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Nevin Manimala Statistics

Effects of Statistical Practices for Longitudinal Group Comparison of the Penetration-Aspiration Scale on Power and Effect Size Estimation: A Monte Carlo Simulation Study

Dysphagia. 2024 Aug 17. doi: 10.1007/s00455-024-10738-7. Online ahead of print.

ABSTRACT

Multiple bolus trials are administered during clinical and research swallowing assessments to comprehensively capture an individual’s swallowing function. Despite valuable information obtained from these boluses, it remains common practice to use a single bolus (e.g., the worst score) to describe the degree of dysfunction. Researchers also often collapse continuous or ordinal swallowing measures into categories, potentially exacerbating information loss. These practices may adversely affect statistical power to detect and estimate smaller, yet potentially meaningful, treatment effects. This study sought to examine the impact of aggregating and categorizing penetration-aspiration scale (PAS) scores on statistical power and effect size estimates. We used a Monte Carlo approach to simulate three hypothetical within-subject treatment studies in Parkinson’s disease and head and neck cancer across a range of data characteristics (e.g., sample size, number of bolus trials, variability). Different statistical models (aggregated or multilevel) as well as various PAS reduction approaches (i.e., types of categorizations) were performed to examine their impact on power and the accuracy of effect size estimates. Across all scenarios, multilevel models demonstrated higher statistical power to detect group-level longitudinal change and more accurate estimates compared to aggregated (worst score) models. Categorizing PAS scores also reduced power and biased effect size estimates compared to an ordinal approach, though this depended on the type of categorization and baseline PAS distribution. Multilevel models should be considered as a more robust approach for the statistical analysis of multiple boluses administered in standardized swallowing protocols due to its high sensitivity and accuracy to compare group-level changes in swallowing function. Importantly, this finding appears to be consistent across patient populations with distinct pathophysiology (i.e., PD and HNC) and patterns of airway invasion. The decision to categorize a continuous or ordinal outcome should be grounded in the clinical or research question with recognition that scale reduction may negatively affect the quality of statistical inferences in certain scenarios.

PMID:39153045 | DOI:10.1007/s00455-024-10738-7

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Nevin Manimala Statistics

Comparative effectiveness of frame-based and mask-based Gamma Knife stereotactic radiosurgery in brain metastases: A 509 patient meta-analysis

J Neurooncol. 2024 Aug 17. doi: 10.1007/s11060-024-04738-8. Online ahead of print.

ABSTRACT

PURPOSE: Stereotactic Radiosurgery (SRS) is the primary treatment for patients with limited numbers of small brain metastases. Head fixation is usually performed with framed-based (FB) fixation; however, mask-based (MB) fixation has emerged as a less invasive alternative. A comparative meta-analysis between both approaches has not been performed.

METHODS: Databases were searched until August 28th, 2023, to identify studies comparing MB and FB SRS in the treatment of brain metastases. Our outcomes of interest included local tumor control (LTC), radiation necrosis (RN), mortality, and treatment time (TT). Mean difference (MD), risk ratio (RR), and hazard ratio (HR) were used for statistical comparisons.

RESULTS: From 295 articles initially identified, six studies (1 clinical trial) involving 509 patients were included. LTC revealed comparable RR at 6-months (RR = 0.95[95%CI = 0.89-1.01], p = 0.12) and a marginal benefit in FB SRS at 1-year (RR = 0.87[95%CI = 0.78-0.96], p = 0.005). However, in oligometastases exclusively treated with single-fraction SRS, LTC was similar among groups (RR = 0.92 [95%CI = 0.89-1.0], p = 0.30). Similarly, in patients with oligometastases treated with single-fraction SRS, RN (HR = 1.69; 95%CI = 0.72-3.97, p = 0.22), TT (MD = -29.64; 95%CI = -80.38-21.10, p = 0.25), and mortality were similar among groups (RR = 0.62; 95%CI = 0.22-1.76, p = 0.37).

CONCLUSION: Our findings suggest that FB and MB SRS, particularly oligometastases treated with single-fraction, are comparable in terms of LTC, RN, TT, and mortality. Further research is essential to draw definitive conclusions.

