bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessing the State of Population Health by Age-adjusted Life Expectancies
Authors: Mehnert R. F. , Feldmann U. 
Published: March 2018

Summary

Objectives:
A gain in life expectancy of a population is commonly interpreted as an effect of improved health care. After the reunion of Germany in 1990 life expectancy at birth grew extremely in the new federal states. Within one decade after reunion the new federal states had a gain in life expectancy of about five years while the gain in the old federal states was only about two years.

Methods:
It has been widely argued that this phenomenon is caused by an obviously improved public health service and environmental protection or even by an increased social status in the new federal states. On the other hand, the median population age grew rapidly in the new federal states, caused by a dramatic reduction of the birth rate as well as a high emigration rate of young people. Using real time series for three selected federal states and for the total Federal Republic of Germany, it is derived that most of the gain in life expectancy is explained by population ageing.

Results:
An elementary probabilistic procedure is proposed allowing for estimating the amount in life expectancy not attributable to population ageing.

Conclusions:
The age-adjusted life expectancy can be regarded as an unbiased measure of a populations’ state of health that stays comparable both over time and across countries.
A Framework for Characterizing Terminological Systems
Authors: de Keizer N. F. , Abu-Hanna A. , Cornet R. 
Published: March 2018

Summary

Objectives:
The notion of a terminological system (TS) is complex due to the broad range of systems, applications, and clinical domains. A uniform approach to describe the characteristics of TSs is lacking. This impedes furthering understanding, applicability, mutual comparison and development of TSs. For these reasons we propose a terminological systems characterization framework.

Methods:
Relevant issues pertaining to TSs and terminology servers have been extracted from literature describing requirements and functionality of TSs. From these issues, features have been distilled and further refined. A categorization has been developed to provide a convenient arrangement of these features.

Results:
The framework distinguishes between application-dependent and application-independent features of TSs. Definitions are provided for measures of content coverage, which was identified as the only application-dependent feature. Application-independent features are categorized along two axes: their respective type of TS and the particular element within that system, i.e. the formalism, the content, or the functionality. For each feature we provide an explicit question, the answer to which yields a feature value. The framework has been applied to SNOMED CT and the CLUE browser.

Conclusions:
We present and apply a framework to support a feature-based characterization of terminological systems. Standardized methods for content coverage studies reduce the effort of assessing the applicability of a TS for a specific clinical setting. A two-axial categorization provides a convenient arrangement of the large number of application-independent features. Application of the framework increases comparability of terminological systems. This framework may also help TS developers determine how their system can be improved.
Assessing the Difficulty and Time Cost of De-identification in Clinical Narratives
Authors: Phillips W. F. , Phansalkar S. , Sims S. A. , Hurdle J. F. , Dorr D. A. 
Published: March 2018

Summary

Objective:
To characterize the difficulty confronting investigators in removing protected health information (PHI) from cross-discipline, free-text clinical notes, an important challenge to clinical informatics research as recalibrated by the introduction of the US Health Insurance Portability and Accountability Act (HIPAA) and similar regulations.

Methods:
Randomized selection of clinical narratives from complete admissions written by diverse providers, reviewed using a two-tiered rater system and simple automated regular expression tools. For manual review, two independent reviewers used simple search and replace algorithms and visual scanning to find PHI as defined by HIPAA, followed by an independent second review to detect any missed PHI. Simple automated review was also performed for the “easy” PHI that are number- or date-based.

Results:
From 262 notes, 2074 PHI, or 7.9 ± 6.1 per note, were found. The average recall (or sensitivity) was 95.9% while precision was 99.6% for single reviewers. Agreement between individual reviewers was strong (ICC = 0.99), although some asymmetry in errors was seen between reviewers (p = 0.001). The automated technique had better recall (98.5%) but worse precision (88.4%) for its subset of identifiers. Manually de-identifying a note took 87.3 ± 61 seconds on average.

Conclusions:
Manual de-identification of free-text notes is tedious and time-consuming, but even simple PHI is difficult to automatically identify with the exactitude required under HIPAA.
Process Potential Screening
Authors: Ammenwerth E. , Haux R. , Ehlers F. 
Published: March 2018

Summary

Objectives:
Hospitals are increasingly under pressure to optimize their processes. So far, an instrument to systematically identify the potentials for improvement of a given business process is missing. The aim of this project is to develop such an instrument.

Methods:
Initially, central aspects of the quality of a hospital process were identified on the basis of a systematic literature review. Secondary to that, criteria to measure quality aspects were defined: More than 300 criteria from medical and business informatics, economics and quality management publications were gathered and systematically aggregated.

