COVID-19 AND MORTALITY IN HYPERTENSIVE PATIENTS ACCORDING TO CARDIORESPIRATORY FITNESS

Abstract

Objective: COVID-19 mortality risk increases with the presence of underlying comorbidities, including hypertension. Epidemiologic evidence also suggests an inverse association between self-reported physical activity and COVID-19 cases and deaths. However, no information exists regarding the association between cardiorespiratory fitness (CRF) assessed objectively by a standardized exercise treadmill test (ETT) and mortality in hypertensive patients. We assessed the hypothesis that CRF is inversely and independently associated with COVID-19 mortality risk in non-vaccinated hypertensive patients Design and method: From 2020 to 2021, we identified 17,358 hypertensive patients (mean age: 60.3 ± 8.2 years) with a normal response to an exercise tolerance test (ETT), prior to COVID-19. We established five CRF categories based on age-stratified quintiles of peak metabolic equivalents (MET) achieved: Least-Fit (4.7 ± 1.2 METs; n = 3,486); Low-Fit (7.1 ± 1.3; n = 4,616); Moderate-Fit (8.4 ± 1.3 METs; n = 3,320); Fit (10.3 ± 0.9 METs; n = 4,084); and High-Fit (12.8 ± 1.6 METs; n = 1,852). Multivariable Cox proportional hazard models were constructed to estimate hazard ratios (HR) and 95% confidence intervals [CI] for mortality across CRF categories. The models were adjusted for age, gender, race, comorbidities, medications, hospitalization, intubation, and time elapsed between ETT and COVID-19. The Least-Fit category was used as the reference group. Results: Results: During the follow-up of 100 days, 1,853 individuals died (10.7%). The risk for death was 7% lower for each 1-MET increase in exercise capacity (HR = 0.93, CI: 0.92-0.95; p < 0.001). The risk across fitness categories declined progressively with increased CRF and was 26% lower for the Least-Fit individuals (HR = 0.74; CI: 0.66 - 0.84), approximately 30% to 40% lower for Moderate-Fit and Fit, and 50% lower (HR = 0.50; CI: 0.41 - 0.62; p < 0.001) for High-Fit patients. Conclusions: Increased CRF was inversely related to COVID-19 mortality risk in hypertensive patients. The association was graded and independent of comorbidities.