Reliability of the 2- and 6-minute walk tests in neuromuscular diseases.

OBJECTIVE

The 2- and 6-minute walk tests are used to evaluate walking capacity, but reliability has been sparsely investigated in patients with neuromuscular diseases. The aim of this study was to investigate the relative and absolute reliability of the 2- and 6-minute walk tests in patients with neuromuscular diseases.

DESIGN

Each patient performed a 2- and a 6-minute walk test on 2 test days separated by 1-2 weeks.

SUBJECTS

A total of 93 adult patients (mean age 53 years, age range 22-83 years) with 12 different neuromuscular diseases were included.

RESULTS

The mean walking distance increased by 4.3 and 11.2 m (p < 0.001) in repeated 2- and 6-minute walk tests, respectively. Intraclass correlation coefficient in the 2- and 6-minute walk tests was 0.99 (p < 0.001). Standard error of measurement was 4.9 m in the 2-minute walk test and 14.0 m in the 6-minute walk test. Minimal detectable difference was 13.7 m in the 2-minute walk test and 38.8 m in the 6-minute walk test.

CONCLUSION

These findings show good relative reliability of the 2- and 6-minute walk tests in patients with neuromuscular diseases. However, absolute reliability demonstrated variability in neuromuscular diseases. This should be considered when interpreting a change in walking distance.