Test-Retest Reliability of a Performance-Based Test Battery in Patients with Fibromyalgia According to...

Area of Science:

• Rehabilitation Medicine
• Clinical Assessment
• Fibromyalgia Research

Background:

• Performance-based tests (PBTs) objectively measure functional capacity, complementing patient-reported outcomes (PROMs) in fibromyalgia (FM).
• Limited evidence exists on PBT reliability, especially concerning patients' socio-occupational status.
• This study investigated PBT test-retest reliability in women with FM and the impact of employment status.

Purpose of the Study:

• To determine the test-retest reliability of a standardized PBT battery in women with FM.
• To examine how employment status influences the measurement stability of PBTs in FM patients.

Main Methods:

• 119 women (89 with FM) underwent testing, including the 6-minute walk test (6MWT), handgrip strength test (HST), and 8-feet up and go test (8FUGT).
• Test-retest reliability was assessed using intraclass correlation coefficient (ICC), standard error of measurement (SEM), and smallest real difference (SRD).
• Analyses were performed on the total FM group and subgroups based on employment status (working, claiming disability, permanent disability).

Main Results:

• All PBTs demonstrated excellent test-retest reliability, with higher stability observed in controls.
• The handgrip strength test (HST) showed reduced reproducibility (higher SEM% and SRD%) in the disability-claiming group.
• The 6-minute walk test (6MWT) and 8-feet up and go test (8FUGT) maintained excellent reliability across all groups; PROMs showed good-to-excellent reliability.

Conclusions:

• Performance-based tests (PBTs) are reliable for assessing functional capacity in women with fibromyalgia.
• Reliability of PBTs, particularly the handgrip strength test (HST), varies across socio-occupational groups, with reduced reproducibility in those claiming disability.
• Patient-reported outcomes (PROMs) exhibited lower reliability compared to PBTs.