What are the functional and clinical characteristics shared by fibromyalgia and low back pain? A scoping review.

Background: Fibromyalgia and chronic primary low back pain are two chronic pain conditions with a significant biopsychosocial burden. Recently, the International Association for the Study of Pain has grouped them under the term chronic primary pain. To further explore similarities and differences between these two conditions, the objective of this scoping review is to explore the pain-related, physiological and psychological outcomes in individuals with fibromyalgia and low back pain.

Methods: The following databases were used to find relevant studies, using the PRISMA guidelines: Medline, Psycinfo, and CINAHL. Studies were included if they encompassed both participants with fibromyalgia or low back pain, with the objective to compare pain-related, physiological and/or psychological outcomes.

Results: Nineteen studies were selected for extraction. Among the 2801 participants, 968 had fibromyalgia (mean age 48.56 ± 7.97 years, with 94% being female) and 896 had low back pain (mean age 47.48 ± 8.15 years, with 80% being female). Pain sensitivity, physical dysfunction, illness perception, psychological distress, alexithymia, depression, and anxiety were generally more severe in participants with fibromyalgia. Most studies found similar levels of pain intensity, kinesiophobia, quality of pain, quality of life, impact of pain, suicidal risk, anger, and social support comparing individuals with fibromyalgia and individuals with low back pain.

Discussion: This scoping review highlights that although both conditions show similar pain intensity and impact on quality of life, fibromyalgia is associated with greater overall severity than low back pain, especially in sensitivity to pain and depression/anxiety.