Creation of a model comparing 6-minute walk test to metabolic equivalent in evaluating treatment effects in pulmonary arterial hypertension.


Journal Article

BACKGROUND: The 6-minute walk test (6MWT) is the current standard to assess exercise capacity in pulmonary arterial hypertension (PAH). We compared the Naughton-Balke treadmill test reported in exercise metabolic equivalents (METs) with the 6MWT to evaluate whether MET could be a useful tool to assess exercise capacity. METHODS: Serial 6MWTs followed by Naughton-Balke treadmill tests were performed in 47 PAH patients initiating a change in PAH therapy at baseline (i.e., Time 0) and Weeks 6, 12, 24 and 48; New York Heart Association (NYHA) functional class (FC) was also assessed. Hemodynamics data were recorded at baseline and Weeks 12 and 48. Treadmill time was converted to MET. Generalized estimating equation models, receiver-operating characteristic curves and fixed-effect linear models were utilized to create a model comparing 6MWT to MET. RESULTS: MET correlated with 6MWT (r = 0.62). Piecewise linear function described the relationship between 6MWT and MET. 6MWT and MET were both associated with FC (p < 0.001) with similar ability to discriminate FC. Changes in hemodynamics in response to a change in PAH therapy correlated with changes in both 6MWT and MET. In less sick patients (i.e., FC II), the changes in 6MWT were less pronounced than with MET. CONCLUSIONS: MET appears to be a reliable measure of exercise capacity in PAH, and correlates with 6MWT. MET can be used in clinical assessment and is helpful in demonstrating improvements in exercise capacity in less sick patients.

Full Text

Cited Authors

  • Gomberg-Maitland, M; Huo, D; Benza, RL; McLaughlin, VV; Tapson, VF; Barst, RJ

Published Date

  • July 2007

Published In

Volume / Issue

  • 26 / 7

Start / End Page

  • 732 - 738

PubMed ID

  • 17613405

Pubmed Central ID

  • 17613405

Electronic International Standard Serial Number (EISSN)

  • 1557-3117

International Standard Serial Number (ISSN)

  • 1053-2498

Digital Object Identifier (DOI)

  • 10.1016/j.healun.2007.04.013


  • eng