Purpose. To assess the association between peak oxygen uptake (VO2peak), determined using a perceptually regulated 1-Km walking test (1k-TWT), and all-cause mortality in cardiac patients. Methods. 1255 male patients, aged 25-85 years, completed a moderate 1k-TWT to estimate VO2peak. Subjects were followed for all-cause mortality for up to 10 years. Cox proportional hazard models were employed to determine variables associated with mortality. Based on estimated VO2peak, the sample was subdivided into quartiles and mortality risks were calculated. To assess the discriminatory accuracy of estimated VO2peak for estimating survival, receiveroperating- characteristics curves were constructed. Results. During a median 8.2 years follow-up, a total of 141 deaths from any cause occurred, yielding an average annual mortality of 1.4%. The strongest predictor of all-cause mortality was estimated VO2peak (c-statistic 0.71, 95% confidence intervals: 0.69-0.74, P<0.0001). Survival decreased in a graded fashion from highest estimated VO2peak quartile to the lowest quartile. Compared to the lowest quartile, the hazard ratios (95% confidence intervals) for the second, third, and fourth quartiles were 0.85 (0.58-1.26), 0.50 (0.29-0.88), and 0.33 (0.16-0.69) respectively (P for trend <0.0001). An 89% reduction in mortality risk was observed among a subset of subjects in the fittest quartile who improved their estimated VO2peak over the follow-up period relative to subjects in the least fit quartile who did not improve. Conclusion. VO2peak estimated by a novel 1k-TWT predicts survival in subjects with stable cardiovascular disease.
Association between VO2peak estimated by a 1-Km treadmill walk and mortality. A 10-year follow-up study in patients with cardiovascular disease
GRAZZI, Giovanni;VOLPATO, Stefano;MAZZONI, Gianni;
2014
Abstract
Purpose. To assess the association between peak oxygen uptake (VO2peak), determined using a perceptually regulated 1-Km walking test (1k-TWT), and all-cause mortality in cardiac patients. Methods. 1255 male patients, aged 25-85 years, completed a moderate 1k-TWT to estimate VO2peak. Subjects were followed for all-cause mortality for up to 10 years. Cox proportional hazard models were employed to determine variables associated with mortality. Based on estimated VO2peak, the sample was subdivided into quartiles and mortality risks were calculated. To assess the discriminatory accuracy of estimated VO2peak for estimating survival, receiveroperating- characteristics curves were constructed. Results. During a median 8.2 years follow-up, a total of 141 deaths from any cause occurred, yielding an average annual mortality of 1.4%. The strongest predictor of all-cause mortality was estimated VO2peak (c-statistic 0.71, 95% confidence intervals: 0.69-0.74, P<0.0001). Survival decreased in a graded fashion from highest estimated VO2peak quartile to the lowest quartile. Compared to the lowest quartile, the hazard ratios (95% confidence intervals) for the second, third, and fourth quartiles were 0.85 (0.58-1.26), 0.50 (0.29-0.88), and 0.33 (0.16-0.69) respectively (P for trend <0.0001). An 89% reduction in mortality risk was observed among a subset of subjects in the fittest quartile who improved their estimated VO2peak over the follow-up period relative to subjects in the least fit quartile who did not improve. Conclusion. VO2peak estimated by a novel 1k-TWT predicts survival in subjects with stable cardiovascular disease.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
