VALIDATION DATA

The Cronbach’s alpha coefficient for internal consistency of FLARE was 0.95 for the total score, 0.91 for the arthritis-related subscale, and 0.95 for the general subscale.

The ICC for reliability after 3 months was 0.94 (95% confidence interval [95% CI] 0.92–0.96) (total), 0.91 (95% CI 0.87–0.93) (arthritis related subscale), and 0.92 (95% CI 0.89–0.94) (general subscale). The Bland-Altman graph  showed <5% of points (4.6%) outside the confidence interval; the mean+-SD difference between the 2 measures was -0.24+-0.82; the smallest detectable difference 1.61.

Both patient- and physician-reported domains were used to develop the Flare Assessment in Rheumatoid Arthritis (FLARE) self-administered questionnaire. During the final meeting between the senior rheumatologists and the health psychologists in charge of the interview analysis, all domains were collected, and an affirmative statement was formulated for each domain. This format was preferred over an interrogative one, because the latter is usually perceived as intrusive by patients. The response modality was a Likert scale of six answers ranging from ‘absolutely true’ to ‘completely untrue’.

At the month 3 visit, 117 patients were considered stable and continued to receive the same DMARD; the mean FLARE-RA score in this group was 2.2. Five patients discontinued their ongoing DMARD due to loss of efficacy; the mean FLARE-RA score in these patients was 5.4. Finally, 4 patients underwent drug tapering due to sustained remission; the mean FLARE-RA score in these patients was 1.1.

The convergent validity was assessed in different ways. The FLARE-RA total score and the 2 subdomain scores showed high correlation with data for 4 outcome measures (DAS28, RAPID 3, RAID, HAQ) collected at the same time as the FLARE-RA questionnaire. The capacity of the FLARE-RA questionnaire to identify disease activity exacerbation that occurred before the visit to the rheumatologist was assessed by the correlation between FLARE-RA scales and the integrated disease activity in the 3 months preceding the visit, as assessed by the weekly RAPID-3, yielding a significant correlation between the FLARE-RA at month 3 and RAPID-3−based disease activity, as expressed by the RAPID-3 AUC (r = 0.68), the maximum RAPID-3 value (r = 0.75), or change over the 3-month period (r = 0.48). Besides, the correlation between change in the DAS28 and change in the FLARE-RA arthritis subscore between month 0 and month 3 was statistically significant, with an ICC of 0.22.