Causal or Casual?

Abstract

As with any other study method, 'spontaneous reporting' in pharmacovigilance is a process of data acquisition, assessment, presentation and interpretation. The provision of information (i.e. of interpreted data) concerning previously unknown, or otherwise important adverse drug reactions is a major goal. The assessment of case reports in spontaneous reporting takes place in 2 steps: first the assessment of each case individually, and secondly the interpretation of the aggregated data. The latter step is only completed for a minority of case reports, such as when actions or measures are deemed necessary. Uncertainty in case reports regarding the involvement of the suspected drugs is an inherent drawback of spontaneous reporting. Standardised case-causality assessment has become a routine at pharmacovigilance centres around the world. It aims at a decrease in ambiguity of the data and plays a role in data exchange and the prevention of erroneous conclusions. A variety of systems for standardised causality assessment have been developed, ranging from short questionnaires to comprehensive algorithms. Since none of the available assessment systems has been validated (i.e. shown to consistently and reproducibly produce a fair approximation of the truth), causality assessment has only limited scientific value. Causality assessment neither eliminates nor quantifies uncertainty but, at best, categorises it in a semiquantitative way. Routine causality assessment is usually part of the first step in case assessment, and is based on a general system that is intended for all reactions and all drugs. During the subsequent phase of aggregated assessment, causality assessment is likely to be repeated and the use of a specific aetiological-diagnostic system may be more appropriate. It may be recommended to restrict case-causality assessment to selected case reports that are likely to play an active role in pharmacovigilance and to use specific systems, adapted to the reaction or problem involved. It is an inherent limitation of spontaneous reporting that, with the exception of rare proof-positive case reports, conclusive evidence cannot usually be produced. Standardised causality assessment has not really changed this situation. As a rule, confirmation of the connection between a drug and an adverse reaction requires further analytical or experimental study.

Rare cause of acute hepatitis: a common energy drink

“…In the absence of a rechallenge, the association is probable/likely (according to the WHO-UMC causality categories) as the transaminitis occurred with a reasonable time sequence to the energy drink intake, was unlikely to be attributed to other drugs or concurrent diseases and followed a clinically reasonable response to withdrawal. 6 Energy drinks contain a mixture of B vitamins and an 'energy blend'. 3 As listed on the manufacturer's label, the energy blend includes taurine, glucuronic acid, malic acid, N-acetyl l-tyrosine, l-phenylalanine, caffeine and citicoline.…”

The Incidence and Risk Factors of Infusion-Related Reactions to Rituximab for Treating B Cell Malignancies in a Single Tertiary Hospital

“…For each patient, all electronic medical record data at the time of rituximab administration were retrospectively reviewed for potential IRR cases by nurses professionally trained to screen for and treat adverse drug reactions, and later confirmed by two allergy specialists using the WHO-UMC causality assessment system [10,11]. The cases were included in the study when rituximab was assessed as the ‘probable' or ‘certain' causative drug for an occurrence of IRR.…”

Vigilância de eventos adversos pós-vacinação e segurança de programas de imunização

“…58,77 Complementary investigations in the form of observational studies are necessary to establish such relationships.…”