The WinBUGS software can be called from either R (provided R2WinBUGS as an R package) or Stata software for network meta-analysis. Unlike R, Stata software needs to create relevant ADO scripts at first which simplify operation process greatly. Similar with R, Stata software also needs to load another package when drawing network plots. This article briefly introduces how to implement network meta-analysis using Stata software by calling WinBUGS software.
Objective To analyze the status of applying diagnostic test in imaging scientific study internationally and domestically, and to compare the application of the image diagnostic studies of our country with that of abroad. Method We hand-searched the diagnosis tests published in the "Chinese Journal of Radiology", the most influential in China, and in "Radiology’’, the most influential abroad, from 1998 to 1999 respectively. Then we evaluated each of the diagnosis tests according to the international standards. Results We searched 408 original articles in "Chinese Journal of Radiology" in which the diagnostic test articles were 12%, and 796 original articles in "Radiology" with the diagnostic test articles 23% from 1998 to 1999 respectively. In these diagnosis tests, by comparing the "Chinese journal of radiology" with the "Radiology", it was found that 19% applied blind comparison with Gold Standard, 28% calculated sensitivity, specificity and accuracy, 9% both calculated negative predictive value and positive predictive value and none calculated likelihood ratios in the former versus 64%, 57%, 33% and 26% and 3% respectivdy in the latter. Conclusions Compared with the international level, both the quality and the quantity of the diagnosis tests applied in the specialty of imaging scientific study in China are much lower and far from meeting the clinical requirement. Improving the methods of scientific study and carrying on more diagnosis tests with high qualities are of important significance in improving the diagnostic level of imaging.
The valid results of Meta-analysis on biomedical data, will have an important value to clinical practice and health policy making. To review the validity of meta-analysis results, one should consider the following issues: The coverage ratio of included studies, quality of data, publication bias and its effect, heterogeneity, the correct selection of statistical methods as well as clinical significance and external validity of overall effect size. The results of Meta-analysis will keep on updating as new related studies are located and included.
ObjectiveTo analyze the risk factors of severe retinopathy of prematurity (ROP) and provide consultable evidence for the rational establishment of screening standard.MethodsThe clinical data of 168 prematureinfants (gestational age less than 37 weeks) who was diagnosed in our department from Dec 2002 to Apr 2004 was analyzed retrospectively. Gender, birth count (BC), gestational age (GA), birth weight (BW), duration of oxygen therapy and vascularization devlopment of posterior and peripheral retina examined by binocular indirect ophthalmoscope after mydriasis were recorded. The results were recorded by the international classification of ROP (ICROP), and stage 1, 2 and 3 were mild ROP while threshold disease, stage 4 and 5 were severe ROP. Logistic regression was appliedto analyze the relationship of ROP and gender, BC, GA, BW, and oxygen therapy. ResultsSevere ROP was found in 91 eyes (27.1%) of 47 infants (28.0%) in 336 eyes of 168 premature infants, including threshold disease in 20 eyes (6.0%) and disease at stage 4 in 11 eyes (3.3%) in which the diseases at stage 4A was foundin 2 eyes (0.6%) and stage 4B in 9 eyes (2.7%). There were 60 eyes (17.8%) at stage 5. In all of the factors, GA, BW and oxygen therapy were found to have a significant impact on severe ROP (P=0.000, 0.000 and 0.015,α=0.05) while gender and BC were not (P=0.640 and 0.084, α=0.05). Statistic analysis of subgroupshowed that the risk of severe ROP in premature infants would increase significantly when GA≤30 weeks, BW≤1500 g or oxygen therapy gt;4 days. Conclusions Severe ROP relates to GA, BW and oxygen therapy instead of gender and BC. The risk of occurrence of severe ROP in premature infants increases significantly when GA≤30 weeks, BW≤1500g or oxygen therapy gt;4 days, so it is recommended to screen such premature infants carefully. (Chin J Ocul Fundus Dis,2005,21:271-274)
Objective To investigate confidence interval estimation for the amount of heterogeneity in meta-analysis. Methods On the basis of BT’s method, the approximate Q-statistic distribution following linear transformation of Chi-square was applied to improve the accuracy of Q-statistic distribution, and to obtain the confidence interval for the amount of heterogeneity in meta-analysis. Results In case, the Q1 distribution obtained 95%CI 0.07 to 2.20, while the Q2 distribution obtained 95%CI 0.00 to 1.41; The proposed method Q2 narrowed down the range of confidence interval. Conclusion On account of improving the accuracy of Q-statistic distribution, the proposed method effectively strengthens the coverage probabilities of the confidence interval for the amount of heterogeneity. And the proposed method can also improve the precision of the confidence interval estimation for the amount of heterogeneity.
