Objective To assess the frequency of fibromyalgia (FM) in patients with psoriatic arthritis (PsA) and its impact on disease activity indices, fatigue and health‐related quality of life (QOL). Methods This cross‐sectional study randomly recruited patients with PsA attending an outpatient clinic between June 2017 and December 2018. Disease activity, functional ability, fatigue, and QOL were assessed for all patients. The recruited PsA patients were screened for concomitant FM, then classified into group Ι, patients with PsA only, and group ΙI, patients with FM‐PsA. The severity and impact of FM were assessed for group II patients. Results A total of 60 patients with PsA were assessed with a mean age of 49.30 ± 11.69 years, of which 43.3% were female. A total of 23 PsA patients had concomitant FM (38.3%). Patients with FM‐PsA showed a statistically higher disease activity in all aspects of PsA except for C‐reactive protein, swollen joint count (SJC) and dactylitis count. Patients in both groups had similar functional levels, while fatigue and QOL were statistically worse in patients with FM‐PsA than in patients with PsA only. Conclusion These results might highlight the importance of considering FM as a contextual factor in disease activity assessment in patients with PsA, especially in those with discrepancies in tender joint count/patient‐reported outcomes vs SJC/inflammatory markers and those with persistently high disease activity indices.

Background:Psoriatic arthritis (PsA), causes inflammation in joints and enthesis, emotional instability and poor quality of life (QOL).1Fibromyalgia (FM) may coexist with PsA, complicating its diagnosis and management.2The effect of FM on the QOL and fatigue in PsA patients has not been vastly studied.3Objectives:Assess the effect of FM on PsA patients’ disease activity indices, QOL and fatigue.Methods:This study included Group I: 37 PsA only patients (61.7%), 48.38 ± 11.69 years and group II: 23 FM-PsA patients (38.3%), 50.78 ± 11.8 years, according to classification criteria for PsA and 2016 Revisions to 2010/2011 FM diagnostic criteria. Psoriasis area severity index (PASI), disease activity in PsA (DAPSA), composite PsA activity index (CPDAI), PsA QOL and multidimensional assessment of fatigue (MAF) were assess in both groups. The severity and impact of FM was assessed in group II.Results:Patients with FM-PsA had a statistically higher PsA disease activity in subjective measures only but not in objective measures. Table 1Table 1.Comparison between the studied groups according to disease activityGroup I(37)Group II(23)Test ofSignificancePMean ± SDtCPDAI8.68 ± 3.3311.26 ± 2.033.735*<0.001*Median (Minimum – Maximum)UPASI8.3 (0 – 45.7)14.4(0.9 – 49.6)292.5*0.043*DAPSA29 (14 – 89)45.5 (20.5 – 99)226.0*0.002*C-reactive protein (mg/dl)6.3 (0.3 – 72)6 (0.8 – 61.6)409.50.80268 Tender joint count7 (2 – 64)23 (8 – 68)112*<0.001*66 Swollen joint count2 (0 – 23)4 (0 – 10)300.50.055Leeds enthesitis index2 (0 – 6)6 (3 – 6)76.5*<0.001*Dactylitic count0 (0 – 8)0 (0 – 7)4210.924U: Mann Whitney testt: Student t-testp: p value for comparing between the studied categories*: Statistically significant at p ≤ 0.05Patients in both groups had similar functional level by health assessment questionnaire (HAQ) (U=339, p=0.188) and QOL by PsAQOL (U=306, p=0.068). While, MAF was statistically higher in group II patients 34 ranging from 28 to 48.7 in group II vs 26.5 ranging from 0 to 49.5 in group I (U=172.5, p<0.001).In group II patients: the mean tender point count was 16.50 ± 1.84, fibromyalgia severity scale (FSS) was 20.7 ± 3.99 and fibromyalgia impact questionnaire (FIQ) was 57.22 ± 7.30. There was a statistically significant correlation between FSS and DAPSA (rs=0.59, p=0.003), PsAQOL (rs=0.64, p=0.001) and HAQ (rs=0.613, p=0.002), and between FIQ and PASI (r=0.488, p=0.018), PsAQOL (r=0.576, p=0.004), HAQ (r=0.557, p=0.006) and MAF (r=0.619, p=0.002).Conclusion:These results might highlight the importance of considering FM as a contextual factor in disease activity assessment in patients with PsA, especially in those with discrepancies in TJC/patients reported outcomes versus SJC/inflammatory markers or persistently high disease activity indices.References:[1]Turkiewicz AM, Moreland LW. Psoriatic arthritis: Current concepts on pathogenesis-oriented therapeutic options. Arthritis Rheum 2007;56(4):1051-66. 2. Husted JA, Thavaneswaran A, Chandran V, Gladman DD. Incremental Effects of Comorbidity on Quality of Life in Patients with Psoriatic Arthritis. J Rheumatol 2013;40(8):1349-56. 3. Brikman S, Furer V, Wollman J, Borok S, Matz H, Polachek A, et al. The effect of the presence of fibromyalgia on common clinical disease activity indices in patients with psoriatic arthritis: a cross-sectional study. J Rheumatol 2016;43(9):1749-54.Acknowledgments:Our sincere gratification to our mentor the late Prof. Dr. Abdel Moneim Helal.Disclosure of Interests:None declared