Background Patients with psoriasis (PsO) are at an increased risk of developing psoriatic arthritis (PsA).¹ It has been observed that scalp PsO is indicative of more severe PsO, and increased PsO severity plus scalp PsO are associated with an increased risk of PsA.^2,3

Objectives To determine if baseline scalp PsO is associated with baseline severity of PsA and if it is predictive of treatment response to etanercept (ETN).

Methods In the PRESTA study (clinicaltrials.gov NCT00245960), patients with PsA plus PsO received either ETN 50 mg twice weekly for 12 wks followed by ETN 50 mg once weekly (QW; n=379) or ETN 50 mg QW for 24 wks (n=373). For this analysis, patients who received ETN 50 mg QW were analyzed by their scalp PsO status (scalp+ versus scalp–). Baseline characteristics investigated in scalp+ vs scalp– patients included age, gender, race, family history of PsO and PsA, and PsA subtype. The following treatment outcomes were compared in scalp+ vs scalp– patients at baseline and in improvements at Wks 12 and 24: C-reactive protein levels and fatigue score; skin involvement measures including body surface area, PsO area severity index, and physician global assessment (PGA) PsO; joint involvement outcomes including the disease activity score in 28-joints, duration of morning stiffness, PGA arthritis, subject global assessment (SGA) of disease activity, subject assessment of joint pain, painful joints (28/68 joint counts), swollen joints (28/66 joint counts), digits with dactylitis, and points with enthesitis; quality of life (QoL) EuroQoL-5D (EQ-5D) and health assessment questionnaire (HAQ) scores. The % of patients achieving dactylitis ≤1, enthesitis ≤1, and HAQ ≤0.5 at Wks 12 and 24 were also calculated.

Results In the ETN QW cohort, 273/373 (73.2%) patients had scalp PsO. Spondyloarthropathy was the only PsA subtype shown to be significantly higher in scalp+ vs scalp– patients: 43/49 (87.8%) vs. 521/702 (74.2%; P=0.03). At baseline, scalp– patients were older (49.4 years vs 46.0; P=0.010), with more females (52% vs 33%; P=0.001), and a significantly higher number of painful joints (28-joint count; Table). Scalp+ patients had a significantly higher baseline SGA of disease activity. Improvements from baseline at Wks 12 and 24 for both fatigue and subject assessment of joint pain were significantly higher for scalp+ patients with significantly better final Wk 12 and 24 results. However, only improvement in the number of painful joints (28-joint count) was significantly greater for the scalp– group with similar final Wk 12 and 24 results for scalp+ and scalp– patients. Significantly more patients in the scalp– group had dactylitis ≤1 at Wk 24 and enthesitis ≤1 at Wk 12, but significantly more scalp+ patients had HAQ ≤0.5 at Wk 12. No significant differences were observed between the scalp+ and scalp– patients in the other baseline values or in the improvements from baseline for the other treatment outcomes tested.

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Conclusions Significant differences were observed in joint involvement and QoL in patients with scalp+ vs scalp– at baseline and after 12 and 24 wks of ETN treatment, indicating a relationship between joint involvement and scalp PsO status and between QoL and scalp PsO status.

References

1. Gladman DD et al. Ann Rheum Dis 2005;64 Suppl 2:ii14-7.

2. Haroon M et al. Ann Rheum Dis 2013;72:736-40.

3. Wilson FC et al. Arthritis Rheum 2009;61:233-9.

Acknowledgements This study was sponsored by Pfizer Inc. Medical writing support was provided by Kim Brown of Engage Scientific and funded by Pfizer Inc.

Disclosure of Interest K. de Vlam Consultant for: Pfizer Inc., UCB, Abbott, Celgene and Janssen, Speakers bureau: Pfizer Inc., UCB, Abbott, Celgene and Janssen, A. Szumski Employee of: Inventiv Health Inc who were paid contractors to Pfizer Inc., L. Mallbris Employee of: Pfizer Inc., H. Jones Employee of: Pfizer Inc.

DOI 10.1136/annrheumdis-2014-eular.2949