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Nevin Manimala Statistics

A Note on Improving Variational Estimation for Multidimensional Item Response Theory

Psychometrika. 2023 Nov 18. doi: 10.1007/s11336-023-09939-0. Online ahead of print.

ABSTRACT

Survey instruments and assessments are frequently used in many domains of social science. When the constructs that these assessments try to measure become multifaceted, multidimensional item response theory (MIRT) provides a unified framework and convenient statistical tool for item analysis, calibration, and scoring. However, the computational challenge of estimating MIRT models prohibits its wide use because many of the extant methods can hardly provide results in a realistic time frame when the number of dimensions, sample size, and test length are large. Instead, variational estimation methods, such as Gaussian variational expectation-maximization (GVEM) algorithm, have been recently proposed to solve the estimation challenge by providing a fast and accurate solution. However, results have shown that variational estimation methods may produce some bias on discrimination parameters during confirmatory model estimation, and this note proposes an importance-weighted version of GVEM (i.e., IW-GVEM) to correct for such bias under MIRT models. We also use the adaptive moment estimation method to update the learning rate for gradient descent automatically. Our simulations show that IW-GVEM can effectively correct bias with modest increase of computation time, compared with GVEM. The proposed method may also shed light on improving the variational estimation for other psychometrics models.

PMID:37979074 | DOI:10.1007/s11336-023-09939-0

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Nevin Manimala Statistics

Virtual reality is effective in the management of chronic low back ache in adults: a systematic review and meta-analysis of randomized controlled trials

Eur Spine J. 2023 Nov 18. doi: 10.1007/s00586-023-08040-5. Online ahead of print.

ABSTRACT

BACKGROUND: Chronic low back ache (CLBA) is a common condition that is conventionally managed with physical therapy and analgesics. Recently, virtual reality-based interventions have been tried out in the management of CLBA. Their effectiveness, however has not been established. This meta-analysis aims to find out if the application of VR will lead to better pain relief, as compared to conventional techniques in adults with CLBA.

METHODS: The literature search was carried out in three online databases for potential randomized controlled trials that compared VR-based interventions with conventional treatment in CLBA. Data on outcome parameters were recorded. Meta-analysis was carried out with the help of appropriate software.

RESULTS: Seven studies having data on 507 subjects were included in the meta-analysis. Their mean ages were 48.4 years. There were 252 subjects in the VR group and 255 in the control group. VR-based interventions were found to have a statistically significant improvement in the pain intensity compared with conventional techniques (p – 0.005).

CONCLUSION: VR-based interventions are effective in the management of CLBA in the short term. Further research with longer follow-up is required to evaluate if these improvements are persistent in the long term.

PMID:37979068 | DOI:10.1007/s00586-023-08040-5

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Nevin Manimala Statistics

Epidemiological and clinical characteristics of children with peripheral neuroblastic tumors: a study on a Moroccan population

J Cancer Res Clin Oncol. 2023 Nov 18. doi: 10.1007/s00432-023-05502-7. Online ahead of print.

ABSTRACT

PURPOSE: Peripheral neuroblastic tumors are the most common extracranial cancers found in children, and they are characterized by a diverse spectrum of clinical manifestations and heterogeneous behaviors. This study aimed to investigate the epidemiological and clinical characteristics of children with peripheral neuroblastic tumors admitted to the Department of Pediatric Hematology and Oncology of the Hospital August 20 in Casablanca.

METHODS: The medical files of 48 children with peripheral neuroblastic tumors addressed to our department between February 2018 and February 2023 were reviewed. The clinical and demographic characteristics of patients were analyzed by the Statistical Package for the Social Sciences (SPSS), survival curves were obtained by Kaplan-Meier technique, and we assigned the tumor stage to patients based on the International Neuroblastoma Risk Group Staging System (INRGSS).

RESULTS: The median age of diagnosis was 30 months (1-174), with a ratio F/M of 1.28. 93.75% of patients had neuroblastoma, and the rest had ganglioneuroma. About 64.6% of patients had at their initial presentations stage M of peripheral neuroblastic tumors. The adrenal region made up 71% of the primary tumor site. The bone was one of the most prevalent metastatic sites (54.2%). The five-year overall survival rate was 35.4%.

CONCLUSION: Overall, this study revealed a high stage of peripheral neuroblastic tumors in the majority of the diagnosed patients in our Department of Pediatric Hematology and Oncology. Moreover, the heterogeneity of peripheral neuroblastic tumors makes clinical recognition difficult and, in general, too late.

PMID:37979055 | DOI:10.1007/s00432-023-05502-7

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Nevin Manimala Statistics

Causal Association of Cytokines and Growth Factors with Stroke and Its Subtypes: a Mendelian Randomization Study

Mol Neurobiol. 2023 Nov 18. doi: 10.1007/s12035-023-03752-7. Online ahead of print.

