Background Persistent pain is the hallmark of various rheumatologic conditions, including systemic lupus erythematosus (SLE). The presence of diffuse pain compromises the quality of life of the patients. Fibromyalgia (FM) is a syndrome that can be associated with several rheumatic diseases and it is characterised by chronic pain and functional disability. However, it is still incompletely understood how FM could influence on perception of pain and its impact on quality of life in SLE.
Objectives To characterise distribution of various pain characteristics in SLE patients and whether FM associated pain contributes to functional disability in this group of patients.
Methods 101 SLE patients (age 48.71 ± 16.1 years, SLEDAI 5.27 ± 0.45) could be included in this study. 72 patients received corticosteroids, 51 patients were on hydroxychloroquine, 23 patients got azathioprine, and 27 patients were on mycophenolate therapy. Fibromyalgia (FM) was diagnosed according to the ACR 1990 criteria and the following questionnaires were utilised: Fibromyalgia Impact Questionnaire, painDETECT test, visual analogue scale for pain (VAS), Perceived Stress Questionnaire, SF - 36 and Health Assessment Questionnaire (HAQ). The subgroup of SLE patients with FM was compared to 56 age and sex matched patients with primary FM without rheumatologic disease.
Results 30 SLE patients were diagnosed with associated FM. Patient reported pain was significantly higher across all measured categories in SLE patients with associated FM compared to SLE patients without FM: current pain (4.4 ± 0.4 vs. 2.8 ± 0.3, p < 0.01), worst pain during last 4 weeks (6.9 ± 0.4 vs. 4.9 ± 0.3, p < 0.01), average pain during last 4 weeks (5.5 ± 0.3 vs. 3.5 ± 0.3, p < 0.01), daytime pain (5.6 ± 0.4 vs. 3.8 ± 0.3, p < 0.01) and night pain (4.9 ± 0.5 vs. 2.9 ± 0.3, p < 0.01). Furthermore, a significant difference was detected in the HAQ score between the SLE groups with and without additional FM, respectively (0.79 ± 0.13 vs. 0.47 ± 0.06, p < 0.05). However, the dependable variable FM in the whole SLE population yielded significant differences in several SF - 36 categories such as pain (p < 0.01), physical functioning (p < 0.01), social functioning (p < 0.01), mental health status (p < 0.01) and role dysfunction due to emotional problems (p < 0.01). Comparing SLE patients with associated FM to primary FM patients revealed significant differences for current pain (4.4 ± 0.4 cm vs. 5.5 ± 0.3 cm, p < 0.05) and patient reported worst pain during last 4 weeks (6.9 ± 0.4 cm vs. 8.0 ± 0.2 cm, p < 0.05). No significant difference in functional disability was found between patients with SLE + FM compared to primary FM patients (HAQ 0.79 ± 0.13 and 0.95 ± 0.07 accordingly). Perceived stress did correlate with patient reported pain (current, average and worst pain) in FM patients, however, in the SLE + FMS group these correlations could not be observed.
Conclusions The presence of FMS in SLE yielded significant disability regarding quality of life. Chronic pain as well as a relationship between pain and fibromyalgia could further contribute to pain management strategies that should be implemented in the treatment of SLE patients. The role of emotional stress as an aggravating factor for pain in SLE patients is not clear. Further studies are warranted to reveal factors contributing to pain in rheumatologic patients.
Disclosure of Interest None Declared