Table 2.

Key Steps in Conducting a Systematic Review

Step	Components
Define the clinical question	Use the PICO format (population, intervention, control, outcome).
Define inclusion and exclusion criteria	Consider study design, time of follow-up, clinical setting, comordities, demographic characteristics (e.g., age groups, sex), characteristics of the control group, outcome importance, language of publication, date of publication (as a range of years).
Conduct literature search	Consider appropriate databases, number of databases, publication date range, grey literature.
Select studies	Use at least 2 independent reviewers. Have the reviewers use the inclusion and exclusion criteria as the basis for their selections. Specify a method to resolve discrepancies (e.g., consensus, third reviewer).
Extract the data	Develop a data extraction form based on PICO. Have 2 researchers extract the data independently.
Determine level of bias (previously termed “study quality”) of included studies	The risk-of-bias tool is currently the preferred method. A different tool may be needed if non–randomized controlled trials are included.
Determine heterogeneity (qualitatively)	Determine whether there are major differences between studies in terms of patients, interventions, outcomes, study design (quality).
If appropriate, conduct meta-analysis	Using appropriate statistical software and the I2 statistic, combine the data. Reassess outcomes for statistical heterogeneity. Generate summary estimates and confidence intervals.
Evaluate and interpret results	Consider clinical significance and practice context.
Publish	Follow the PRISMA guidelines6 in drafting your manuscript.

PRISMA = Preferred Reporting Items for Systematic Reviews and Meta-Analyses.