ABSTRACT

Cytokines and growth factors contribute to nerve growth and angiogenesis and are associated with the development of vascular disease. This Mendelian randomization (MR) study was designed to examine the causal relationship between factors associated with stem cell paracrine mechanisms and with stroke and its subtypes. We used pooled statistics on cytokine levels from three studies (INTERIAL, Olink Proseek CVD array, and KORA) encompassing 7795 participants in Europe. Data for stroke and its subtypes were pooled from these European populations (40,585 cases and 406,111 controls) in a multiprogenitor genome-wide association study (GWAS). MR was performed using established analytical methods, including inverse variance weighting (IVW), weighted median (WM), and MR-Egger. Genetically determined high IGF-1 levels were found to associate negatively with risk of stroke, ischemic stroke (large-artery atherosclerosis), and ischemic stroke (cardiogenic embolism). Meanwhile, high IL-13 levels had a positive causal relationship with ischemic stroke (large-artery atherosclerosis). An additional 27 cytokines were found to have a causal association with stroke or its subtypes. However, these results should be interpreted with caution given that the power efficacy was <80%. This MR study supports the concept of a causal relationship of 29 cytokines with stroke or its subtypes. Our genetic analysis provides new insights into stroke prevention and treatment by demonstrating an association of stem cell paracrine-related cytokines with stroke risk.

PMID:37979035 | DOI:10.1007/s12035-023-03752-7

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Nevin Manimala Statistics

Explainability of random survival forests in predicting conversion risk from mild cognitive impairment to Alzheimer’s disease

Brain Inform. 2023 Nov 18;10(1):31. doi: 10.1186/s40708-023-00211-w.

ABSTRACT

Random Survival Forests (RSF) has recently showed better performance than statistical survival methods as Cox proportional hazard (CPH) in predicting conversion risk from mild cognitive impairment (MCI) to Alzheimer’s disease (AD). However, RSF application in real-world clinical setting is still limited due to its black-box nature.For this reason, we aimed at providing a comprehensive study of RSF explainability with SHapley Additive exPlanations (SHAP) on biomarkers of stable and progressive patients (sMCI and pMCI) from Alzheimer’s Disease Neuroimaging Initiative. We evaluated three global explanations-RSF feature importance, permutation importance and SHAP importance-and we quantitatively compared them with Rank-Biased Overlap (RBO). Moreover, we assessed whether multicollinearity among variables may perturb SHAP outcome. Lastly, we stratified pMCI test patients in high, medium and low risk grade, to investigate individual SHAP explanation of one pMCI patient per risk group.We confirmed that RSF had higher accuracy (0.890) than CPH (0.819), and its stability and robustness was demonstrated by high overlap (RBO > 90%) between feature rankings within first eight features. SHAP local explanations with and without correlated variables had no substantial difference, showing that multicollinearity did not alter the model. FDG, ABETA42 and HCI were the first important features in global explanations, with the highest contribution also in local explanation. FAQ, mPACCdigit, mPACCtrailsB and RAVLT immediate had the highest influence among all clinical and neuropsychological assessments in increasing progression risk, as particularly evident in pMCI patients’ individual explanation. In conclusion, our findings suggest that RSF represents a useful tool to support clinicians in estimating conversion-to-AD risk and that SHAP explainer boosts its clinical utility with intelligible and interpretable individual outcomes that highlights key features associated with AD prognosis.

PMID:37979033 | DOI:10.1186/s40708-023-00211-w

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Nevin Manimala Statistics

Reduction of contrast medium for transcatheter aortic valve replacement planning using a spectral detector CT: a prospective clinical trial

Eur Radiol. 2023 Nov 18. doi: 10.1007/s00330-023-10403-x. Online ahead of print.

ABSTRACT

INTRODUCTION: This study investigated the use of dual-energy spectral detector computed tomography (CT) and virtual monoenergetic imaging (VMI) reconstructions in pre-interventional transcatheter aortic valve replacement (TAVR) planning. We aimed to determine the minimum required contrast medium (CM) amount to maintain diagnostic CT imaging quality for TAVR planning.

METHODS: In this prospective clinical trial, TAVR candidates received a standardized dual-layer spectral detector CT protocol. The CM amount (Iohexol 350 mg iodine/mL, standardized flow rate 3 mL/s) was reduced systematically after 15 patients by 10 mL, starting at 60 mL (institutional standard). We evaluated standard, and 40- and 60-keV VMI reconstructions. For image quality, we measured signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and diameters in multiple vessel sections (i.e., aortic annulus: diameter, perimeter, area; aorta/arteries: minimal diameter). Mixed regression models (MRM), including interaction terms and clinical characteristics, were used for comparison.

