Bath Ankylosing Spondylitis Functional Index (BASFI) is a better indicator of poor quality of life than Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) in ankylosing spondylitis: results from SIRAS - the Scotland and Ireland Registry for Ankylosing Spondylitis

Gareth T Jones, Linda E Dean, Gary J Macfarlane, Scotland Ireland Registry

Research output: Contribution to journalAbstractpeer-review


Background/Purpose: Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Functional Index (BASFI) are validated instruments used to determine disease activity and function amongst ankylosing spondylitis patients. BASDAI is more commonly collected in clinic due, in part, to its use as a clinical criterion for commencing biologic therapy, however the relationship between both BASDAI and BASFI, and quality of life (QoL), is not well established. The aim of this study was to investigate this relationship in the context of other QoL markers.

Methods: The Scotland and Ireland Registry for Ankylosing Spondylitis (SIRAS) collects data on clinically diagnosed ankylosing spondylitis patients in Scotland. Various clinical measures including BASDAI, BASFI are obtained from medical records, and postal questionnaires provide various demographic and patient-reported data, including pain, fatigue, extra spinal manifestations and QoL as determined by the Ankylosing Spondylitis Quality of Life (ASQoL) instrument. In addition, patient postcodes were used to determine a deprivation score from 1 (most affluent) to 20 (most deprived) using the Scottish Index of Multiple Deprivation scale. Factors associated with poor QoL (characterised by an ASQoL score 11) were examined using Poisson regression, and results are given as risk ratios with 95% confidence intervals.

Results: As of the 26th March 2012, 311 patients had been recruited and provided complete data on BASDAI, BASFI and QoL (75% male; median age 51yrs inter-quartile range: 42–61yrs; median ASQoL: 6.0,: 1–11). Poor QoL was associated with both high disease activity (BASDAI 4: risk ratio: 3.7, 95%CI 2.3–6.0) and poor function (BASFI 4: 6.1; 3.4–10.9). However, these were not independent of each other. After mutual adjustment only poor function (BASFI) remained an independent predictor of QoL (4.8; 2.4–9.6). The relationship with disease activity (BASDAI) was greatly reduced and no longer statistically significant (1.4; 0.8–2.4). Other factors independently associated with poor QoL were: female gender (1.6; 1.1–2.4), reporting either chronic widespread body pain (2.7; 1.5–4.8) or moderate/severe fatigue (1.8; 1.2–2.8), ever receiving anti-TNF therapy (1.5; 1.0–2.2), and social deprivation (RR (most versus least deprived): 2.0; 1.1–3.5). No other clinical measures, including markers of inflammation (CRP or ESR), any peripheral joint involvement, or co-morbid disease of the eyes, skin or gut, were associated with poor QoL.

Conclusion: As it is integral to anti-TNF prescribing guidelines, disease activity (BASDAI) is considered as the important clinical indicator in AS. However, clinicians should be aware that function (BASFI) is a stronger predictor of poor QoL. Patients with a high BASFI were almost five times more likely to report poor QoL than other patients. In addition, after adjusting for BASFI, few other clinical variables were independently associated with QoL.
Original languageEnglish
Article number601
Pages (from-to)S261
Number of pages1
JournalArthritis & Rheumatism
Issue numberS10
Publication statusPublished - Oct 2012
EventAnnual Scientific Meeting of the American-College-of-Rheumatology (ACR) and Association-of-Rheumatology-Health-Professionals (ARHP) - Washington, United Kingdom
Duration: 9 Nov 201214 Nov 2012

Cite this