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Objective: To evaluate the measurement properties of the Psoriasis Symptom Inventory (PSI) in psoriatic arthritis (PsA)., Methods: The PSI is an 8-item, patient-reported outcome measure of the severity of psoriasis signs and symptoms. This was a secondary analysis of pooled data from a phase II study evaluating the efficacy of brodalumab in patients with PsA. Unidimensionality and item evaluation were assessed using factor and Rasch analyses. Reliability was assessed using Cronbach's alpha (internal consistency) and intraclass correlation coefficients (ICCs) for PSI scores in patients with stable disease (test-retest). Construct validity was evaluated by correlations between PSI scores and body surface area (BSA) affected by psoriasis and selected Short Form 36 (SF-36) health survey domains. Known-groups validity was evaluated based on BSA severity categories, and the ability to detect change was evaluated based on improvement in the subject's global assessment (SGA)., Results: The analysis sample (n = 154) was 93.5% white and 63.0% female. The mean ± SD baseline affected BSA was 10.4% ± 15.6%, and age was 52.2 ± 11.5 years. The PSI demonstrated unidimensionality, with good item fit and correctly ordered categories, excellent internal consistency (α = 0.95), good test-retest reliability (total score ICC 0.70; item ICCs range 0.67-0.81), convergent validity based on moderate correlations with BSA (r = 0.50), discriminant validity based on small baseline correlations (r <-0.3) with the SF-36 domains (role-physical, role-emotional, vitality), known groups validity based on significant differences between BSA groups, and responsiveness based on SGA improvements (P < 0.05)., Conclusion: The PSI demonstrated excellent test-retest and internal consistency reliability and good construct validity in measuring psoriasis signs and symptoms severity in PsA., (© 2015, American College of Rheumatology.)

Objective: Serum 14-3-3η is a novel joint-derived proinflammatory mediator implicated in the pathogenesis of rheumatoid arthritis (RA). In our study, we assessed the diagnostic utility of 14-3-3η and its association with standard clinical and serological measures., Methods: A quantitative ELISA was used to assess 14-3-3η levels. Early (n=99) and established patients with RA (n=135) were compared to all controls (n=385), including healthy subjects (n=189). The sensitivity, specificity, positive and negative predictive values of 14-3-3η, and the likelihood ratios (LR) for RA were determined through receiver-operator curve analysis. The incremental value of adding 14-3-3η to anticitrullinated protein antibody (ACPA) and rheumatoid factor (RF) in diagnosing early and established RA was assessed., Results: Serum 14-3-3η differentiated established patients with RA from healthy individuals and all controls (p<0.0001). A serum 14-3-3η cutoff of ≥0.19 ng/ml delivered a sensitivity and specificity of 77% and 93%, respectively, with corresponding LR positivity of 10.4. At this cutoff in early RA, 64% of patients with early RA were positive for 14-3-3η, with a corresponding specificity of 93% (LR+ of 8.6), while 59% and 57% were positive for ACPA or RF, respectively. When ACPA, RF, and 14-3-3η positivity were used in combination, 77 of the 99 patients (78%) with early RA were positive for any 1 of the 3 markers. Serum 14-3-3η did not correlate with C-reactive protein, erythrocyte sedimentation rate, or Disease Activity Score, but patients who were 14-3-3η-positive had significantly worse disease., Conclusion: Serum 14-3-3η is a novel RA mechanistic marker that is highly specific, associated with worse disease, and complements current markers, enabling a more accurate diagnosis of RA.