PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) is an evidence-based reporting guideline designed to improve the transparency, completeness, and reliability of systematic reviews (SRs) and meta-analyses (MAs). Unlike AMSTAR-2 (quality assessment) or ROBIS (bias evaluation), PRISMA focuses on standardized reporting rather than methodological rigor.
PRISMA: Step-by-Step Guide
1. Understand the PRISMA Components
PRISMA consists of:- A 27-item checklist (key elements to report).
- A flow diagram (visualizes study selection process).
2. When to Use PRISMA?
✔ When conducting a new SR/MA. ✔ When evaluating an existing SR for completeness. ✔ For peer review (journals often require PRISMA compliance).PRISMA Checklist (Key Items)
Section 1: Title & Abstract
- Title: Identify as a systematic review/meta-analysis.
- Structured Abstract: Include objectives, data sources, methods, results, and conclusions.
Section 2: Introduction
- Rationale: Why was the review conducted?
- Objectives: Clearly state research question (PICO format preferred).
Section 3: Methods
- Protocol Registration: Was the review preregistered (e.g., PROSPERO)?
- Eligibility Criteria: Define PICO (Population, Intervention, Comparison, Outcome).
- Information Sources: List databases (PubMed, Embase, etc.) + search dates.
- Search Strategy: Provide full search syntax (e.g., MeSH terms, keywords).
- Study Selection: Describe screening process (e.g., dual reviewers, software used).
- Data Extraction: Methods for collecting data (e.g., piloted forms).
- Risk of Bias (RoB): Tool used (e.g., Cochrane RoB 2.0, Newcastle-Ottawa).
- Synthesis Methods: Meta-analysis approach (fixed/random effects), heterogeneity tests (I²).
Section 4: Results
- Study Selection: PRISMA flow diagram (see below).
- Study Characteristics: Table summarizing included studies.
- Risk of Bias: Present RoB assessment (e.g., graph, table).
- Synthesis Results: Forest plots, effect sizes, subgroup analyses.
Section 5: Discussion
- Summary of Evidence: Key findings.
- Limitations: Study biases, heterogeneity issues.
- Conclusions: Implications for practice/research.
Section 6: Funding
- Conflict of Interest: Declare any financial/non-financial COIs.
PRISMA Flow Diagram
A 4-stage flowchart showing:- Records identified (database + other sources).
- Records after duplicates removed.
- Records screened (title/abstract).
- Full-text assessed for eligibility.
- Studies included in review.
Identification → Screening → Eligibility → Included (n=5000) → (n=3000) → (n=100) → (n=50)
How to Apply PRISMA?
For Authors Conducting a Review
- Before starting:
- Register protocol (PROSPERO).
- Download the PRISMA checklist & flow diagram template.
- While writing:
- Fill in each checklist item (e.g., "We searched PubMed, Embase...").
- Generate the flow diagram (use tools like Lucidchart, PRISMA2020).
- Before submission:
- Cross-check manuscript against the checklist.
For Readers/Reviewers Evaluating a Review
✔ Check if the manuscript follows PRISMA guidelines. ✔ Look for missing items (e.g., no search strategy = red flag).PRISMA 2020 Updates
The PRISMA-2020 version includes:- New items (e.g., equity considerations, reporting automation tools).
- Revised flow diagram (now includes "database registers").
PRISMA vs. AMSTAR-2 vs. ROBIS
| Feature | PRISMA | AMSTAR-2 | ROBIS |
|---|---|---|---|
| Purpose | Reporting guideline | Quality assessment | Bias assessment |
| Use Case | Writing SRs | Appraising SRs | Detecting bias in SRs |
| Output | Checklist + flow diagram | Confidence rating (High/Low) | Risk of bias (Low/High) |