Viewing interactions for a drug-event combination

Information about an event and drug interactions is represented as a nested confidence interval graph of EB05-EB95 confidence intervals and EBGM values for two drugs and the event. Data represented in the graph includes all available data up through the current time period. The signals were generated by a particular run that was set up for the purpose of viewing interactions.

For each combination of two drugs and the event, the graph displays a series of confidence intervals, with the highest dimension shown first. The first confidence interval is for Event+Drug+Drug. The other two confidence intervals are for Event+Drug. You can compare the strength of the interaction between the two drugs and the event with the strength of the interaction between the individual drugs and the event.

In each confidence interval bar, the EB05 value is at the left end, the EBGM value is the dot on the bar, and the EB95 value is at the right end. The count (N) of cases with the combination is also shown at the end of each bar. Bars are colored according to the color key below the graph. To indicate a possible interaction, the confidence interval for the Event+Drug+Drug combination displays in red when the INTSS (Interaction Signal Score) value is greater than a predefined threshold that is set when signal management is configured. For more information about INTSS, see interaction scores.

Note that:

• The Event+Drug+Drug combinations are shown in descending order of their INTSS values.
• To conserve space in labeling, the event from the drug-event combination is referred to by the label, Event, in the graph.
• Below the graph, there may be additional text provided by a site option.

1.         On the Drug-Event Combinations page (or the Similar Combinations page), click the row menu () for a combination, and then click View Interactions.

The Interactions dialog box appears.

Note: A message informs you if there are no combinations of the drug and another drug with the event. Depending on how your signal management data was prepared, this option might not be available at all for some drug-event combinations or there may be multiple links for different runs.

2.         If you point to a confidence interval, the names of the event and the two drugs appear. The following information for the Event+Drug+Drug combination also appears:

• N—Observed number of cases with this Event+Drug+Drug combination.
• EBGM—Empirical Bayesian Geometric Mean. A more stable estimate than RR; the so-called shrinkage estimate. For more information, see MGPS computations.
• EB05—A value such that there is approximately a 5% probability that the true Relative Ratio lies below it.
• EB95—A value such that there is approximately a 5% probability that the true Relative Ratio lies above it.
• INTSS—Interaction Signal Score. A way of measuring of the strength of a higher-order association above and beyond what would be expected from any of the component pairs of items of different types.
• EXCESS2—A conservative estimate of how many extra cases were observed over what was expected assuming that only a single cross-item interaction is present.

3.         To work with the cases represented by any of the confidence intervals, you can click the bar to see an action menu of options.

4.         To save the graph as an attachment to a topic, click Save to Topic (available if the topics feature has been set up). The graph is attached to a PDF file.

For information about copying or printing a graph, see Working with results graphs.

5.         To close the Interactions dialog box, click Close.