News 08/07/2021: registration data required in a new column 4. Enter No if not registered or NA if either unknown resistration or you do not intend a subgroup by registration. Note, this only addresses whether registration done and not whether done timely and without changes in primary outcome or other attributes that could bias the results. The rationale for this is re-analysis of the role of tramadol for chronic back pain (PMID 29204613). In this example, the data is further weakened by the outcome in the Lee study not matching the outcome in the trial registration.
Enter inputs
To perform a meta-analysis of interventions:
  • Revise or replace the example data below as needed or
  • Upload a csv file formatted like these examples with dichotomous or continous outcomes.
    1st row is column names?
Required columns: 1) study name, 2) year, 3) PMID, 4) trial registration number, 5) events or mean (SD) in intervention group, 6) total in intervention group, 7) events or mean (SD) in control group, 8) total in control group.
Optional columns for up to five cofactors
Separate columns with commas. Click here to add commas.
The initial data shown below is fictitious and is instructional.
Wells, 2012, 12345678, NA, 36, 100, 50, 100, high-dose, 30, Ford, 2013, 12345678, NA, 50, 100, 50, 100, low-dose, 35, Freud, 2014, 12345678, NA, 38, 100, 50, 100, high-dose, 40, Pavlov, 2015, 12345678, NCT12345678, 52, 100, 50, 100, low-dose, 45, Malthus, 2016, 12345678, NCT12345678, 40, 100, 50, 100, high-dose, 50,
Meta-analysis settings

 
Analysis method:
Knapp-Hartung adjustment should be clicked unless heterogeneity is insig per PMID: 24727843. However, unclick this if yields wacky confidence intervals when less than 5 studies available.
 
 
Example analyses

Teaching example 1: Soma (fictitious)

Fictitious example based on Brave New World
Before making the plot
  • Do you believe Soma will show a benefit when the studies are pooled?
Now, look at the plot
  • What does I2 indicate? (help)
Before making the plot
  • Do you believe Soma will show a benefit when the studies are pooled?
Now, look at the plot
  • What does I2 indicate? (help)

Teaching example 2: back pain treatment with tramadol

From PMID 29204613. Note that the trial by Lee was prospectively registered, the primary outcome in the publication was not prospectively registered.

Meta-analysis of binary outcomes

When pooled, is there a significant difference? What does i-squared suggest?
What does subgrouping reveal?

Meta-analysis of continuous outcomes

When pooled, is there a significant difference? What does i-squared suggest?
About standardized mean differences
The standardized mean difference (SMD) is:
SMD
In the interpretation of SMD:
  • 0.2 represents a small effect
  • 0.5 a moderate effect
  • > 0.8 a large effect
The 'standardization' allows pooling of different types of outcomes.

Meta-regression

What is the relationship between reduction in mortality and the baseline serum lactate? How about with the morality in the control group?
 
Hint: if bad spacing between title/footer text and the plot, click 'png' file type in upper right of plot. Then after the image opens in a new browser window, alter the image's dimensions in the url of the window. Click here to see screen capture of an exampleopens in new window

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