A moderate walking test predicts survival in women with cardiovascular disease

Introduction

Cardiovascular disease (CVD) is the principal cause of death in US women. Peak oxygen
uptake (VO_2peak) is strongly related to mortality and CVD. This study aimed to investigate the association
between estimated VO_2peak, determined using a moderate 1-km walking test (1k-TWT), and all-cause mortality
in female patients with stable CVD.

Methods

Of the 482 women comprising in our registry between 1997-2020, we included 430 participants
in the analysis (age 67 [34-88] years). A Cox proportional hazard model was used to
determine variables significantly associated with mortality. Based on the VO_2peak estimated using the 1k-TWT, the sample was subdivided into tertiles, and mortality
risk was calculated. The discriminatory accuracy of VO_2peak in estimating survival was assessed by receiver-operating-characteristic (ROC) 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 VO_2peak 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 to the lowest group, hazard
ratios (95% confidence intervals) 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 VO_2peak levels were associated with a lower risk of all-cause mortality. The indirect estimation
of VO_2peak using the 1k-TWT is feasible and can be applied for risk stratification among female
patients undergoing secondary prevention programs.