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In this paper, we use a regression model for modeling bounded outcome scores (BOS), where the outcome is Kumaraswamy distributed. Similar to the Beta distribution, this distribution can take a variety of shapes while being computationally easier to use. Thus, it is deemed as a suitable alternative distribution to the Beta in modeling bounded random processes. In the proposed model, the median of a bounded response is modeled by the linear predictors which is defined through regression parameters and explanatory variables. We obtained the maximum likelihood estimates (MLE) of the parameters, provided closed-form expressions for the score functions and Fisher information matrix, and presented some diagnostic measures. We conducted Monte Carlo
Graft-versus-host disease (GVHD) is one of the major causes of morbidity and mortality in 25–70% of patients. The gold standard (GS) test to confirm the diagnosis of GVHD has some limitations. The current study was conducted to evaluate the accuracy of three serum markers in diagnosing GVHD without a GS. 94 patients who were hospitalized for allogeneic transplantation were studied. Mean levels from day of haematopoietic stem cell transplantation (HSCT) to discharge of serum uric acid (UA), lactate dehydrogenase (LDH), and creatinine (Cr) were measured for all participants. We adapted a Bayesian latent class analysis to modelling the results of each marker and combination of markers. The Sensitivity, Specificity, and area under receiver op
Gestational diabetes mellitus (GDM) is associated with adverse diabetic complications for both mother and child during pregnancy. The common Gold Standard (GS) for diagnosis of GDM is 75 g oral glucose tolerance test (OGTT) during 24–28 gestational weeks which seems a little late for any proper intervention. This study aimed to employ the Bayesian latent class models (LCMs) for estimating the early diagnostic power of combination of serum multiple marker in detecting GDM during 14–17 weeks of gestation. Data from a sample of 523 pregnant women who participated in gestational diabetes screening tests at health centers affiliated to Shahid Beheshti University of Medical Sciences in Tehran, Iran from 2017 to 2018 were used. The beta-hu
Materials and Methods: In this retrospective survival study, 342 breast cancer patients whose records were registered at the Shohada Tajrish Hospital Cancer Research Center (Tehran, Iran) were investigated in 2005-2015. Patients were monitored for at least 6 months after diagnosis and their last condition was recorded in this study, the joint frailty survival model was used and data analysis was done in R software version 3.4. 1.Results: The 3-year and 5-year survival rates were 0.79 and 0.68 respectively. According to the results of the fitted joint frailty model, it can be said that the risk of multiple recurrence is increased for patients with tumor grade greater than I. Also, tumor size (> 20 mm) has a significant effect on the risk of
Results: The IC 50 values of autumn and spring extracts of A. aucheri was estimated about 136 μg/ml and 119 μg/ml, respectively, in treated T. gondii tachyzoites. After 24 hours of macrophage incubation, the highest rate of cytotoxicity was observed in high concentrations of spring and autumn A. aucheri extracts. Based on the flow cytometry results the rates of normal, necrotic, and apoptotic cells treated with autumn extract were 93.1%, 2.45%, and 4.49%, respectively, and when with spring extract was treated, the rates were 60.4%, 3.99%, and 35.54%, respectively.Discussion and Conclusion: We concluded that the autumn and spring extracts of A. aucheri has lethal effect on T. gondii tachyzoites and also induces the apoptosis in parasites.