PMID:39153030 | DOI:10.1007/s11060-024-04738-8

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Nevin Manimala Statistics

Untargeted stimulated and unstimulated salivary metabolomics and saliva flow rate in children

Clin Oral Investig. 2024 Aug 17;28(9):489. doi: 10.1007/s00784-024-05883-0.

ABSTRACT

OBJECTIVE: The present study aimed to determine the salivary flow and metabolomic profile of stimulated and unstimulated saliva in children.

MATERIALS AND METHODS: Children who attended the Pediatric Dentistry Clinic of the State University of Rio de Janeiro -UERJ between 3 and 12 years of age were selected. Unstimulated and stimulated whole saliva, using mechanical stimulus, were collected. The samples were centrifuged at 12,000 g, 4oC for 1 h. The 1H- NMR spectra were acquired in 500 MHz equipment. The data were extracted into 0.03 ppm buckets in AMIX, and multivariate analysis (PLS-DA and O-PLS-DA) was performed in Metaboanalyst 2.0. For other analyses, such as salivary flow, the data was tabulated in the SPSS 20.0 statistical package, analyzed descriptively, and after applying the Wilcoxon test. The interval of confidence was set at 95%.

RESULTS: The mean age was 7.5 (± 1.94), and 47.0% (n = 31) were female, 63.6% (n = 42). The median flow rate for stimulated saliva was 0.74 (IC 0.10-2.40) and was statistically higher (p < 0.001; Wilcoxon test) than unstimulated was 0.39 (IC 0.00-1.80). Children older than seven years old also presented a higher difference between unstimulated and stimulated saliva (p = 0.003; Mann-Whitney test). The PLS-DA and O-PLS-DA demonstrated a different profile in stimulated and unstimulated saliva. Acetate, glucose, propionate, and lysine were higher in the unstimulated whole saliva than in stimulated saliva. Isoleucine, N-acetyl sugar, hydroxybutyrate, glutamate, leucine, propionate, butyrate, valine, isoleucine, succinate, saturated fatty acid, and histidine were found in greater amounts in the saliva of patients with stimulated saliva.

CONCLUSION: The stimulated saliva presented a higher flow rate, and older children exhibited a higher flow rate resulting from it’s the stimulus. The mechanical stimulus increased the levels of the major metabolites.

PMID:39153029 | DOI:10.1007/s00784-024-05883-0

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Nevin Manimala Statistics

Asymptotically Correct Person Fit z-Statistics For the Rasch Testlet Model

Psychometrika. 2024 Aug 17. doi: 10.1007/s11336-024-09997-y. Online ahead of print.

ABSTRACT

A well-known person fit statistic in the item response theory (IRT) literature is the l z statistic (Drasgow et al. in Br J Math Stat Psychol 38(1):67-86, 1985). Snijders (Psychometrika 66(3):331-342, 2001) derived l z , which is the asymptotically correct version of l z when the ability parameter is estimated. However, both statistics and other extensions later developed concern either only the unidimensional IRT models or multidimensional models that require a joint estimate of latent traits across all the dimensions. Considering a marginalized maximum likelihood ability estimator, this paper proposes l zt and l zt , which are extensions of l z and l z , respectively, for the Rasch testlet model. The computation of l zt relies on several extensions of the Lord-Wingersky algorithm (1984) that are additional contributions of this paper. Simulation results show that l zt has close-to-nominal Type I error rates and satisfactory power for detecting aberrant responses. For unidimensional models, l zt and l zt reduce to l z and l z , respectively, and therefore allows for the evaluation of person fit with a wider range of IRT models. A real data application is presented to show the utility of the proposed statistics for a test with an underlying structure that consists of both the traditional unidimensional component and the Rasch testlet component.

PMID:39153026 | DOI:10.1007/s11336-024-09997-y

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Nevin Manimala Statistics

Meta-analysis of Pregnancy Events in Biomedical HIV Prevention Trials in Sub-Saharan Africa: Implications for Gender Transformative Trials

AIDS Behav. 2024 Aug 17. doi: 10.1007/s10461-024-04459-z. Online ahead of print.

