Contents
Is there a control group in meta-analysis?
Therefore, studies that do not have control groups are likely included in the meta-analytic data base. Without evidence from a control group, it is not possible to correct a single study estimate for the influence of extraneous factors, which may have magnified or diminished its influence.
How do you interpret odds ratio in meta-analysis?
An odds ratio or relative risk greater than 1 indicates increased likelihood of the stated outcome being achieved in the treatment group. If the odds ratio or relative risk is less than 1, there is a decreased likelihood in the treatment group.
How is assumed control risk calculated?
PubMed PMID: 19821263.
- Computing ARR and NNT from Relative Risk. When RR is reported in a meta-analysis, determine (this is a judgment) the assumed control risk (ACR)—i.e., the risk in the group being compared to the new intervention—from the control event rate or other data/source.
- Formula: ARR=100 X ACR X (1-RR)
How do you convert RR to NNT?
The RR = (8/1000) / (10/1000) = 0.8 making the RRR = (1-0.8/1)=0.2 or 20%. Although this sounds impressive, the absolute risk reduction is only 0.01-0.008=. 002 or 0.2%. Thus the NNT is 1/0.002=500 patients.
How are odds ratios calculated in a meta-analysis?
The results of the different studies, with 95% CI, and the overall effect with 95% CI are shown in a forest plot: Note that the Odds ratios with 95% CI are drawn on a logarithmic scale. Borenstein M, Hedges LV, Higgins JPT, Rothstein HR (2009) Introduction to meta-analysis.
How is the risk ratio and the odds ratio related?
The risk ratio (or relative risk) is the ratio of the risk of an event in the two groups, whereas the odds ratio is the ratio of the odds of an event (see Box 9.2.a ). For both measures a value of 1 indicates that the estimated effects are the same for both interventions.
How is the odds ratio calculated in MedCalc?
The program lists the results of the individual studies: number of positive cases, total number of cases, and the odds ratio with 95% CI. The pooled odds ratio with 95% CI is given both for the Fixed effects model and the Random effects model.
When is the pooled odds ratio statistically significant?
The pooled odds ratio with 95% CI is given both for the Fixed effects model and the Random effects model. If the value 1 is not within the 95% CI, then the Odds ratio is statistically significant at the 5% level (P<0.05).