CARDIORESPIRATORY FITNESS AND STROKE INCIDENCE IN HYPERTENSIVE PATIENTS

Abstract

Objective: Stroke incidence is significantly higher in hypertensive patients compared to normotensive subjects. Cardiorespiratory fitness (CRF) is associated with a more favorable cardiovascular health. The CRF-stroke incidence association in hypertensive patients has not been fully explored. Thus, the objective of the current study was to evaluate the association between CRF assessed objectively by a standardized exercise test, and stroke incidence in hypertensive patients. Design and method: From 1999 to 2020, we identified 460,172 hypertensive patients (mean age: 63.1 ± 8.7 years) with a normal response to an exercise treadmill test (ETT) and no prior history of stroke. We established five CRF categories based on age-stratified quintiles of peak metabolic equivalents (MET) achieved: Least-Fit (4.5 ± 1.2 METs; n = 106,620); Low-Fit (6.9 ± 1.1; n = 120,327); Moderate-Fit (8.3 ± 1.2 METs; n = 89,748); Fit (10.3 ± 0.9 METs; n = 107,323); and High-Fit (13.1 ± 1.6 METs; n = 36,154). A multivariable Cox proportional hazards model was constructed to estimate hazard ratios (HR) and 95% confidence intervals [CI] for incidence of stroke across CRF categories. The model was adjusted for age, resting blood pressure, gender, race, coronary artery disease, smoking status, chronic kidney disease, atrial fibrillation, other cardiac risk factors, and medications. The Least-fit category was used as the reference group. Results: During follow-up (median = 10.6 years; 4,955,021 person-years), 11,868 individuals had a stroke (2.4 events per 1,000 person-years). The risk for stroke was 8% lower for each 1-MET increase in exercise capacity (HR = 0.92, CI: 0.91 - 0.93; p < 0.001). The risk across fitness categories, declined progressively with increased CRF and was by 15% for the Least-Fit individuals (HR = 0.85; CI: 0.81 - 0.89), approximately 30% to 40% for Moderate-fit and Fit individuals, and 45% lower (HR = 0.55; CI: 0.50 - 0.60; p < 0.001) for High-Fit individuals. Conclusions: Increased CRF was inversely related to stroke incidence in hypertensive patients. The association was independent and graded. These finding support the concept that health care professional should encourage patients to engage in habitual physical activity of moderate intensity and progressively aim to meet the physical activity guidelines proposed by authorities.