Shima Aran MD, Presenter: Nothing to Disclose

Khalid Walid Shaqdan MD, Abstract Co-Author: Nothing to Disclose

Hani H. Abujudeh MD, MBA, Abstract Co-Author: Research Grant, Bracco Group Consultant, RCG HealthCare Consulting Author, Oxford University Press

The Weber effect states that adverse event reporting tends to increase in the first two years after introduction of a new agent or a new indication, and then declines. We aim to present our experience with adverse reaction reporting pattern of Gadopentetate Dimeglumine.

IRB approved the retrospective study. Data in the electronic incident reporting system was searched between Jan-01-2007 to Jan-14-2014. Gadopentetate Dimeglumine (Mag) and Gadobenate Dimeglumine (Mul) were studied. Our institution developed new guidelines for the use of gadolinium based contrast agents (GBCAs) due to the risk of developing NSF as a result of Mag administration in May-07. In Oct-07 Mag was replaced with Mul for patients with an eGFR <60 mL/min/m2. We continued to use Mag for Other patients. We discontinued the use of Mul in Dec-08 due to concerns about acute allergic reactions. As a result the clinical indications for Mag use were changed again and it was used for all clinical indications based on a newly defined guideline. Table shows the time frame of events.

Of 184,218 injections, 174(0.09%) patients (mean age: 45.6±15.1) showed allergic reaction, consisted of 48 (27.6%) males and 126 (72.4%) females. The highest rates of reactions were observed in the first year (Period-3; 0.167%) after the change in clinical indications followed by the second year (Period-4; 0.109%). Period-3 was statistically significantly different from all other periods except period-4.

A Weber pattern was observed in our study following a change in clinical indications for the use of Mag. As institutions consider changing the type of GBCA they use for their general patient population, they should be aware that the overall risk of adverse events could increase. Considering the influence of Weber effect, the increase in adverse events could be attributed to epidemiologic reporting bias and may not represent a true difference in adverse events based on the pharmacologic structure of the GBCA.

Our investigation showed that the weber effect does happen with GBCAs and that Radiology departments should be aware of this effect when substituting the GBCAs or their clinical indications.

Aran, S, Shaqdan, K, Abujudeh, H, The Weber Effect; A Multi-Year Experience with Gadopentetate Dimeglumine Administration.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14002765.html