Publications by authors named "Ross Williams"

Background: Prognostic models help aid medical decision-making. Various prognostic models are available via websites such as MDCalc, but these models typically predict one outcome, for example, stroke risk. Each model requires individual predictors, for example, age, lab results and comorbidities.

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  • The study investigated the relationship between testosterone levels, muscle mass, and strength in pre-menopausal females undergoing a 12-week resistance training program, finding no link with total circulating testosterone.
  • Bioavailable testosterone and the localization of androgen receptors (AR) in the nucleus were positively associated with muscle mass and strength, suggesting a unique role of these factors in muscle development for females.
  • In vitro experiments indicated that high doses of testosterone increased muscle cell size without activating the previously assumed Akt/mTOR pathway, instead enhancing the nuclear presence of the AR.
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  • Researchers aimed to create and validate new models to predict the risk of dementia over the next five years, focusing on ease of implementation and lower complexity.
  • They used logistic regression models across five observational databases, employing regularization methods like L1 and Broken Adaptive Ridge (BAR) to improve model performance with different sets of predictors, including age, sex, and disease-related factors.
  • The study found that BAR was more effective for variable selection compared to L1 and that adding relevant predictors improved model accuracy, although results varied between German and US data, with the BAR model on the clinically relevant predictor set performing best overall.
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Objective: This study evaluates regularization variants in logistic regression (L1, L2, ElasticNet, Adaptive L1, Adaptive ElasticNet, Broken adaptive ridge [BAR], and Iterative hard thresholding [IHT]) for discrimination and calibration performance, focusing on both internal and external validation.

Materials And Methods: We use data from 5 US claims and electronic health record databases and develop models for various outcomes in a major depressive disorder patient population. We externally validate all models in the other databases.

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Purpose: To develop prediction models for short-term mortality risk assessment following colorectal cancer surgery.

Methods: Data was harmonized from four Danish observational health databases into the Observational Medical Outcomes Partnership Common Data Model. With a data-driven approach using the Least Absolute Shrinkage and Selection Operator logistic regression on preoperative data, we developed 30-day, 90-day, and 1-year mortality prediction models.

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The Health-Analytics Data to Evidence Suite (HADES) is an open-source software collection developed by Observational Health Data Sciences and Informatics (OHDSI). It executes directly against healthcare data such as electronic health records and administrative claims, that have been converted to the Observational Medical Outcomes Partnership (OMOP) Common Data Model. Using advanced analytics, HADES performs characterization, population-level causal effect estimation, and patient-level prediction, potentially across a federated data network, allowing patient-level data to remain locally while only aggregated statistics are shared.

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Lipids are a geologically robust class of organics ubiquitous to life as we know it. Lipid-like soluble organics are synthesized abiotically and have been identified in carbonaceous meteorites and on Mars. Ascertaining the origin of lipids on Mars would be a profound astrobiological achievement.

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Aging is associated with a loss of skeletal muscle mass and function that negatively impacts the independence and quality of life of older individuals. Females demonstrate a distinct pattern of muscle aging compared to males, potentially due to menopause, when the production of endogenous sex hormones declines. This systematic review aims to investigate the current knowledge about the role of estrogen in female skeletal muscle aging.

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The Deposit, Evaluate and Lookup Predictive Healthcare Information (DELPHI) library provides a centralised location for the depositing, exploring and analysing of patient-level prediction models that are compatible with data mapped to the observational medical outcomes partnership common data model.

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We investigated a stacking ensemble method that combines multiple base learners within a database. The results on external validation across four large databases suggest a stacking ensemble could improve model transportability.

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  • The study aimed to create and validate prediction models to identify rheumatoid arthritis (RA) patients at high risk for adverse health outcomes while starting first-line methotrexate (MTX) treatment.
  • Data from 15 different claims and health record databases across 9 countries were analyzed, focusing on risks for various conditions at different time frames (3 months, 2 years, and 5 years) after treatment initiation.
  • The models showed good performance in predicting serious infections, myocardial infarction, and stroke, indicating potential for practical clinical application in monitoring RA patients on MTX.
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In the United States, nearly 28 people die in alcohol-related motor vehicle crashes every day (1 fatality every 52 min). Over decades, states have enacted multiple laws to reduce such fatalities. From 1982 to 2019, the proportion of drivers in fatal crashes with a blood alcohol concentration (BAC) above 0.

