A Moderate Walking Test Predicts Survival in Women With Cardiovascular Disease

Introduction: Cardiovascular disease (CVD) is the principal cause of death in U.S. women. Peak oxygen uptake is strongly related to mortality and CVD. This study aimed to investigate the association between estimated peak oxygen uptake, determined using a moderate 1-km walking test, and all-cause mortality in female patients with stable CVD. Methods: Of the 482 women in our registry between 1997 and 2020, we included 430 participants in the analysis (aged 67 [34-88] years). A Cox proportional hazard model was used to determine the variables significantly associated with mortality. On the basis of the peak oxygen uptake estimated using the 1-km walking test, the sample was subdivided into tertiles, and mortality risk was calculated. The discriminatory accuracy of peak oxygen uptake in estimating survival was assessed by receiver operating characteristic curves. All results were adjusted for demographic and clinical covariates. Results: A total of 135 deaths from any cause occurred over a median of 10.4 years (IQR=4.4-16.4), with an average annual mortality of 4.2%. Estimated peak oxygen uptake was a stronger predictor of all-cause mortality than demographic and clinical variables (c-statistic-0.767; 95% CI=0.72, 0.81; p<0.0001). The survival rate decreased from the highest tertile of fitness to the lowest. Compared with the lowest group, hazard ratios (95% CIs) for the second and third tertiles were 0.55 (0.37, 0.83) and 0.29 (0.16, 0.51), respectively (p for trend <0.0001). Conclusions: Higher peak oxygen uptake levels were associated with a lower risk of all-cause mortality. The indirect estimation of peak oxygen uptake using the 1-km walking test is feasible and can be applied for risk stratification among female patients undergoing secondary prevention programs.