Results:
As a result, the Process Potential Screening (PPS) instrument was developed. The PPS is a matrix containing two axes: Axis I comprises 30 quality aspects referring to results, execution and control of hospital processes. Axis II comprises 16 quality criteria (e.g., customer satisfaction, time). The PPS displays approximately 400 relevant combinations of those quality aspects and quality criteria that help to identify potentials for improvement of a given hospital process. It utilizes different methods for the measurement of the criteria and for application by way of individuals or groups.

Conclusions:
In using the PPS, relevant potentials for improvement were identified in ten typical hospital processes. The instrument’s practicability must now be examined in further studies by the final target group (e.g., quality or project managers, and the staff responsible for processes).
Estimates of the Number of Cancer Patients Hospitalized in a Geographic Area Using Claims Data without a Unique Personal Identifier
Authors: Couris C. M. , Gutknecht C. , Ecochard R. , Gelas-Dore B. , Hajri T. , Colin C. , Schott A.-M. 
Published: March 2018

Summary

Objective:
In French national claims databases, claims are currently anonymous i.e. not linked to individual patients. In order to improve our estimate of the medical activity related to cancer in one French region, a statistical method was developed to use claims data to assess the number of cancer patients hospitalized in acute care.

Methods:
This method used the medical and administrative information available in the claims (i.e. age, primary site, length of stay) to predict an average number of stays per patient, followed by a number of patients. It was based on a two-phase study design using an internal dataset which contained personal identifiers to estimate the model parameters.

Results:
The predicted number of acute care patients hospitalized in one or several health care centers in one French region was 38,109 with a 95% predictive interval (37,990; 38,228) for the first six months of 2002. A prediction error of 24% was found.

Conclusion:
We provide a good estimate of the morbidity in acute care hospitals using claims data that is not linked to individual patients. This estimate reflects the medical activity and can be used to anticipate acute care needs.
Two Models for Outcome Prediction
Authors: Linder R. , Weimar C. , Diener H. C. , Pöppl S. J. , Ziegler A. , König I. R. 
Published: March 2018

Summary

Objectives:
Accurately predicting disease progress from a set of predictive variables is an important aspect of clinical work. For binary outcomes, the classical approach is to develop prognostic logistic regression (LR) models. Alternatively, machine learning algorithms were proposed with artificial neural networks (ANN) having become popular over the last decades. Although some studies have compared predictive accuracies of LR and ANN models, some concerns regarding their methodological quality have been voiced. Our comparison has the advantage of being based on two large independent data sets allowing for elaborate model development and independent validation.

Methods:
From the German Stroke Database, a learning data set including 1754 prospectively recruited patients with acute ischemic stroke was used. Utilizing LR and ANN, two prognostic models were developed predicting restitution of functional independence and survival after 100 days. The resulting models were applied to classify 1470 patients with acute ischemic stroke; this test data set was collected independently from the learning data. Error fractions in the test data were determined, and differences in error fractions between the algorithms were calculated with 95% confidence intervals.

Results:
For most prognostic models, error fractions in the test data were below 40%. There was no difference between the algorithms except for the model predicting completely versus incompletely restituted or deceased patients (difference in error fractions = 4.01% [2.10-5.96%], p = 0.0001).

Conclusions:
The conscientiously applied LR remains the gold standard for prognostic modelling; however, ANN can be an alternative automated “quick and easy” multivariate analysis.
Measuring Agreement for Ordered Ratings in 3 x 3 Tables
Authors: Aubas P. , Seguret F. , Kramar A. , Dujols P. , Neveu D. 
Published: March 2018

Summary

Objectives:
When two raters consider a qualitative variable ordered according to three categories, the qualitative agreement is commonly assessed with a symmetrically weighted kappa statistic. However, these statistics can present paradoxes, since they may be insensitive to variations of either complete agreements or disagreements.

Methods:
Agreement may be summarized by the relative amounts of complete agreements, partial and maximal disagreements beyond chance. Fixing the marginal totals and the trace, we computed symmetrically weighted kappa statistics and we developed a new statistic for qualitative agreements. Data sets from the literature were used to illustrate the methods.

Results:
We show that agreement may be better assessed with the unweighted kappa index, κc, and a new statistic ζ, which assesses the excess of maximal disagreements with respect to the partial ones, and does not depend on a particular weighting system. When ζis equal to zero, maximal and partial disagreements beyond chance are equal. With its estimated large sample variance, we compared the values of two contingency tables.

Conclusions:
The (κc, ζ) pair is sensitive to variations in agreements and/or disagreements and enables locating the difference between two qualitative agreements. The qualitative agreement is better with increasing values of κc and ζ.
Electrodynamic Heart Model Construction and ECG Simulation
Authors: Huo M. , Wei Q. , Liu F. , Crozier S. , Xia L. 
Published: March 2018

Summary

Objectives:
In this paper, we present a unified electrodynamic heart model that permits simulations of the body surface potentials generated by the heart in motion. The inclusion of motion in the heart model significantly improves the accuracy of the simulated body surface potentials and therefore also the 12-lead ECG.

