Effects of Comorbidity on Physical Function in AS and PsA

Physical functioning was found to be affected by factors including the presence of comorbidities, female sex, disease duration and activity in patients with psoriatic arthritis (PsA), and factors including age, disease activity, and treatment with biologics in patients with ankylosing spondylitis (AS), according to a study published in Arthritis Care & Research (Hoboken).

With this cross-sectional analysis of baseline data from the ongoing 10-year, prospective, Spanish multicenter, national Cardiovascular in Rheumatology (CARMA) study, investigators sought to assess the effect of comorbidities on the physical function of patients with AS and PsA. The study’s primary outcome was physical function, which was assessed using validated versions of the Bath AS Functional Index in patients with AS and using the Health Assessment Questionnaire in participants with PsA. Erythrocyte sedimentation rate (ESR) and Bath AS Disease Activity Index Spanish validated version and Disease Activity Score using 28 joints and ESR (DAS28-ESR) were used to assess disease activity in AS and PsA, respectively.

A proxy for the Charlson Comorbidity Index, sociodemographic data, disease duration, radiographic damage, and treatments (including nonsteroidal anti-inflammatory drugs, glucocorticoids, and biologic agents) were also assessed.

A total of 738 participants with AS and 721 participants with PsA were included in the study, 21% of whom had >1 comorbidity. Comorbidity burden, as evaluated with Charlson Comorbidity Index, was found to be independently associated with worse adjusted physical function in patients with PsA (β, 0.11; 95% CI, 0.05-0.17; P <.001).

In addition, female sex (β, 0.14; 95% CI, 0.06-0.22; P <.001), disease duration (β, 0.01; 95% CI, 0.00-0.01; P =.015), disease activity evaluated with DAS28-ESR (β, 0.19; 95% CI, 0.16-0.22; P <.001), nonsteroidal anti-inflammatory drug use (β, 0.09; 95% CI, 0.02-0.17; P =.017), glucocorticoid use (β, 0.11; 95% CI, 0.01-0.21; P =.026), and use of biologics (β, 0.15; 95% CI, 0.07-0.23; P <.001) were all associated with worse physical function in patients with PsA.

In participants with PsA, a higher educational level was associated with reduced physical disability (β, −0.14; 95% CI, −0.24 to −0.04; P =.004).

In participants with AS, per Bath AS Functional Index, age (β, 0.03; 95% CI, 0.02-0.05; P <.001), disease activity evaluated with Bath AS Disease Activity Index (β, 0.81; 95% CI, 0.75-0.86; P <.001), radiographic damage (β, 0.61; 95% CI, 0.28-0.95; P <.001), and the use of biologic agents (β, 0.51; 95% CI, 0.27-0.76; P <.001), but not the presence of comorbidities (β, 0.03; 95% CI, −0.13 to 0.20; P =.701), were all independently associated with worse physical function in multivariate analyses.

“The presence of comorbidities in patients with PsA is independently associated with worse physical function. The detection and control of comorbidities [in those patients] may yield an integral management of their disease,” concluded the study authors.

Reference

Fernández-Carballido C, Martín-Martínez MA, García-Gómez C, et al; CARMA Project Collaborative Group. Impact of comorbidity on physical function in patients with ankylosing spondylitis and psoriatic arthritis attending rheumatology clinics. results from the CARdiovascular in rheuMAtology (CARMA) study [published online April 29, 2019]. Arthritis Care Res (Hoboken). doi:10.1002/acr.23910