Background/Purpose: Functional status gets worse with comorbidities regardless of disease activity in patients with rheumatoid arthritis (RA). However, the impact of comorbidities on physical function in ankylosing spondylitis (AS) and psoriatic arthritis (PsA) is less known.

The aim of this study is to assess the impact of comorbidities on physical function in patients with AS and PsA.

Methods: Analysis of the baseline visit from the ongoing multicentric, observational, prospective, CARdiovascular in rheuMAtology (CARMA) study. For this study, data from patients with AS and PsA were analyzed. Two different multivariate models were performed, where physical function was the dependent variable (using BASFI in AS and HAQ in PsA) and the following independent variables: comorbidities, a proxy for the Charlson index (CCIp) (minimum 0; maximum 27), sociodemographic (age, sex and educational level), disease activity (ESR, CRP and BASDAI in AS; while SJC, TJC, CRP, ESR, DAS, dactylitis count and PASI in PsA), disease duration, radiographic damage (defined as “spinal radiographic changes” in AS and “presence of erosions” for PsA), and treatments (for the rheumatic disease and comorbidities); adjusted for disease activity, radiographic damage and sociodemographic variables. Results are presented as β coefficients and p-values.

Results: 738 patients with AS and 721 with PsA included (mean age at inclusion 48.1±11.7 and 51.8 ±12 years, respectively, p<0.001). Patients with AS: median BASFI 3.1 [interquartile range (IQR): 1.3-5.2], BASDAI 3.5 [IQR: 1.7-5.3], mean CCIp 1.32±0.73. PsA patients: HAQ 0.4 [IQR: 0.0-0.9], DAS28 2.9 [IQR 2.0-3.8], mean CCIp 1.30±0.66. A CCIp >1 was found in 21% of the patients. Patients with PsA have higher BMI and more hypercholesterolemia; on the other hand, we found more smokers among patients with AS (all p<0.001). No differences between the two groups were found regarding the different comorbidities, except for a higher prevalence of chronic pulmonary disease in patients with AS. Patients with PsA with higher CCIp showed worse adjusted physical function (β: 0.09; p=0.005). In patients with AS, the CCIp was not independently associated with physical function, but thyroid disease (β: 1.18, p=0.002), disease activity (BASDAI; β: 0.81, p<0.001) and spinal radiographic damage (β: 0.61, p<0.001) were independently associated. In patients with PsA, obesity (β: 0.09; p=0.04), disease duration (β: 0.01; p=0.009), disease activity (DAS-28, β: 0.19; p<0.001) and NSAIDs (β: 0.1; p=0.014), corticosteroids (β: 0.12; p=0.02) and biologic DMARD use (β: 0.15; p<0.001) were associated with worse physical function. In contrast, a higher educational level was associated with less disability (β: -0.27; p=0.004).

Conclusion: The presence of comorbidities in patients with PsA is independently associated with worse physical function, similar to what happens in RA. Early detection and control may yield an integral management of the disease and better final outcomes.

Acknowledgements: This project has been supported by an unrestricted grant from Abbvie, Spain. The design, analysis, interpretation of results and preparation of the manuscript has been done independently of Abbvie.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-impact-of-comorbidities-on-physical-function-in-patients-with-ankylosing-spondylitis-and-psoriatic-arthritis-attending-rheumatology-clinics-results-of-a-national-study/