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Demonstrating that ICES drug safety research has changed physician prescribing behaviour

The Story and Impact

""The blood thinner clopidogrel is widely used for the treatment of ischemic heart disease and stroke. Proton pump inhibitors (PPIs) are often co-prescribed to offset the risks from gastric bleeding associated with the use of blood thinners. In the late 2000s, concerns were raised of an increased risk of recurrent heart attacks in patients co-prescribed a PPI and clopidogrel.

2009: A highly-publicized ICES population-wide study showed that patients who took clopidogrel following a heart attack were at significant risk of a recurrent heart attack if they were also taking certain PPIs. Unlike other studies, the ICES paper determined that one PPI, pantoprazole, was not tied to this higher risk.

Before the 2009 study, pantoprazole represented only 24% of all PPI prescriptions dispensed to patients receiving clopidogrel. Only nine months after the study, the proportion of pantoprazole use had rapidly expanded to 53%.

""2015: Assessed the impact of the 2009 publication on physician prescribing behaviour, in particular, on whether there was a shift in how many patients were prescribed pantoprazole (rather than another PPI) while taking clopidogrel.

The 2015 study demonstrated that other 2009 studies and an FDA warning about clopidogrel and PPI risk did not differentiate between PPI formulations, so this shift could only be attributed to the extensive media attention surrounding the ICES study.

  • Confirmed the power of ICES’ large linked data holdings to investigate system-wide temporal trends.
  • Provided more clarity about the differentiated risks of PPI formulations for patients receiving clopidogrel.
  • Demonstrated that news campaigns can influence physician prescribing behaviour.

The Scientists

Published in the 2015-16 ICES Annual Report

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