ijsmr
Abstract : Prediction and Identification of Covariates of Intra-cerebral Hemorrhage
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Abstract: The authors investigate the effects of clinical covariates upon the outcome of Intra-cerebral Hemorrhage (ICH) patients by applying a discriminate model of logistic regression. About 985 patients’s data with ICH have been collected using the International classification of diseases; ninth revision codes are also included. Diagnostic codes (434 for stroke and 431 for ICH) were used to identify patients and confirmed by neuro-imaging of the patients using CT scan and MRI. A univariate analysis of 88 covariates was undertaken and 46 of them reached statistical significance at an acceptable level of p < 0.05. The multivariable analysis exhibited a significant negative relationship between ICH and hypertension. The improvement among ICH patients having hypertension was found to be 0.5 with the p=0.001, ARR=0.5, 95% C.I. 0.3 – 0.8. The development among ICH patients using antihypertensive medicine was 1.3 with p = 0.021, ARR=1.3, 95% C.I. 1.0 – 1.6. Thus present study manifested that ICH has strong relationship with use of antihypertensive medicine. The rate of perfection in the patients physiological conditions using antihypertensive medicine at the time of discharge was 2.9 times acquiring p < 0.001, ARR=2.9, 95% C.I. 2.7 – 3.2 as compared to those who could not use antihypertensive medicine. The change in ARR from 1.3 to 2.9 times depict that the exercise of antihypertensive medicine and ICH outcome are positively associated. The fluctuations in ARR of hypertensive range of systolic blood pressure (SBP) also indicate that the blood pressure range and ICH outcome are negatively correlated. The neurological symptomoatology, indistinct speech and double vision are important factors of proposed models. Moreover, a clear decrease was found in mental status from normal to coma in most suitable model. Surgery is an important part of recovery, and estimated that the improvement among the ICH patients, who were treated under surgical aspects, was 1.4 times with significant p-value in the best models. The complication of pneumonia during treatment of ICH subjects has highly significant showing negative correlation with the given outcome variable. The current model has 89.3% area under the curve with sensitivity (82.6%), specificity (81.3%) and p-value (0.308). This indicates that the constructed model bestows the well performance of the ICH outcome and the model is considered as excellent. Keywords: Intracerebral Hemorrhage, clinical covariates, multivariable analysis, logistic regression, Hosmer-Lemeshow test, discriminate model, sensitivity and specificity.Download Full Article |
Abstract : Evaluating Treatment Effect in Multicenter Trials with Small Centers Using Survival Modeling
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Abstract: Clinical trials of rare diseases commonly enlist several centers to achieve recruitment goals. The aim of this study is to examine the estimation of treatment effects for survival outcomes in multicenter clinical trials with varying numbers of centers and few patients per center for rarer disease outcomes (i.e. rare cancers). We modeled the heterogeneity between centers using Cox frailty models to account for the variability in patients and patient care between centers and examined measures of model fit via smoothed functions of a prognostic factor. Through a simulation study, we were able to examine the consequence of having only a few centers or a few patients per center on the treatment and prognostic factor effects and model performance indices. Overall, we found it is preferable to have more patients per site and more sites in a multicenter trial as expected. However, having a few patients per site is feasible if there are many sites in a trial. Keywords: Frailty, survival, clinical trial, prognostic factor, rare disease.Download Full Article |
Abstract : Bayesian Inference Supports the Use of Bypass Surgery Over Percutaneous Coronary Intervention To Reduce Mortality in Diabetic Patients with Multivessel Coronary Disease
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Abstract: Background: Coronary artery bypass graft (CABG) surgery may confer a survival advantage over percutaneous coronary intervention (PCI) in diabetic patients with multivessel coronary artery disease (CAD), but results of individual studies have been mixed. The primary aim of the current study was to compare mortality rates in diabetic patients with multivessel CAD randomized to either or CABG or PCI at 5 years or longest follow-up. Methods: Using a Bayesian approach, we updated a prior probability distribution elicited from 8 clinical trials (N=2024) with the likelihood obtained from the Future Revascularization Evaluation in Patients with Diabetes Mellitus: Optimal Management of Multivessel Disease (FREEDOM) (N=1460) to determine whether clinical trial evidence supports the underlying hypothesis that CABG is superior to PCI for diabetics with multivessel CAD. Results:A conjugate normal model comparing mortality rates favored the use of CABG (posterior mean odds ratio [OR] = 0.58, 95% Bayesian credible interval [BCI] = 0.48–0.71). Models weighted by the use of drug-eluting stents also favored the use of CABG over PCI (OR = 0.61, 95% BCI 0.48–0.78), as did models weighted by study age (OR=0.64, 95% BCI 0.52–0.80) or use of arterial conduits (OR=0.64, 95% BCI 0.51–0.81). The results were supported by a Bayesian hierarchical meta-analysis using a non-informative prior distribution (OR=0.55, 95% BCI 0.37–0.76). Conclusions: By integrating evidence from various studies, Bayesian methods directly support the underlying hypothesis that revascularization with CABG improves survival compared with PCI in diabetic patients with multivessel CAD. Keywords: Health policy and outcome research, catheter-based coronary interventions, stents, CV surgery, coronary artery disease, diabetes mellitus.Download Full Article |
Abstract : Establishing Reliability When Multiple Examiners Evaluate a Single Case-Part II: Applications to Symptoms of Post-Traumatic Stress Disorder (PTSD)
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Abstract: In an earlier article, the authors assessed the clinical significance of each of 19 Clinician Administered PTSD Scale items and composite scores (CAPS-1) [1] when 12 clinicians evaluated a Vietnam era veteran. A second patient was also evaluated by the same 12 clinicians and used for cross-validation purposes [2]. The objectives of this follow-up research are: (1) to describe and apply novel bio-statistical methods for establishing the statistical significance of these reliability estimates when the same 12 examiners evaluated each of the two Vietnam era patients. This approach is also utilized within the broader contexts of the ideographic and nomothetic conceptualizations to science, and the interplay between statistical and clinical or practical significance; (2) to detail the steps for applying the new methodology; and (3) to investigate whether the quality of the symptoms (frequency, intensity); item content; or specific clinician affect the levels of rater reliability. The more typical (nomothetic) reliability research design focuses on group averages and broader principles related to biomedical issues, rather than the focus on the individual case (ideographic approach). Both research designs (ideographic and nomothetic) have been incorporated in this follow-up research endeavor. Keywords: Multiple Raters, Single Case, Nomothetic, Ideographic, PTSD, Statistical Significance, Clinical Significance.Download Full Article |
