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Systematic Reviews & Other Review Types

What is a Network Meta-Analysis?

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

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

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)

How a Network Meta-Analysis differs from a traditional Systematic Review

Timeframe: 12-18+ months.  Same as a traditional systematic review.

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 -- 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

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

Temple Attribution

Adapted with permission from Temple University Libraries.

Touro College of Osteopathic Medicine and College of Pharmacy
Harlem Campus 230 West 125th Street New York, NY 10027 (212) 851-1199