Trial Sequential Analysis (TSA), one kind of cumulative meta-analysis, is a method which introduces sequential analysis into traditional meta-analysis to avoid random errors (false positive or false negative outcomes) that occurred during repeated updates when traditional meta-analysis is performing. It is also applied to calculate required information size (RIS) of a firm conclusion. This study aims to summarize the proposal, fundamental theory, application software, and current limitation of TSA, and to clarify the advantages of TSA on the basis of detailed examples, in order to attract more attention of researchers and promote the methodological development of meta-analysis in China.
This is the seventh paper in the evidence-based medicine glossary series. In this paper, We mainlyintroduced five terms related to meta-analysis——prospective meta-analysis, individual patient data meta-analysis,cumulative meta-analysis, multiple-treatments meta-analysis and meta regression.We also gave some examples to helpreaders better understand and use them.
To put forward a simple algorithm for the pooled effect size of cumulative meta-analysis based on the random effects model. Firstly, the heterogeneity variance based on the previous k studies and the combined effect size of the previous k studies are both calculated. When adding the effective size of k+1 study, we use recursive method to calculate heterogeneity variance and the corresponding pooled size of the previous k+1 studies. Whenever we add one new study to the previous studies, we carry out one recursive operation to rapidly calculate the heterogeneity variance and the corresponding overall effect size by using recursive formulas. This method is easy and effective, with no need to write programs to obtain these results.
ObjectiveTo evaluate the effect of prone position ventilation on mortality in ARDS patients by cumulative meta-analysis.MethodsDatabases including PubMed, EMbase, Web of Science, The Cochrane Library, CBM, CNKI, VIP, WanFang Data were searched from inception to September 30th, 2016 to collect randomized controlled trials (RCTs) about prone position ventilation in ARDS patients. Two reviewers independently screened literature, extracted data, and assessed the risk of bias of included studies. In accordance with the published literature or published in chronological order, cumulative meta-analysis was performed using Stata12.0 software, and the trial sequencing analysis (TSA) method was used to assess the reliability and authenticity of the results.ResultsA total of 9 RCTs involving 2 359 patients were included. The cumulative meta-analysis results showed that the prone position ventilation could reduce the mortality in ARDS patients (OR=0.60, 95%CI 0.40 to 0.90). The TSA results showed that the definite conclusion had been obtained before the desired amount of information had been reached.ConclusionThe current evidence shows that prone position ventilation is associated with decreased mortality in ARDS patients. Due to limited quality and quantity of included studies, the above results are needed to validate by more studies.
ObjectiveTo evaluate the effect of airway pressure release ventilation (APRV) on the hospital mortality of patients with acute respiratory distress syndrome (ARDS) by using cumulative meta-analysis. MethodsThe PubMed, Web of Science, Cochrane Library, WanFang Data, CNKI, and VIP databases were electronically searched to collect randomized controlled trials (RCTs) related to the objective from inception to June 30, 2022. Two reviewers independently screened literature, extracted data and assessed the risk of bias of the included studies. A cumulative meta-analysis was then performed by using StataSE 12.0 software. ResultsA total of 9 RCTs involving 533 patients were included. The results of meta-analysis showed that APRV could reduce the hospital mortality of patients with ARDS (RR=0.70, 95%CI 0.54 to 0.91, P<0.01) compared with traditional mechanical ventilation. ConclusionCurrent evidence shows that APRV can reduce the hospital mortality of patients with ARDS. Due to the limited quality and quantity of the included studies, more high quality studies are needed to verify the above conclusion.