Cardiorespiratory fitness change linked to survival in patients with or without CVD

Changes in cardiorespiratory fitness (CRF) appear to predict the risk of mortality in patients with and without cardiovascular disease (CVD), suggest the results of a study.

A total of 93,060 individuals aged 30‒95 years participated in this study, all of whom completed two symptom-limited exercise treadmill tests, ≥1 years apart with no evidence of overt CVD.

The investigators then assigned the participants to age-specific fitness quartiles based on peak metabolic equivalent (MET) achieved on the baseline exercise treadmill test. They also stratified each CRF quartile based on CRF changes (increase, decrease, or change) seen on the final exercise treadmill test. Finally, hazard ratios (HRs) were estimated using multivariable Cox models.

Of the participants, 18,302 died during a median follow-up of 6.3 years (average annual mortality rate, 27.6 events per 1,000 person-years).

Changes in CRF ≥1.0 MET significantly correlated with inverse and proportionate changes in mortality risk, irrespective of baseline CRF status. Specifically, a CRF decline of >2.0 METS resulted in a 74-percent increase in mortality risk (HR, 1.74, 95 percent confidence interval [CI], 1.59‒1.91) for low-fit individuals with CVD and a 69-percent increase (HR, 1.69, 95 percent CI, 1.45‒1.96) for those without CVD.

“Changes in CRF reflected inverse and proportional changes in mortality risk for those with and without CVD,” the investigators said. “The impact of relatively small CRF changes on mortality risk has considerable clinical and public health significance.”