Intra-rater reliability of the 6-min walk test in people with liver cirrhosis.

BACKGROUND

Liver cirrhosis often leads to significant impairments in functional capacity, which are associated with disease severity and prognosis. Simple, reliable, and low-cost tests are essential to monitor these patients in clinical practice. The 6-min walk test (6MWT) is widely used in other chronic conditions, but its measurement properties in cirrhosis remain underexplored.

AIM: To assess the reliability of the 6MWT in patients with liver cirrhosis (LC).

METHODS

This cross-sectional study was conducted at a teaching hospital in Juiz de Fora-Minas Gerais. Patients diagnosed with LC at any stage of the disease and under clinical follow-up were included. Patients with grade 2 or higher encephalopathy, respiratory, and/or musculoskeletal diseases or who did not understand the test were excluded. Initially, anamnesis and anthropometric evaluation were performed, followed by the 6MWT. After 24 h the test was repeated. Descriptive statistics were used to present the data. Continuous variables were tested for normality using the Shapiro-Wilk test. The reliability of the 6MWT was tested through Bland-Altman analysis, typical error of measurement, and intraclass correlation coefficient (ICC) as well as a one-sample t-test. A paired Student's t-test was used to check for differences between means, and Pearson's correlation coefficient was used to verify the relationship between the two moments [first 6MWT (6MWT-1) and second 6MWT (6MWT-2)].

RESULTS

The mean difference between 6MWT-2 and 6MWT-1 was -18.9 m; the lower limit of the Bland-Altman agreement was -83.5 m, and the upper limit was 45.7 m. One participant was excluded from further analyses for being outside these limits. The typical error of measurement was 18.9 m. The ICC showed excellent reliability between the two tests (ICC = 0.97, 95% confidence internal: 0.90-0.99, P < 0.001). The Student's one-sample t-value was -2.35 (P = 0.03). The paired t-value was 2.35 (P = 0.03). Pearson's correlation coefficient between the 6MWT-1 and 6MWT-2 was r = 0.98 (P = 0.0001).

CONCLUSION

The 6MWT is a test with excellent reliability. It is safe, easy to administer, inexpensive, and can be introduced into routine practice without loss of diagnostic precision in estimating the functional capacity of patients with LC.