Six minute walk test

Dr Refsgaard¹ and Dr Hager have commented our article regarding ‘Six minute walk test’ (6MWT).² We concluded that ‘6MWT’ is a simple and inexpensive test, which is not robust enough to evaluate treatment effects in clinical trials. However, it may have a role in clinical practice as a routine part of evaluation (as many patients avoid symptoms by reducing their activity). A recently published trial on 1077 elderly heart failure patients shows that change in symptoms corresponds with change in 6MWT walking distance.³ The corridor walk test is limited by some very practical consideration such as the length of a quiet corridor where the patient's performance will not be affected by the staff. We agree that encouragement should be administered, not only for improving patients performance on 6MWT, but also to comfort the patient who might find it awkward to walk in silence for 6 min. Standardization of encouragement may be of value. The value of repeated baseline walk tests is disputed. In the statement issued by the American Thoracic Society (ATS) regarding execution of the 6MWT change in walk length from first to second walk varied from 0 to 17% in a variety of diseases including chronic heart failure, and the authors concluded repeated baseline tests to be unneccessary in most settings.⁴ Indeed, 6MWT has proven to yield equally stable results regardless of repeated walk tests.^3,5

Ultimately, the 6MWT can be of use in the clinical setting and in evaluating treatment in selected heart failure patients, but in order to ascertain comparable and reliable results there is a need for further standardization. We agree with Dr Hager that the statement issued by ATS can provide the framework for this.

Regarding peak oxygen uptake as the ‘golden standard’ of heart failure assessment we must respectfully disagree with the author. Peak oxygen uptake has in our opinion, with the exception of patients eligible for heart transplant, not outperformed 6MWT, neither as a prognostic indicator nor in the evaluation of treatment⁶ and is more expensive to use and more cumbersome for the patient.

Conflict of interest: none declared.

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