The Role of Comorbidities on Disease Activity in Psoriatic Arthritis

Psoriatic arthritis (PsA) is often associated with comorbidities, which can have an impact on the main disease domains, such as disease activity, patient impact, function, and quality of life, according to a study published in Rheumatology and Therapy.

Researchers evaluated the impact of comorbidities on disease domains by having patients undergo a complete physical examination, collecting clinical/laboratory data, and assessing disease activity.

While it is well recognized which conditions are the most prevalent associated with PsA, including cardiovascular disease, obesity, metabolic syndrome, depression, anxiety, fibromyalgia (FM), and osteoporosis (OP), less is known about the impact that these comorbidities can have on different disease domains,” the authors explained.

The study enrolled 144 patients with PsA, who were at least 18 years old and had at least 6 months of follow-up at the study visit. The patients were enrolled at the Rheumatology Unit of the Department of Medicine and Health Science at the University of Molise in Italy and at Servicio de Reumatología-Hospital Clínic de Barcelona in Spain.

The researchers assessed disease activity using the Disease Activity Score for Psoriatic Arthritis (DAPSA), minimal disease activity (MDA), the Psoriatic Arthritis Impact of Disease (PsAID), the Health Assessment Questionnaire-Disability Index (HAQ-DI), and the Patient Global Assessment of disease activity (PtGA).

Patients were considered in MDA if they satisfied 5 of the following: tender joint count ≤1, swollen joint count ≤1, body surface area ≤3%, patient pain score ≤15, PtGA of ≤20, HAQ-DI ≤0.5, and tender entheseal points ≤1. Slightly more than half (52%) of the patients satisfied MDA 5/7 criteria.

The DAPSA median (interquartile range [IQR]) was 8.4 (IQR, 4.3-16), PsAID median was 2.2 (IQR, 0.8-4), HAQ-DI median was 0.25 (IQR, 0-0.75), and PtGA median was 3 (IQR, 2-6). There was at least 1 comorbidity registered in 72.2% of the patients, and the researchers found that the number of comorbidities impacted DAPSA, PsAID, HAQ-DI, and PtGA:

• For every increase of 1 comorbidity, the DAPSA score increased by a mean of 1.48 points, with anxiety, FM, and OP all showing an impact on DAPSA.
• For every increase of 1 comorbidity, the PsAID score increased by a mean of 0.41 points, with anxiety and FM having a significant impact on PsAID.
• For every increase of 1 comorbidity, the HAQ-DI score increased by a mean of 0.11 points, with anxiety, FM, and OP having a significant impact on function.
• For every increase of 1 comorbidity, the PtGA score increased by a mean of 0.5, with FM and OP having a significant impact on PtGA.

Although a simple logistic regression analysis showed no statistically significant association between MDA and simple comorbidity count, a multiple logistic regression analysis showed a negative impact in reaching MDA in patients with FM. The findings indicate that while MDA may not be influenced by the number of comorbidities, it seems to be more affected by FM.

The authors concluded that the findings “should be considered in routine clinical care, as well in [treat to target] strategy, and longitudinal observational studies could provide more data on this intriguing management aspect of PsA patients.”

Reference

Lubrano E, Scriffignano S, Belen Azuaga A, Ramirez J, Cañete JD, Massimo Perrotta F. Impact of comorbidities on disease activity, patient global assessment, and function in psoriatic arthritis: a cross-sectional study. Rheumatol Ther. Published online August 17, 2020. doi:10.1007/s40744-020-00229-0