Evaluation of a German version of the Bath Ankylosing Spondylitis Functional Index (BASFI) and Dougados Functional Index (D-FI).
OBJECTIVE
Transcultural adaptation of the two most widely used and accepted functional indices in ankylosing spondylitis, the Bath Ankylosing Spondylitis Functional Index (BASFI) and Dougados Functional Index (D-FI).


METHODS
The instruments were translated and tested for internal consistency (Cronbach's coefficient alpha), test-retest reliability (intraclass correlation coefficient, ICC), construct validity (testing for association with Schober's test, finger floor distance, occiput wall distance, frequency and duration of awakenings at night, and a visual analog scale pain), and responsiveness (standardized response mean, SRM).


RESULTS
The study sample consisted of 72 patients of a randomized, controlled clinical trial receiving either Diclofenac or placebo. Visual assessment of distribution patterns revealed a ceiling effect of both instruments. Both questionnaires had a high internal consistency (Cronbach alpha: 0.81 [BASFI], 0.85 [D-FI] and a high test-retest reliability (ICC: 0.92 [BASFI], 0.89 [D-FI]). The limited responsiveness to Diclofenac treatment (SRM: 0.46 [BASFI], 0. 33 [D-FI]) may be related to the selected study sample. The BASFI was significantly correlated with all tested validation parameters. The D-FI was only significantly correlated with finger floor distance, occiput wall distance, and duration of awakenings at night.


CONCLUSIONS
The transculturally adapted version of both functional indices are valid, reliable, and internally consistent. Because of psychometric advantages, the BASFI may be preferred in clinical trial settings.
Ruof
J
J
Klinik für Physikalische Medizin und Rehabilitation, Ludwig Maximilians-Universität, Marchionistr. 15 D-81377 München.
Sangha
O
O
Stucki
G
G
D000203:Activities of Daily Living / Q000145:classification*; D000328:Adult; D000368:Aged; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use; D003431:Cross-Cultural Comparison; D004008:Diclofenac / Q000627:therapeutic use; D004311:Double-Blind Method; D005260:Female; D005858:Germany; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D015203:Reproducibility of Results; D013167:Spondylitis, Ankylosing / Q000175:diagnosis* / Q000188:drug therapy
D000894:Anti-Inflammatory Agents, Non-Steroidal; D004008:Diclofenac