthickness >3 standard deviations) and were excluded from the statistics. The outliers were investigated with the help of the manufacturer, who discovered that a systematic error was accidentally introduced into the 22-mm mold.

CONCLUSIONS: Due to manufacturing errors or variability, the Silastic inserts used in COMS eye plaques may be thicker or thinner than the design standard. Such variations may impact tumor control or increase the risk of normal tissue side effects. A standardized QA program is recommended to detect variations and communicate unusual findings to the manufacturer.

PMID:34231949 | DOI:10.1002/acm2.13325

Cereb Cortex. 2021 Jul 7:bhab209. doi: 10.1093/cercor/bhab209. Online ahead of print.

ABSTRACT

The study of states of arousal is key to understand the principles of consciousness. Yet, how different brain states emerge from the collective activity of brain regions remains unknown. Here, we studied the fMRI brain activity of monkeys during wakefulness and anesthesia-induced loss of consciousness. We showed that the coupling between each brain region and the rest of the cortex provides an efficient statistic to classify the two brain states. Based on this and other statistics, we estimated maximum entropy models to derive collective, macroscopic properties that quantify the system’s capabilities to produce work, to contain information, and to transmit it, which were all maximized in the awake state. The differences in these properties were consistent with a phase transition from critical dynamics in the awake state to supercritical dynamics in the anesthetized state. Moreover, information-theoretic measures identified those parameters that impacted the most the network dynamics. We found that changes in the state of consciousness primarily depended on changes in network couplings of insular, cingulate, and parietal cortices. Our findings suggest that the brain state transition underlying the loss of consciousness is predominantly driven by the uncoupling of specific brain regions from the rest of the network.

PMID:34231843 | DOI:10.1093/cercor/bhab209

J Neuroimaging. 2021 Jul 7. doi: 10.1111/jon.12903. Online ahead of print.

ABSTRACT

BACKGROUND AND PURPOSE: Glioblastoma (GBM) is an aggressive primary CNS neoplasm with poor overall survival (OS) despite standard of care. On MRI, GBM is usually characterized by an enhancing portion (CET) (surgery target) and a nonenhancing surrounding (NET). Extent of resection is a long debated issue in GBM, with recent evidence suggesting that both CET and NET should be resected in <65 years old patients, regardless of other risk factors (i.e., molecular biomarkers). Our aim was to test a radiomic model for patient survival stratification in <65 years old patients, by analyzing MRI features of NET, to aid tumor resection.

METHODS: Sixty-eight <65 years old GBM patients, with extensive CET resection, were selected. Resection was evaluated by manually segmenting CET on volumetric T1-weighted MRI pre and postsurgery (within 72 h). All patients underwent the same treatment protocol including chemoradiation. NET radiomic features were extracted with a custom version of Pyradiomics. Feature selection was performed with principal component analysis (PCA) and its effect on survival tested with Cox regression model. Twelve months OS discrimination was tested by t-test followed by logistic regression. Statistical significance was set at p<0.05. The most relevant features were identified from the component matrix.

RESULTS: Five PCA components (PC1-5) explained 90% of the variance. PC5 resulted significant in the Cox model (p = 0.002; exp(B) = 0.686), at t-test (p = 0.002) and logistic regression analysis (p = 0.006). Apparent diffusion coefficient (ADC)-based features were the most significant for patient survival stratification.

CONCLUSIONS: ADC radiomic features on NET predict survival after standard therapy and could be used to improve patient selection for more extensive surgery.

PMID:34231927 | DOI:10.1111/jon.12903

Dental Press J Orthod. 2021 Jun 30;26(3):e2119288. doi: 10.1590/2177-6709.26.3.e2119288.oar. eCollection 2021.

ABSTRACT

OBJECTIVE: The aim of this study was to evaluate characteristics of African-Brazilians young adults with excellent dental occlusion, including bimaxillary protrusion; compare them to European-American Caucasian standards, and determine whether there is sexual dimorphism in the display of this phenotype.

METHODS: Lateral cephalometric radiographs were obtained from 43 African-Brazilians within military personnel (28 males and 15 females, average age 22.4 ± 3.4 years) with normal occlusion, selected from a group of 394 volunteers. Thirty-one angular and linear measurements were evaluated. Student’s t-test for independent samples was used to compare results with those established by European-American standards, previously described in the literature.

RESULTS: Considering the dentoalveolar pattern, seven angular and six linear measurements showed statistically significant differences (p< 0.001) when compared to Caucasian cephalometric standards. African-Brazilians’ subjects showed lower cranial base angle (SNAr = 119.87 ± 5.66º) and anterior cranial base length (SN-distance = 68.63 ± 4.50 mm) (p< 0.001). The maxilla (SNA = 88.51 ± 3.23º) and the mandible (SNB = 85.06 ± 3.24º) were protruded in relation to the SN line (p< 0.001). Sexual dimorphism was significant for L1.NB (degrees) (p< 0.01), and interincisal angle (U1.L1) (p< 0.05).

CONCLUSION: African-Brazilian young adults presented differences regarding dental and craniofacial characteristics, when compared to European-American norms. It can be stated that Caucasian cephalometric norms should not be applied to African-Brazilian faces.

PMID:34231833 | DOI:10.1590/2177-6709.26.3.e2119288.oar