Determining the best percent-predicted equation for estimated VO2 peak by a 1-km moderate perceptually-regulated treadmill walk to predict mortality in outpatients with cardiovascular disease

Abstract Objectives To determine the prognostic ability of established percent-predicted equations of peak oxygen consumption (%PRED) estimated by a moderate submaximal walking test in a large cohort of outpatients with cardiovascular disease (CVD). Design Population-based prospective study. Methods A total of 1442 male patients aged 25–85 years at baseline, underwent a moderate perceptually-regulated (11–13 on the 6–20 Borg scale) treadmill walk (1k-TWT) for peak oxygen consumption estimation (VO2 peak). %PRED was derived from ACSM, Ades et al, Morris et al, and the Wasserman/Hansen equations, and their prognostic performance was assessed. Overall mortality was the end point. Participants were divided into quartiles of %PRED, and mortality risk was estimated using a Cox regression model. Results During a median 8.2 year follow-up, 167 all-cause deaths occurred. The Wasserman/Hansen equation provided the highest prognostic value. Mortality rate was lower across increasing quartiles of %PRED. Compared to the first quartile, after adjustment for confounders, the mortality risk decreased for the second, third, and fourth quartiles, with HRs of 0.75 (95% CI 0.44–1.29, p = 0.29), 0.67 (95% CI 0.38–1.18, p = 0.17), and 0.37 (95% CI 0.10–0.78, p = 0.009), respectively (p for trend