Impact of Comorbidities on Disease Activity, Patient Global Assessment, and Function in Psoriatic Arthritis: A Cross-Sectional Study

Introduction The aim of this study was to evaluate the impact of comorbidities on disease activity, patient’s impact of the disease, patient global assessment, and function in psoriatic arthritis (PsA). Methods Consecutive PsA patients were enrolled in this cross-sectional study. During the visit, the patients underwent a complete physical examination and clinical/laboratory data were collected, including type and number of comorbidities, recorded as simple comorbidity count (SCC). Disease activity was assessed using the Disease Activity Score for Psoriatic Arthritis (DAPSA) and the Minimal Disease Activity (MDA) was also evaluated. The Psoriatic Arthritis Impact of Disease (PsAID), the Health Assessment Questionnaire-Disability Index (HAQ-DI), and the Patient Global Assessment of disease activity (PtGA) were also collected. Results A total of 144 patients were enrolled. At least one comorbidity was registered in 104 (72.2%) patients. The SCC was associated with DAPSA (β = 1.48, p = 0.013), PsAID (β = 0.41, p < 0.01), HAQ-DI (β = 0.11, p < 0.01) and PtGA (β = 0.50, p < 0.01). The comorbidities that showed an impact on outcome measures were anxiety and fibromyalgia (FM). Anxiety showed an impact on DAPSA (β = 14.46, p < 0.001), PsAID (β = 1.98, p = 0.039) and HAQ-DI (β = 0.54, p = 0.036). FM showed an impact on DAPSA (β = 6.46, p = 0.025), PsAID (β = 2.88, p < 0.001), HAQ-DI (β = 0.70, p < 0.001), PtGA (β = 2.00, p = 0.014), and MDA (β = − 2.79, p = 0.01). The median PtGA value was different among patients with different numbers of comorbidities. Conclusions This study showed that comorbidities, either as a simple comorbidity count number or as single comorbidity, might have an impact on the main domains affecting PsA patients in real clinical practice.