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Abstract : Comparative Analysis of the Effects of Three Antithrombotic Regimens on Clinical Outcomes of Patients with Atrial Fibrillation and Recent Percutaneous Coronary Intervention with Stent. A Retrospective Cohort Study
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Abstract: Introduction: Chronic atrial fibrillation (AF), coexisting with a history of recent coronary angioplasty with stent (PCI-S) represents an encoded indication for oral anticoagulation with warfarin (OAC) plus dual antiplatelet therapy (DAPT). Methods:Using a retrospective cohort study we determined the respective impacts on cardio- vascular outcomes of three different pharmacologic regimens, i.e., triple therapy (TT) with warfarin + clopidogrel and aspirin, dual therapy (DT) with warfarin +clopidogrel or aspirin, dual antiplatelet therapy (DAPT) with clopidogrel + aspirin. Outcomes of interest were all-cause mortality, ischemic cardiac events, ischemic cerebral events, bleeding events. The inclusion criterion was the coexistence of an indication for OAC (e.g., chronic AF) with an indication for dual antiplatelet therapy due to recent PCI-S. Results: Among the 98 patients enrolled, 48 (49%), 31 (31.6%), and 19(19.4%) patients were prescribed TT, DT, and DAPT, respectively. Throughout a mean follow-up of 378± 15.7days, there were no significant differences between the three regimens for all abovementioned outcomes. In particular, the total frequency of major bleeding was similar in the three groups: 5 cases (10.4%) in TT, one case (3.22%) in DT and no case in DAPT groups (p [chi-square test] = 0.1987). Conclusions: TT, DT and DAPT displayed similar efficacy and safety. Although the superiority of OAC vs. DAPT for stroke prevention in AF patients has been demonstrated by previous randomized trials, a smaller frequency of high thromboembolic risks' features in DAPT group of the present study may have prevented the observation of a higher incidence of ischemic stroke in this group. Keywords: Atrial fibrillation, percutaneous coronary intervention, oral anticoagulant therapy, antithrombotic therapy, major adverse cardiovascular events, bleeding.Download Full Article |
Abstract : Comparative Study of Human and Automated Screening for Antinuclear Antibodies by Immunofluorescence on HEp-2 Cells
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Abstract: Background:Several automated systems had been developed in order to reduce inter-observer variability in indirect immunofluorescence (IIF) interpretation. We aimed to evaluate the performance of a processing system in antinuclear antibodies (ANA) screening on HEp-2 cells. Patients and Methods:This study included 64 ANA-positive sera and 107 ANA-negative sera that underwent IIF on two commercial kits of HEp-2 cells (BioSystems® and Euroimmun®). IIF results were compared with a novel automated interpretation system, the “CyclopusCADImmuno®” (CAD). Results:All ANA-positive sera images were recognized as positive by CAD (sensitivity = 100%), while 17 (15.9%) of the ANA-negative sera images were interpreted as positive (specificity = 84.1%), κ=0.799 (SD=0.045). Comparison of IIF pattern determination between human and CAD system revealed on HEp-2 (BioSystems®), a complete concordance in 6 (9.37%) sera, a partial concordance (sharing of at least 1 pattern) in 42 (65.6%) cases and in 16 (25%) sera the pattern interpretation was discordant. Similarly, on HEp-2 (Euroimmun®) the concordance in pattern interpretation was total in 5 (7.8%) sera, partial in 39 (60.9%) and absent in 20 (31.25%). For both tested HEp-2 cells kits agreement was enhanced for the most common patterns, homogenous, fine speckled and coarse speckled. While there was an issue in identification of nucleolar, dots and nuclear membranous patterns by CAD. Conclusion:Assessment of ANA by IIF on HEp-2 cells using the automated interpretation system, the “CyclopusCADImmuno®” is a reliable method for positive/negative differentiation. Continuous integration of IIF images would improve the pattern identification by the CAD. Keywords: Autoantibodies, HEp-2, Immunofluorescence, autoimmune diseases, automated screening, standardization.Download Full Article |
Abstract : A Contribution to the Genetic Epidemiology of Structured Populations
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Abstract: A matingsystem, previously derived, which is more general than random mating is defined by the gene frequency q and a parameter F which measures divergence from Hardy-Weinberg proportions commonly used in genetic analysis. F can be viewed as the average coefficient of inbreeding in a population, the use emphasized here. Also it can characterize the variation in gene frequency in a stratified population. Taking q as fixed, the distribution of F over values admissible under the general mating system is derived by simulation. The mating system may be seen to be based on indifference as to choice of mates. This is the first object of the paper. The second uses the derived distribution of F to make a Bayesian estimate of F from a single sample of genotypic counts. Such an estimate has a number of uses in genetic analysis. Keywords: Genetic Equilibrium, Hardy-Weinberg Law, Mate choice indifference, Inbreeding coefficient, Bayesian estimation.Download Full Article |
Abstract : Assessment of Statistical Approaches to Model Low Count Data: An Empirical Application to Youth Delinquency
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Abstract: Objectives: The aim of this study was to identify the risk factors associated with number of crime committed by youth (Youth Delinquency) between ages 10-17, using Ordinary Least Square (OLS), Poisson Regression model (PRM), Negative Binomial Regression model (NBRM)& Zero Inflated Negative Binomial (ZINB) with the aim to choose the most appropriate model for the observed count data. Methodology: The data in the study was collected from youth whose mothers enrolled in Philadelphia Collaborative Perinatal Project (CPP). School and delinquency record (between ages 10-17) was obtained by the Centre for studies in Criminology and Criminal Law. Literature search suggest that factors associated with child delinquency can be divided into four main factors as Individual, Family, School and Peer. Therefore we included variables in the analysis accordingly. Result: For OLS scatter plot of residuals versus estimated counts showed definite pattern of heterogeneity (non-constant variance). The likelihood-ratio (LR) test of over dispersion yields the significant p-value, which implied that the outcome variable is overdispersed. The plot of the difference between the actual probabilities and the mean predicted probabilities for each model showed that PRM has poor predictions for low counts (0-2). Conclusion:NBRM and ZINB both performed well, however fit statistics revealed that NBRM has provided more closed predication as compare ZINB.NB modeling techniques provides much more compelling and accurate results instead of basic PRM or those available through simple linear or log-linear modeling techniques. Keywords: Count Data, Poisson regression model, Negative Binomial Regression.Download Full Article |
