Simplified Ankylosing Spondylitis Disease Activity Score (SASDAS) Versus ASDAS: A Post Hoc Analysis of a Randomized Controlled Trial

Emilce E Schneeberger; Gustavo Citera; Dario Ponce de Leon; Annette E Szumski; Kenneth Kwok; Mariel Cutri; Maxime Dougados

doi:10.3899/jrheum.211075

Simplified Ankylosing Spondylitis Disease Activity Score (SASDAS) Versus ASDAS: A Post Hoc Analysis of a Randomized Controlled Trial

J Rheumatol. 2022 Oct;49(10):1100-1108. doi: 10.3899/jrheum.211075. Epub 2022 Jul 15.

Authors

Emilce E Schneeberger¹, Gustavo Citera², Dario Ponce de Leon³, Annette E Szumski⁴, Kenneth Kwok⁵, Mariel Cutri⁶, Maxime Dougados⁷

Affiliations

¹ E.E. Schneeberger, MD, G. Citera, MD, Department of Rheumatology, Instituto de Rehabilitación Psicofísica, Buenos Aires, Argentina; eschneeb@gmail.com.
² E.E. Schneeberger, MD, G. Citera, MD, Department of Rheumatology, Instituto de Rehabilitación Psicofísica, Buenos Aires, Argentina.
³ D. Ponce de Leon, MD, Medical Affairs, Pfizer Inc., Lima, Peru.
⁴ A.E. Szumski, MA, Biostatistics, Syneos Health, Princeton, NJ, USA.
⁵ K. Kwok, MSc, Global Biostatistics and Data Management, Pfizer Inc., New York, NY, USA.
⁶ M. Cutri, MD, Immunology & Inflammation, Pfizer Inc., Buenos Aires, Argentina.
⁷ M. Dougados, MD, Department of Rheumatology, Paris Descartes University, Rheumatology Department, Hôpital Cochin, AP-HP, and INSERM (U1153): Clinical Epidemiology and Biostatistics, PRES Sorbonne Paris-Cité, Paris, France.

PMID: 35840157
DOI: 10.3899/jrheum.211075

Abstract

Objective: To compare the Simplified Ankylosing Spondylitis Disease Activity Score (SASDAS) against the Ankylosing Spondylitis Disease Activity Score (ASDAS) for measuring and categorizing disease activity using data from the EMBARK trial (ClinicalTrials.gov: NCT01258738), a randomized controlled trial of etanercept (ETN) for axial spondyloarthritis (axSpA).

Methods: Patients with early active axSpA received ETN 50 mg once weekly (n = 106) or placebo (PBO; n = 109) for 12 weeks in a double-blind manner; they then received open-label ETN for 92 weeks. For this analysis, ASDAS-C-reactive protein (CRP) and SASDAS-CRP were calculated at baseline, week 12, and week 24. The SASDAS was calculated by the linear addition of the ASDAS components without adjustment.

Results: A very strong correlation, as determined by the Spearman correlation coefficient, was observed between the ASDAS and SASDAS for continuous variables at baseline and during treatment. For pooled categorical data at baseline, the SASDAS placed 69.9% of patients in the same disease categories as the ASDAS but overestimated for 17.8% of patients and underestimated for 12.2% of patients. A similar pattern was seen postbaseline. Cohen weighted [Formula: see text] statistics for all individual and pooled treatments and timepoints (0.54-0.73) reflected moderate to substantial agreement. The capacity to differentiate between treatments (ie, ETN and PBO/ETN) was higher with the ASDAS (effect size -0.74, 95% CI -1.03 to -0.46) compared with the SASDAS (effect size -0.51, 95% CI -0.79 to -0.23), but sensitivity to change was generally similar.

Conclusion: A very strong correlation between the SASDAS and ASDAS was observed when considering continuous variables; however, moderate to substantial agreement was observed for categorical data, and the SASDAS classified a lower proportion of patients as being in the inactive and low disease activity categories.

Keywords: axial spondyloarthritis; clinical trials; etanercept; outcome.

Publication types

Randomized Controlled Trial
Research Support, Non-U.S. Gov't

MeSH terms

C-Reactive Protein
Double-Blind Method
Etanercept / therapeutic use
Humans
Severity of Illness Index
Spondylitis, Ankylosing* / drug therapy

Substances

Etanercept
C-Reactive Protein

Associated data

ClinicalTrials.gov/NCT01258738