Many people with chronic pain take pain relief medication, but randomized controlled trials—the gold standard for testing new treatments—often don't fully consider how these medications can affect the results of the trials. This can lead to an underestimation of how effective the treatments really are. To correct this issue, UW researchers present two new ideas in a new article:
- A new way to measure pain called the Numeric Rating Scale of Underlying Pain without concurrent Analgesic use (NRS-UP(A)). This measures how intense the pain would be if pain relief medications weren't being used at the time of the study. This can help understand the true effect of a treatment on pain.
- A new pain construct: an individual’s perceived effect of analgesic use on pain intensity (EA), which is a measure of how much a person thinks that pain medication is helping their pain.
In a study of 662 adults with back pain, it was found that the pain score was 1.2 points higher on this new scale than on the usual pain scale, suggesting that people felt their medication reduced their pain by that amount. Whether people thought the medication was effective wasn't related to how intense their pain was, what type of pain medication they were using, or the dose of their medication. However, this new pain scale and the concept of how people perceive the effectiveness of their medication were linked to whether they would use pain medication in the future.
Including the NRS-UP(A) as a secondary measure in pain studies could lead to better understanding and evaluation of pain treatments in research, but more studies are needed to see how useful it can be.
This study was written by Pradeep Suri, MD, Professor; Mark Jensen, PhD, Professor; as well as Patrick Heagerty, PhD, from the UW Department of Biostatistics; and Andrew Timmons, MS, from the Seattle Epidemiologic Research and Information Center. The study is online now in the journal Pain.