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  • This study explores the use of ensemble approaches to improve the accuracy and transportability of prognostic models across different healthcare databases.
  • Five single database models were trained independently, and various ensemble techniques (like fusion and stacking) were tested to see if they performed better on unseen data compared to individual models.
  • Results showed that fusion ensembles generally performed better and were more stable when applied to new datasets, while stacking ensembles struggled with limited label information and calibration issues persisted across all models.
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  • External validation of prediction models in healthcare is essential but difficult due to inconsistencies in healthcare databases; improved interoperability can help standardize this process.
  • The Iterative Pairwise External Validation (IPEV) framework allows for a more contextualized assessment of model performance by rotating model development and validation across multiple databases.
  • In a study involving 403,187 patients with type 2 diabetes, five predictive models for heart failure risk were developed and showed strong internal performance, but validation in new databases revealed varying effectiveness for three of the models.
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Objective: This systematic review aims to assess how information from unstructured text is used to develop and validate clinical prognostic prediction models. We summarize the prediction problems and methodological landscape and determine whether using text data in addition to more commonly used structured data improves the prediction performance.

Materials And Methods: We searched Embase, MEDLINE, Web of Science, and Google Scholar to identify studies that developed prognostic prediction models using information extracted from unstructured text in a data-driven manner, published in the period from January 2005 to March 2021.

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  • The study aimed to develop COVID-19 prediction models using influenza data to quickly and accurately assess risks of hospital admission and death in patients diagnosed with COVID-19.
  • The researchers created three COVID-19 Estimated Risk (COVER) scores that quantify risks related to pneumonia and mortality based on historical data and validated them using a large dataset of COVID-19 patients across multiple countries.
  • They found that seven key health predictors, along with age and sex, effectively distinguished which patients were likely to face severe outcomes, achieving strong performance in model validation.
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Objectives: This systematic review aims to provide further insights into the conduct and reporting of clinical prediction model development and validation over time. We focus on assessing the reporting of information necessary to enable external validation by other investigators.

Materials And Methods: We searched Embase, Medline, Web-of-Science, Cochrane Library, and Google Scholar to identify studies that developed 1 or more multivariable prognostic prediction models using electronic health record (EHR) data published in the period 2009-2019.

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Background: Increasing evidence suggests that sarcopenia and a higher systemic immune-inflammation index (SII) are linked with morbidity in patients with COPD. However, whether these two conditions contribute to all-cause mortality in middle-aged and older patients with COPD or asthma is unclear. Therefore, we investigated the association between sarcopenia, SII, COPD or asthma and all-cause mortality in a large-scale population-based setting.

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Objectives: The aim was to develop a prediction model of sustained remission after cessation of biologic or targeted synthetic DMARD (b/tsDMARD) in RA.

Methods: We conducted an explorative cohort study among b/tsDMARD RA treatment episode courses stopped owing to remission in the Swiss Clinical Quality Management registry (SCQM; 2008-2019). The outcome was sustained b/tsDMARD-free remission of ≥12 months.

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Purpose: The purpose of this study was to develop and validate a prediction model for 90-day mortality following a total knee replacement (TKR). TKR is a safe and cost-effective surgical procedure for treating severe knee osteoarthritis (OA). Although complications following surgery are rare, prediction tools could help identify high-risk patients who could be targeted with preventative interventions.

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Doppler ultrasound has become a standard method used to diagnose and grade vascular diseases and monitor their progression. Conventional focused-beam color Doppler imaging is routinely used in clinical practice, but suffers from inherent trade-offs between spatial, temporal and velocity resolution. Newer, plane-wave Doppler imaging offers rapid simultaneous acquisition of B-mode, color and spectral Doppler information across large fields of view, making it a potentially useful method for quantitative estimation of blood flow velocities in the clinic.

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Sarcopenia is a heterogeneous skeletal muscle disorder involving the loss of muscle mass and function. However, the prevalence of sarcopenia based on the most recent definition remains to be determined in older people with chronic airway diseases. The aim was to evaluate sarcopenia prevalence and association with chronic airway diseases and its lung function in an older population, using the European Working Group on Sarcopenia in Older People 2 (EWGSOP2) criteria.

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  • The COVID-19 vulnerability (C-19) index was developed to predict which patients might need hospitalization for pneumonia related to COVID-19 but is at risk of bias and lacks external validation.
  • The study aimed to externally validate the C-19 index using data from various healthcare settings and target populations to determine its predictive capabilities for hospitalization due to pneumonia.
  • Results showed that while the C-19 index performed moderately well in internal validation, its external validation yielded low predictive accuracy across different countries, suggesting that it may underestimate the actual risk of hospitalization.
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Background: Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) have been postulated to affect susceptibility to COVID-19. Observational studies so far have lacked rigorous ascertainment adjustment and international generalisability. We aimed to determine whether use of ACEIs or ARBs is associated with an increased susceptibility to COVID-19 in patients with hypertension.

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