Methods:
The key step is to construct an electromechanical heart model. The cardiac excitation propagation is simulated by an electrical heart model, and the resulting cardiac active forces are used to calculate the ventricular wall motion based on a mechanical model. The source-field point relative position changes during heart systole and diastole. These can be obtained, and then used to calculate body surface ECG based on the electrical heart-torso model.

Results:
An electromechanical biventricular heart model is constructed and a standard 12-lead ECG is simulated. Compared with a simulated ECG based on the static electrical heart model, the simulated ECG based on the dynamic heart model is more accordant with a clinically recorded ECG, especially for the ST segment and T wave of a V1-V6 lead ECG. For slight-degree myocardial ischemia ECG simulation, the ST segment and T wave changes can be observed from the simulated ECG based on a dynamic heart model, while the ST segment and T wave of simulated ECG based on a static heart model is almost unchanged when compared with a normal ECG.

Conclusions:
This study confirms the importance of the mechanical factor in the ECG simulation. The dynamic heart model could provide more accurate ECG simulation, especially for myocardial ischemia or infarction simulation, since the main ECG changes occur at the ST segment and T wave, which correspond with cardiac systole and diastole phases.
The Impact of Rotary Blood Pump in Conjunction with Mechanical Ventilation on Ventricular Energetic Parameters
Authors: Darowski M. , Ferrari G. , Pisanelli D. M. , Tosti G. , De Lazzari C. 
Published: March 2018

Summary

Objectives:
Aim of this work is to study the impact of left ventricular rotary blood pump assistance, on energetic variables, when mechanical ventilation (MV) of the lungs is applied.

Methods:
Computer simulation was used to perform this study. Lumped parameter models reproduce the circulatory system. Variable elastance models reproduce the Starling’s law of the heart for each ventricle. After the reproduction of ischemic heart disease left ventricular assistance was applied using a model of rotary blood pump. The pump speed was changed in steps and was assumed to be constant during each step. The influence of mechanical ventilation was introduced by different values of positive mean thoracic pressure.

Results:
The increase of the rotational speed has a significant influence on some ventricular energetic variables. In fact it decreased left ventricular external work, left and right ventricular pressure-volume area and the left ventricular efficiency. Finally, it increased the right ventricular efficiency but had no influence on the right ventricular external work. The increase of thoracic pressure from –2 to +5 mmHg caused a significant decrease of external work, pressure-volume area (right ventricular pressure-volume area dropped up to 50%) and an increase of right ventricular efficiency (by 40%) while left ventricular efficiency remained almost stable.

Conclusions:
Numerical simulation is a very suitable tool to predict changes of not easily measurable parameters such as energetic ventricular variables when mechanical assistance of heart and/or lungs is applied independently or simultaneously.
Bayesian Random-effect Model for Predicting Outcome Fraught with Heterogeneity
Authors: Yen A. M. -F. , Liou H.-H. , Lin H.-L. , Chen T. H.-H. 
Published: March 2018

Summary

Objective:
The study aimed to develop a predictive model to deal with data fraught with heterogeneity that cannot be explained by sampling variation or measured covariates.

Methods:
The random-effect Poisson regression model was first proposed to deal with over-dispersion for data fraught with heterogeneity after making allowance for measured covariates. Bayesian acyclic graphic model in conjunction with Markov Chain Monte Carlo (MCMC) technique was then applied to estimate the parameters of both relevant covariates and random effect. Predictive distribution was then generated to compare the predicted with the observed for the Bayesian model with and without random effect. Data from repeated measurement of episodes among 44 patients with intractable epilepsy were used as an illustration.

Results:
The application of Poisson regression without taking heterogeneity into account to epilepsy data yielded a large value of heterogeneity (heterogeneity factor = 17.90, deviance = 1485, degree of freedom (df) = 83). After taking the random effect into account, the value of heterogeneity factor was greatly reduced (heterogeneity factor = 0.52, deviance = 42.5, df = 81). The Pearson χ2 for the comparison between the expected seizure frequencies and the observed ones at two and three months of the model with and without random effect were 34.27 (p = 1.00) and 1799.90 (p <0.0001), respectively.

