Is there any gender-specific difference in the cut-off values of ankylosing spondylitis disease activity score in patients with axial spondyloarthritis?

To assess the validity of Assessment in Spondyloarthritis International Society (ASAS) endorsed Ankylosing Spondylitis Disease Activity Score (ASDAS) C-reactive protein (-CRP) and ASDAS erythrocyte sedimentation rate (-ESR) in axial spondyloarthritis (axSpA) and to estimate the cut-off values for male and female patients with axSpA. Patients with axSpA were assessed for disease activity, functions, mobility and AS Quality of Life (ASQoL) and pain. The discriminant ability of ASDAS versions was assessed using standardized mean differences. Optimal cut-off values of ASDAS versions were calculated. Patients with axSpA were included (196 AS, 164 non-radiographic axSpA). ASDAS versions and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) had good correlations with patient's global (PtG) and physician's global (PhG) assessment in both groups; however, men had relatively higher coefficients. Women had significantly higher pain, ASQoL, ASDAS-ESR, BASDAI item scores, PtG, PhG and ESR. Discriminant abilities of ASDAS-CRP, ASDAS-ESR and BASDAI were similar in men and women regarding low and high disease activity. ASDAS cut-offs are quite similar in both genders and in accordance with predefined values. The cut-offs for ASDAS-ESR were relatively lower than ASDAS-CRP and women tend to have higher cut-offs than men. The construct validity of ASDAS-CRP to discriminate low and high disease activity and cut-off values are similar in male and female patients with axSpA; however, cut-offs for ASDAS-ESR need to be defined.

Kilic G ，Kilic E ，Ozgocmen S 《-》

Discriminant validity of the Ankylosing Spondylitis Disease Activity Score (ASDAS) in patients with non-radiographic axial spondyloarthritis and ankylosing spondylitis: a cohort study.

Kilic E ，Kilic G ，Akgul O ，Ozgocmen S ... -  《-》

Validity and reliability of the Ankylosing Spondylitis Disease Activity Score with C-reactive protein (ASDAS-CRP) and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) in patients with axial spondyloarthritis (axSpA) in Singapore.

The Ankylosing Spondylitis Disease Activity Score with C-reactive protein (ASDAS-CRP) and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) are commonly used instruments for measuring disease activity. However, few studies have assessed their psychometric properties in patients with axial spondyloarthritis (axSpA). We aimed to assess the validity and reliability of ASDAS-CRP and BASDAI in patients with axSpA in Singapore. Cross-sectional data from 280 patients with axSpA from a dedicated axSpA clinic in a Singapore tertiary referral hospital from 2011 to 2019 were used. Internal consistency was assessed using Cronbach's alpha. Construct validity was assessed through 12 a priori hypotheses by correlation of overall ASDAS-CRP and BASDAI score with other patient-reported outcomes measures (PROMs). Structural validity was evaluated via confirmatory factor analysis using maximum-likelihood method, where Comparative Fit Index (CFI) >0.95, Tucker-Lewis Index (TLI) >0.95, Root Mean Square Error of Approximation (RMSEA) <0.06 and Standardized Root Mean Residuals (SRMR) <0.08 were indicative of good fit. Among 280 patients (78.2% Male; 92.5% Chinese), ASDAS-CRP showed poor internal consistency of 0.33, while BASDAI showed high internal consistency of 0.87. Convergent and divergent construct validity were demonstrated by fulfillment of 11 out of 12 a priori hypotheses when ASDAS-CRP and BASDAI were compared with other PROMs. Our proposed ASDAS-CRP and BASDAI model showed good fit for a 1-factor structure respectively (CFI = 0.993, TLI = 0.984, RMSEA = 0.036, SRMR = 0.026 for ASDAS-CRP; CFI = 0.993, TLI = 0.985, RMSEA = 0.057, SRMR = 0.022 for BASDAI), demonstrating structural validity. This study supports the use of both ASDAS-CRP and BASDAI in measuring disease activity in patients with axSpA in Singapore.

Kwan YH ，Tan JJ ，Phang JK ，Fong W ，Lim KK ，Koh HL ，Lui NL ，Tan CS ，Østbye T ，Thumboo J ，Leung YY ... -  《-》

Clinimetric properties of the ASAS health index in a cohort of Italian patients with axial spondyloarthritis.

Di Carlo M ，Lato V ，Carotti M ，Salaffi F ... -  《Health and Quality of Life Outcomes》

Cut-Offs for Disease Activity States in Axial Spondyloarthritis With Ankylosing Spondylitis Disease Activity Score (ASDAS) Based on C-Reactive Protein and ASDAS Based on Erythrocyte Sedimentation Rate: Are They Interchangeable?

Ankylosing Spondylitis Disease Activity Score based on C-reactive protein (ASDAS-CRP) is recommended over ASDAS based on erythrocyte sedimentation rate (ASDAS-ESR) to assess disease activity in axial spondyloarthritis (axSpA). Although ASDAS-CRP and ASDAS-ESR are not interchangeable, the same disease activity cut-offs are used for both. We aimed to estimate optimal ASDAS-ESR values corresponding to the established ASDAS-CRP cut-offs (1.3, 2.1, and 3.5) and investigate the potential improvement of level of agreement between ASDAS-ESR and ASDAS-CRP disease activity states when applying these estimated cut-offs. We used data from patients with axSpA from 9 European registries initiating a tumor necrosis factor inhibitor. ASDAS-ESR cut-offs were estimated using the Youden index. The level of agreement between ASDAS-ESR and ASDAS-CRP disease activity states was compared against each other. In 3664 patients, mean ASDAS-CRP was higher than ASDAS-ESR at both baseline (3.6 and 3.4, respectively) and aggregated follow-up at 6, 12, or 24 months (1.9 and 1.8, respectively). The estimated ASDAS-ESR values corresponding to the established ASDAS-CRP cut-offs were 1.4, 1.9, and 3.3. By applying these cut-offs, the proportion of discordance between disease activity states according to ASDAS-ESR and ASDAS-CRP decreased from 22.93% to 19.81% in baseline data but increased from 27.17% to 28.94% in follow-up data. We estimated the optimal ASDAS-ESR values corresponding to the established ASDAS-CRP cut-off values. However, applying the estimated cut-offs did not increase the level of agreement between ASDAS-ESR and ASDAS-CRP disease activity states to a relevant degree. Our findings did not provide evidence to reject the established cut-off values for ASDAS-ESR.

Georgiadis S ，Ørnbjerg LM ，Michelsen B ，Kvien TK ，Di Giuseppe D ，Wallman JK ，Závada J ，Provan SA ，Kristianslund EK ，Rodrigues AM ，Santos MJ ，Rotar Ž ，Pirkmajer KP ，Nordström D ，Macfarlane GJ ，Jones GT ，van der Horst-Bruinsma I ，Hellamand P ，Østergaard M ，Hetland ML ... -  《-》