Association of Nociplastic Pain Features with Function in Aging Veterans with Chronic Low Back Pain

BACKGROUND: Chronic low back pain (CLBP) affects nearly one million Veterans and is a leading cause of disability. Nociplastic pain, characterized by altered central nervous system processing, widespread pain and sleep disturbance, may negatively impact treatment response in this population, yet remains underrecognized. OBJECTIVE: Determine the prevalence and association of nociplastic features with function among aging Veterans with CLBP. DESIGN: Cross-sectional survey of Veterans aged 50-89 years with CLBP identified through VA administrative data. A stratified random sampling design oversampled women and Black/African-American veterans. PARTICIPANTS: Of 800 invited, 361 responded (45.1% response rate); after excluding those without CLBP, 342 participants were included (mean age 69.2 years, 19.2% women, 17.8% Black/African-American). MAIN MEASURES: Nociplastic features were assessed using the Fibromyalgia Survey Questionnaire to calculate a fibromyalgia severity score. Function was assessed via the Veterans RAND 12-Item Health Survey (VR-12) Physical (PCS) and Mental Component Summary (MCS) scores. Regression models adjusted for sociodemographics, comorbidities, opioid use, pain intensity, and surgical history. KEY RESULTS: Nociplastic characteristics were highly prevalent (fibromyalgia severity score mean 11.3, SD 5.9). Overall, 36% screened positive for fibromyalgia via American College of Rheumatology criteria, however, over half of respondents aged 50-64 years met criteria. Widespread pain was common; on average, pain was experienced in six discrete locations. Physical function was severely impaired (mean VR-12 PCS 30.2, nearly 2 SD below population norms); psychological function was moderately impaired (mean MCS 45). Higher fibromyalgia severity scores independently associated with poorer physical function (β= -0.30 per point increase, 95% CI -0.49, -0.12; p = 0.0014) and psychological function (β= -0.64, 95% CI -0.93, -0.35; p < 0.001) after adjustment. Gender, BMI, comorbidities, and back surgery were also associated with poorer function. CONCLUSIONS: Nociplastic features are highly prevalent in aging Veterans with CLBP and demonstrate a dose-response relationship with impaired functioning. Recognition may guide more effective, mechanism-based treatment approaches and reduce harm.