with wider confidence interval), but the results from the two models usually agree where there is no heterogeneity. The random effects model will tend to give a more conservative estimate (i.e. If the value 1 is not within the 95% CI, then the Odds ratio is statistically significant at the 5% level (P<0.05). The pooled odds ratio with 95% CI is given both for the Fixed effects model and the Random effects model. The program lists the results of the individual studies: number of positive cases, total number of cases, and the odds ratio with 95% CI. Funnel plot: creates a funnel plot to check for the existence of publication bias.Diamonds for pooled effects: option to represent the pooled effects using a diamond (the location of the diamond represents the estimated effect size and the width of the diamond reflects the precision of the estimate).Plot pooled effect - random effect model: option to include the pooled effect under the random effects model in the forest plot.Plot pooled effect - fixed effects model: option to include the pooled effect under the fixed effects model in the forest plot.You can choose the fixed effect model weights or random effect model weights. Marker size relative to study weight: option to have the size of the markers that represent the effects of the studies vary in size according to the weights assigned to the different studies.Number with positive outcome: a variable containing the number of cases with positive outcome in the control groups of the different studiesĪ filter to include only a selected subgroup of studies in the meta-analysis.įilter: a filter to include only a selected subgroup of cases in the graph.Total number of cases: a variable containing the total number of cases in the control groups of the different studies.Number with positive outcome: a variable containing the number of cases with positive outcome in the intervention groups of the different studies.Total number of cases: a variable containing the total number of cases in the intervention groups of the different studies.Studies: a variable containing an identification of the different studies. The dialog box for "Meta-analysis: odds ratio" can then be completed as follows: On the next rows of the spreadsheet follow the data of 4 other studies. 23 cases received a placebo and 3 of these had a positive outcome. In this example, in a first study 73 cases were treated with an active substance and of these, 15 had a positive outcome. The data of different studies can be entered as follows in the spreadsheet: Next the heterogeneity statistic is incorporated to calculate the summary odds ratio under the random effects model (DerSimonian & Laird, 1986). MedCalc uses the Mantel-Haenszel method (Mantel & Haenszel, 1959) for calculating the weighted pooled odds ratio under the fixed effects model. For a short overview of meta-analysis in MedCalc, see Meta-analysis: introduction.
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