PainRelief.com Interview with:
Ben Alter, MD, PhD
Director, Translational Pain Research
Division of Pain Medicine
Department of Anesthesiology and Perioperative Medicine
University of Pittsburgh Medical Center
PainRelief.com: What is the background for this study? What are the main findings?
Response: In the clinical environment, I am often asking patients where their pain is. There is a large amount of research establishing that widespread or “all-over” pain is difficult to manage and impacts nearly every aspect of a patient’s life. In fact, a tally of body areas is involved with the diagnosis of fibromyalgia, although this is not the only diagnostic criteria. What wasn’t clear to us was whether patterns of pain across the body also impacted important facets of the pain experience.
PainRelief.com: Do patients fill out a pain map on the medical record?
Response: At the University of Pittsburgh, patients fill out a questionnaire prior to their clinical visit that includes a pain map. This is a common practice for pain management specialists, and body maps are included in several research questionnaires about pain. What is unique about our clinical group is that patients also fill out surveys that measure “patient-reported outcomes”, using a software developed at Stanford called CHOIR and implemented by our research team, directed by Dr. Ajay Wasan. This is a real game-changer because we can quantitatively track a patient’s pain and its impact over time. This allows research insights, such as our study, and is important for multidisciplinary pain management.
In other clinical settings, the pain body map is not routinely used. I believe it’s a fair assessment that most clinicians do not systematically track pain outcomes either. If anything, a pain intensity score (0-10 numeric rating scale) is used, which only tells part of the picture. This makes it difficult to diagnose and manage chronic pain, since it’s not being well measured and tracked. Imagine managing high blood pressure without measuring it!
Our research suggests that including a body map in the assessment of patients with chronic pain could improve the ability of all clinicians to manage chronic pain. This is especially likely as we are developing tools to identify subgroups of patients that may respond better to different treatments.
PainRelief.com: What are the main findings?
Response: We took a large sample of patients referred to our pain management clinics and examined only the body map, using hierarchical clustering, to see if there were subgroups within the larger sample. There indeed were unique subgroups. Pain intensity, quality, and impact on patient’s physical function and mental health were all different between the subgroups. Importantly, we found that the subgroup assignment predicted pain intensity and quality while controlling for the related variable of total number of body areas affected by pain. This shows that there’s something specific about the pattern of pain and not just the number of body areas that’s influencing pain intensity and quality. Finally, we found that the subgroups differed in whether pain improved at follow-up. This is really remarkable because it shows that how the patients answered “where it hurts” impacted changes in pain 3 months later.
PainRelief.com: What should readers take away from your report?
Response: The takeaway is that different patterns of pain influence pain intensity, quality, and impact at initial presentation to a pain clinic and over time.
PainRelief.com: What recommendations do you have for future research as a result of this work?
Response: It will be important to see how the subgroups relate to current diagnosis and what kinds of treatments were used for each subgroup. Both questions are active areas of investigation for our team. More broadly, it will be interesting to see whether these subgroups could be useful in the development of a comprehensive “biosignature” for chronic pain. The concept here is that within a given diagnosis, such as arthritis or sciatica, there are differences between patients. Anecdotally and in clinical practice, we know this. Even in clinical trials, only a subset of enrolled patients ever respond to a pain management intervention. A “biosignature”, which could include information about how patients respond to questionnaires, genetics, sensory testing, brain activity, and more, might help identify who will get better with a particular treatment. Developing these “biosignatures” in conjunction with developing promising treatments through clinical trials is critical to improve pain management for patients suffering from all types of chronic pain.
PainRelief.com: Is there anything else you would like to add?
Response: I would like to thank all the members of our research team, our colleagues in the University of Pittsburgh Pain Medicine clinics, and most importantly all of our patients for making this study possible.
I have no disclosures.
Citation: Benedict J. Alter, Nathan P. Anderson, Andrea G. Gillman, Qing Yin, Jong-Hyeon Jeong, Ajay D. Wasan. Hierarchical clustering by patient-reported pain distribution alone identifies distinct chronic pain subgroups differing by pain intensity, quality, and clinical outcomes. PLOS ONE, 2021; 16 (8): e0254862 DOI: 10.1371/journal.pone.0254862
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