A new study shows the importance of making patients aware of pros and cons in taking certain drugs
A widely used class of blood-pressure medications has been linked to a slightly elevated chance of lung cancer, according to new research.
In a study just published in the BMJ, Canadian researchers followed nearly one million patients in the UK who were treated with anti-hypertension drugs such as angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs), reported CBC News. Long prescribed to millions of patients, ACE inhibitors stop the production of angiotensin, a hormone that can constrict blood vessels.
According to Dr. Jacob Udell, a cardiologist at Women's College Hospital and Toronto General Hospital and co-investigator in the study, the drug class has a great track record for effectively controlling blood pressure as well as general safety. But there have also been suspicions that ACE inhibitor usage could also be associated with an increased risk of lung cancer.
By analyzing a large population of patient histories spanning 10 years, Udell and his colleagues found a small but statistically significant correlation between taking ACE inhibitors and developing lung cancer, with four lung cancer cases observed per 1,000 patients. On the other hand, they found no association between ARB use and the disease.
The study raises a potentially important point: rather than prescribing ACE inhibitors or ARBs via a “dealer’s choice” approach — which Udell said current Canadian cardiovascular guidelines effectively leads to —practitioners have to talk to their patients and weigh potential risks.
But not everyone in the medical community is ready to change tacks. “I don't know if I'm convinced as of yet,” Dr. Sacha Bhatia, a cardiologist colleague of Udell’s who wasn’t involved in the study, told CBC News. For example, while the research factored in whether the subjects were smokers or non-smokers, Bhatia said it would be more informative to consider a continuum that includes heavy smokers and light smokers.
“I think what we would say is … the absolute risk [of ACE inhibitors causing cancer], in fact, is very, very small,” he said.
Patients need help to make sense of medical studies delving into the risks and benefits of drugs, which often include complex research statistics, noted Dr. Kimberly Wintemute, a family physician at Toronto's North York General Hospital. She is also co-lead of Choosing Wisely Canada, which advocates for informed conversations between patients and their doctors about medications.
Getting useful information of such studies can mean translating “relative risk” percentages into absolute numbers — converting percentage numbers into expected number of cases per 1,000 patients, for example. To Wintemute, even a small percentage risk has to be discussed.
“[I]t's not for me to decide if that difference means something to my patient," she said. “My duty … is to give them the information in a way that's easy to understand, which means first I have to understand it, and then I have to present it in an understandable way.”
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