Injection drug equipment. File photo courtesy of Lawson Health Research Institute.Injection drug equipment. File photo courtesy of Lawson Health Research Institute.
London

Injection opioid use linked to increased heart infections

London-based researchers have linked a specific injection opioid to a rise in a potentially fatal heart infection in Ontario.

The study by Lawson Health Research Institute, Institute for Clinical Evaluative Sciences (ICES), and Western University found an increase of infective endocarditis, a serious bacterial heart infection, among those who use injection drugs coincided with a bump in the number of hydromorphone prescriptions issued.

Researchers examined 60,529 hospital admissions related to injection drug use across the province between 2006-2015 and identified 733 patients who had infective endocarditis. The risk of the potentially deadly infection jumped from 13.4 admissions to 35.1 admissions every three months over the study period.

At the same time, the number of prescriptions for hydromorphone increased from 16 per cent of all opioid prescriptions in 2006 to 53 per cent by 2015.

“The opioid crisis is one of the most pressing health issues of our time. Our findings not only confirm an increasing risk of infective endocarditis in persons who inject drugs but also offer the first evidence for why it might be happening,” said Dr. Matthew Weir, an adjunct scientist at ICES and associate scientist at Lawson.

Controlled-release hydromorphone, the more common form of the drug, can be difficult to dissolve, leaving residue in injection equipment, which tends to be re-used or shared by injection drug users. This allows multiple opportunities for bacterial contamination, increasing the chances that bacteria will be injected when the equipment is next used.

Infective endocarditis occurs when the inner lining of the heart becomes infected.

Researchers had anticipated the rise of the life-threatening illness would coincide with the elimination of the easy to dissolve controlled-release oxycodone from the market in 2011. But in a surprising discovery, researchers determined the increase in infective endocarditis began in 2010.

“While the timing was not what we expected, we did find a correlation between the rise in infective endocarditis and hydromorphone prescriptions,” said Dr. Sharon Koivu, Lawson scientist and associate professor at Western's Schulich School of Medicine & Dentistry. “Our research is now focused on better understanding the potential relationship between the injection of hydromorphone and risk of infective endocarditis.”

Ongoing studies by the research team are examining whether bacteria that causes infective endocarditis are more likely to survive in equipment used to prepare hydromorphone compared to other drugs.

The study was published Monday in the Canadian Medical Association Journal.

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