Lung Risk in Diabetes Drug of Choice

Along the road to improving diabetes care, both doctors and scientists have disagreed about which treatments are best. Now, there is disagreement about the safety of one of the most common diabetes drugs.

Researchers found that type 2 diabetes patients taking metformin may not have a lower risk of lung cancer than those taking other diabetes drugs.

This finding goes against past studies.

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Metformin is the oldest and one of the most commonly used diabetes drugs. One reason the drug is still popular is its safety profile. That is, the drug has few dangerous side effects while also being effective.

Past observational studies have linked metformin use to a lower risk of lung cancer in people with type 2 diabetes. However, these studies had major flaws in their setup, said Samy Suissa, PhD, of McGill University, and fellow researchers in their recent study.

Dr. Suissa and colleagues set out to study the relationship between lung cancer risk and metformin use while avoiding the biases they saw in past studies.

They found that metformin was not associated with a lower risk of lung cancer.

Patients taking metformin basically had the same risk of developing lung cancer as patients taking other diabetes drugs.

"The decreased risk reported in other observational studies is likely due to bias from methodological shortcomings," the authors concluded.

Still, more research is needed to see if the current study or those past studies had it right.

The current study included 115,923 diabetes patients. Of these, 1,061 developed lung cancer. That is a rate of 2 lung cancer cases per 1,000 person years.

Results of the study were published August 24 in Diabetes Care, a journal of the American Diabetes Association.