Systematic Reviews and Review Types: What is a Network Meta-Analysis?

This is a version of the LibGuide I started while employed at Temple University Health Sciences Library from July 2015-September 12, 2022. I removed anything that was specific to Temple University and any affiliated links. If you want to receive guide updates from the original content creator of this guide, subscribe to my newsletter!

Other names for a Network Meta-Analysis

NMA, MTC Meta-Analysis, Multiple Treatment Meta-Analysis, Mixed Treatments Comparison, Multiple Treatments Comparison, Pair-Wise Meta-Analysis, Indirect Treatment Comparison, Multiple Treatment Comparison Meta-Analysis, Live Cumulative Network Analysis (New type)

What is a Network Meta-Analysis?

“Network meta-analysis compares multiple interventions simultaneously by analyzing studies making different comparisons in the same analysis.”

Source: M. Petticrew et al. (2013)

Network meta-analyses are best designed for:

  • Conditions with multiple interventions
  • Many combinations of direct or indirect interactions 
  • To answer more relevant clinical questions
  • To make treatment estimates for an entire treatment network instead of scanning each individual pair-wise comparison
  • To give the “full picture” to clinicians
  • Gain precision by considering all available evidence, not just (A vs. B comparisons)
  • Potential to more explicitly “rank” treatments using summary outputs

What is a Network Meta-Analysis? Outline of Stages

Timeframe: 12-18+ months.  Same as a traditional systematic review.  *Varies beyond the type of review. Depends on many factors such as but not limited to: resources available, the quantity and quality of the literature, and the expertise or experience of reviewers” (Grant et al. 2009)

Question: Addresses PICO for multiple interventions or treatments (3 or more).  These may be broad or narrow.  Combines indirect (triangular approach) or direct comparisons (pairwise approach). 

Sources and searches: Requires a large search to locate all of the trials using transparent & reproducible methods.

Selection: Same as a systematic review–based upon clear inclusion/exclusion criteria.  Requires a lot more screening of trials.

Appraisal: Formal quality assessment of all studies.  Still includes Risk of Bias and quality of evidence assessments.

Synthesis: Statistical analysis when possible (heterogeneity a potential problem with indirect comparisons)–uses different statistical methods than a systematic review. Creates a web-like analysis called a Network Diagram or Network Comparison.  May use bayesian frameworks or meta-regression analysis.

Limitations of a Network Meta-Analysis

  • Requires specialist statistical expertise and software
  • Assumes that all interventions included in the “network” are equally applicable to all populations and contexts of the studies included.
  • May introduce study selection bias.
  • Ease of software may lead researchers to undertake this type of review even though it may not be the most appropriate study design for their research question.
  • Complex methodological approaches
  • Still an evolving method

Source: M. Petticrew et al. (2013) and Li T. et al. (2011)

Example of a published Treatment Network for the Drugs Considered in the Example Multiple Treatment Comparison on Generalized Anxiety Disorder

a network diagram for a network analysis


Mills, Edward J., John P. A. Ioannidis, Kristian Thorlund, Holger J. Schünemann, Milo A. Puhan, and Gordon H. Guyatt. 2012. How to use an article reporting a multiple treatment comparison meta-analysis. Jama 308 (12): 1246-53.


Assessing the Feasibility of a Network Meta-Analysis (VIDEO

Petticrew M, Rehfuess E, Noyes J, et al.  Synthesizing evidence on complex interventions:

how meta-analytical, qualitative, and mixed method approaches can contribute.  

J Clin Epid. 2013;66:1230-1243.

Li T, Puhan MA, Swaroop SV, Dickersin K, et al.  Network meta-analysis-highly attractive

but more methodological research is needed.  BMC Medicine.  2011.  

Reporting Standards-PRISMA NMA for Network Meta-Analyses 

Cochrane Network Meta-analysis Toolkit 

Link to Published Network Meta-Analyses 

Graphical Tools for Network Meta-Analysis in STATA 

ISPOR Task Force on Indirect Comparisons and Network Meta-Analysis

This link opens to a PDF document.

What is a Live Cumulative (NMA) Network Meta-Analysis:

An NMA that is updated at regular intervals via crowdsourcing of a research community.


Créquit P, Trinquart L, Ravaud P.  Live cumulative network meta-analysis: protocol for second-line treatments in advanced non-small-cell lung cancer with wild-type or unknown status for epidermal growth factor receptor.  BMJ Open 2016;6:e011841. 

Oops, if you find any broken links, please contact me!