Inter-observer reliability of the Spondylitis Functional Index Instrument for assessing spondylarthropathies

Area of Science:

• Rheumatology
• Physical Therapy
• Clinical Assessment

Background:

• The Spondylitis Functional Index (SFI) is an instrument used to assess functional abilities in patients with spondylitis.
• Evaluating the reliability of assessment tools is crucial for accurate clinical evaluation and research in rheumatologic conditions.

Purpose of the Study:

• To evaluate the inter-observer reliability and agreement of the Spondylitis Functional Index (SFI) when used by physical therapists.
• To compare physical therapists' observations using the SFI with patients' self-reported functional abilities.

Main Methods:

• Thirty patients with spondylitis (ankylosing spondylitis, psoriatic arthritis, Reiter's syndrome) participated.
• Two physical therapists observed patients performing tasks assessed by the SFI.
• Statistical analyses included percent agreement, Cohen's kappa, and Pearson correlation coefficients.

Main Results:

• High inter-observer agreement was found between the two physical therapists (93% agreement, kappa = 0.86).
• Agreement between therapists and patients was significantly lower (66-67% agreement, kappa = 0.39).
• Pearson correlation coefficients indicated moderate agreement between observers and patients (r = 0.52-0.53).

Conclusions:

• The Spondylitis Functional Index (SFI) demonstrates high reliability when used by trained physical therapists.
• There is poor agreement between physical therapists' SFI observations and patients' self-reported functional abilities.
• The SFI is a reliable tool for assessing functional changes in spondylitis patients when utilized by trained observers.