Predictive validity analysis of six reference equations for the 6-minute walk test in healthy Brazilian men: a cross-sectional study.
Alexandher Negreiros, Rosimeire Simprini Padula, Rosane Andrea Bretas Bernardes and 3 others
PMID 28734576WHAT IT FOUND
For healthy Brazilian men, the Britto equation using age, gender, and BMI predicted walking distance closest to actual performance.
It was more accurate than five other equations, though all models left considerable variability unexplained.
Key findings
01The Britto equation using age, gender, and BMI provided predictions closest to the actual distance walked by participants.
02The actual mean distance walked was 663.43 meters, while the most accurate equation predicted 647.62 meters.
03None of the six tested equations could explain more than 69% of the variability in walking distance.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The study used a convenience sample of healthy men employed in manual labor or university settings, which may not represent the general population. The participants were predominantly active (90.2%) and had a mean BMI of 25.81 (overweight), which may skew the applicability of the equations to sedentary or underweight individuals. Handgrip strength was only measured in 45 of the 103 participants, limiting the robustness of the analysis for equations requiring this variable. The study only included men, so the findings cannot be generalized to women.
Declared interests
The authors declare no conflicts of interest.
The easy way to misread this
Do not assume the Britto equation is precise for individual patients. While it was the most accurate on average, the study notes that no equation explains more than 69% of the variability in walking distance, meaning a 30% difference between predicted and actual distance is expected.