Through collecting and synthesizing the paper concerning the method of dealing with heterogeneity in the meta analysis, to introduce the multi-levels statistical models, such as meta regression and baseline risk effect model based on random effects, and random effects model based on hierarchical bayes, and to introduce their application of controlling the meta analysis heterogeneity. The multi-levels statistical model will decompose the single random error in the traditional model to data structure hierarchical. Its fitting effect can not only make the meta-analysis result more robust and reasonable, but also guide clinical issues through the interpretation of association variable.
The selection of summary statistics to use in a meta-analysis is very important for the interpretation and application of its results. This paper introduces some basic concepts of summary statistics in meta-analysis. The selection of a summary statistic for a meta-analysis depends on the following factors: design of the studies being combined, type of data, consistency among the included studies, mathematical properties and ease of interpretation. For continuous data, the weighted mean difference (WMD) is recommended when all trials use the same scale to report their outcomes, while standardized mean difference (SMD) is more appropriate when trials use different scales to report their outcomes, or the means of their outcomes differ greatly. For dichotomous data, rate ratio or relative risk (RR) is bly recommended to be the summary statistics for meta-analyses of randomized trials. The use of odds ratio (OR) as the summary statistic is similar to that of RR, if the event being studied in both the intervention (exposure) and the control group is rare. There is no single measurement that is uniformly best for all meta-analyses.
The phase-locking relationship between the firings of neuronal action potentials (i.e., spikes) and the oscillations of local field potentials (LFP) reflects important neural coding information. However, the present analysis methods can only determine whether there has phase-locking, but not the different strengths among various types of phase-locking. In the present paper, we used spike-triggered average (STA) signals and the percentage ratio (named φ) of the STA power to the power of original LFP as an index to evaluate the strengths of phase-locking. Experimental recordings obtained from rat hippocampal CA1 region as well as simulation data were used to evaluate the method. The results showed that the index φ changed monotonically as a function of the strength of phase-locking, and it could provide an effective critical value to divide phase-locking from non-phase-locking. Because the calculation of the index does not need pre-filtering, it can avoid the unwanted influences caused by intentionally limiting the frequencies of LFP oscillations such as in the traditional bin statistical method. Therefore, the index φ provides a novel method to investigate the mechanisms underlying neuronal coding in brain.
Multivariate time series problems widely exist in production and life in the society. Anomaly detection has provided people with a lot of valuable information in financial, hydrological, meteorological fields, and the research areas of earthquake, video surveillance, medicine and others. In order to quickly and efficiently find exceptions in time sequence so that it can be presented in front of people in an intuitive way, we in this study combined the Riemannian manifold with statistical process control charts, based on sliding window, with a description of the covariance matrix as the time sequence, to achieve the multivariate time series of anomaly detection and its visualization. We made MA analog data flow and abnormal electrocardiogram data from MIT-BIH as experimental objects, and verified the anomaly detection method. The results showed that the method was reasonable and effective.
The key for performing meta-analysis using WinBUGS software is to construct a model of Bayesian statistics. The hand-written code model and Doodle model are two major methods for constructing it. The approach of hand-written code is flexible and convenient, but the language programming is fallibility. The Doodle is complicated, but it is benefit to understand the structure of hand-written code model and prevent error. This article briefly describes how to construct the Doodle model for binary and continuous data of head to head meta-analysis, indirect comparison and network meta-analysis, and ordinal variables meta-analysis.