Co-occurrence of fibromyalgia with psoriatic arthritis (PsA) is associated with significant sleep disturbances, poor quality of life (QoL), fatigue, and higher enthesopathy scores, according to study results published in the International Journal of Rheumatic Diseases.
Researchers enrolled patients in the study who received care at rheumatology outpatient clinics of a major research hospital in Turkey. Adult patients with a clinical diagnosis of PsA were eligible for inclusion in the study. Demographic features were collected. Clinical variables of interest included disease duration, disease activity, and exposure to disease-modifying antirheumatic drugs. Disease Activity Score-28 and Maastricht Ankylosing Spondylitis Enthesitis Score were used to assess disease activity and enthesopathy, respectively. Fibromyalgia was diagnosed based on the American College of Rheumatology (ACR) criteria and the Fibromyalgia Impact Questionnaire (FIQ) was used to determine the effect of fibromyalgia on daily functioning. In addition, PsA-related QoL, sleep, and fatigue were measured using the PsA Quality of Life (PsAQoL), Pittsburgh Sleep Quality Index, and Multidimensional Assessment of Fatigue scales, respectively. Sleep, QoL, and fatigue parameters were compared between patients with and without co-occurring fibromyalgia. Hierarchic multiple regression was used to examine the contributions of various demographic and clinical factors to FIQ scores.
The study cohort included 50 patients with PsA (mean age and disease duration at enrollment were 49.5±10.2 years and 7.5±7.5 years, respectively), among whom 31 (62.0%) were women. Overall, 32 patients (64.0%) had co-occurring fibromyalgia. Fibromyalgia was more commonly observed among women compared with men (80.6% vs 58.3%, respectively; P =.002). Patients who were considered “poor sleepers” (n=27), according to the Pittsburgh Sleep Quality Index, frequently had co-occurring fibromyalgia (n=24; 88.88%). The FIQ scores were significantly higher among women (40.1±25.9) compared with men (25.2±25.9; P =.03).
According to hierarchic regression analysis, the full model of sex, body mass index (BMI), disease activity, enthesopathy, PsA-related QoL, sleep quality, and fatigue was found to be statistically significant (P <.0005) . The overall model accounted for 69% of the variance in FIQ scores. The model using sex and BMI only contributed to 24.4% of the variance (P =.001). After controlling for sex and BMI, the researchers observed that activity score and enthesopathy accounted for an additional 33% (P <.0005). Finally, metrics of QoL, sleep, and fatigue led to an additional increase in model fit (P =.005).
Overall, these data suggest that fibromyalgia is highly prevalent in PsA and contributes to a poorer quality of life. In regression models, all functional parameters assessing QoL, sleep, and fatigue were associated with fibromyalgia severity. Specifically, higher FIQ scores were associated with being women, higher disease activity, greater enthesopathy scores, worse QoL, poor sleep, and increased fatigue.
One of the study limitations included the lack of outcome measures directly measuring depression and anxiety.
“It is important to recognize and treat [fibromyalgia syndrome] in these patients because it can impair QoL [and] increase fatigue and sleep disturbances by affecting disease activity and entheseal involvement,” the researchers concluded.
Ulutatar F, Unal-Ulutatar C, Duruoz MT. Fibromyalgia in patients with psoriatic arthritis: relationship with enthesopathy, sleep, fatigue and quality of life. Published online September 19, 2020. Int J Rheum Dis. doi:10.1111/1756-185X.13963