Equal Treatment, Unequal Outcomes? Debunking the Racial Disparity in Renin Angiotensin Aldosterone System Inhibitor Associated Reduction in Heart Failure Hospitalizations.

Background: Renin angiotensin aldosterone system inhibitors (RAASi) are a mainstay treatment in patients with heart failure with reduced ejection fraction (HFrEF) in part to prevent hospitalizations. However, whether RAAS inhibitors reduce the risk of hospitalization in Black patients is not entirely clear because enrollment of Black patients in previous clinical trials was low, and a previous meta-analysis showed a significant racial disparity: reduction in hospitalizations with an RAAS inhibitor in White patients but not Black patients. Previous studies relied on the use of self-identified race instead of genomic ancestry. Therefore, this study aimed to investigate the role of self-identified race and genomic ancestry in the racial disparity in RAAS inhibitor associated reductions in HFrEF hospitalizations.

Methods: The primary outcome was time to first heart failure hospitalization. A (de-identified) heart failure patient registry and data from the GUIDE-IT multi-center randomized control trial were analyzed with Cox proportional hazards models un/adjusted for clinical risk factors, death as a competing risk, and time-varying RAAS inhibitor exposure. The proportion of Yoruba African ancestry was quantified.. Analysis of self - identified race were performed in both the registry and GUIDE-IT. Analysis of genomic ancestry was only performed in the registry since this information was not available in GUIDE-IT. A fixed effect meta-analysis combined results of both the registry and GUIDE-IT for race.

Results: The registry had 1010 total HFrEF patients (Black = 509 and White = 501) with 852 having ancestry quantification (>80% Yoruba African Ancestry = 381 and <5% Yoruba African Ancestry = 471). GUIDE-IT had 810 HFrEF patients (Black = 322 and White = 488). There was no significant difference in the association of RAAS inhibitor exposure with heart failure hospitalization by race (meta-analysis p-value for race*RAAS inhibitor exposure interaction = 0.49; Black patients HR [95% CI] for RAAS inhibitor exposure = 0.89 [0.64-1.23)] P = 0.47; White patients = 1.20 (0.83-1.75) P = 0.34). Results were similar when analyzed by ancestry (p-value for ancestry*RAAS inhibitor exposure interaction = 0.57; >80% Yoruba African Ancestry = 0.93 [0.51-1.69] P = 0.80; <5% Yoruba African Ancestry = 1.29 [0.57-2.92] P = 0.54).

Conclusions: In contrast to a previous meta-analysis, this more contemporary analysis of 2 HFrEF patient datasets demonstrates the absence of a racial disparity in RAAS inhibitor associated reductions in heart failure hospitalizations. The difference in this racial disparity over time may be due to improvements in background heart failure therapies, racial differences in healthcare usage, and the use of more advanced statistical approaches.