Functional tests for adults with asthma: validity, reliability, minimal detectable change, and feasibility

Area of Science:

• Pulmonary Medicine
• Rehabilitation Science
• Clinical Assessment

Background:

• Asthma significantly impacts functional capacity, affecting daily activities and quality of life.
• Objective measures are needed to quantify functional limitations in adults with asthma.
• Existing functional tests require validation for this specific patient population.

Purpose of the Study:

• To evaluate the validity, reliability, learning effect, Minimal Detectable Change (MDC), and feasibility of four functional tests for adults with asthma.
• Specifically, 4-Meter Gait Speed (4MGS), Timed Up-and-Go (TUG), Sit-To-Stand (STS), and Short Physical Performance Battery (SPPB) were assessed.
• To establish these tests as practical tools for assessing functional capacity in asthma patients.

Main Methods:

• A cross-sectional study involving 52 adults with stable asthma.
• Subjects performed three sets of 4MGS, TUG, STS, and SPPB protocols in random order, assessed by two raters.
• Validation involved comparison with a control group, correlation with the Six Minute Walking Test (6MWT), peripheral muscle strength, quality of life, and asthma control questionnaires.

Main Results:

• Adults with asthma showed poorer performance in functional tests compared to controls, except for SPPB.
• All tests demonstrated significant correlations with 6MWT and peripheral muscle strength (r values ranging from 0.32 to 0.67).
• Good to excellent intra-rater reliability (ICC ≥ 0.75) was observed, with a notable learning effect requiring the use of the best of two measurements; MDC ranged from 15-31%. Tests were feasible, quick, and safe.

Conclusions:

• The 4MGS, TUG, STS, and SPPB are valid, reliable, and feasible for assessing functional capacity in adults with asthma.
• These tests provide quick, practical, and alternative methods for evaluating physical function in this population.
• The findings support the integration of these functional tests into routine clinical practice for asthma management.