Characterizing Juvenile Fibromyalgia in a Large Cohort of Adolescents

Juvenile Fibromyalgia (JFM) is a widespread, disabling pain condition that is inconsistently conceptualized and classified compared to adult fibromyalgia (FM). The aim of this study was to comprehensively phenotype JFM in a pediatric population using a representative sample of adolescents from a multi-site JFM clinical trial and evidence-based measures of functional and psychosocial outcomes. Participants were 203 adolescents (12-17 years) diagnosed with JFM based on 2010 ACR FM criteria, verified by the Pain and Symptom Assessment Tool (PSAT) adapted for adolescents. The PSAT yields information on pain locations (Widespread Pain Index; WPI) and presence and intensity of somatic symptoms (Symptom Severity (SS) scale). Participants also completed self-report measures of pain intensity, functional disability, pain interference, fatigue and depression as part of baseline assessment in an ongoing clinical trial. Participants endorsed moderate pain intensity (M = 5.9), a median of 11 (of 18) pain locations (WPI), and a median score of 9 (of 12) on the SS scale. Specifically, they reported an average of 12 (of 24) somatic symptoms, which were primarily neurological/autonomic symptoms. The cardinal symptoms of fatigue and nonrestorative sleep were endorsed frequently as a moderate or severe problem (85%), which was corroborated by self-report fatigue ratings (PROMIS Fatigue) that were two standard deviations above the mean. Correlations between the WPI, SS scale, and outcome measures showed the WPI was significantly associated with pain intensity only. However, the SS scale was significantly correlated with pain intensity, fatigue, functional disability, pain interference, and depressive symptoms. JFM appears to be closely aligned with the adult manifestation of FM. Comorbid somatic symptoms associated with JFM require further study to understand their unique contribution to functioning and coping. The PSAT appears useful for assessing pain locations and symptom severity and may help more systematically identify and characterize JFM. National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) of the National Institutes of Health award numbers U34AR067978 and R01AR070474 (PI: Kashikar-Zuck) Clinical trials.gov Registration: NCT 03268421. Juvenile Fibromyalgia (JFM) is a widespread, disabling pain condition that is inconsistently conceptualized and classified compared to adult fibromyalgia (FM). The aim of this study was to comprehensively phenotype JFM in a pediatric population using a representative sample of adolescents from a multi-site JFM clinical trial and evidence-based measures of functional and psychosocial outcomes. Participants were 203 adolescents (12-17 years) diagnosed with JFM based on 2010 ACR FM criteria, verified by the Pain and Symptom Assessment Tool (PSAT) adapted for adolescents. The PSAT yields information on pain locations (Widespread Pain Index; WPI) and presence and intensity of somatic symptoms (Symptom Severity (SS) scale). Participants also completed self-report measures of pain intensity, functional disability, pain interference, fatigue and depression as part of baseline assessment in an ongoing clinical trial. Participants endorsed moderate pain intensity (M = 5.9), a median of 11 (of 18) pain locations (WPI), and a median score of 9 (of 12) on the SS scale. Specifically, they reported an average of 12 (of 24) somatic symptoms, which were primarily neurological/autonomic symptoms. The cardinal symptoms of fatigue and nonrestorative sleep were endorsed frequently as a moderate or severe problem (85%), which was corroborated by self-report fatigue ratings (PROMIS Fatigue) that were two standard deviations above the mean. Correlations between the WPI, SS scale, and outcome measures showed the WPI was significantly associated with pain intensity only. However, the SS scale was significantly correlated with pain intensity, fatigue, functional disability, pain interference, and depressive symptoms. JFM appears to be closely aligned with the adult manifestation of FM. Comorbid somatic symptoms associated with JFM require further study to understand their unique contribution to functioning and coping. The PSAT appears useful for assessing pain locations and symptom severity and may help more systematically identify and characterize JFM. National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) of the National Institutes of Health award numbers U34AR067978 and R01AR070474 (PI: Kashikar-Zuck) Clinical trials.gov Registration: NCT 03268421.