Selecting events for logistic regression

When defining a logistic regression run, you specify values (that is, responses) for the event variable that you are investigating with the run on the Select Event Values page. The application computes separate results for each specified event value.

The run computes values for an event only if it finds a sufficient number of reports. Results are not produced for an event if either of the following situations exists:

• For all drugs explicitly included in the run no reports are found with the event and, in addition, the drugs that do occur in combination with the event most frequently do not meet the specified minimum number of occurrences for inclusion. (For more information on specifying drug values see Specifying drugs for logistic regression.)
• For the covariate variables selected for the run, the number of reports that include the event and each of the possible covariate values averages less than 10. This is determined as follows:
• 10 * the total number of possible values for all covariate variables that occur with this event > count of reports for the event.

If an event is specified for the run but results are not produced, one of these reasons appears in the lr.log file produced for the run.

If you specify a single event and that event is not found in the data used in the run, the run fails and an error appears on the Jobs for Run page. If you specify multiple events and any one of them is not found, the run fails and a message appears in the error log. You can access the lr.log and the error log from the Job Detail page.

Typically, logistic regression data mining runs do not include every possible drug+event combination. Instead, they are generally used to focus on specific medically related adverse events (response values) and drugs of interest (predictors). For some investigations, you may wish to compute scores for all adverse events in the selected data configuration (after database restrictions are applied).

Note: When selecting events, keep in mind that there is a logistic regression computation for each response value. The more events you select as responses, the longer the LR run takes

• To select individual event terms from the hierarchy browser, click Select <hierarchy> Terms.

This option appears if your user preference, Enable Adverse Event Hierarchy Browser, is checked. (For more information, see Drug and event hierarchies.)

or

To select values from a list, click Select Available Values.

or

To refer to a saved list of terms, including custom terms, click Select Saved List.

If you created a custom term for the event variable in the run, the application includes it by default in the list of selected event values. If you remove it, the custom term is not be included in run results.

• To include all of the events in the configuration in your run, select the Select all available values check box.

Click Next to open the Select Drugs page, and continue with specifying drug values.