Exercise Test Predicts Both Noncardiovascular and Cardiovascular Death in a Primary Prevention Population.

OBJECTIVE: To identify specific causes of death and determine the prevalence of noncardiovascular (non-CV) deaths in an exercise test referral population while testing whether exercise test parameters predict non-CV as well as CV deaths. PATIENTS AND METHODS: Non-imaging exercise tests on patients 30 to 79 years of age from September 1993 to December 2010 were reviewed. Patients with baseline CV diseases and non-Minnesota residents were excluded. Mortality through January 2016 was obtained through Mayo Clinic Records and the Minnesota Death Index. Exercise test abnormalities included low functional aerobic capacity (ie, less than 80%), heart rate recovery (ie, less than 13 beats/min), low chronotropic index (ie, less than 0.8), and abnormal exercise electrocardiogram (ECG) of greater than or equal to 1.0 mm ST depression or elevation. We also combined these four abnormalities into a composite exercise test score (EX_SCORE). Statistical analyses consisted of Cox regression adjusted for age, sex, diabetes, hypertension, obesity, current and past smoking, and heart rate-lowering drug. RESULTS: The study identified 13,382 patients (females: n=4736, 35.4%, 50.5±10.5 years of age). During 12.7±5.0 years of follow-up, there were 849 deaths (6.3%); of these 162 (19.1%) were from CV; 687 (80.9%) were non-CV. Hazard ratios for non-CV death were significant for low functional aerobic capacity (HR, 1.42; 95% CI, 1.19 to 1.69; P<.0001), abnormal heart rate recovery (HR, 1.36; 95% CI, 1.15 to 1.61; P<.0033), and low chronotropic index (HR, 1.49; 95% CI, 1.26 to 1.77; P<.0001), whereas abnormal exercise ECG was not significant. All exercise test abnormalities including EX_SCORE were more strongly associated with CV death versus non-CV death except abnormal exercise ECG. CONCLUSION: Non-CV deaths predominated in this primary prevention cohort. Exercise test abnormalities not only predicted CV death but also non-CV death.

Effect of Cardiorespiratory Fitness on Co-Morbidities and Mortality in Never, Past, and Current Smokers.

Smoking is a strong risk factor for cardiovascular (CV) disease and mortality, but quitting may cause weight gain and increase the risk of co-morbidities. Our aim was to investigate the effect of smoking and exercise on weight-associated co-morbidities and mortality. We included Minnesota residents without baseline CV disease who underwent exercise testing from 1993 to 2010. Mortality was determined from Mayo Clinic records and Minnesota Death Index. Total, CV and cancer mortality by smoking status and cardiorespiratory fitness (CRF): (1) <80%, (2) 80% to 99%, (3) ≥100%. Differences were tested using logistic and Cox regression adjusting for age and gender. A total of 21,981 patients (7,090 past, 2,464 current smokers) were included. Past smokers had more obesity, hypertension, diabetes, and low CRF compared with never smokers. Current smokers did not show increased risk factor prevalence compared with never smokers but had higher rates of low CRF. There were 1,749 deaths; mean follow-up was 12 ± 5 years. Mortality was only slightly increased in past versus never smokers (Hazard Ratio: 1.2; 95% confidence interval 1.12 to 1.38) but was much higher in current smokers (Hazard Ratio 2.4; 95% confidence interval 2.05 to 2.80). Mortality in never, past, and current smokers was inversely related to CRF level. In conclusion, past smokers showed higher rates of co-morbidities and low CRF, but mortality was only mildly increased versus never smokers, whereas current smokers carried a high mortality risk. Our data suggest that quitting smoking is beneficial despite the increased co-morbidities. Exercise may potentially mitigate the risk of co-morbidities and death in those who quit smoking.