PT - JOURNAL ARTICLE AU - Andrea García-Valle AU - Jesús María Andrés-de Llano AU - Aarón Josué Fariña-González AU - Roberto Daniel González-Benítez AU - Rubén Queiro-Silva TI - Construct Validity of the Routine Assessment of Patient Index Data 3 (RAPID3) in the Evaluation of Axial Spondyloarthritis AID - 10.3899/jrheum.201362 DP - 2021 Jul 15 TA - The Journal of Rheumatology PG - jrheum.201362 4099 - http://www.jrheum.org/content/early/2021/09/13/jrheum.201362.short 4100 - http://www.jrheum.org/content/early/2021/09/13/jrheum.201362.full AB - Objective Although there are different tools to evaluate axial spondyloarthritis (axSpA), they are hardly used in routine clinical practice due to time constraints. The Routine Assessment of Patient Index Data 3 (RAPID3) is a composite measure feasible for use as a sole metric in busy clinics. We aimed to test its measurement properties in patients with axial SpA in a real-world clinical setting. Methods This cross-sectional study included 131 consecutive patients with axial SpA. The convergent (Spearman ρ) and discriminant (receiver-operating characteristic [ROC] curve analysis) validity of RAPID3 were tested against several axSpA-specific measures (Bath Ankylosing Spondylitis Disease Activity Index [BASDAI], Ankylosing Spondylitis Disease Activity Score [ASDAS], Bath Ankylosing Spondylitis Functional Index [BASFI], and modified Stoke Ankylosing Spondylitis Spinal Score [mSASSS]). A multivariate model was built to detect disease factors associated with RAPID3 remission (values ≤ 3). Results The study included 82 men and 49 women, with a median age of 55 (IQR 46–61) years, and a median disease duration of 11 (IQR 6–24) years. Mean RAPID3 was 9.45 ± 6.7. The BASDAI showed moderate correlation with ASDAS (ρ 0.66, P < 0.0001), but higher correlations with BASFI (ρ 0.78, P < 0.0001) and RAPID3 (ρ 0.75, P < 0.0001). The ASDAS had moderate correlations with BASFI, BASDAI, and RAPID3 (ranges 0.66–0.68, P < 0.0001). Higher correlations were found between BASFI and BASDAI (ρ 0.78, P < 0.0001), and BASFI and RAPID3 (ρ 0.73, P < 0.0001). The mSASSS did not show any correlation with any of the above composite measures. κ agreement between RAPID3 remission and other SpA remission criteria was moderate (κ 0.46–0.56). The RAPID3 thresholds to define remission ranged from values ≤ 2 to ≤ 6 with areas under the ROC curve between 0.86–0.91. Female sex (OR 0.34, 95% CI 0.12–0.90, P = 0.03) and nonsteroidal antiinflammatory drug intake (OR 0.26, 95% CI 0.10–0.66, P = 0.005) were independently associated with lower odds of achieving RAPID3 remission. Conclusion RAPID3 demonstrated construct validity in this cross-sectional study. This index can be useful for a more comprehensive assessment of axSpA in busy clinical settings.