Background/Purpose

Patients with new onset ankylosing spondylitis (AS) and those naïve to the Ankylosing Spondylitis Disease Activity Score (ASDAS) have voiced confusion over the use of the term “AS” in these instruments. Our previous abstract (EULAR 2013) compared the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) against a modified BASDAI and determined the relationship between working status and disability with Bath Ankylosing Spondylitis Functional Index (BASFI), BASDAI and modified BASDAI.   It is unknown whether these tools may be applied to other forms of spondyloarthritis (SpA). In this abstract we:  1) validate slightly modified versions of the ASDAS questionnaires for use in non-AS SpA by assessing its ability to predict working status and disability; and  2)  compare the disease-specific patient global assessment used in the ASDAS (PG) with the MD-HAQ version, and the disease activity scores based on these instruments.

Methods

Adult patients with SpA-associated conditions from three locations of the Program to Understand the Longterm outcomes of SpondyloARthritis (PULSAR) completed both traditional ASDAS questionnaire and modified version of the ASDAS instrument (PULSAR-modified ASDAS, [PuASDAS]) during visits with health care providers.  The PuASDAS replaces references to “AS” with the term “inflammatory arthritis” and uses a non-disease specific patient global assessment that is similar to the multidimensional health assessment questionnaire global assessment (MD-HAQ); Scores from traditional and modified questionnaires were compared using Spearman correlations. The association of ASDAS and PuASDAS scores with disability status (according to federal program criteria) and self-reported working status were determined using logistic regression.

Results

Sixty-two patients participated in the study. Correlation between ASDAS and PuASDAS scores was high, recapitulating the previously demonstrated correlation between BASDAI and PuBaDAI (Spearman’s rho=0.84, p<0.001, and Spearman's rho=0.92, p<0.001, respectively). Similarly, the PG had good correlation with the MD-HAQ (rho=0.766, p<0.001). The ASDAS (OR 1.34, 95% C.I. 1.02-1.76) and PuASDAS (OR 1.62, 95% C.I. 1.07-2.49) predicted federally-determined disability.

Conclusion

Preliminary data suggest that the PuASDAS may be used in non-AS SpA and that scores from these instruments correlate well with traditional form of the questionnaire. Correlation between the two versions of the patient’s global assessments was good.  PuASDAS scores predicted disability status at least as well as the ASDAS.