Race, exercise training, and outcomes in chronic heart failure: Findings from Heart Failure - A Controlled Trial Investigating Outcomes in Exercise TraiNing (HF-ACTION)

Abstract

Background The strength of race as an independent predictor of long-term outcomes in a contemporary chronic heart failure (HF) population and its association with exercise training response have not been well established. We aimed to investigate the association between race and outcomes and to explore interactions with exercise training in patients with ambulatory HF. Methods We performed an analysis of HF-ACTION, which randomized 2331 patients with HF having an ejection fraction ≤35% to usual care with or without exercise training. We examined characteristics and outcomes (mortality/hospitalization, mortality, and cardiovascular mortality/HF hospitalization) by race using adjusted Cox models and explored an interaction with exercise training. Results There were 749 self-identified black patients (33%). Blacks were younger with significantly more hypertension and diabetes, less ischemic etiology, and lower socioeconomic status versus whites. Blacks had shorter 6-minute walk distance and lower peak VO2 at baseline. Over a median follow-up of 2.5 years, black race was associated with increased risk for all outcomes except mortality. After multivariable adjustment, black race was associated with increased mortality/hospitalization (hazard ratio [HR] 1.16, 95% CI 1.01–1.33) and cardiovascular mortality/HF hospitalization (HR 1.46, 95% CI 1.20–1.77). The hazard associated with black race was largely caused by increased HF hospitalization (HR 1.58, 95% CI 1.27–1.96), given similar cardiovascular mortality. There was no interaction between race and exercise training on outcomes (P >.5). Conclusions Black race in patients with chronic HF was associated with increased prevalence of modifiable risk factors, lower exercise performance, and increased HF hospitalization, but not increased mortality or a differential response to exercise training.

Ventricular Conduction and Long-Term Heart Failure Outcomes and Mortality in African Americans

“…21 We found that the vast majority of Jackson Heart Study participants with QRS prolongation had a QRS duration of 100 to 119 msec (ie, 89% of prolongation cases). These findings support previous research suggesting important differences in ventricular conduction by race 10,22,23 and highlight the high prevalence of mild QRS prolongation in African Americans. Genetic differences may explain, in part, these racial differences in QRS duration.…”

“…3,8 Racial differences in ventricular conduction have been identified in the general population and among patients with cardiac disease. 9,10 However, associations between QRS duration and clinical outcomes in African Americans have not been well characterized. The availability of electrocardiogram information on more than 5000 African American participants in the Jackson Heart Study allows a comprehensive investigation of the relationship between QRS duration and mortality in this population.…”

Clinical Implications of Chronic Heart Failure Phenotypes Defined by Cluster Analysis

“…Lastly, it appears that the highest rates of rehospitalization in these patients occurred despite their objective measures of milder HF; this implies that therapies aimed at improving disease state alone would not decrease these patients’ rehospitalization rates. Rather, a focused effort on understanding the global reasons for rehospitalization might result in more effective preventive methods (31,32). …”

Statins and Exercise Training Response in Heart Failure Patients

“…The primary outcomes for the present analysis were change in peak VO 2 and change in KCCQ from baseline to 3 months, as in previous HF-ACTION analyses, because of the increased missingness at later time points (15,16). The secondary outcome was change in 6MWD from baseline to 3 months.…”

“…To account for the missing data at 3 months for the outcomes of interest, inverse weighting for missingness was performed. Specifically, subjects in the regression model were weighted by the inverse of their probability of having a nonmissing response similar to recent analyses in HF-ACTION (15,16). This should reduce the bias that would have been present in a complete case analysis by assigning higher weight to observed data subjects who were similar to subjects who were more likely to have missing data (15).…”