**Question:** All are True regarding **Meta-analysis** except:

A. A systematic review is a prerequisite for a proper **metanalysis**.
B. A **metanalysis** combines data from multiple studies to increase statistical power and precision.
C. A **metanalysis** can only be performed on studies with identical interventions and outcomes.
D. A **metanalysis** is not affected by publication bias because it incorporates unpublished studies as well.

**Correct Answer:** C. **A metanalysis** can only be performed on studies with identical interventions and outcomes.

**Core Concept:**

A **metanalysis** is a statistical approach that combines results from multiple studies to provide a comprehensive summary of findings in a particular research question or topic. The goal of a metanalysis is to increase statistical power and precision, allowing for more accurate conclusions and estimates of treatment effects.

**Why the Correct Answer is Right:**

Option C is incorrect because a metanalysis requires that the studies included share the same interventions and outcomes to ensure comparable data across studies. If interventions or outcomes differ between studies, it becomes difficult to combine data and draw meaningful conclusions.

**Why Each Wrong Option is Incorrect:**

A. A systematic review, which is a comprehensive search for all relevant studies, is a prerequisite for a metanalysis to ensure that all available evidence is included. However, the statement about a systematic review is not incorrect; it is a necessary step in the metanalysis process.

B. While a metanalysis does combine data from multiple studies, this statement is not inherently wrong; it highlights the purpose of the metanalysis.

D. Publication bias, which refers to the unequal reporting of study results based on their significance, can affect a metanalysis if unpublished studies (also known as "grey literature") are not included. Including unpublished studies can help mitigate publication bias, and option D is incorrect because it suggests that publication bias does not impact a metanalysis.

**Clinical Pearl:**

Understanding the nuances of metanalysis is crucial for healthcare professionals, as it enables them to critically appraise research findings and make evidence-based decisions in patient care. Always ensure that the studies included in the metanalysis have comparable interventions, outcomes, and study designs to derive meaningful conclusions.