Collecting adverse drug events from healthcare professionals and the public is mandatory for manufacturers. Minimum criteria apply to make such a case report valid. A valid case report must involve a suspect drug and a suspected adverse drug event, an identifiable patient, and an identifiable reporter.
The ability to identify a reporter is essential to enable follow-up and avoid duplication of reports and fraud. The verification of the existence of the patient and a reporter is tricky for a variety of reasons, namely local privacy laws. The reporter must have first-hand knowledge of the event and the patient, with a defined relationship to the patient, such as a parent, caregiver, or a healthcare professional directly involved n the patient’s care. Basic valid identifiers of a patient include gender, age, age category (i.e. adult, elderly, or adolescent), initials, date of birth, name, or a unique identifier such as patient number linkable to the patient’s identity. Accurate information about the patient’s demographic characteristics and medical history enables the detection of incompatibilities specifically listed in contraindications and special warnings sections.
At least one suspect product needs to exist for a case to be valid. A suspect product can be identified by its brand name (e.g. Lyrica) or a generic name (e.g. pregabalin). Since numerous manufacturers of a generic drug typically exist, a vague description of a product creates a significant opportunity for multiplication of reports when the same case is picked up, processed, and submitted by multiple different manufacturers. This opportunity for error is even greater if multiple suspect drugs exist. Accurate identification of suspect products ensures the case is routed to the correct manufacturers, preventing duplication.
Additional information about the drug such as dosage, indication, route of administration, and dates taken enable appropriate assessment of the case, such as dose-related toxicity, off-label use, medication errors, latency (time between the first administration of the suspect drug and the onset of the event) and last dose latency (time between the last administration of the suspect drug and event onset). Without an accurately described temporal relationship between the administration of suspect drugs and event onset and without information on the result of dechallenge and rechallenge, a causal relationship cannot be established, and the case will remain not assessable.
Source reliability, information credibility assessment
Formal evaluation of reliability and competence of source and credibility of information from that source is a standard part of intelligence reporting. Sources are categorized by their reliability and competence, and the information they provide is graded to express credibility (Irwin and Mandel, 2019).
With adverse drug events, the analogical approach can be used to express the reliability of reporters who submit reports from their practice on a regular basis and distinguish them from first-time reporters and those with a history of poor-quality, unverified, and non-valid reports. It is prudent to treat reporter’s qualification and competence as two separate characteristics, of which one (qualification) defines the educational background such as a licensed physician, nurse, pharmacist, other healthcare professions (e.g. medical scribe), patients and caregivers while the other (competence) defines specific training in pharmacovigilance reporting.
Grading the credibility of information that comes from our sources is a formal approach to the evaluation of the accuracy of the information provided, verification of each component of the report, and the presence of components required for the assessment of the seriousness and causality. The credibility of a case report depends on the provision of patient demographics and medical history, identification of the suspect and concomitant drugs, reconciliation of information on prescription, dispensed medication, instructions given to the patient and how the medication was taken by the patient, verification of any action taken in response to the event, and follow-up including treatment of the event until resolution.
The WHO-UMC causality categories rely on the temporal relationship between suspect medications and the event, results of dechallenge (i.e. what happened upon cessation of the suspect drug) and rechallenge (did the event reappear after re-administration of the suspect drug?), biological plausibility and the absence of alternative explanations (The Uppsala Monitoring Centre, n.d.). The inclusion of the adverse event on the drug label or a known drug-drug interaction can serve as a reasonably accurate proxy for the detection of biological plausibility.
A credible, high-quality adverse drug event report from a reliable source represents valuable actionable intelligence for pharmaceutical manufacturers.