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Validation of prognostic value of the hemodynamic gain index in different groups of patients undergoing exercise
Thanat Chaikijurajai1,2, Yuping Wu3, Justin L Grodin4
1Department of Cardiovascular Medicine, Heart, Vascular and Thoracic Institute, Cleveland Clinic, Cleveland, OH, United States of America.
Insights
The hemodynamic gain index (HGI) predicts mortality across diverse patient groups, including men, women, and those with heart conditions. This validated index also correlates with exercise capacity (METs).
Area of Science:
- Cardiology
- Exercise Physiology
- Predictive Analytics
Background:
- The hemodynamic gain index (HGI) is a novel predictor of all-cause mortality and linked to exercise capacity (METs).
- External validation of HGI's prognostic value across diverse patient subgroups was previously lacking.
Purpose of the Study:
- To externally validate the hemodynamic gain index (HGI) as a predictor of all-cause mortality.
- To assess HGI's prognostic implications in specific subgroups: gender, BMI, heart failure (HF), coronary artery disease (CAD), and beta-blocker use.
Main Methods:
- Analysis of 126,356 patients undergoing treadmill exercise testing (1991-2015).
- Calculation of HGI using peak and resting systolic blood pressure (SBP) and heart rate (HR).
- Cox regression models were employed to assess associations between HGI quartiles and all-cause mortality, adjusting for covariates.
Main Results:
- Lower HGI was independently associated with increased all-cause mortality across the entire cohort (Q1 vs Q4: aHR 1.33 [1.21-1.45], p<0.001).
- This association remained significant in subgroups of men, women, patients with BMI <35 kg/m², and those with/without HF, CAD, or beta-blocker use.
- HGI demonstrated a strong correlation with metabolic equivalents (METs) across all analyzed subgroups.
Conclusions:
- The hemodynamic gain index (HGI) is a robust predictor of long-term mortality.
- HGI's predictive power is independent of traditional cardiovascular risk factors and exercise performance.
- HGI offers valuable prognostic information across a wide spectrum of patient populations.
Background:
Recently, the hemodynamic gain index (HGI) has shown to be a strong independent predictor of all-cause mortality and associated with metabolic equivalents (METs) in a cohort of male patients. However, the prognostic implications of the HGI have never been externally validated with subgroup analyses based on gender, body mass index (BMI) of 35 kg/m2, history of heart failure (HF), coronary artery disease (CAD) and beta-blocker use.
Methods:
We identified 126,356 consecutive patients undergoing treadmill exercise testing between January 1st, 1991 and February 27th, 2015. HGI was calculated using the formula: [(SBPpeak × HRpeak) - (SBPrest × HRrest)] / (SBPrest × HRrest). Cox regression models were used to determine the associations between HGI quartiles and all-cause mortality with adjustment for cardiovascular risk factors and exercise testing parameters.
Results:
Mean age was 53.5 ± 12.6 years. There were 74,724 (59.1 %) male, 5940 (4.7 %) HF, 21,123 (16.7 %) CAD, and 30,568 (24.2 %) beta-blocker-using patients. During the median follow up of 7.1 years, 9929 (7.9 %) died. Median HGI was 1.93 (interquartile range [IQR] 1.40-2.54) bpm/mmHg. After adjustment for the covariates, lower HGI was independently associated with all-cause mortality in the entire cohort (quartile 1 vs 4, adjusted hazard ratio [95 % confidence interval] 1.33 [IQR 1.21-1.45], p < 0.001), and subgroups of men, women, patients with body mass index <35 kg/m2, with and without HF, CAD, and beta-blocker use. The HGI also correlates well with METs in every subgroup.
Conclusions:
The HGI is a strong predictor of long-term mortality independently of traditional cardiovascular risk factors, and exercise performance across patient subgroups.
