To allow patients to better appreciate the intensity of their chronic pain, and especially to better communicate this information to the physician, researchers have developed a rating scale based on body pain maps. This system revealed nine groups of chronic pain, each with differences in terms of location and intensity of pain, but also in remission three months later. 

Chronic pain has nine distinct types according to one study

Pain is considered chronic when it persists beyond what is usual for its initial cause (more often beyond 3 months), when it responds poorly to treatment and when it induces a deterioration of functional capacities. The most common chronic pain conditions are headache, low back pain, neuropathic pain, arthritis pain and musculoskeletal pain. Beyond the societal impact in both direct and indirect costs, they can disrupt sleep, interfere with work and relationships, and even alter the way emotions are processed by causing physiological changes in the brain.

But the experience of chronic pain itself is complicated and varies among individuals, making it difficult to explain and quantify. According to a study published in the journal PLOS ONE, the distribution of pain as reported on a body map can be used to assign patients to distinct subgroups associated with differences in pain intensity, quality, day-to-day impact and clinical outcomes three months later. "We find that how a patient reports the body distribution of their pain affects almost all aspects of the pain experience, including what happens three months later," the scientific team explains.

Neck, back, arm... notable differences by pain location

They analyzed data from 21,658 patients seen at University of Pittsburgh pain management clinics between 2016 and 2019. All patients were asked to fill out a body map of pain, on which pain areas can be selected on drawings (of the front and back of the body), with 74 possible body regions offered. Other information about the patients' pain, health and outcomes was available in their electronic medical records. Using this method, they found that patients fell into nine different chronic pain groups, with variations in several areas.

For example, demographic and medical characteristics, pain intensity, impact, and quality of pain varied between patient subgroups. For example, the neck and shoulder group had lower pain intensity than the lower back pain radiating below the knee and the neck, shoulder, and lower back pain groups, while the group with the highest pain intensity consisted of patients with severe pain, associated with low physical function, severe depression, and high sleep disturbance. A subset of 7,000 patients also completed a follow-up questionnaire three months after the body pain map.

An avenue for personalized pain management

It turns out that differences also existed between patient groups in terms of improvements in pain and physical function. While patients with abdominal pain showed the most progress, with nearly half reporting significant improvement, those with neck, shoulder and lower back pain showed the worst results, with 37% improvement. This led the scientific team to question whether this subgroup might be at an early stage of chronic widespread pain. "Algorithmic grouping by pain distribution could be an important facet of personalizing pain management," she notes.

While more studies are needed to confirm the reliability of this process, the researchers hope that "this ability of body pain maps to indicate likely patient outcomes could help identify those at risk for poor outcomes at their first visit to the pain clinic." This is an important finding since chronic pain can be responsible for drug misuse as in the case of chronic daily headaches. According to the finding recalled in the 2017 White Paper on Pain and established by the French Society for the Study and Treatment of Pain, 12 million French people suffer from chronic pain, 70% of whom do not receive appropriate treatment.