when we conducted a meta-analysis, it is often an annoying thing to deal with the data of discrete exposure and multiple outcomes. Conventional "high VS low" approach abandoned the information of middle category, and led to the loss of statistical power. In this paper, we introduced a method and software to combine the groups of discrete exposure and multiple outcomes in the meta-analysis of epidemiological studies. Firstly, we introduced the transforming and combination theory and method, and then, we conducted the combination using EXCEL macro software. The result was consistent with the results of the original data in the combination of discrete exposure and multiple outcome data. Therefore, in the case of the original research data cannot be acquired, EXCEL macro software can be a good solution.
Dose-response meta-analysis, as a subset of meta-analysis, plays an important role in dealing with the relationship between exposure level and risk of diseases. Traditional models limited in linear regression between the independent variables and the dependent variable. With the development of methodology and functional model, Nonlinear regression method was applied to dose-response meta-analysis, such as restricted cubic spline regression, quadratic B-spline regression. However, in these methods, the term and order of the independent variables have been assigned that may not suit for any trend distribution and it may lead to over fitting. Flexible fraction polynomial regression is a good method to solve this problem, which modelling a flexible fraction polynomial and choosing the best fitting model by using the likelihood-ratio test for a more accurate evaluation. In this article, we will discuss how to conduct a dose-response meta-analysis by flexible fraction polynomial.
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.
ITC (Indirect Treatment Comparison) software and indirect procedure of Stata software are especially used for indirect comparison nowadays, both of which possess the characteristics of friendly concise interface and support for menu operation. ITC software needs the application of other software to yield effect estimation and its confidence interval of direct comparison firstly; while Stata-indirect procedure can complete direct comparison internally and also operate using commands, which simplifies complicated process of indirect comparison. However, both of them only perform "single-pathway" of data transferring and pooling, which is a common deficiency. From the results, their results are of high-degree similarity.
ObjectiveTo explore the effectiveness of thoracoscopic surgery for treating late-presenting congenital diaphragmatic hernias and summarize the experience. MethodsBetween October 2012 and February 2015, 21 children with late-presenting congenital diaphragmatic hernias underwent thoracoscopic surgery. Of the 21 cases, 12 were girls and 9 were boys with a median age of 1 year and 3 months (range, 2 months to 8 years). Eight patients had obvious symptom in the initial stage:shortness of breath and dyspnea; 13 cases were found occasionally through chest radiography. Of 21 cases, 17 had left diaphragmatic hernias and 4 had right diaphragmatic hernias. The emergency surgery was performed in 5 cases because oppressed obviously and selective operation in 16 cases. Hernial sac existed in 5 cases; there were 19 cases of Bochdalek's hernia and 2 cases of Morgagni's hernia. The size of diaphragmatic defect ranged from 3 cm×2 cm to 5 cm×5 cm. ResultsThe operation time was 35-80 minutes (mean, 50 minutes), and intraoperative blood loss was 3-5 mL (mean, 3.8 mL). Primary healing of incision was obtained. Postoperative abdominal distension and pneumothorax occurred in 12 and 2 cases respectively. The follow-up time was 1-3 years (mean, 20 months). All the cases had a good recovery and satisfactory appearance of the thoracic incision. The symptoms and signs of shortness of breath and dyspnea disappeared. There was no recurrence and chest infection. ConclusionUnder the conditions of mastering operative indications strictly, thoracoscopic repair for late-presenting congenital diaphragmatic hernia is safe and feasible. It can facilitate the procedure and decrease the recurrence rate relying on intraoperative application of hernia repair needle, knot pusher-assistant, and reasonable processing defect periphery.
In evidence-based practice and decision, dose-response meta-analysis has been concerned by many scholars. It can provide unique dose-response relationship between exposure and disease, with a high grade of evidence among observational-study based meta-analysis. Thus, it is important to clearly understand this type of meta-analysis on software implementations. Currently, there are different software for dose-response meta-analysis with various characteristics. In this paper, we will focus on how to conduct dose-response meta-analysis by Stata, R and SAS software, which including a brief introduction, the process of calculation, the graph drawing, the generalization, and some examples of the processes.
Restricted cubic spline function is an ideal model in trend approximation, which is widely used in doseresponse meta-analysis. The spline function, based on parameter technique, is a smoothly joined piecewise polynomial of each knot, with a cubic polynomial in each sub-interval of the slope which fits well in the non-linear trend by changing the number and (or) the sites of the knots. We have introduced the methodology of linear and non-linear slope model in dose-response meta-analysis in the previous article, and in this one, we will give a more detailed discussion on restricted cubic spline function mainly in the following aspects: model building, parameters pooling and knots selecting.
As a valid method in systematic review, dose-response meta-analysis is widely used in investigating the relationship between independent variable and dependent variable, and which usually based on observational studies. With large sample size, observational studies can provide a reasonable amount of statistical power for meta-analysis. However, due to the design defects of observational studies, they tend to introduce many kinds of biases, which may influence the final results that make them deviation from the truth. Given the dead zone of methodology, there is no any bias adjusting method in dose-response meta-analysis. In this article, we will introduce some bias adjusting methods from other observational-study-based meta-analysis and make them suit for dose-response meta-analysis, and then compare the advantages and disadvantages of these methods.
The reporting checklist of health technology assessment (HTA) was a tool developed by the International Network of Agencies for Health Technology Assessment (INAHTA) to be used to guide the reporting of HTA. Experiential evidence showed that the tool was effective to improve the reporting quality of HTA and also could be used as a reference in performing HTA and translating the research evidence into decision-making. This paper introduced the background, developing process and main contents of the checklist, so as to improve the reporting quality of HTA in China.
Dose-response relationship model has been widely used in epidemiology studies, as well as in evidence-based medicine area. In dose-response meta-analysis, the results are highly depended on the raw data. However, many primary studies did not provide sufficient data and led the difficulties in data analysis. The efficiency and response rate of collecting the raw data from original authors were always low, thus, evaluating and transforming the missing data is very important. In this paper, we summarized several types of missing data, and introduced how to estimate the missing data and transform the effect measure using the existed information.