Conclusion:
The Bayesian acyclic model using the MCMC method was demonstrated to have great potential for disease prediction while data show over-dispersion attributed either to correlated property or to subject-to-subject variability.
Modeling in Biomedical Informatics – An Exploratory Analysis (Part 1)
Authors: Hasman A. , Haux R. 
Published: March 2018

Summary

Objectives:
Modeling is a significant part of research, education and practice in biomedical and health informatics. Our objective was to explore, which types of models of processes are used in current biomedical/ health informatics research, as reflected in publications of scientific journals in this field. Also the implications for medical informatics curricula were investigated.

Methods:
Retrospective, prolective observational study on recent publications of the two official journals of the International Medical Informatics Association (IMIA), the International Journal of Medical Informatics (IJMI) and Methods of Information in Medicine (MIM).

Results:
384 publications have been analyzed, 190 of IJMI and 194 of MIM. In regular papers (69 in IJMI, 62 in MIM), analyzed here in part 1, all of these model types could be found. In many publications we observed a mixture of models, being used to solve the ‘core’ research questions and also to systematically evaluate the research done. Knowledge of (and models for) software engineering and project management are also often needed. IJMI seems to have a closer focus on research concerning health information systems and electronic patient records, with a strong emphasis on evaluation. MIM seems to have a broader range of research approaches, including also statistical modeling and computational intensive approaches. The aim to provide solutions for problems related to data, information and knowledge processing and to study the general principles of processing data, information and knowledge in medicine and health care in order to contribute to improve the quality of health care, and of research and education in medicine and the health sciences was given in all publications.

Conclusions:
Modeling continues to be a major task in research, education and practice in biomedical and health informatics. Knowledge and skills concerning a broad range of model types is needed.
Integrating Genomics into Health Information Systems
Authors: Maojo V. , Lopez-Campos G. , Martin-Sanchez F. 
Published: March 2018

Summary
Objective: To outline the main issues related to the impact of the data generated by the Human Genome Project on health information systems. A major challenge for medical informatics is identified, consisting of adapting traditional systems to new genetic-based diagnostic and therapeutic tools. Methods: Reviewing and analysing the different health information levels from an organisational complexity point of view. A model is proposed to explain the interactions between health informatics, bioinformatics and molecular medicine.
Results: We suggest a new framework that integrates genetic data into health information systems. Using this model, new topics for future research and development are identified.
Conclusions: We are witnessing the birth of a new era (post-genomics). In this era technological advancements in genomics offer new opportunities for clinical applications. Medical informaticians should play an important role in this new endeavour.
Theory, Abstraction and Design in Medical Informatics
Authors: Martín F. , Crespo J. , Billhardt H. , Maojo V. 
Published: March 2018

Summary
Objective: To analyze the scientific and engineering components of Medical Informatics. A clear characterization of these components should be undertaken to categorize different areas of Medical Informatics and create a research agenda for the future. Methods: We have adapted a classical ACM and IEEE report on computing to analyze Medical Informatics from three different viewpoints: Theory, Abstraction, and Design.
Results: We suggest that Medical Informatics can be considered from these three perspectives: (1) Theory, from which medical informaticians formally characterize the properties of the objects of study, creating new theories or using and adapting existing theories (e.g., from mathematics), (2) Abstraction, from which medical informaticians deal with all aspects of medical information and create new abstractions, methods, and technology-independent models, which can be experimentally verified, and (3) Design, from which medical informaticians develop systems or act as information brokers or advisors between medical and technology professionals, to improve the quality of computer applications in medicine.
Conclusion: Based on this framework, we suggest that Medical Informatics has an independent scientific character, different from other applied informatics areas. Finally, we analyze these three perspectives using data mining in medicine.
Reflections on an Arranged Marriage between Bioinformatics and Health Informatics
Authors: Moshyk A. M. , Kushniruk A. , Moehr J. R. , Grant A. M. 
Published: March 2018

Summary
Objective: To compare the discussions of two workshops held during 2001 by two Canadian organisations, HEALNet, a Network of Centres of Excellence for research in health information applications, and Genome Canada, a national research funding agency for genomics and proteomics, in collaboration with the Institute of Genetics of the Canadian Institutes of Health Research, to examine strategic research development in Health Informatics and Bioinformatics respectively.
Methods: Invited workshops with structured debate. Concept analysis of preparative material and debates. Results: A predominantly common set of concepts was discerned from both workshops. Analysis of published definitions showed an inability to distinguish a definition that would suggest that health informatics and bioinformatics are separate disciplines. In both workshops there was evidence of deep concerns of identity, the lack of clear structures to support research funding as well as uncertainty in distinguishing between service and research.
Conclusions: Many deep issues currently inhibit the recognition and funding of research in health and bioinformatics in Canada and elsewhere. Some of these issues are common to both health and bioinformatics. The overlap in prevailing definitions, research concerns and methodological content in the respective domains suggest that common research needs should be better identified and reinforced for the benefit of both.