Browsing by Subject "Health insurance"

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Open Access
A comprehensive methodology for determining the most informative mammographic features
(2013) Wu, Y.; Alagoz O.; Ayvaci, M.U.S.; Munoz Del Rio, A.; Vanness, D.J.; Woods, R.; Burnside, E.S.
This study aims to determine the most informative mammographic features for breast cancer diagnosis using mutual information (MI) analysis. Our Health Insurance Portability and Accountability Act-approved database consists of 44,397 consecutive structured mammography reports for 20,375 patients collected from 2005 to 2008. The reports include demographic risk factors (age, family and personal history of breast cancer, and use of hormone therapy) and mammographic features from the Breast Imaging Reporting and Data System lexicon. We calculated MI using Shannon's entropy measure for each feature with respect to the outcome (benign/malignant using a cancer registry match as reference standard). In order to evaluate the validity of the MI rankings of features, we trained and tested naïve Bayes classifiers on the feature with tenfold cross-validation, and measured the predictive ability using area under the ROC curve (AUC). We used a bootstrapping approach to assess the distributional properties of our estimates, and the DeLong method to compare AUC. Based on MI, we found that mass margins and mass shape were the most informative features for breast cancer diagnosis. Calcification morphology, mass density, and calcification distribution provided predictive information for distinguishing benign and malignant breast findings. Breast composition, associated findings, and special cases provided little information in this task. We also found that the rankings of mammographic features with MI and AUC were generally consistent. MI analysis provides a framework to determine the value of different mammographic features in the pursuit of optimal (i.e., accurate and efficient) breast cancer diagnosis. © 2013 Society for Imaging Informatics in Medicine.
Open Access
Demographics, treatment and outcomes of atrial fibrillation in a developing country: the population-based TuRkish Atrial Fibrillation (TRAF) cohort
(Oxford University Press, 2017) Yavuz, B.; Ata, N.; Oto, E.; Katircioglu-Öztürk, D.; Aytemir, K.; Evranos, B.; Koselerli, R.; Ertugay, E.; Burkan, A.; Ertugay, E.; Gale, C. P.; Camm, A. J.; Oto, A.
Aims: Although atrial fibrillation (AF) is increasingly common in developed countries, there is limited information regarding its demographics, co-morbidities, treatments and outcomes in the developing countries. We present the profile of the TuRkish Atrial Fibrillation (TRAF) cohort which provides real-life data about prevalence, incidence, comorbidities, treatment, healthcare utilization and outcomes associated with AF. Methods and results: The TRAF cohort was extracted from MEDULA, a health insurance database linking hospitals, general practitioners, pharmacies and outpatient clinics for almost 100% of the inhabitants of the country. The cohort includes 507 136 individuals with AF between 2008 and 2012 aged >18 years who survived the first 30 days following diagnosis. Of 507 136 subjects, there were 423 109 (83.4%) with non-valvular AF and 84 027 (16.6%) with valvular AF. The prevalence was 0.80% in non-valvular AF and 0.28% in valvular AF; in 2012 the incidence of non-valvular AF (0.17%) was higher than valvular AF (0.04%). All-cause mortality was 19.19% (97 368) and 11.47% (58 161) at 1-year after diagnosis of AF. There were 35 707 (7.04%) ischaemic stroke/TIA/thromboembolism at baseline and 34 871 (6.87%) during follow-up; 11 472 (2.26%) major haemorrhages at baseline and 10 183 (2.01%) during followup, and 44 116 (8.69%) hospitalizations during the follow-up. Conclusion: The TRAF cohort is the first population-based, whole-country cohort of AF epidemiology, quality of care and outcomes. It provides a unique opportunity to study the patterns, causes and impact of treatments on the incidence and outcomes of AF in a developing country. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017.
Open Access
Estimating the efficiency of the system of healthcare financing in achieving better health
(Routledge, 2006) Grosskopf, S.; Self, S.; Zaim, O.
This paper contributes to the effort to model and measure how the method of financing of health expenditure affects the efficiency with which better health can be achieved. The focus is on the health system efficiency at the country level, which provides an alternative to the work done in the WHO in this regard. The approach uses frontier techniques as in the WHO studies; however the paper appeals to the economic index number theory of quantity and productivity indexes, which have well-established axiomatic properties, and provides a means for aggregating multiple health output proxies without having to attach arbitrary weights. This allows the proposal of a specification that embeds health sector performance in a broader index of economic inputs and outputs and allows for comparisons across countries and time. © 2006 Taylor & Francis.