VALIDATION OF THE TWO-MINUTE STEP TEST IN HOSPITALIZED PATIENTS WITH EXACERBATION OF COPD: A STUDY PROTOCOL
该研究方案旨在验证两分钟踏步测试在COPD急性加重住院患者中的有效性，为医院空间有限时提供一种便携、可靠的运动能力评估工具，帮助制定个体化运动处方。
Introduction: Exacerbations of Chronic Obstructive Pulmonary Disease (ECOPD) often require hospitalization and impair exercise tolerance. Assessing functional capacity is essential for tailored exercise prescription, yet conventional walking tests like the six-minute walk test (6MWT) require space (e.g., a 30-meter corridor) that is unavailable in most hospital settings. Step tests, such as the 2-minute step test (2MST), emerge as practical alternatives due to minimal space requirements and functional relevance. However, the measurement properties of the 2MST have not yet been assessed in the specific context of hospitalized patients with ECOPD. This study aims to evaluate the construct validity and test-retest reliability of the 2MST in hospitalized patients with ECOPD. Materials and Methods: Based on COSMIN recommendations, a convenience sample of ≥50 patients hospitalized for ECOPD and patients with stable COPD meeting GOLD criteria, will be recruited. Participants will complete two trials of the 2MST, six-minute stepper test (6MSpT), five-times sit-to-stand test (5STS), and patient-reported outcome measures (PROM: CAT, mMRC, FACIT-Fatigue). Construct validity will be assessed by correlating 2MST performance with 6MSpT, 5STS, and PROM. Known-groups validity will be tested by comparing 2MST results between hospitalized and stable patients. Reliability and agreement will be determined through two 2MST repetitions on the same day, using the Intraclass Correlation Coefficient (ICC), the Standard Error of Measurement (SEM), and the Bland and Altman analysis. The Minimal Detectable Change (MDC) will also be assessed. Results: The study is ongoing. A strong positive correlation (r>0.70) is expected between 2MST and 6MSpT. Moderate to strong negative correlations (r<-0.50) are anticipated with PROM scores. Significant differences in 2MST performance are expected between hospitalized and stable COPD groups (p<0.05). An ICC≥0.70 and a small SEM are also anticipated. Conclusions: Validating the 2MST will provide clinicians with a portable and reliable tool for assessing exercise capacity in hospital settings, ultimately improving physiotherapy intervention during ECOPD recovery. Acknowledgements: This work was developed in the context of ongoing research activities related to the project SCALE UP, which is supported by the COMPETE2030 programme – Portugal 2030 (cofunded by FEDER/European Union; Ref. COMPETE2030-FEDER-00916100) and by Fundação para a Ciência e a Tecnologia (FCT, Ref. 2023.16009.ICDT, https://doi.org/10.54499/2023.16009.ICDT). JC and CGS acknowledge the support of the Center for Innovative Care and Health Technology (ciTechCare) of the Polytechnic of Leiria, funded by Portuguese national funds provided by FCT (UIDB/05704/2025, DOI: https://doi.org/10.54499/UID/05704/2025).