Usefulness of Improvement in Walking Distance Versus Peak Oxygen Uptake in Predicting Prognosis After Myocardial Infarction and/or Coronary Artery Bypass Grafting in Men

Information is limited on the influence of a change in fitness and/or physical activity on mortality in cardiac patients who undergo exercise rehabilitation. This was studied in 6,956 men (4,713 with myocardial infarctions, 2,243 who underwent coronary bypass surgery) completing a 12-month walking-based training regimen and followed for a median of 9 years (range 4 to 26; 67,820 patient-years). Peak oxygen uptake (VO 2peak ) was measured at the beginning and the end of the program, and walking distance and pace were recorded weekly. These and other pertinent data were entered into a Cox proportional-hazards model and tested for associations with time to cardiac and all-cause death. In total, 2,016 deaths were recorded (737 cardiac, 1,279 all-cause). The mean increase in VO 2peak was 4.9 ml/kg/min (95% confidence interval [CI] 4.7 to 5.0, p 2peak was significant on univariate analysis (hazard ratio [HR] 0.98) but not on multivariate analysis. Distance increase was a significant predictor of cardiac and all-cause death on multivariate analysis, with each 1-mi improvement conferring a 20% reduction in cardiac death (HR 0.80, 95% CI 0.71 to 0.87, p 2.8 mi, increased walking distance of 1.3 to 2.8 and of >2.8 mi yielded 24% (HR 0.76, 95% CI 0.62 to 0.92, p = 0.005) and 48% (HR 0.52, 95% CI 0.40 to 0.68, p 2peak .