Concurrent validity between field tests and cardiopulmonary exercise testing in patients with idiopathic pulmonary fibrosis

ABSTRACT

Background

Maximal treadmill cardiopulmonary exercise testing is the gold standard for assessing functional capacity in patients with idiopathic pulmonary fibrosis (IPF).

Purpose

Primarily to investigate the concurrent validity between three field tests and cardiopulmonary exercise testing in these patients.

Methods

Patients performed the cardiopulmonary exercise testing, a six-minute walk test, an incremental shuttle walk test, and, the Glittre–ADL test. For cardiopulmonary exercise testing, the ten seconds with the higher average of the peak oxygen uptake obtained within the last 30 seconds were considered; for six-minute walk test and incremental shuttle walk test, the longer distance; and for the Glittre-ADL test, the shorter time spent. Concurrent validity was assessed using different regression models based on the best adjustment of the data.

Results

Twenty-two patients with IPF were assessed, aged: 68 ± 8.1 years, 13 male. Patients presented a peak oxygen uptake of 16.5 ± 3.6 mL.kg^−1.min¹, achieving a distance of 512.6 ± 102.8 meters in the six-minute walk test and 415.7 ± 125.1 meters in incremental shuttle walk test. The walking distance in the six-minute walk test and the incremental shuttle walk test explained, respectively, 64% and 56% peak oxygen uptake variance observed in the cardiopulmonary exercise testing (R² = 0.64,p < .001; R² = 0.56,p < .001). The time spent in the Glittre-ADL test was 233.4 ± 88.7 seconds and explained 47% of the peak oxygen uptake variance observed in cardiopulmonary exercise testing (R² = 0.47,p = .001).

Conclusion

The six-minute walk test, incremental shuttle walk test, and Glittre-ADL test were considered valid tests to explain the peak oxygen uptake variance obtained by the cardiopulmonary exercise testing in patients with IPF.

KEYWORDS:

• Walk tests
• measurement properties
• six-minute walk test
• incremental shuttle walk test
• Glittre–ADL test
• exercise testing

Acknowledgments

The authors thank Provatis Academy Services for providing scientific language translation and editing.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was partly supported by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior [CAPES] – Brazil, under Grant Finance Code 001; and Conselho Nacional de Desenvolvimento Científico e Tecnológico [CNPq] Brazil, under Grant 309990/2017-3. The funding sources had no role in the design, conduct, or reporting of this study.