1,405 research outputs found
Zinc-methionine supplementation for dairy cows: a study of effects on plasma zinc, wound healing, mammary health, and immune responses
Psychometric sensitivity analyses can identify bias related to measurement properties in trials that use patient-reported outcome measures : a secondary analysis of a clinical trial using the disabilities of the arm, shoulder and hand questionnaire
Objectives
Demonstrate psychometric sensitivity analyses for testing the stability of study findings to assumptions made about patient-reported outcome measures.
Study Design and Setting
We performed secondary analyses of Disability of Arm, Shoulder, and Hand (DASH) data collected within the Prevention of Shoulder Problems clinical trial, which compared upper limb function scores in women who had undergone breast cancer surgery, randomized to either an exercise program or usual care. We repeated the principal trial analyses after grouping DASH items into subscales suggested by factorial analyses in this dataset and applied item response theory to account for unequal item weighting. We checked for measurement invariance by participant age and response shift bias using established techniques.
Results
Our analyses suggested that the DASH measured two constructs: motor function and sensory symptoms. The majority of the six-month difference in DASH score was driven by motor function. With item response theory scoring, we found differences in both constructs at 12 months (P = 0.019 and P = 0.007), but in neither construct at 6 months, contrary to the original trial results. We found no differential item function by age or between baseline and 12-month measurements.
Conclusions
Psychometric sensitivity analyses aid in the interpretation of the Prevention of Shoulder Problems trial’s results
The use of Botulinum toxin in the management of Hidradenitis Suppurativa : a systematic review
Background:
Hidradenitis suppurativa (HS) is a chronic inflammatory skin condition characterized by suppurative infection, sinus tract, and abscess formation. International management guidelines are largely consensus-based. Botulinum toxin (BTX) has been widely used in the treatment of apocrine and eccrine gland disorders, such as hyperhidrosis, although the effectiveness of BTX in the treatment of HS remains unknown. The aim of this systematic review was to understand the published evidence of BTX safety and effectiveness in the management of HS.
Methods:
We conducted a PRISMA-compliant, prospectively registered (PROSPERO, CRD42021228732), systematic review. We devised bespoke search strategy and applied it to the Cochrane Central Register of Controlled Trials, Medline, Embase, and OpenGrey up until March 2022. We included all clinical studies that reported outcomes following BTX treatment in patients diagnosed with HS (both adult and pediatric).
Results:
A total of 4658 studies were identified, of which six met full inclusion criteria reporting data on 26 patients. The six identified studies included one randomized control trial, one case series, and four case studies. The one included randomized control trial demonstrated a significant reduction in the Dermatology Life Quality Index score at 3 months following treatment with BTX.
Conclusions:
The effectiveness and safety of BTX in the treatment of HS remain unknown. This systematic review identified a paucity of high-quality clinical data. Evidence of treatment effectiveness is likely to come from registry-based cohort studies using established core outcome sets in the first instance
Modified scoring of the QuickDASH can achieve previously-unattained interval-level measurement in Dupuytren disease and carpal tunnel syndrome
Background: Rasch measurement theory can be used to identify scales within questionnaires and to map responses to more precise continuous scales. The aim of this article was to use RMT to refine the scoring of the QuickDASH in patients with Dupuytren disease and carpal tunnel syndrome (CTS). Methods: Data were collected between 2013 and 2019 from a single center in the UK. Preoperative QuickDASH responses from patients diagnosed with Dupuytren disease and CTS were used. RMT was used to reduce the number of items in the QuickDASH and examine the reliability and validity of each subscale. Results: The preoperative QuickDASH responses of 750 patients with Dupuytren disease and 1916 patients with CTS were used. The median age of participants was 61 years, and 46% were men. Exploratory factor analysis suggested two distinct subscales within the QuickDASH: task items 1–6 and symptom items 9–11. These items were fitted to the Rasch model, and disordered response thresholds were collapsed. In Dupuytren disease, the two worst responses or each item were disordered. After collapsing these options, good Rasch model fit was demonstrated. CTS responses fitted without modification. Item targeting was more appropriate for CTS than Dupuytren disease. Conclusions: This study proposes a modification to the scoring system for the QuickDASH that provides high-quality, continuous, and condition-specific scales for the QuickDASH. The identification of distinct subscales within the QuickDASH can be used to identify distinct improvements in hand function and/or symptoms in previous, current, and future work
Item response theory assumptions were adequately met by the Oxford hip and knee scores
Objectives:
To develop item response theory (IRT) models for the Oxford hip and knee scores which convert patient responses into continuous scores with quantifiable precision and provide these as web applications for efficient score conversion.
Study Design and Setting:
Data from the National Health Service patient-reported outcome measures program were used to test the assumptions of IRT (unidimensionality, monotonicity, local independence, and measurement invariance) before fitting models to preoperative response patterns obtained from patients undergoing primary elective hip or knee arthroplasty. The hip and knee datasets contained 321,147 and 355,249 patients, respectively.
Results:
Scree plots, Kaiser criterion analyses, and confirmatory factor analyses confirmed unidimensionality and Mokken analysis confirmed monotonicity of both scales. In each scale, all item pairs shared a residual correlation of ≤ 0.20. At the test level, both scales showed measurement invariance by age and gender. Both scales provide precise measurement in preoperative settings but demonstrate poorer precision and ceiling effects in postoperative settings.
