Abstract

Background: Most of the step tests applied in people with COPD were not specifically designed for this population. A new incremental step test (IST) was developed for this purpose based on the characteristics of an original test for COPD, the incremental shuttle walk test (ISWT). The measurement properties of the IST still need to be determined, and, therefore, to contribute to the validity (construct validity) of this new test, we aimed to correlate the performances between the IST and ISWT in people with COPD.

Methods: A cross-sectional study was conducted in participants with COPD recruited from hospitals and clinics. Participants attended two sessions to perform the IST and the ISTW, separately. The IST was developed to present the same characteristics of the ISWT (same total duration, same duration on each level and same total number of levels). Spearman's correlations (?) were used between the highest number of steps and level reached in the IST and the highest distance walked and level reached in the ISWT.

Results: 40 people with COPD (6710 years, FEV1 5521pp) participated. The number of steps and the level reached in IST were significant and strongly correlated with the distance walked (?=0.77, p<0.001) and level in the ISWT (?=0.76, p<0.001).

Conclusion: Strong correlations between the performances of IST and ISWT were identified. These results support the need to determine the level of evidence for the validity of the IST in the future, based on the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) guidelines.