The risk of chronic opioid use increases with the most common types of surgery, researchers say.
The study, published in JAMA Internal Medicine, was led by Dr. Eric Sun and co-authored by Prof. Beth Darnall, from the Stanford University School of Medicine in California.
According to the Centers for Disease Control and Prevention (CDC), prescription painkillers became more affordable and available in the mid-1990s. Since then, drug overdose rates in the U.S. have more than tripled.
Every day, 78 Americans die from an opioid overdose.
Opioids target the nervous system in the body or receptors in the brain, reducing pain intensity. However, they can be highly addictive, and more than 3 in 5 drug overdoses involve an opioid.
"Even when taken exactly as prescribed, opioids carry significant risks and side effects," says Prof. Darnall.
Dr. Sun adds that "there is a higher chance of getting hooked on painkillers" for many surgeries. As such, the researchers looked at 11 common surgeries and examined the risks of chronic opioid use following them.
Study included hydrocodone, oxycodone, and fentanyl
Although previous studies have uncovered risks of chronic opioid use after surgery, Dr. Sun and colleagues wanted to study patients who had not received prescriptions for opioids for at least 1 year before their surgery.
- Since 1999, overdose deaths from opioids have nearly quadrupled
- Deaths from drug overdoses are up in men and women, all races, and adults of all ages
- In 2014, overdoses involving opioids killed more than 28,000 people.
Previous studies have not included this detail in their design.
The prescription opioid drugs the researchers examined included hydrocodone, oxycodone, and fentanyl, which is the drug responsible for the accidental drug overdose death of renowned musician Prince.
To carry out their study, the team examined health claims filed between 2001-2013 from over 640,000 privately insured patients aged 18-64 who had not filled an opioid prescription in the year before their surgery.
The researchers then compared them with around 18 million nonsurgical patients who had also not filled opioid prescriptions.
Next, the team looked at post-surgery records and defined chronic opioid use as patients who filled 10 or more prescriptions or who received more than a 120-day supply of an opioid in the first year following surgery.
This excludes the first 3 months after surgery.
Results showed that patients undergoing knee surgery had the highest risk; they were around five times more likely to chronically use opioids than the control group. Those undergoing gallbladder surgery were not far behind, with a 3.5-times higher risk than the control group.
Dr. Sun says that there was also "an increased risk among women following cesarean section, which was somewhat concerning since it is a very common procedure." He adds that the risk was 28% higher for these women than among the control group.
Final results revealed that being male, elderly, taking antidepressants, or abusing drugs were other factors contributing to an increased risk for chronic opioid use.
'Reduce risk by finding other ways of controlling pain'
The researchers say that aside from minor procedures that are somewhat pain-free - such as cataract surgery and laparoscopic appendectomy - all of the types of surgery they studied were linked with an increased risk of chronic opioid use.
However, the researchers make clear that they are not advising patients to avoid surgery.
"The message isn't that you shouldn't have surgery. Rather, there are things that anesthesiologists can do to reduce the risk by finding other ways of controlling the pain and using replacements for opioids when possible."
Dr. Eric Sun, Stanford University School of Medicine
Prof. Darnall adds that "a lot of chronic pain develops from surgery, and pre-surgical pain 'catastrophizing' is a major risk factor for having a lot of pain. We hope that by optimizing patients' psychology - and giving them skills to calm their own nervous system - they will have less pain after surgery, need fewer opioids, and recover quicker."
Although their study extends previous work in many ways, the researchers note some limitations. Firstly, they say their nonsurgical population differed from their surgical population, and as such, difference in opioid use between both groups could be "due to unobserved confounding," including socioeconomic status.
Additionally, because their study was limited to privately insured patients between 18-64 years of age, their findings may not generalize to other populations, including the elderly or those on Medicaid.
Still, their findings are significant, and the researchers conclude their study by noting that they "surmise that chronic opioid use following surgery occurs because surgery may unmask an individual's susceptibility toward long-term opioid use."