Conclusion:
We provide IRT parameters and web applications that can convert Oxford Hip Score or Oxford Knee Score response sets into continuous measurements and quantify individual measurement error. These can be used in sensitivity analyses or to administer truncated and individualized computerized adaptive tests
Computerized adaptive testing of symptom severity : a registry-based study of 924 patients with trapeziometacarpal arthritis
We aimed to develop a computerized adaptive testing (CAT) version of the 11 item Patient Evaluation Measure (PEM), using an item response theory model. This model transformed the ordinal scores into ratio-interval scores. We obtained PEM responses from 924 patients with trapeziometacarpal osteoarthritis to build a CAT model and tested its performance on a simulated cohort of 1000 PEM response sets. The CAT achieved high precision (median standard error or measurement 0.26) and reduced the number of questions needed for accurate scoring from 11 to median two. The CAT scores and item-response-theory-based 15-item PEM scores were similar, and a Bland–Altman analysis demonstrated a mean score difference of 0.2 between the CAT and the full-length PEM scores on a scale from 0 to 100. We conclude that the CAT substantially reduced the burden of the PEM while also harnessing the validity of item response theory scoring
Item response theory may account for unequal item weighting and individual-level measurement error in trials that use PROMs : a psychometric sensitivity analysis of the TOPKAT trial
To apply item response theory as a framework for studying measurement error in superiority trials which use patient-reported outcome measures (PROMs). We reanalyzed data from the TOPKAT trial, which compared the Oxford Knee Score (OKS) responses of patients undergoing partial or total knee replacement, using traditional sum-scoring, after accounting for OKS item characteristics with expected a posteriori (EAP) scoring, and after accounting for individual-level measurement error with plausible value imputation (PVI). We compared the marginalized mean scores of each group at baseline, 2 months, and yearly for 5 years. We used registry data to estimate the minimal important difference (MID) of OKS scores with sum-scoring and EAP scoring. With sum-scoring, we found statistically significant differences in mean OKS score at 2 months (p=0.030) and 1 year (p=0.030). EAP scores produced slightly different results, with statistically significant differences at 1 year (p=0.041) and 3 years (p=0.043). With PVI, there were no statistically significant differences. Psychometric sensitivity analyses can be readily performed for superiority trials using PROMs and may aid the interpretation of results. [Abstract copyright: Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.
Recursive partitioning vs computerized adaptive testing to reduce the burden of health assessments in cleft lip and/or palate : comparative simulation study
Background:
Computerized adaptive testing (CAT) has been shown to deliver short, accurate, and personalized versions of the CLEFT-Q patient-reported outcome measure for children and young adults born with a cleft lip and/or palate. Decision trees may integrate clinician-reported data (eg, age, gender, cleft type, and planned treatments) to make these assessments even shorter and more accurate.
Objective:
We aimed to create decision tree models incorporating clinician-reported data into adaptive CLEFT-Q assessments and compare their accuracy to traditional CAT models.
Methods:
We used relevant clinician-reported data and patient-reported item responses from the CLEFT-Q field test to train and test decision tree models using recursive partitioning. We compared the prediction accuracy of decision trees to CAT assessments of similar length. Participant scores from the full-length questionnaire were used as ground truth. Accuracy was assessed through Pearson’s correlation coefficient of predicted and ground truth scores, mean absolute error, root mean squared error, and a two-tailed Wilcoxon signed-rank test comparing squared error.
Results:
Decision trees demonstrated poorer accuracy than CAT comparators and generally made data splits based on item responses rather than clinician-reported data.
Conclusions:
When predicting CLEFT-Q scores, individual item responses are generally more informative than clinician-reported data. Decision trees that make binary splits are at risk of underfitting polytomous patient-reported outcome measure data and demonstrated poorer performance than CATs in this study
Stock Market Integration, Return Forecastability and Implications for Market Efficiency: A Panel Study
Continent elevation, mountains, and erosion : freeboard implications
Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 114 (2009): B05410, doi:10.1029/2008JB006176.To the simplest approximation, Earth's continental crust is a floating aggregate on the planet's surface that is first attracted to subduction zones and, upon arrival, thickened by mountain building (then producing some extension). Thickened regions are thinned again by erosion. A comparison between 65 Ma and the present shows that the modern state is significantly more mountainous. An estimated average continental elevation increase relative to average ocean floor depth of about 54 m and sea level decrease relative to the ocean floor of about 102 m add up to a 156-m increase of continent elevation over sea level since 65 Ma. Both are affected most strongly by the roughly 1.7% continent surface area decrease caused by Cenozoic mountain building. This includes contributions from erosion. Volumes of sediments in deltas and submarine fans indicate an average thickness of 371 m deposited globally in the ocean basins since 65 Ma. This relatively large change of continent area over a short span of Earth history has significant consequences. Extrapolating, if continent area change exceeded 5% in the past, either severe erosion or flooded continents occurred. If continent elevation (freeboard) remains at the present value of a few hundred meters, the past continent-ocean area ratio might have been quite different, depending on earlier volumes of continental crust and water. We conclude that, along with the ages of ocean basins, continental crustal thickening exerts a first-order control on the global sea level over hundreds of million years
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