Characterization of chronic overlapping pain conditions in patients with chronic migraine: A CHOIR study.

Objective: Chronic overlapping pain conditions (COPCs) represent a co-aggregation of widespread pain disorders. We characterized differences in physical and psychosocial functioning in patients with chronic migraine (CM) and those with CM and COPCs.

Background: Patients with CM and COPCs have been identified as a distinct subgroup of patients with CM, and these patients may be vulnerable to greater symptom severity and burden.

Methods: Data were extracted from Collaborative Health Outcomes Information Registry (an open-source learning health-care system), completed at the patients' first visit at a large tertiary care pain management center and electronic medical records. In 1601 patients with CM, the number of non-cephalic areas of pain endorsed on a body map was used to examine the differences in pain, physical and psychosocial function, adverse life experience, and health-care utilization.

Results: Patients endorsing more body map regions reported significantly worse symptoms and function across all domains. Scored on a t-score metric (mean = 50, SD = 10), endorsement of one additional body map region corresponded with a 0.69-point increase in pain interference (95% CI = 0.55, 0.82; p < 0.001; Cohen's f = 0.328), 1.15-point increase in fatigue (95% CI = 0.97, 1.32; p < 0.001; Cohen's f = 0.432), and 1.21-point decrease in physical function (95% CI = -1.39, -1.03; p < 0.001; Cohen's f = 0.560). Patients with more widespread pain reported approximately 5% more physician visits (95% CI = 0.03, 0.07; p < 0.001), and patients reporting adverse life events prior to age 17 endorsed 22% more body map regions (95% CI = 0.11, 0.32; p < 0.001).

Conclusions: Patients with CM and other overlapping pain conditions as noted on the body map report significantly worse pain-related physical function, psychosocial functioning, increased health-care utilization, and greater association with adverse life experiences, compared with those with localized CM. This study provides further evidence that patients with CM and co-occurring pain conditions are a distinct subgroup of CM and can be easily identified through patient-reported outcome measures.