Search results for "Confidence Intervals"
showing 10 items of 111 documents
Statistical methods for the comparison of measurements derived from orthodontic imaging
2000
Biometric comparison procedures for dental imaging methods with continuous outcome were reviewed, mainly concentrating on assessment and comparison of accuracy and precision according to the study design. Univariate graphical and numerical representations of corresponding deviations were summarized to derive a 'check list' of minimum information necessary to compare the measurement methods. The methods reviewed in this investigation are illustrated by the comparison of conventional (radiographic) cephalometry versus assessment using the DigiGraph in 50 female children. A paired t-test and the corresponding confidence interval approach were used to assess deviations in location of two imagin…
Genetic polymorphisms affecting the phenotypic expression in familial hypercholesterolemia
2004
The clinical expression of heterozygous familial hypercholesterolemia (FH) is highly variable even in patients carrying the same LDL receptor (LDL-R) gene mutation. This variability might be due to environmental factors as well as to modifying genes affecting lipoprotein metabolism. We investigated Apo E (2, 3, 4), MTP (-493G/T), Apo B (-516C/T), Apo A-V (-1131T/C), HL (-514C/T and -250G/A), FABP-2 (A54T), LPL (D9N, N291S, S447X) and ABCA1 (R219K) polymorphisms in 221 unrelated FH index cases and 349 FH relatives with defined LDL-R gene mutations. We found a significant and independent effect of the following polymorphisms on: (i) plasma LDL-C (Apo E, MTP and Apo B); (ii) plasma HDL-C (HL, …
Modelling the dynamics of the students’ academic performance in the German region of the North Rhine-Westphalia: an epidemiological approach with unc…
2013
Student academic underachievement is a concern of paramount importance in Europe, where around 15% of the students in the last high school courses do not achieve the minimum knowledge academic requirement. In this paper, we propose a model based on a system of differential equations to study the dynamics of the students academic performance in the German region of North Rhine-Westphalia. This approach is supported by the idea that both, good and bad study habits, are a mixture of personal decisions and influence of classmates. This model allows us to forecast the student academic performance by means of confidence intervals over the next few years.
Severe hypoglycemia is associated with antidiabetic oral treatment compared with insulin analogs in nursing home patients with type 2 diabetes and de…
2015
Abstract Objectives Severe hypoglycemia is associated with cognitive decline and dementia in older persons with type 2 diabetes. The role of antidiabetic treatments on severe hypoglycemia is unknown in dementia. The aims were to determine the prevalence of severe hypoglycemic events and investigate associations among severe hypoglycemic and specific antidiabetic treatments (classes of oral agents and types of insulin analogs) in a large sample of nursing home patients with diabetes according to dementia status. Design Cross-sectional observational study. Setting A total of 150 nursing homes across Italy. Participants A total of 2258 patients with type 2 diabetes (dementia = 1138, no dementi…
Insulin resistance and atrial fibrillation (from the Framingham Heart Study)
2011
Diabetes mellitus and obesity are increasing in prevalence and are associated with an elevated risk of atrial fibrillation (AF). Given the aging of the United States population, AF is projected to concomitantly increase in prevalence in the upcoming decades. Both diabetes and obesity are associated with insulin resistance. Whether insulin resistance is an intermediate step for the development of AF is uncertain. We hypothesized that insulin resistance is associated with an increased risk of incident AF. We examined the association of insulin resistance with incident AF using multivariate Cox proportional hazards regression analysis adjusting for the established AF risk factors (i.e., age, g…
Global treatment patterns and outcomes among patients with recurrent and/or metastatic head and neck squamous cell carcinoma: Results of the GLANCE H…
2020
Abstract Objectives Given a lack of universally-accepted standard-of-care treatment for patients with recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC), study objectives were to assess treatment utilization and survival outcomes for R/M HNSCC in the real-world setting. Materials and methods A multi-site retrospective chart review was conducted in Europe (Germany, United Kingdom, Italy, Spain), Asia Pacific (Australia, South Korea, Taiwan), and Latin/North America (Brazil and Canada) to identify patients who initiated first-line systemic therapy for R/M HNSCC between January 2011 and December 2013. Patients were followed through December 2015 to collect clinical characte…
Carotid atherosclerosis and chronic hepatitis C: A prospective study of risk associations
2011
BACKGROUND AND AIMS: There are contrasting results in studies of cardiovascular risk in patients with genotype 1 chronic hepatitis C (G1 CHC). We evaluated the prevalence of carotid atherosclerosis compared with a control population in order to assess the potential association between atherosclerosis, host and viral factors, and liver histological features. MATERIALS AND METHODS: One hundred seventy-four consecutive biopsy-proven G1 CHC patients were evaluated by anthropometric and metabolic measurements. One hundred seventy-four patients attending an outpatient cardiology unit were used as controls. Intima-media thickness (IMT) and carotid plaques, defined as focal thickening of > 1.3 mm a…
Error analysis and performance of different retention models in the transference of data from/to isocratic/gradient elution.
2003
The transferability of retention data among isocratic and gradient RPLC elution modes is studied. For this purpose, 16 beta-blockers were chromatographed under both isocratic and gradient elution with acetonitrile-water mobile phases. Taking into account the elution mode where the experimental data come from, and the mode where the retention should be predicted, the following combinations are possible: isocratic predictions from (i) isocratic or (ii) gradient experimental designs; and gradient predictions from (iii) isocratic or (iv) gradient data. Each of these possibilities was checked using three retention models that relate the logarithm of the retention factor: (a) linearly and (b) qua…
Estimation of confidence limits for descriptive indexes derived from autoregressive analysis of time series: Methods and application to heart rate va…
2017
The growing interest in personalized medicine requires making inferences from descriptive indexes estimated from individual recordings of physiological signals, with statistical analyses focused on individual differences between/within subjects, rather than comparing supposedly homogeneous cohorts. To this end, methods to compute confidence limits of individual estimates of descriptive indexes are needed. This study introduces numerical methods to compute such confidence limits and perform statistical comparisons between indexes derived from autoregressive (AR) modeling of individual time series. Analytical approaches are generally not viable, because the indexes are usually nonlinear funct…
Can visualization alleviate dichotomous thinking? Effects of visual representations on the cliff effect
2021
Common reporting styles for statistical results in scientific articles, such as $p$ p -values and confidence intervals (CI), have been reported to be prone to dichotomous interpretations, especially with respect to the null hypothesis significance testing framework. For example when the $p$ p -value is small enough or the CIs of the mean effects of a studied drug and a placebo are not overlapping, scientists tend to claim significant differences while often disregarding the magnitudes and absolute differences in the effect sizes. This type of reasoning has been shown to be potentially harmful to science. Techniques relying on the visual estimation of the strength of evidence have been recom…