Section 2 Preclinical Systematic Reviews

2.1 What is a systematic review?

A systematic review (SR) is a literature review that involves systematically locating, appraising, and synthesising evidence from scientific studies to answer a defined research question based on pre-specified criteria.

The methods of a systematic review (and meta-analysis) should be transparent and reproducible. This means that the methods are planned, conducted, and reported in a way that can be repeated by other research groups.

2.2 What is a meta-analysis?

A meta-analysis is a method of combining quantitative results from individual studies identified through systematic review in an overall statistical analysis.

2.3 Clinical & preclinical reviews

There are many differences between preclinical and clinical systematic reviews, which is why we developed this Wiki, specific to preclinical systematic review methodology.

Preclinical Clinical
# of included studies High Low
Sample size within studies Low High
Experimental design Variable Consistent
  • Investigate translational failure
  • Explore differences between studies (heterogeneity) e.g. internal & external validity
  • Inform future preclinical studies e.g. model selection
  • Inform early phase clinical trials
  • Explain discrepancies in preclinical vs. clinical trial results
  • Inform 3Rs decisions
  • Explore heterogeneity e.g. clinical populations
  • Inform later phase clinical studies
  • Inform clinical practice and guidelines

2.4 Why perform preclinical SRs?

There are many reasons to perform preclinical systematic reviews:

  • To summarise evidence from multiple similar studies to allow for more accurate estimates of effect
  • The methods used to find and select studies are transparent and reproducible, reducing bias and increasing the likeliness of producing reliable and accurate conclusions.
  • Summarise findings from all available studies making information easier for the end-user to read and understand
  • Analyse individual study quality to inform confidence in the results
  • Quantitative synthesis of results (meta-analysis)
  • Allow for evidence-based inferences

The results of preclinical systematic reviews can:

  • Provide evidence to change research practice by identifying risks of bias in preclinical experiments
  • Influence development of reporting guidelines and editorial policies
  • Provide evidence to support reporting of positive, negative and neutral results through detection of publication bias
  • Identify study design features that compromise potential clinical application
  • Contribute to evidence-based clinical trial design