Quantifying Chronic Overlapping Pain Conditions (COPCs) in Fibromyalgia versus Headache and Back Pain

Abstract

Many chronic pain conditions tend to co-occur, termed chronic overlapping pain conditions (COPCs), which may reflect certain degree of common underlying pathophysiology. Therefore, it would be of value to compare the phenotypic characteristics of COPCs. The purpose of this study was to perform a secondary analysis of COPC survey data targeting individuals with fibromyalgia (FM), back or neck pain (spine), or headache (HA). 1034 chronic pain patients (791 female) were recruited: 647 FM (96% female), 135 HA without FM (72% female), 124 spine pain without FM (50% female), and 128 with other pain conditions. Chi-square and odds ratios (ORs) were used to assess for group differences adjusting sex, BMI and age. Individuals with FM reported significantly higher frequency of COPCs (p <0.001, Chi-Square test). The most frequently reported COPCs for FM included 1) spine pain (73%), 2) lower extremity pain (63%), 3) headache (51%), and tied for 4) upper extremity pain and irritable bowel syndrome (IBS) (45%). Other common COPCs for FM (> 20%) included: chronic fatigue (CFS), restless leg (RLS), temporomandibular (TMD) and post-traumatic stress (PTSD) syndrome/disorder. For spine pain, the most common COPCs were musculoskeletal: upper and lower extremity pain (65-81%) and HA (69%). Similarly, for HA, 64% had spine pain, and 36-46% upper and lower extremity pain. Furthermore, those with FM were 10 times more likely to have CFS, and 4-4.8 times IBS, painful bladder syndrome, PTSD, and Vulvodynia. However, those with HA or spine pain were no more likely to report specific COPCs than other forms of chronic pain patients. Thus, while COPCs are common among multiple forms of chronic pain, the type and distribution of COPCs do not substantially differ between HA and spine pain, but is different for FM. This knowledge may help better understand the uniqueness and commonality between different chronic pain patients.