Trends in Acid Suppressant Drug Prescriptions in Primary Care in the United Kingdom

Date of ISAC Approval: 
28/06/2019
Lay Summary: 
Acid suppressant drugs, including proton pump inhibitors and histamine-2 receptor antagonists, are used to manage stomach conditions, such as peptic ulcer disease and gastroesophageal reflux disease. These drugs are very commonly prescribed; proton pump inhibitors in particular are one of the most commonly used medications worldwide. While typically indicated for short-term use, some evidence suggests that they are increasingly being used for longer periods, often times in individuals without underlying disease or for longer durations than necessary. As a result, there have been efforts to implement programs to decrease the use of proton pump inhibitors, though the effectiveness of such programs is unknown. This is against a backdrop of safety concerns with proton pump inhibitors, with recent evidence suggesting that chronic use may be associated with a number of safety concerns. Finally, it remains possible that the use of proton pump inhibitors in the United Kingdom has been underestimated by previous studies, as these drugs have been available for purchase over the counter in pharmacies since 2004, but this impact has not been studied. Given the pervasiveness of acid suppressant drugs, understanding their patterns of use over time and the impact of existing deprescribing programs is an important concern. Thus, we will conduct a drug utilization study to examine the prescribing patterns of these drugs over time. We will also investigate their intensity of use, persistence patterns, and the impact of over the counter drug availability. Studies of this nature may inform future programs which target medication overuse.
Technical Summary: 
Proton pump inhibitors and histaimine-2 receptor antagonists are acid suppressant drugs used by millions of individuals across the United Kingdom to manage the symptoms of several gastric diseases. In recent years, the use of PPIs has been steadily increasing, with over 50 million PPI prescriptions dispensed in 2015 in England alone. As a result of this dramatic increase, and given the risks associated with PPI use, the National Institute for Clinical Evidence recommended deprescribing PPIs in primary care as of 2014. Deprescribing can be described as dose de-escalation, or yearly treatment reassessment. However, there is little evidence on the effectiveness of this recommendation, and whether or not this has influenced prescribing practices of general practitioners. It is also unknown whether the over the counter availability of proton pump inhibitors has influenced their prescribing rates among general practitioners. Thus, we will conduct a drug utilization study to examine the existing gaps in knowledge in the utilization of acid suppressant drugs in the United Kingdom. Specifically, we will examine yearly prescribing incidence rates for both classes of acid suppressant drugs and examine patterns of use among certain subgroups (stratified by age, sex, indication and country). We will also examine persistence patterns to determine the impact of the latest deprescribing guidelines published by the National Institute for Clinical Evidence. Finally, we will conduct an interrupted time series analysis to determine whether the over the counter availability has influenced prescribing rates of general practitioners. Overall, this study will examine how acid suppressant drugs are being used in clinical practice and may help determine if new deprescribing initiatives are necessary.
Health Outcomes to be Measured: 
The outcomes of interest for this study are rates of proton pump inhibitor (PPI) and histamine-2 receptor antagonist (H2RA) prescriptions over time. Prescriptions for both drug classes will be identified using BNF codes.
Collaborators: 

Samy Suissa - Chief Investigator - McGill University
Devin Abrahami - Collaborator - McGill University
Dr Emily McDonald - Collaborator - McGill University
Dr Laurent Azoulay - Corresponding Applicant - McGill University
Professor Mireille Schnitzer - Collaborator - University Of Montreal