ABSTRACT

Historically, pregnant and lactating populations (PLP) have been excluded or disenrolled from biomedical HIV prevention trials, despite being more likely to acquire HIV during pregnancy and the post-partum period. We conducted a meta-analysis of pregnancy events in biomedical HIV prevention trials in sub-Saharan Africa to support trialists moving toward more inclusive clinical and implementation studies. We searched peer-reviewed literature reporting pregnancy events and contraceptive requirements in HIV prevention trials between 2001 and 2022. We hypothesized four variables to explain variation: contraceptive requirements, study start year, study product, and sub-region. We fit a meta-analytic model to estimate individual effect sizes and sampling variances, then conducted sub-group analyses to assess moderating effects. We identified 38 references for inclusion, across which the proportion of pregnancy events was 8% (95% confidence interval [CI]: 6-10%) with high heterogeneity (I2 = 99%). Studies not requiring contraceptives (21%, 95%CI: 7-48%) reported a significantly higher proportion of pregnancy events than studies requiring two methods (5%, 95%CI: 2-10%). Studies launched between 2001 and 2007 (11%, 95%CI: 8-16%), microbicide gel trials (12%, 95%CI: 8-18%), and studies conducted in Western Africa (28%, 95%CI: 13-51%) reported higher proportions of pregnancy events than reference groups. Together, these variables have a moderating effect on pregnancy events (p < 0.0001), explaining 63% of heterogeneity in trials. Results describe how, over time, more stringent contraceptive requirements reduced pregnancy events, which ensured necessary statistical power but limited reproductive choice by participants. With the move toward continuing PLP on experimental products, trialists can utilize estimated pregnancy events reported here to inform strategies that accommodate participants’ changing fertility preferences.

PMID:39153025 | DOI:10.1007/s10461-024-04459-z

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Nevin Manimala Statistics

Phenotypic and transcriptomics characterization uncovers genes underlying tuber yield traits and gene expression marker development in potato under aeroponics

Planta. 2024 Aug 17;260(3):74. doi: 10.1007/s00425-024-04507-x.

ABSTRACT

Transcriptome analysis in potato varieties revealed genes associated with tuber yield-related traits and developed gene expression markers. This study aimed to identify genes involved in high tuber yield and its component traits in test potato varieties (Kufri Frysona, Kufri Khyati, and Kufri Mohan) compared to control (Kufri Sutlej). The aeroponic evaluation showed significant differences in yield-related traits in the varieties. Total RNA sequencing was performed using tuber and leaf tissues on the Illumina platform. The high-quality reads (QV > 25) mapping with the reference potato genomes revealed statistically significant (P < 0.05) differentially expressed genes (DEGs) into two categories: up-regulated (> 2 Log2 fold change) and down-regulated (< -2 Log2 fold change). DEGs were characterized by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Collectively, we identified genes participating in sugar metabolism, stress response, transcription factors, phytohormones, kinase proteins, and other genes greatly affecting tuber yield and its related traits. A few selected genes were UDP-glucose glucosyltransferase, glutathion S-transferase, GDSL esterase/lipase, transcription factors (MYB, WRKY, bHLH63, and BURP), phytohormones (auxin-induced protein X10A, and GA20 oxidase), kinase proteins (Kunitz-type tuber invertase inhibitor, BRASSINOSTEROID INSENSITIVE 1-associated receptor kinase 1) and laccase. Based on the selected 17 peptide sequences representing 13 genes, a phylogeny tree and motifs were analyzed. Real time-quantitative polymerase chain reaction (RT-qPCR) analysis was used to validate the RNA-seq results. RT-qPCR based gene expression markers were developed for the genes such as 101 kDa heat shock protein, catechol oxidase B chloroplastic, cysteine protease inhibitor 1, Kunitz-type tuber invertase inhibitor, and laccase to identify high yielding potato genotypes. Thus, our study paved the path for potential genes associated with tuber yield traits in potato under aeroponics.

