Objectives: The objective of this study is to determine the prevalence of fibromyalgia (FM) in systemic lupus erythematosus (SLE) patients and to study its relationship to depression and other SLE-related factors.
Methods: A cross-sectional data analysis from the RELESSER-Transversal Spanish Registry, which includes SLE patients in a national multicentre retrospective charts review, was performed.
Inclusion criteria: patients who fulfilled ≥4 ACR 1997 SLE criteria. Main variables were disease duration, depression, sociodemographics, comorbidities, SLE activity symptoms, serological findings, therapies and different disease status indices. Statistical analyses included a descriptive, associative and logistic regression analyses. A literature review was performed.
Results: 3,591 SLE patients were included, 90.1% women, 34.6 years of age at diagnosis (SD 14.6 years) and 93.1% Caucasians. FM prevalence was 6.2%. SLE patients with disease duration >5 years showed more FM than those with duration <5 years: 6.9% vs. 4.0%, respectively (p<0.05). SLE-FM patients showed higher prevalence of depression compared to non-FM-SLE patients: 53.1% vs. 14.6%, respectively (p<0.001). After adjusting by risk factors, the OR (CI) of suffering depression in FM-SLE patients was 6.779 (4.770-9.636), p<0.001. The OR of having secondary Sjögren's 2.447 (1.662-3.604), p<0.001, photosensitivity 2.184 (1.431-3.334), p<0.001, and oral ulcers 1.436 (1.005-2.051), p=0.047.
Conclusions: Prevalence of FM in Caucasian SLE patients was high compared to the general population, and was significantly higher in those in later stages of disease. SLE patients with depression showed a strong risk of developing FM. Photosensitivity, oral ulcers and secondary Sjögren's were the only SLE-related factors associated with FM.