Cardiorespiratory Fitness Change and Mortality Risk Among Black and White Patients: Henry Ford Exercise Testing (FIT) Project.

BACKGROUND

Little is known about the relationship of change in cardiorespiratory fitness and mortality risk in Black patients. This study assessed change in cardiorespiratory fitness and its association with all-cause mortality risk in Black and White patients.

METHODS

This is a retrospective, longitudinal, observational cohort study of 13,345 patients (age = 55 ± 11 years; 39% women; 26% black) who completed 2 exercise tests, at least 12 months apart at Henry Ford Hospital, Detroit, Mich. All-cause mortality was identified through April 2013. Data were analyzed in 2015-2016 using Cox regression to calculate hazard ratios (HR) for risk of mortality associated with change in sex-specific cardiorespiratory fitness.

RESULTS

Mean time between the tests was 3.4 years (interquartile range 1.9-5.6 years). During 9.1 years (interquartile range 6.3-11.6 years) of follow-up, there were 1931 (14%) deaths (16.5% black, 13.7% white). For both races, change in fitness from Low to the Intermediate/High category resulted in a significant reduction of death risk (HR 0.65 [95% confidence interval (CI), 0.49-0.87] for Black; HR 0.41 [95% CI, 0.34-0.51] for White). Each 1-metabolic-equivalent-of-task increase was associated with a reduced mortality risk in black (HR 0.84 [95% CI, 0.81-0.89]) and white (HR 0.87 [95% CI, 0.82-0.86]) patients. There was no interaction by race.

CONCLUSIONS

Among black and white patients, change in cardiorespiratory fitness from Low to Intermediate/High fitness was associated with a 35% and 59% lower risk of all-cause mortality, respectively.