Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement
Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.
Performance of the Ankylosing Spondylitis Disease Activity Score (ASDAS) in Patients Under Biological Therapies in Daily PracticeResults From the Portuguese Register Reuma.Pt.
Ramiro1, Sofia, Machado2, Pedro, Roque3, Raquel, Santos4, Helena, Polido-Pereira5, Joaquim, Peixoto6, Daniela, Duarte7, Cátia
Hospital Garcia de Orta, Almada, Portugal and Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
Maastricht University Medical Center, Maastricht, Netherlands
Leiden University Medical Center, Leiden, Netherlands
Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
Hospitais da Universidade de Coimbra, Coimbra, Portugal and Leiden University Medical Center, Leiden, Netherlands
Hospital Garcia de Orta, Almada, Portugal
Instituto Português de Reumatologia, Lisboa, Portugal
Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa and Rheumatology Department, Centro Hospitalar de Lisboa Norte, EPE, Hospital de Santa Maria, Lisboa, Portugal
Centro Hospitalar do Alto Minho, Hospital de Ponte de Lima, Ponte de Lima, Portugal
Hospitais da Universidade de Coimbra, Coimbra, Portugal
Centro Hospitalar de Lisboa Ocidental, Hospital Egas Moniz, Lisboa, Portugal
Centro Hospitalar de Lisboa Norte, Hospital de Santa Maria, Lisboa, Portugal
The Ankylosing Spondylitis Disease Activity Score (ASDAS) is the new index to measure disease activity in Ankylosing Spondylitis (AS). Our aim was to address validity and discriminatory aspects of the ASDAS, as well as to analyse the performance of the ASDAS disease activity states and response criteria in the setting of an observational cohort of patients with AS starting biological therapies.
Patients with AS under biological therapy and followed in the Portuguese register of rheumatic diseases (Reuma.pt) were included in this analysis. Reuma.pt is used as an electronic medical record and assessments are performed by rheumatologists. All patients with baseline data were used for cross-sectional analysis (n = 264). For the longitudinal analyses, follow-up visits at 12 and 24 weeks and with an ASDAS-CRP available were required (n = 109). Pearson coefficients were calculated to establish the correlation between disease activity measurements at baseline. Discrimination between patients with low versus high disease activity according to the patient's global assessment (PGA) was analysed as the standardised mean difference (SMD). The percentage of patients within each ASDAS disease activity state at each time point and the percentage of patients achieving ASDAS improvement criteria at 12 and 24 weeks were determined and the latter were compared with other response measures.
The ASDAS showed a good correlation with the PGA (0.66), and simultaneously a good correlation with acute phase reactants (CPR 0.61; ESR 0.52). The ASDAS was discriminatory, with similar SMDs to the ones from BASDAI. Results were consistent for the whole population as well as in subgroups of baseline CRP (at a cutoff of 5g/l) and disease duration (at a cutoff of 5 years). ASDAS disease activity in states showed a clinically meaningful shift from high to low over time (Table 1). The same pattern was found in the subgroups of CRP and disease duration. The ASDAS improvement criteria identified more patients with clinically meaningful improvement than the classical criteria did (Table 2), and the same results were also found in the subgroups of CRP and disease duration.
Table 1. Longitudinal evolution of ASDAS disease activity states
|Time point||N||ASDAS < 1.3N (%)||1.3 <= ASDAS < 2.1N (%)||2.1 <= ASDAS < 3.5N (%)||ASDAS > 3.5N (%)|
|Baseline||109||0 (0%)||3 (2.8%)||46 (42.2%)||60 (55.0%)|
|12 weeks||109||33 (30.3%)||25 (22.9%)||42 (38.5%)||9 (8.3%)|
|24 weeks||109||30 (27.5%)||29 (26.6%)||40 (36.7%)||10 (9.2%)|
Table 2. Percentage of patients achieving different improvement criteria
|12 weeks(n = 91)||24 weeks(n = 91)|
|D ASDAS >= 1.1||57 (62.6%)||55 (60.4%)|
|D ASDAS >= 2.0||36 (39.6%)||34 (37.4%)|
|D BASDAI >= 2.0||46 (50.6%)||46 (50.6%)|
|BASDAI50||40 (44.0%)||37 (40.7%)|
|ASAS20||51 (56.0%)||51 (56.0%)|
|ASAS40||42 (46.2%)||44 (48.4%)|
The ASDAS is a discriminatory instrument for disease activity in the setting of usual clinical practice.
To cite this abstract, please use the following information:
Ramiro, Sofia, Machado, Pedro, Roque, Raquel, Santos, Helena, Polido-Pereira, Joaquim, Peixoto, Daniela, et al; Performance of the Ankylosing Spondylitis Disease Activity Score (ASDAS) in Patients Under Biological Therapies in Daily PracticeResults From the Portuguese Register Reuma.Pt. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :507