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.


Improvement in Ankylosing Spondylitis Disease Activity Score in Patients with Ankylosing Spondylitis Treated with Tumor Necrosis Factor-Alpha Blocking Therapy.

Arends1,  Suzanne, van der Veer1,  Eveline, Houtman2,  Pieternella M., Leijsma1,  Martha K., Kallenberg1,  Cees G.M., Brouwer1,  Elisabeth, Spoorenberg2,  Anneke

University Medical Center Groningen, Groningen, Netherlands
Medical Center Leeuwarden, Leeuwarden, Netherlands

Background/Purpose:

The Ankylosing Spondylitis Disease Activity Score (ASDAS) has been developed to assess the full concept of disease activity with aspects of both subjective and objective nature. Recently, the cut-off values for ASDAS improvement were defined. Our aim was to assess the percentage of AS patients achieving ASDAS improvement, in comparison to ASAS and BASDAI response, after tumor necrosis factor-alpha (TNF-a) blocking therapy in daily clinical practice.

Methods:

Between November 2004 and April 2010, 217 consecutive AS outpatients from the MCL and UMCG who started TNF-a blocking therapy because of active disease were included in the GLAS study, a prospective longitudinal observational cohort study. All patients fulfilled the modified New York criteria for AS or the ASAS criteria for axial spondyloarthritis. Infliximab (n=31) (5mg/kg) was administered intravenously at 0, 2, and 6 weeks and then every 8 weeks; etanercept (n=135) (50mg once a week or 25mg twice a week) and adalimumab (n=51) (40mg on alternate weeks) were given subcutaneously. After 3 and 6 months, response to treatment was defined using ASDAS clinically important improvement (>=1.1 improvement in ASDAS-CRP), ASDAS major improvement (>=2.0 improvement), ASAS20 (>=20% and >=1 unit improvement in >=3 of the 4 domains physical function, pain, patient's global disease activity, and inflammation, with no worsening >=20% in the remaining domain), ASAS40 (>=40% and >=2 units improvement in >=3 of 4 domains, with no worsening in remaining domain), and BASDAI50 (>=50% improvement in BASDAI).

Results:

Mean age of the 217 AS patients was 42.9 years (SD±11.9), median disease duration was 15 years (range 1–53), and 69% were male. Mean ASDAS was 3.8 (SD±0.8) at baseline, 2.1 (SD±0.9) after 3 months (p=0.000), and 2.0 (SD±0.8) after 6 months (p=0.000) of treatment. After 3 months, 67% and 35% of patients achieved ASDAS clinically important and major improvement, respectively. After 6 months, these percentages were 66% and 38%, respectively. For ASAS and BASDAI response see Table 1.

Table 1. Percentage of AS patients achieving response after 3 and 6 months of TNF-a blocking therapy (n=217)

 3 months6 months
Missing data6 (3%)12 (6%)
DASDAS >=1.1142 (67%)135 (66%)
DASDAS >=2.074 (35%)78 (38%)
ASAS20142 (67%)129 (63%)
ASAS40101 (48%)94 (46%)
BASDAI50102 (48%)101 (49%)

Conclusion:

Approximately two-third of the AS patients achieved ASDAS clinically important improvement and approximately one-third ASDAS major improvement after 3 and 6 months of TNF-a blocking therapy. These data indicate that the response rate for ASDAS clinically important improvement is comparable to ASAS20 response, while ASDAS major improvement seems to reflect response in fewer patients than ASAS40 and BASDAI50 response.

To cite this abstract, please use the following information:
Arends, Suzanne, van der Veer, Eveline, Houtman, Pieternella M., Leijsma, Martha K., Kallenberg, Cees G.M., Brouwer, Elisabeth, et al; Improvement in Ankylosing Spondylitis Disease Activity Score in Patients with Ankylosing Spondylitis Treated with Tumor Necrosis Factor-Alpha Blocking Therapy. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :1322
DOI:

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