RESULTS: Sixty consecutive patients (mean age, 79.4 ± 7.5 years; 28 females, 46.7%) were included. In pre-TAVR CT, the CM reduction to 40 mL is possible without affecting the image quality (MRM: SNR: -1.1, p = 0.726; CNR: 0.0, p = 0.999). VMI 40-keV reconstructions showed better results than standard reconstructions with significantly higher SNR (+ 6.04, p < 0.001). Reduction to 30 mL CM resulted in a significant loss of quality (MRM: SNR: -12.9, p < 0.001; CNR: -13.9, p < 0.001), regardless of the reconstruction. Across the reconstructions, we observed no differences in the metric evaluation (p > 0.914).

CONCLUSION: Among TAVR candidates undergoing pre-interventional CT at a dual-layer spectral detector system, applying 40 mL CM is sufficient to maintain diagnostic image quality. VMI 40-keV reconstructions improve the vessel attenuation and are recommended for evaluation.

CLINICAL RELEVANCE STATEMENT: Contrast medium reduction to 40 mL in pre-interventional transcatheter aortic valve replacement CT using dual-energy CT maintains image quality, while 40-keV virtual monoenergetic imaging reconstructions enhance vessel attenuation. These results offer valuable recommendations for interventional transcatheter aortic valve replacement evaluation and potentially improve nephroprotection in patients with compromised renal function.

KEY POINTS: • Patients undergoing transcatheter aortic valve replacement (TAVR), requiring pre-interventional CT, are often multimorbid with impaired renal function. • Using a spectral detector dual-layer CT, contrast medium reduction to 40 mL is feasible, maintaining diagnostic image quality. • The additional application of virtual monoenergetic image reconstructions with 40 keV improves vessel attenuation significantly in clinical practice.

PMID:37979008 | DOI:10.1007/s00330-023-10403-x

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A Cross-Sectional Comparative Study of Nurses’ and Family Members’ Perceptions on Priority and Satisfaction in Meeting the Needs of Family Members at the Emergency Department

J Emerg Nurs. 2023 Nov 17:S0099-1767(23)00253-2. doi: 10.1016/j.jen.2023.10.003. Online ahead of print.

ABSTRACT

INTRODUCTION: Family members experience considerable physiological, psychological, and emotional pressure when accompanying a critically ill relative in the emergency department. The culture and context of care influence the needs of the family, and a thorough understanding of these needs by health care professionals is essential to providing patient- and family-centered care. This study aimed to compare nurses’ and family members’ perceptions of the priorities of family member needs and their satisfaction with meeting those needs in the emergency department.

METHODS: A comparative, cross-sectional descriptive study was conducted. Participants were 140 family members of patients receiving care and 122 nurses working in the emergency department in hospitals of Tabriz University of Medical Science, in Iran. The data were collected through Critical Care Family Needs Inventory-ED and analyzed with SPSS Statistics software.

RESULTS: Family members rated their care needs as significantly greater than did nurses (129.45 [31.5] vs 124.45 [24.8], P = .003). Families rated their needs as having been met significantly less than the nurses estimated (103.6 [17.6] vs 110.8 [19.61], P < .05).

DISCUSSION: The perceived importance of the patient’s family’s needs differed from the viewpoints of the patient’s family members and the nurses. In addition, emergency nurses overestimated the extent to which family members’ needs were met compared with family members. To more adequately gauge and meet the needs of family members, nurses need to acquire more knowledge about patient family needs in the emergency department.

PMID:37978980 | DOI:10.1016/j.jen.2023.10.003

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Ninety-Hz Spinal Cord Stimulation-Induced Analgesia Is Dependent on Active Charge Balance and Is Nonlinearly Related to Amplitude: A Sham-Controlled Behavioral Study in a Rodent Model of Chronic Neuropathic Pain

Neuromodulation. 2023 Nov 16:S1094-7159(23)00751-1. doi: 10.1016/j.neurom.2023.09.005. Online ahead of print.

ABSTRACT

BACKGROUND: Ninety-Hz active-recharge spinal cord stimulation (SCS) applied at below sensory-threshold intensity, as used with fast-acting subperception therapy spinal cord stimulation, has been shown clinically to produce significant analgesia, but additional characterization is required to better understand the therapy. This preclinical study investigates the behavioral effect of multiple 90-Hz SCS variants in a rodent model of neuropathic pain, focusing on charge balance and the relationship between 90-Hz efficacy and stimulation intensity.

MATERIALS AND METHODS: Rats (n = 24) received a unilateral partial sciatic nerve ligation to induce neuropathic pain and were implanted with a quadripolar lead at T13. Mechanical hypersensitivity was assessed before, during, and after 60 minutes of SCS. After a prescreen with 50-Hz SCS 67% motor threshold ([MT], the positive control), rats underwent a randomized-crossover study including sham SCS and several 90-Hz SCS paradigms (at 40% MT or 60% MT, either using active or pseudopassive recharge) (experiment 1, n = 16). A second, identical experiment (experiment 2) was performed to supplement data with 90-Hz SCS at 20% and 80% MT (experiment 2, n = 8).

