The Relation of Pain, Fatigue, Disease Impact, and Psychological Factors with Physical Function in post-COVID-19 Syndrome, Fibromyalgia, and Chronic Fatigue Syndrome

This research sought to identify the relation of pain, fatigue, disease impact, and psychological factors with physical function in individuals with post-COVID-19 syndrome (post-COVID), fibromyalgia, chronic fatigue syndrome (CFS), and those with combined diagnoses of post-COVID, FMS, and/or CFS (multi-Dx). Individuals with post-COVID, fibromyalgia, or CFS were invited to complete an anonymous survey. The following patient-reported outcome measures were collected: PROMIS-Physical Function (PROMIS-PF), PROMIS-Pain Interference (PROMIS-PI), Pain Severity (NRS; 0-10), 2016 Fibromyalgia Diagnostic Criteria Survey (FSS), Fatigue Severity (NRS; 0-10), PROMIS-Fatigue, Multisensory Amplification Scale (MSAS), PROMIS-Sleep Disturbance (PROMIS-SD), PROMIS-Dyspnea Severity (PROMIS-DS), Symptom Impact Questionnaire-Revised (SIQR), Coping Strategies Questionnaire-Catastrophizing Subscale (CSQ-CAT), Tampa Scale of Kinesiophobia-11 (TSK-11), and Hospital Anxiety and Depression Scale (HADS). Stepwise multiple linear regressions examined relationships between symptoms, disease impact, and psychological factors on physical function in each cohort. Results show 707 individuals (294-males, 413-females) completed surveys including 203 post-COVID, 99 FMS, 87 CFS, and 318 multi-Dx. Physical function was impaired in each cohort (post-COVID: 40.7±8.6; FMS: 39.5±5.5; CFS: 39.5±7.2; multi-Dx: 39.3±5.5). Regression analyses were significant for post-COVID (R2=.668, p<.001), fibromyalgia (R2=.502, p<.001), CFS (R2=.663, p<.001), and multi-Dx (R2=.611, p<.001). Unique factors significantly predicted physical function in each cohort as follows: 1) Post-COVID - dyspnea (β=-.453, p<.001), fatigue (β=-.182, p=.003), pain interference (β=-.196, p=.007), anxiety (β=.138, p=.007), symptom impact (β=-.185, p=.026); 2) fibromyalgia - fatigue (β=-.470, p<.001), symptom impact (β=-.351, p<.001); 3) CFS - symptom impact (β=-.427, p<.001), anxiety (β=.328, p<.001), dyspnea (β=-.210, p=.007), fatigue (β=-.334, p<.001), sleep disturbance (β=.249, p=.002), kinesiphobia (β=-.200, p=.014); 4) multi-Dx - fatigue (β=-.350, p<.001), symptom impact (β=-.201, p<.001), sleep disturbance (β=-.183, p<.001), pain interference (β=-.181, p<.001). Disease impact and fatigue related to physical function in all cohorts while pain interference, dyspnea, sleep disturbance, and psychological factors had varying relationships with physical function among individuals with post-COVID, FMS, CFS, and multi-Dx. Grant support from National Institutes of Neurological Disease and Stroke (NINDS) of the NIH under Award Number U24NS112873-03S2.