Opioids are associated with a higher risk of pneumonia, according to a study of 3061 adults aged 65 to 95 years, according to research published in the Journal of the American Geriatrics Society. The study from researchers at Group Health Research Institute and the University of Washington also found that benzodiazepines, which are generally prescribed to treat insomnia and anxiety, did not affect pneumonia risk.
“Pneumonia is a common infection that can have serious consequences in older adults,” said lead author Sascha Dublin, MD, PhD, of Group Health, in a statement. “Opioids and benzodiazepines work in different ways, but both can decrease the breathing rate. Both are also sedatives, which can increase the risk of aspiration.”
A 2009 study estimated that 2 million Americans aged 65 and older received long-term opioid treatment for non-cancer pain. Prescription opioid use has been on the rise in the United States, according to earlier Group Health research, which found that the use of chronic opioid therapy for chronic non-cancer pain doubled in the prior decade. In addition, a 1998 report found that one in 10 older Americans used benzodiazepines.
Dr. Dublin and colleagues hypothesized that the risk of pneumonia would be higher in individuals using opioids or benzodiazepines than in those not using these medications, and would be highest for opioids that suppress the immune system. The researchers conducted a case-control study, matching patients who had pneumonia during the study period of 2000 to 2003 with similar patients who did not have pneumonia. All participants were living in the community and were not hospitalized or in nursing homes. Individuals whose immune systems were suppressed were excluded from the study.
The authors measured whether individuals with pneumonia were more likely than controls to have taken opioids or benzodiazepines before the start of their illness. Among pneumonia cases, 13.9% were using opioids and 8.4% were using benzodiazepines. In subjects without pneumonia, 8.0% were using opioids and 4.6% were using benzodiazepines.
Statistical analysis by the researchers showed that:
- Patients taking long-acting opioids such as sustained-release morphine were more than 3 times as likely to acquire pneumonia as were those not taking opioids.
- Recently starting use was a risk factor: During their first 14 days of use, patients who took opioids were more than 3 times as likely to get pneumonia as were those not taking opioids.
- Patients using immunosuppressing opioids were nearly 1.9 times as likely to get pneumonia as were those not using opioids.
- Use of opioids for a longer time period—defined as 3 months or more before getting pneumonia—was not associated with infection.
- Taking benzodiazepines did not affect the risk of getting pneumonia.
With the study, which was the first to examine how opioid use affects the risk of acquiring pneumonia in a general population, researchers hope to lay the foundation for research on additional questions about the safety of opioid drugs in older Americans.
“Benzodiazepines don't seem to be associated with increased risk of pneumonia,” said Dr. Dublin. “But our results mean that it is crucial to look more closely at opioid prescriptions and infections.”