RESULTS: Experiment 1: At 40% MT, 90-Hz active-recharge SCS produced a significantly larger recovery to baseline than did 90-Hz pseudopassive SCS at both tested intensities and sham SCS. Experiment 2: Only the 90-Hz SCS active recharge at 40% MT and 50-Hz SCS positive control caused mean recovery to baseline that was statistically better than that of sham SCS.

CONCLUSIONS: The degree to which 90-Hz SCS reduced mechanical hypersensitivity during stimulation depended on the nature of charge balance, with 90-Hz active-recharge SCS generating better responses than did 90-Hz pseudopassive recharge SCS. In addition, our findings suggest that the amplitude of 90-Hz active-recharge SCS must be carefully configured for efficacy.

PMID:37978974 | DOI:10.1016/j.neurom.2023.09.005

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Stir-up Regimen After General Anesthesia in the Postanesthesia Care Unit: A Nurse Led Stepped Wedge Cluster Randomized Control Trial

J Perianesth Nurs. 2023 Nov 16:S1089-9472(23)00888-2. doi: 10.1016/j.jopan.2023.07.014. Online ahead of print.

ABSTRACT

PURPOSE: To implement a standardized Stir-up Regimen (deep breathing, coughing, repositioning, mobilization [moving arms/legs], assessing and managing pain and nausea) within the first 30 minutes of arrival in the postanesthesia care unit (PACU), with a goal of decreasing recovery time in the immediate postanesthesia period (Phase I).

DESIGN: A pragmatic stepped wedge cluster randomized control trial. Initially, data were collected on time in Phase I in three PACUs (control). Subsequently, the same three units were randomized to sequentially transition to the Stir-up Regimen (intervention).

METHODS: A stepped wedge cluster randomized control trial design was used to implement a standardized Stir-up Regimen in three PACUs in an academic hospital for adult patients who received at least 30 minutes of general anesthesia. The measured outcome was the PACU time in minutes from patient arrival to when the patient met Phase I discharge criteria. Differences between intervention and control groups were evaluated using a generalized mixed-effects model. Nurses were educated about the Stir-up Regimen in team huddles, in-services, video demonstrations, email notifications/reminders and reminders, and immediate feedback at the bedside. Implementation science principles were used to assess the adoption of the Stir-up Regimen through a presurvey, postsurvey and spot-check observations in all three PACUs.

FINDINGS: A total of 5,809 PACU adult patient admissions were included: control group (n = 2,860); intervention group (n = 2,949); males (n = 2,602), and females (n = 3,206). The intervention was associated with a reduction in overall mean Phase I recovery time of 4.9 minutes (95% CI: -8.4 to -1.4, P = .007). One PACU decreased time by 9.6 minutes (95% CI: -15.3 to -4.0, P < .001). The other units also reduced Phase I recovery time, but this did not reach statistical significance. The spot-check observations confirmed the intervention was adopted by the nurses, as most interventions were nurse-initiated versus patient-initiated during the first 30 minutes in PACU.

CONCLUSIONS: Standardization of a Stir-up Regimen within 30 minutes of patient PACU arrival resulted in decreased Phase I recovery time.

PMID:37978971 | DOI:10.1016/j.jopan.2023.07.014

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Determinants of adherence to treatment in patients with ophthalmic conditions

Expert Rev Clin Pharmacol. 2023 Nov 18:1-11. doi: 10.1080/17512433.2023.2279740. Online ahead of print.

ABSTRACT

BACKGROUND: The objective of this study was to identify and determine factors associated with patients’ ophthalmic adherence in common ocular conditions from randomized clinical trials (RCT).

RESEARCH DESIGN METHODS: A univariate analysis with proportions, a bivariate analysis using polychoric correlations, and logistic regression (LR) models were used. The collected dataset was made up of records from RCT. Using three validated LR models, factors were identified and ranked based on their adjusted odds ratio and their statistical significance to adherence.

RESULTS: A total of 1,087 valid patients were included in this analysis, of which 88.96% presented adherence. All models were calibrated, had a good performance, were well specified and cost-effective using the Hosmer-Lemeshow test, metrics for class imbalance, link test approach and Akaike’s criteriums, respectively.

CONCLUSION: We identified as determinants for encouraging good ophthalmic adherence the adverse events presented, duration of the study, female sex, and older age; other determinants such as medical condition, protocol treatment, type of treatment and disease are all risk factors for adherence. Improvements in ophthalmic adherence may be achieved by focused attention to young male patients with chronic degenerative diseases such as glaucoma or ocular hypertension (especially those who need combination therapy) and developing medications with reduced side effects.

PMID:37978952 | DOI:10.1080/17512433.2023.2279740