Objective: To develop a French version of the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and to determine its metric properties in patients with all forms of spondyloarthropathies (SpA).
Methods: A French version of BASDAI was obtained after a translation and back-translation process. Patients fulfilling the European Spondylarthropathy Study Group or Amor criteria for SpA were included. BASDAI of Day 0, Day 1, and, when treatment was changed, Day 8, and other clinical and biological disease activity variables were recorded, along with assessment of disease activity by the physician or the patient. Scalability, reproducibility, sensitivity to change, internal consistency and redundancy, and construct validity of the index were assessed.
Results: We studied 293 patients. Good scalability, reproducibility, construct, and internal validity were observed for BASDAI. Sensitivity to change could not be assessed.
Conclusion: The French version of BASDAI exhibited good metric properties in patients with all forms of SpA, confirming its utility in further clinical research in SpA. However, sensitivity to changes due to drug therapy remains to be assessed.