PMID:39153022 | DOI:10.1007/s00425-024-04507-x

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Nevin Manimala Statistics

Impact of insurance status on treatment choice and hospitalization rates in bullous pemphigoid patients: a retrospective cross-sectional analysis

Arch Dermatol Res. 2024 Aug 17;316(8):526. doi: 10.1007/s00403-024-03323-3.

NO ABSTRACT

PMID:39153021 | DOI:10.1007/s00403-024-03323-3

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Nevin Manimala Statistics

Research shows statistical analysis can detect when ChatGPT is used to cheat on multiple-choice chemistry exams

Research revealed how the use of ChatGPT to cheat on general chemistry multiple-choice exams can be detected through specific statistical methods.
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Nevin Manimala Statistics

Minimal phenotypes in transgenic mice with the human LOXL1/LOXL1-AS1 locus associated with exfoliation glaucoma

Vision Res. 2024 Aug 15;223:108464. doi: 10.1016/j.visres.2024.108464. Online ahead of print.

ABSTRACT

Exfoliation syndrome is a leading cause of secondary glaucoma worldwide. Among the risk-factors for exfoliation syndrome and exfoliation glaucoma that have been investigated, a genetic association with 15q24.1 is among the most striking. The leading candidates for the causal gene at this locus are LOXL1 and/or LOXL1-AS1, but studies have not yet coalesced in establishing, or ruling out, either candidate. Here, we contribute to studies of the 15q24.1 locus by making a partially humanized mouse model in which 166 kb of human genomic DNA from the 15q24.1 locus was introduced into the mouse genome via BAC transgenesis (B6-Tg(RP11-71M11)Andm). Transgenic expression of human genes in the BAC was only detectable for LOXL1-AS1. One cohort of 34 mice (21 experimental hemizygotes and 13 non-carrier control littermates) was assessed by slit-lamp exams and SD-OCT imaging at early (1-2 months) and mid (4-5 months) time points; fundus exams were performed at 5 months of age. A second smaller cohort (3 hemizygotes) were aged extensively (>12 months) to screen for overt abnormalities. Across all genotypes and ages, 136 slit-lamp exams, 128 SD-OCT exams, and 42 fundus exams detected no overt indices of exfoliation syndrome. Quantitatively, small, but statistically significant, age-related declines in ganglion cell complex thickness and total retinal thickness were detected in the hemizygotes at 4 months of age. Overall, this study demonstrates complexity in gene regulation from the 15q24.1 locus and suggests that LOXL1-AS1 is unlikely to be a monogenic cause of exfoliation syndrome but may contribute to glaucomatous retinal damage.

PMID:39151208 | DOI:10.1016/j.visres.2024.108464

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Nevin Manimala Statistics

Comparison of surgical outcomes of macular telangiectasia type 2 associated macular hole with idiopathic macular hole: A tertiary center review

Retina. 2024 Aug 14. doi: 10.1097/IAE.0000000000004249. Online ahead of print.

ABSTRACT

PURPOSE: To assess the longitudinal surgical outcomes of macular telangiectasia type 2 macular hole (MacTel-MH) and compare them with those of idiopathic MH.

METHODS: This retrospective, single-tertiary center study included patients who underwent MH surgery between January 2015 and September 2023. Patients with characteristic optical coherence tomography (OCT) findings of MacTel in both eyes or those who underwent fluorescence angiography were classified as having MacTel MH. Baseline and postoperative best-corrected visual acuity and OCT parameters were reviewed.

RESULTS: Totally, 27 and 243 eyes with MacTel and idiopathic MH, respectively, were included. MH closure rate was better achieved in idiopathic than in MacTel MH group at 2 years postoperatively. Temporal recovery of ellipsoid zone and external limiting membrane was more prominent in MacTel than in idiopathic MH group. Statistically significant visual acuity improvement was seen between 3 months and 2 years postoperatively in MacTel MH group.

CONCLUSION: To the best of our knowledge, this is the first study to analyze the surgical outcomes of MacTel MH in both anatomical and functional aspects and compare them with patients with idiopathic MH. Postoperative microglia change would have affected the restoration of outer retinal layer of patients; however, further studies are needed for clarification.

PMID:39151202 | DOI:10.1097/IAE.0000000000004249