Duplicates and Follow-Up

Part of Pharmacovigilance and Drug Safety (PV) Training: Intake and Triage.

About 2 minutes. Free, in your language, no account needed.

The same case arrives more than once

A serious event in a trial may reach you from the investigator, from the data management system, from the monitor and from a regulator who received a copy. In the post-marketing world, a single patient may be described by their doctor, their pharmacist and a family member.

Counting one event as four cases distorts everything downstream. A frequency that looks like it has quadrupled may only mean that reporting has quadrupled.

How duplicates are found

Matching is done on the combination of patient identifiers, event, date, product and reporter. No single field is sufficient. Two reports with the same initials and the same event are not necessarily the same person, and the same person may be described with different initials by two reporters.

Where the safety system proposes a match, a human confirms it. Where you suspect a duplicate and cannot prove it, say so in the case rather than merging on a hunch.

Follow-up is part of the case, not an extra

An initial report is usually the least informative version of a case that will ever exist. The follow-up that establishes the outcome, the concomitant medications or the result of stopping the drug is often what makes the case assessable at all.

Follow-up is prioritized by what it would change. A missing date of birth on a non-serious rash is worth one attempt. The outcome of a serious unlisted event is worth persistence.

A follow-up can restart a clock

If follow-up brings significant new information, particularly information that changes the case from non-serious to serious or from expected to unexpected, a new clock begins on the day you received that information. A case you closed is not necessarily finished.