Cross-cultural adaptation and validation of the Brazilian-Portuguese version of the Bath Ankylosing Spondylitis Functional Index (BASFI)

Rev Bras Reumatol. 2012 Oct;52(5):733-41.
[Article in English, Portuguese]


Objective: To conduct a cross-cultural adaptation of the Bath Ankylosing Spondylitis Functional Index (BASFI) into Brazilian-Portuguese language and to assess its measurement properties.

Methods: The BASFI was translated by four rheumatologists and three English teachers. The translated questionnaire was applied to ankylosing spondylitis patients by trained observers, and self-administered in three moments: days 1, 2, and 14. The validity was assessed analyzing the association of BASFI and functional capacity measures (cervical rotation, intermalleolar distance, Schober's test and occiput-to-wall distance). The internal consistence was tested by Cronbach's α coefficient and the reliability by test-retest (intraclass correlation coefficient - ICC).

Results: A total of 60 patients with ankylosing spondylitis was included: 85% male, mean age 47 ± 12 years, and mean disease duration 20 ± 11 years. The intra-observer test-retest (two-week interval) reliability showed a high ICC (0.999, 95% CI: 0.997-0.999) and a high internal consistency (Cronbach's α coefficient: 0.86, CI 95%: 0.80-0.90). Considering the validity, the BASFI indices were correlated with cervical rotation (0.53, P < 0.001) and with intermalleolar distance (0.50, P < 0.001).

Conclusion: The BASFI Brazilian-Portuguese version is reliable and valid for assessment of patients with ankylosing spondylitis.

Publication types

  • Validation Study

MeSH terms

  • Brazil
  • Cultural Characteristics
  • Female
  • Humans
  • Language
  • Male
  • Middle Aged
  • Spondylitis, Ankylosing / diagnosis*
  • Surveys and Questionnaires*
  • Translating