What is the purpose of checking for clinical heterogeneity in a systematic review?

The purpose of checking for clinical heterogeneity in a systematic review is to determine if a meta-analysis is justifiable. Clinical heterogeneity refers to the differences between studies in participant characteristics, interventions, outcomes, or study designs. When significant clinical heterogeneity is observed, it suggests that the studies may not be sufficiently similar to be combined, which can lead to misleading results or interpretations if a meta-analysis is conducted.

By assessing clinical heterogeneity, researchers can make informed decisions about whether it is appropriate to combine the data from the different studies in a quantitative synthesis. If heterogeneity is low, a meta-analysis might yield meaningful insights; if high, it may indicate that a meta-analysis could obscure important variations between the studies. Therefore, checking for clinical heterogeneity is a critical step in the systematic review process that directly informs the feasibility and validity of performing a meta-analysis.