"One of the frequent myths we encounter among clinicians is that some types of opioids, such as hydromorphone, are more dangerous than others," said senior study author and orthopedic surgeon Marilyn Heng, M.D., MPH, FRCSC. "The goal of our study was to assess if the initial opiate type prescribed to postoperative, opiate-naïve orthopedic trauma patients was associated with prolonged opioid use. Our findings demonstrate how current beliefs about the mechanism of prolonged use may be confounded."
The retrospective study conducted by Matthew Basilico, AB, AM and Abhiram R. Bhashyam, M.D., MPP with Dr. Heng consisted of 17,961 adult opiate-naïve patients who had a traumatic musculoskeletal injury and underwent surgery within 14 days of presentation. In order to qualify for the sample, patients had no prior history of opioid abuse and hadn't taken opioids in the six months prior to their injury.
Since different opioids have different strengths per milligram, the researchers calculated the morphine milligram equivalents (MME)––a standardized dosing unit that allows for comparison across opioid types––among all opioids prescribed to the sample population upon discharge from surgery.
Not only did the study find that prolonged opiate use (defined as usage beyond 90 days of initial prescription) correlates to the overall MME prescribed at discharge, rather than opioid type, but the researchers identified a pattern of failure to properly calculate an equivalence dose among opioid types. According to the study, this lack of conversion can result in higher doses and place patients at an increased risk for prolonged use.
"There tends to be bias in how providers prescribe drugs, and it's focused on the number of tablets, instead of MME. However, it's really the amount of MMEs that make a difference," said Dr. Heng.
For example, if an equivalence calculation isn't performed when converting 20 pills of oxycodone to hydromorphone, a patient who is prescribed 20 pills of hydromorphone would receive a dose increase of more than 142 percent in terms of initial opioid quantity.
"This often leads to the notion that certain opioid types appear to be associated with higher odds of complications, when in fact, we are prescribing much more of the stronger drug, which can lead to dependency," said Dr. Heng.
According to the National Survey on Drug Use and Health, prescription opioids significantly contributed to the rise in drug-related deaths over the past decade. With orthopedic surgeons ranking as the third highest prescriber of opioids among U.S. physicians,i these findings provide the next step toward understanding the relationship between opioid prescribing and potential long-term patient dependency.
i Morris BJ, Mir HR: The opioid epidemic: Impact on orthopaedic surgery. J Am Acad Orthop Surg 2015;23:267-271.