Modified 1-min sit-to-stand test for evaluating exercise capacity in pulmonary fibrosis

Area of Science:

• Pulmonary Medicine
• Cardiopulmonary Exercise Testing
• Clinical Trials

Background:

• The 6-minute walk test (6MWT) is the standard for evaluating exercise capacity in pulmonary fibrosis (PF).
• The 6MWT has limitations including temporal and spatial constraints.
• The 1-minute sit-to-stand test (1-MSTST) is a simpler alternative, but its use in PF is not fully validated due to less pronounced oxygen desaturation.

Purpose of the Study:

• To evaluate the efficacy of a modified 1-minute sit-to-stand test (m1-MSTST), incorporating the recovery phase, as a functional exercise test for pulmonary fibrosis (PF).
• To compare the m1-MSTST with the established 6-minute walk test (6MWT) in terms of peripheral oxygen saturation (SpO2) nadir and concordance.

Main Methods:

• A randomized, crossover, single-center trial involving 36 patients with various forms of PF.
• Patients performed both the 6MWT and the m1-MSTST in a randomized order, separated by 30 minutes.
• Equivalence testing was conducted on the peripheral oxygen saturation (SpO2) nadir between the two tests.

Main Results:

• Mean SpO2 nadir was 84.9±4.3% for the 6MWT and 88±3.5% for the m1-MSTST.
• A strong correlation was observed between the SpO2 nadir values from both tests.
• 91.7% of patients (33/36) showed concordant results regarding significant desaturation (SpO2 delta >4% or nadir <88%), a known prognostic factor.

Conclusions:

• The modified 1-minute sit-to-stand test (m1-MSTST) is a viable and practical alternative to the 6-minute walk test (6MWT) for assessing exercise performance in PF patients.
• The m1-MSTST's inclusion of the recovery phase helps compensate for lower desaturation compared to the standard 1-MSTST.
• The m1-MSTST is more practical for patients, especially with the shift of clinical endpoints to outpatient settings; further research on clinical significance and norms is recommended.