====== Network meta-analysis ====== https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7248597/#:~:text=Network%20meta%2Danalysis%20is%20a,Bayesian%20framework%20using%20example%20data. ---- [[Network]] meta-analysis (NMA) is a relatively recent development, which extends principles of [[meta-analysis]] to the [[evaluation]] of multiple [[treatment]]s in a single analysis. This is achieved by combining the direct and [[indirect evidence]]. [[Direct evidence]] refers to evidence obtained from [[randomized control trial]]s (RCTs); for example, in a trial comparing treatments A and B, direct evidence is the estimate of relative effects between A and B. [[indirect evidence]] refers to the evidence obtained through one or more common comparators. For example, in the absence of RCTs that directly evaluate A and B, interventions A and B can be compared indirectly if both have been compared to C in studies (forming an A-B-C “loop” of evidence). The combination of direct and indirect evidence is called [[mixed evidence]]. ---- NMA can be used to answer [[comparative effectiveness]] research questions in which multiple [[intervention]]s are available, or can be used for a given condition. In addition, network meta-analysis can estimate relative rankings of interventions ---- [[Pairwise meta-analysis]] is an established statistical [[tool]] for synthesizing [[evidence]] from multiple [[trial]]s, but it is informative only about the relative [[efficacy]] of two specific interventions. The usefulness of pairwise meta-analysis is thus limited in real-life medical practice, where many competing interventions may be available for a certain condition and studies informing some of the pairwise comparisons may be lacking. This commonly encountered scenario has led to the development of [[network meta-analysis]] (NMA). In the last decade, several applications, methodological developments, and empirical studies in NMA have been published, and the area is thriving as its relevance to public health is increasingly recognized ((Efthimiou O, Debray TP, van Valkenhoef G, Trelle S, Panayidou K, Moons KG, Reitsma JB, Shang A, Salanti G; GetReal Methods Review Group. GetReal in network meta-analysis: a review of the methodology. Res Synth Methods. 2016 Sep;7(3):236-63. doi: 10.1002/jrsm.1195. Epub 2016 Jan 11. PMID: 26754852.)). ---- Network [[meta-analysis]] is a [[technique]] for comparing multiple [[treatment]]s simultaneously in a single [[analysis]] by combining direct and [[indirect evidence]] within a network of [[randomized controlled trial]]s. Network meta-analysis may assist assessing the [[comparative effectiveness]] of different treatments regularly used in clinical practice and, therefore, has become attractive among clinicians. However, if proper caution is not taken in conducting and interpreting network meta-analysis, inferences might be [[bias]]ed ((Rouse B, Chaimani A, Li T. Network meta-analysis: an introduction for clinicians. Intern Emerg Med. 2017 Feb;12(1):103-111. doi: 10.1007/s11739-016-1583-7. Epub 2016 Dec 2. PMID: 27913917; PMCID: PMC5247317.)) ---- Organisations such as the National Institute for Health and Care Excellence require the synthesis of evidence from existing studies to inform their decisions—for example, about the best available treatments with respect to multiple efficacy and safety outcomes. However, relevant studies may not provide direct evidence about all the treatments or outcomes of interest. Multivariate and network meta-analysis methods provide a framework to address this, using correlated or indirect evidence from such studies alongside any direct evidence ((Riley RD, Jackson D, Salanti G, Burke DL, Price M, Kirkham J, White IR. Multivariate and network meta-analysis of multiple outcomes and multiple treatments: rationale, concepts, and examples. BMJ. 2017 Sep 13;358:j3932. doi: 10.1136/bmj.j3932. PMID: 28903924; PMCID: PMC5596393.)) ---- NMA is a relatively novel [[methodology]] that allows the [[inclusion]] of [[indirect evidence]] to evaluate multiple treatments ((Efthimiou O, Debray TPA, van Valkenhoef G, et al. GetReal in network metaanalysis: a review of the methodology. Res Synth Methods. 