Impact of Cardiorespiratory Fitness on Mortality in Black Male Veterans With Resistant Systemic Hypertension

Abstract

Patients with resistant systemic hypertension have poorer outcomes than nonresistant hypertensives. The purpose of this study was to evaluate the association between cardiorespiratory fitness and all-cause mortality in black male Veterans with resistant systemic hypertension. Patients were identified from a cohort undergoing exercise tolerance test at the department of Veterans Affairs Medical Center in Washington, DC. Patients were divided into 4 cardiorespiratory fitness categories based on age-specific peak metabolic equivalents achieved on a standard Bruce protocol. Multivariate Cox models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause mortality across all fitness categories. A total of 1,276 patients out of 9,068 hypertensives had resistant hypertension defined as systolic and/or diastolic blood pressure >140 and/or >90 mm Hg, respectively, on 3 antihypertensive medications, one of which was a diuretic or use of >4 antihypertensive medications. During a follow-up of 9.5 ± 4.2 years, an inverse association was observed between cardiorespiratory fitness and all-cause mortality in patients with resistant hypertension. Compared with the least-fit group, mortality was reduced by 21% in the low-fit group (HR 0.79, CI 0.60 to 1.05; p value: 0.280), 36% in the moderate-fit group (HR 0.64, CI 0.48 to 0.87; p value 0.001), and 62% in the high-fit group (HR 0.38, CI 0.25 to 0.56; p value <0.001). In conclusion, an inverse association was observed between the level of cardiorespiratory fitness and all-cause mortality in patients with resistant systemic hypertension. Compared with the least-fit referent group, the high-fit group had a significant 62% lower risk of all-cause mortality.