Prognostic Value and Clinical Usefulness of the Hemodynamic Gain Index in Men

Although hemodynamic responses to exercise have been studied for decades, comprehensive and definitive prognostic markers are lacking. The present study aimed to assess the association between a new hemodynamic index and all-cause mortality in men. Treadmill exercise testing was performed between 1987 and 2012 in 11,455 men aged 58.5 ± 11 years who were prospectively followed for 9.8 ± 5.8 years. Heart rate (HR) and systolic blood pressure (SBP) responses were used to develop a hemodynamic gain index (HGI) = [(HRpeak × SBPpeak) - (HRrest × SBPrest)]/(HRrest × SBPrest). Multivariable Cox hazard models adjusted for established cardiometabolic diseases, risk factors, cardiorespiratory fitness, and medications were analyzed for HGI and all-cause mortality. During the follow-up, 2,804 participants (24.5%) died, and mean HGI was 1.68 ± 0.83 bpm/mm Hg. In a continuous model, every 1 unit higher in HGI was associated with a 23% (hazard ratio 0.77, 95% confidence interval 0.71-0.82, p <0.001) reduced risk of mortality. In a categorical model, compared with participants <25th percentile (HGI <1.1), participants who were between the 25th and 50th (HGI 1.1-1.59), 50th to 75th (HGI 1.6-2.1) and >75th percentile (HGI >2.1) exhibited 12%, 24%, and 36% reductions in mortality risk (p trend <0.001), respectively. The inverse association between HGI and death was significant across wide-range of age groups and among participants with varied chronic conditions. In conclusion, these novel findings indicate that higher HGI is inversely and independently associated with lower risk of all-cause mortality in men, suggesting its potential prognostic value for risk stratification in clinical and research settings.