Axial Involvement in Psoriatic Arthritis Associated With Poorer Clinical Outcomes, Quality of Life

Researchers analyzed the characteristics of patients with psoriatic arthritis with and without axial involvement.

Patients with psoriatic arthritis (PsA) who had axial involvement exhibited more severe disease, higher disease activity, and greater impairments to quality of life (QoL) compared with patients without axial involvement, according to findings published in The Journal of Rheumatology.

Relatively little is known regarding the effects of axial involvement on clinical disease outcomes, leaving questions about the effects of axial PsA on disease activity and QoL mostly unanswered. Investigators wanted to explore these connections further to offer practitioners better insight to improve disease management for their patients.

Data on a total of 1530 participants enrolled between March 2013 and March 2016 in the Corrona Psoriatic Arthritis/Spondyloarthritis Registry were analyzed. The cohort included 192 patients with axial PsA (mean age, 50.4 years, 54.0% women, mean disease duration, 12.1 years) and 1338 patients with nonaxial PsA (mean age, 54.4 years, 51.6% women, mean disease duration, 11.4 years) at baseline. Axial involvement was defined by clinician reports or evidence of sacroiliitis on imaging. Rheumatologists and patients also filled out semiannual questionnaires during routine office visits.

Patients with axial PsA were younger (P <.001) compared with patients with nonaxial PsA and were more likely to have HLA-B27 positivity (14.1% vs 3.8%, P <.001) and a greater history of biologic use (72.9% vs 59.6%; P <.001) and depression (22.9% vs 12.6%; P <.001). They also demonstrated higher levels of moderate to severe psoriasis using body surface area ≥3% (42.5% vs 31.5%; P =.005) and nail psoriasis by visual analog scale (VAS; 11.4 vs 6.5; P <.001), as well as more enthesitis (30.7% vs 19.2%, P <.001) and elevated swollen joint counts (5.2 vs 3.5; P =.004) compared with patients with nonaxial PsA.

Baseline disease activity measures showed that individuals with axial PsA had less minimal disease activity (30.1% vs 46.2%; P < .001) and higher scores on the Bath Ankylosing Spondylitis Disease Activity Index (4.7 vs 3.5, P <.001), the Bath Ankylosing Spondylitis Functional Index (3.8 vs 2.5; P <.001), and the Ankylosing Spondylitis Disease Activity Score using C-reactive protein (2.2 vs 1.9; P =.001), vs participants with nonaxial PsA. Levels of C-reactive protein were also significantly elevated compared with levels of those without axial involvement (4.1 vs 2.4; P =.02).

Axial involvement also produced worse patient-reported outcomes, with higher pain by VAS (47.7 vs 36.2; P <.001), higher fatigue by VAS (50.2 vs 38.6; P <.001) and greater likelihood of ≥30 minutes of morning stiffness (83.2% vs 69.3% P <.001) compared with no axial involvement. Physical function on the Health Assessment Questionnaire (0.9 vs 0.6; P <.001) and QoL using the EuroQol VAS (65.3 vs 73.3; P <.001) were also worse in people with axial PsA vs those with nonaxial PsA. Work impairment (32.3% vs 16.8%, P <.001) and overall activity impairment (37.0% vs 18.1%; P <.001) were higher in the axial vs nonaxial group.

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Study limitations included the potential for unmeasured confounders, the possibility that participants’ frequency or level of care may not represent that of average patients, and the possibility that axial involvement might be overestimated or underestimated in this sample as a consequence of not requiring verification through imaging.

“These data highlight the need to monitor patients with PsA for axial symptoms to ameliorate disease development and progression of patient-reported measures,” advised the authors. They recommended that additional studies assess diagnosis and treatment, along with outcome measures and patient responses, with a focus on development of better clinical tools for monitoring and management.

Disclosures: In the last 2 years, AbbVie, Amgen, BMS, Crescendo, Genentech, Horizon Pharma USA, Janssen, Eli Lilly, Novartis, Pfizer, and UCB have supported Corrona LLC, through contracted subscriptions. The study design and conduct were the result of a collaborative effort between Corrona and Novartis, and financial support for the study was provided by Novartis. Novartis participated in the interpretation of data, review, and approval of the manuscript.

JB Palmer is an employee of Novartis. M Liu is an employee of Corrona LLC. R Pandurengan and C Karki were employees of Corrona LLC, at the time of this study. JD Greenberg is an employee and shareholder of Corrona LLC.

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Mease PJ, Palmer JB, Liu M, et al. Influence of axial involvement on clinical characteristics of psoriatic arthritis: analysis from the Corrona Psoriatic Arthritis/Spondyloarthritis Registry [published online July 1, 2018]. J Rheumatol. doi: 10.3899/jrheum.171094