Construct Validity and Reliability of the 2-Minute Step Test in Patients with Fibromyalgia

The aim of this study was primarily to assess the validity and reliability of the 2-minute step test (2MST) in patients with fibromyalgia; and secondly, to explore its relationship with the 2-minute walk test (2MWT), the 6-minute walk test (6MWT), as well as fatigue severity and quality of life.

This cross-sectional study involved 55 female patients aged 18-65 diagnosed with fibromyalgia according to the American College of Rheumatology 2010 Diagnostic Criteria. Pain intensity was measured using the Visual Analog Scale, quality of life impact was assessed with the Fibromyalgia Impact Questionnaire, and fatigue severity was evaluated using the Fatigue Severity Scale. Patients underwent initial assessments using the 2MST, 2MWT, and 6MWT. Test-retest reliability of the 2MST was determined with a 7-day interval between assessments.

The study included a cohort of participants with an average age of 45.3 ± 7.7 years. The mean score for the 2MST was 51.9 ± 15.6, with a second 2MST yielding a mean score of 56.1 ± 16.4. The reliability of the 2MST was found to be good (ICC=0.925) in patients with fibromyalgia. The 2MSTexhibited significant correlations with the 2MWT (ρ=0.633) and 6MWT (ρ= 0.703).

In conclusion, this study demonstrates that the 2MST is a reliable tool for evaluating exercise capacity in individuals with fibromyalgia, showing a negative association with age and pain severity.