Background: Restenosis after coronary angioplasty can have serious complications such as coronary artery bypass graft, myocardial infarction, and death. Objectives: The present study aimed at investigating the factors affecting the recurrence of coronary artery stenosis in patients undergoing angioplasty using the recurrent event data analysis. Methods: A cohort study was performed on patients undergoing coronary angioplasty from March 23, 2009, to January 21, 2011. All patients were followed up from angioplasty to January 21, 2015. First, each of the independent variables was entered into the univariate Cox model with a frailty component. Then, variables with p-values of less than 0.2 were entered into the multivariate analysis. The statis
Background: Nowadays, cancer is one of the most important medical problems. Breast cancer is also considered as the most common cancer of women: its prevalence has risen throughout the world in recent centuries and people can experience recurrent events that sometimes accompany with a terminal event. In the present study, using a frailty model we tried to model recurrent event in the precence of terminal event (death) in breast cancer patients.Materials and Methods: In the current retrospective survival study, 342 patients with breast cancer registered in the cancer research center of Shohada-e-Tajrish Hospital were examined. The Liu model was used to joint modeling of recurrent events and terminal events, in which a shared frailty with Gam
Materials and Methods: In this retrospective survival study, 342 breast cancer patients whose records were registered at the Shohada Tajrish Hospital Cancer Research Center (Tehran, Iran) were investigated in 2005-2015. Patients were monitored for at least 6 months after diagnosis and their last condition was recorded in this study, the joint frailty survival model was used and data analysis was done in R software version 3.4. 1.Results: The 3-year and 5-year survival rates were 0.79 and 0.68 respectively. According to the results of the fitted joint frailty model, it can be said that the risk of multiple recurrence is increased for patients with tumor grade greater than I. Also, tumor size (> 20 mm) has a significant effect on the risk of
Background: Nowadays, cancer is one of the most important medical problems. Breast cancer is also considered as the most common cancer of women: its prevalence has risen throughout the world in recent centuries and people can experience recurrent events that sometimes accompany with a terminal event. In the present study, using a frailty model we tried to model recurrent event in the precence of terminal event (death) in breast cancer patients.Materials and Methods: In the current retrospective survival study, 342 patients with breast cancer registered in the cancer research center of Shohada-e-Tajrish Hospital were examined. The Liu model was used to joint modeling of recurrent events and terminal events, in which a shared frailty with Gam
Longitudinal studies are very common in medical, behavioral, and interventional sciences. One measure of effect of interest in longitudinal studies is risk ratio, naturally estimated by log-binomial regression which suffers from convergence problems. Odds ratio (OR) does not approximate risk ratio (RR) well when the outcome is common, so alternative methods have been introduced in cohort studies with one follow-up visit. In this paper, we illustrate two simple methods: the COPY method and the modified log-Poisson regression for RR estimation in longitudinal data setting. Our unpublished simulation study on RR estimation in longitudinal data setting suggests that the COPY method performs well in terms of closeness of the RR estimate and true
The problem of testing Rayleigh distribution against exponentiality, based on a random sample of observations is considered. This problem arises in survival analysis, when testing a linearly increasing hazard function against a constant hazard function. It is shown that for this problem the most powerful invariant test is equivalent to the “ratio of maximized likelihoods” (RML) test. However, since the two families are separate, the RML test statistic does not have the usual asymptotic chi-square distribution. Normal and saddlepoint approximations to the distribution of the RML test statistic are derived. Simulations show that saddlepoint approximation is more accurate than the normal approximation, especially for tail probabilities tha
Objective. Considering the high prevalence of epilepsy in the elderly and the importance of maximising their quality of life (QoL), this study aimed to investigate the relationship between medication adherence and QoL, and the mediating effects of medication adherence on the association between serum antiepileptic drug (AED) level and seizure severity with QoL in elderly epileptics.Methods. In a longitudinal study, 766 elderly patients with epilepsy who were prescribed a minimum of one antiepileptic drug were selected by convenience sampling method. A Medication Adherence Report Scale (MARS-5) questionnaire was completed at the baseline. Seizure severity and QoL were assessed after six months using the Liverpool Seizure Severity Scale (LSSS
Background: Cancer is the second leading cause of death globally, and it was responsible for almost 9.6 million deaths in 2018. Breast cancer (BC) is the most common cancer among women with almost two million new cases worldwide in 2018. Thus, it is necessary to study new methods to estimate the survival predictive factors in BC patients.Objectives: This cohort study aimed to fit a Cox model to BC data using partial likelihood (PL) and new maximum penalized likelihood (MPL) methods in order to determine the predictive factors of survival time and compare the accuracy of these two methods.Methods: This prospective cohort study used the data of 356 women with BC registered at the Cancer Research Center of Shahid Beheshti University of Medical