Construct validity and responsiveness of feasible composite disease activity measures for use in daily clinical practice in patients with psoriatic arthritis.

OBJECTIVE: There is a need for a widely accepted comprehensive disease activity measure for use in daily practice in patients with psoriatic arthritis (PsA). For this reason, the 3-item Visual Analogue Scale (3VAS) and 4-item Visual Analogue Scale (4VAS) were developed. This study aimed to test construct validity and responsiveness of the 3VAS and 4VAS in a population of patients with newly diagnosed PsA receiving usual care. METHODS: Components of the 3VAS (physician global, patient global, patient skin) and 4VAS (physician global, patient pain, patient joint, patient skin) were scored on 0-10 VAS scales. Agreement of low disease activity (LDA) state between 3VAS/4VAS and other composite measures was tested using Venn diagrams. Construct validity and responsiveness (3-month interval) were assessed using Spearman correlation coefficients and standardised response means (SRM) with effect sizes (ES), respectively, following hypothesis generation. Both 3VAS/4VAS were also compared with several patient-reported outcome measures. RESULTS: Data from 629 patients were used. Both 3VAS (ES=0.48, SRM 0.52) and 4VAS (ES=0.48, SRM=0.50) showed responsiveness similar to Disease Activity in PSoriatic Arthritis (DAPSA) and Disease Activity Score-28 (DAS28). Both measures had a strong correlation with DAPSA (r=0.80-0.87), Psoriatic Arthritis Disease Activity Score (PASDAS) (r=0.89) and Routine Assessment of Patient Index Data 3 (RAPID3) (r=0.84-0.92). 3VAS and 4VAS had the highest agreement with PASDAS in categorising patients to LDA at 12 months. CONCLUSION: This is the first study assessing the performance of the 3VAS and 4VAS in an observational cohort of patients with early PsA. Both measures have promising performance characteristics, showing strong correlations and good discrimination with existing composite measures. The 4VAS may be the preferred version with better face validity.

Patient-reported outcomes in newly diagnosed early rheumatoid arthritis patients treated to target with a tocilizumab- or methotrexate-based strategy.

Objective: To evaluate the effect of initiation of tocilizumab, with or without MTX, compared with MTX alone on patient-reported outcomes (PROs), in DMARD-naïve patients with early RA. Methods: In U-Act-Early, patients initiated treat-to-target step-up MTX, tocilizumab or tocilizumab plus MTX therapy. PROs assessed included the Functional Assessment of Chronic Illness Therapy-Fatigue, 36-item Short Form (SF-36), five dimensional EuroQol (EQ-5D) and the Revised Illness Perception Questionnaire. Differences between strategy groups over time and proportions of patients exceeding minimum clinically important differences (MCID) were evaluated. Results: During the 2-year study period, significant improvements were found in the tocilizumab strategies in the SF-36 physical component score (tocilizumab, P = 0.012; tocilizumab plus MTX, P = 0.044) and EQ-5D score (tocilizumab plus MTX, P = 0.020) when compared with the MTX strategy. No significant differences were noted in other PROs (P ⩾ 0.052, except for the domain 'identity' in the Illness Perception Questionnaire; tocilizumab vs MTX, P = 0.048). The proportions of patients achieving MCID in SF-36 physical component score were significantly higher at 12 and 52 weeks (P ⩽ 0.049) in the tocilizumab arms when compared with the MTX arm. At week 24, the proportion achieving MCID in EQ-5D was significantly higher in the tocilizumab plus MTX arm vs the MTX arm (P = 0.045). Conclusion: Initiation of treat-to-target tocilizumab therapy resulted in significantly improved PROs, especially within the first 24 weeks, when compared with initiation of MTX therapy. Also on the patients' level, initiating tocilizumab may be considered as a valuable strategy in DMARD-naïve patients with early RA. Trial registration: ClinicalTrials.gov, http://clinicaltrials.gov, NCT01034137.