Characterization and burden of localized back pain versus back pain with chronic overlapping pain conditions.

BACKGROUND: Chronic low back pain (cLBP) is the most common cause of years lived with disability (YLD). Chronic overlapping pain conditions (COPCs) is a relatively new taxonomy for widespread pain. Researchers have postulated that patients with COPCs have more pain-related impact than those with isolated pain conditions. We know little about the combination of COPCs with cLBP. This study aims to characterize patients with isolated cLBP compared to those with cLBP and associated COPCs across multiple domains of physical, psychological, and social functioning. METHODS: Using Stanford's CHOIR registry-based learning health system, we performed a cross-sectional study on patients with localized cLBP (group L) versus cLBP with COPCs (group W). We used demographic, PROMIS (Patient-Reported Outcomes Measurement Information System), and legacy survey data to characterize the physical, psychological, social, and global health outcomes. We further subdivided the COPCs into intermediate and severe based on the number of body regions involved. We used descriptive statistics and generalized linear regression models to characterize and compare the pain groups. RESULTS: Among 8783 patients with cLBP, 485 (5.5%) had localized cLBP (Group L) without widespread pain. Compared to Group L, patients in Group W were more likely to be females, younger, and reported longer duration of pain. Although the mean pain scores were significantly higher in group W, this difference did not appear clinically significant (average pain scores MD -0.73, 95% CI [-0.91 to -0.55]). Group W had significantly worse outcomes in all PROMIS outcomes. However, outcomes with large clinical differences (Cohen's d > 0.5) were fatigue (MD = -7.0, 95% CI [-8.0 to -6.1]); sleep impairment (MD = -6.2, 95% CI [-7.1 to -5.3]); sleep disturbance (MD = -5.3, 95% CI [-6.2 to -4.5]); pain behavior (MD = -2.2, 95% CI [-2.5 to -1.8]); physical function (MD = 4.0, 95% CI [3.2-5.0]); pain interference (MD = -3.4, 95% CI [-4.0 to -2.8]); and anxiety (MD = -4.9, 95% CI [-5.7 to -4.0]). Adjusted analysis controlling for age, gender, BMI category, and duration of pain confirmed worsening of all outcomes with more widespread pain. CONCLUSION: COPCs are a common presentation with cLBP. The combination of COPCs with cLBP is associated with significantly worse physical, psychological, social, and global health outcomes. This information may identify patients with COPCs and cLBP to optimally risk and treatment stratify their care and individualize their management.