Diabetes: Switching to Sulfonylureas from Metformin Linked to Increased Side Effects

MedicalResearch.com Interview with:

Samy Suissa, PhD Director, Centre for Clinical Epidemiology, Lady Davis Institute Professor, Departments of Epidemiology and Biostatistics and of Medicine McGill University

Dr. Suissa

Samy Suissa, PhD
Director, Centre for Clinical Epidemiology, Lady Davis Institute
Professor, Departments of Epidemiology and Biostatistics and of Medicine
McGill University 

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Sulfonylureas are widely used oral antidiabetic drugs that are recommended as second-line treatments after first-line metformin to treat patients with type 2 diabetes. While their safety has been studied extensively, studies in patients with poorly controlled diabetes in need of pharmacotherapy escalation have been sparse and limited. Our study evaluated whether adding or switching to sulfonylureas after initiating metformin treatment is associated with increased cardiovascular or hypoglycaemic risks, compared with remaining on metformin monotherapy.

Using a large cohort of over 77,000 patients initiating treatment with metformin monotherapy, we found that adding or switching to sulfonylureas is associated with modest increases of 26% in the risk of myocardial infarction and 28% in the risk of death, as well as an over 7-fold major increase in the risk of severe hypoglycaemia leading to hospitalisation.

In particular, we found that switching from metformin to sulfonylureas was associated with higher risks of myocardial infarction and death, compared with adding sulfonylureas to metformin. 

MedicalResearch.com: What should readers take away from your report?

Response: Sulfonylureas as second-line therapy are associated with increased cardiovascular and hypoglycaemic risks, though continuing metformin when introducing sulfonylureas appears to be safer than simply switching to sulfonylurea monotherapy. These results support current treatment guidelines such as those of the American Diabetes Association that recommend maintaining metformin use with each treatment escalation. 

MedicalResearch.com: What recommendations do you have for future research as a result of this work? 

Response: Further observational studies are needed to replicate our findings, to also assess the longer term risks of sulfonylureas as second-line treatments, and to compare these with the newer antidiabetic agents. 

Disclosures: This research was funded in part by grants from the Canadian Institutes of Health Research, the Canadian Foundation for Innovation, and Boehringer-Ingelheim.


Antonios Douros, Sophie Dell’Aniello, Oriana Hoi Yun Yu, Kristian B Filion, Laurent Azoulay, Samy Suissa. Sulfonylureas as second line drugs in type 2 diabetes and the risk of cardiovascular and hypoglycaemic events: population based cohort study. BMJ, 2018; k2693 DOI: 10.1136/bmj.k2693


Jul 19, 2018 @ 2:24 pm 

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