2016;7(3):236-263.)) ((Rouse B, Chaimani A, Li T. Network meta-analysis: an introduction for clinicians. Intern Emerg Med. 2017;12(1):103-111.)) ((Dias S, Caldwell DM. Network meta-Analysis explained. Arch Dis Child Fetal Neonatal Ed. 2019;104(1):F8-F12.)) ((Riley RD, Jackson D, Salanti G, et al. Multivariate and network meta-analysis of multiple outcomes and multiple treatments: rationale, concepts, and examples. BMJ. 2017;358:j3932)) with recent examples in the neurosurgical ((Golub D, Hyde J, Dogra S, et al. Intraoperative MRI versus 5-ALA in high-grade glioma resection: a network meta-analysis. J Neurosurg. 2020;134(2):1-15.)) ((Jain P, Tomlinson G, Snead C, Sander B, Widjaja E. Systematic review and network meta-analysis of resective surgery for mesial temporal lobe epilepsy. J Neurol Neurosurg Psychiatry. 2018;89(11):1138-1144.)) ((3. Henry J, Amoo M, Taylor J, O’Brien DP. Complications of cranioplasty in relation to material: systematic review, network meta-analysis and meta-regression. Neurosurgery. 2021;89(3):383-394)) and general surgical ((Wade RG, Burr NE, McCauley G, Bourke G, Efthimiou O. The comparative efficacy of chlorhexidine gluconate and povidone-iodine antiseptics for the prevention of infection in clean surgery: a systematic review and network metaanalysis. Ann Surg. 2021;274(6):e481-e488)) literature. ---- ---- Several organisations, such as the WHO, have endorsed network meta-analysis (NMA) as a powerful tool in clinical decision making. NMA is a statistical method, which simultaneously compares multiple (three or more) interventions within a single [[framework]], by synthesising direct and indirect evidence from multiple studies, addressing the same scientific question [[Network]] [[meta-analysis]] is a [[technique]] for comparing multiple [[treatment]]s simultaneously in a single [[analysis]] by combining direct and indirect [[evidence]] within a network of [[randomized controlled trial]]s. Network meta-analysis may assist assessing the [[comparative effectiveness]] of different treatments regularly used in [[clinical practice]], and therefore has become attractive among [[clinician]]s. However, if proper caution is not taken in conducting and interpreting network meta-analysis, inferences might be [[bias]]ed. The aim of Rouse et al. in a [[paper]] was to illustrate the process of network meta-analysis with the aid of a working example on first-line medical treatment for primary open-angle glaucoma. They discussed the key assumption of network meta-analysis, as well as the unique considerations for developing appropriate research questions, conducting the literature search, abstracting data, performing qualitative and quantitative synthesis, presenting results, drawing conclusions, and reporting the findings in a network meta-analysis ((Rouse B, Chaimani A, Li T. Network meta-analysis: an introduction for clinicians. Intern Emerg Med. 2017 Feb;12(1):103-111. doi: 10.1007/s11739-016-1583-7. Epub 2016 Dec 2. PMID: 27913917; PMCID: PMC5247317.)). ---- Garg K. Basic assumptions of a network meta-analysis - A neurosurgeon's perspective. Neurosurg Rev. 2021 Apr 21. doi: 10.1007/s10143-021-01546-w. Epub ahead of print. PMID: 33881627. ---- Chen J, Chen X, Huang C, Zhu H, Hou Z, An N, Liu SY, Yang H, Zhang CQ. Predictors of seizure recurrence in patients with surgery for focal cortical dysplasia: pairwise and [[network meta-analysis]] and trial sequential analysis. Childs Nerv Syst. 2019 May;35(5):753-767. doi: 10.1007/s00381-019-04124-0. Epub 2019 Mar 26. PMID: 30911833. ---- Kim DK, Lee JY, Jung JH, Hah YS, Koo KC, Lee KS, Chung BH, Cho KS. What is the most effective local anesthesia for transrectal ultrasonography-guided biopsy of the prostate? A [[systematic review]] and [[network meta-analysis]] of 47 randomized clinical trials. Sci Rep. 2019 Mar 20;9(1):4901. doi: 10.1038/s41598-019-41412-w. PMID: 30894638; PMCID: PMC6426994.