June 23, 2023

Study of Medicare Population Demonstrates Racial and Ethnic Disparities in Aortic Stenosis Management and Outcomes

June 23, 2023—Trends in the role of race and ethnicity in the diagnosis, treatment, and outcomes of aortic stenosis (AS) among Medicare beneficiaries were analyzed in a recent study by Ahmed et al in PLOS One.

KEY FINDINGS

In a population-based cohort of Medicare beneficiaries, racial and ethnic minorities had significantly lower rates of AS diagnosis.
Evaluation by a cardiothoracic surgeon and SAVR/TAVR rates were lower for minority populations.
All-cause hospitalization, heart failure hospitalization, and 1-year mortality were higher for Black patients compared to White patients.

The population-based cohort study included a nationally representative sample of 1,513,455 Medicare beneficiaries aged ≥ 65 years who were diagnosed with aortic stenosis (AS) between 2010 and 2018. Among the representative sample of beneficiaries with AS, 91.3% were White, 4.5% were Black, 1.1% were Hispanic, and 3.1% were Asian and North American Native.

Evaluated outcomes included AS management (number of cardiology, interventional cardiology, and cardiothoracic surgery evaluation and management [E&M] visits and number of transthoracic echocardiograms [TTE] performed), procedural interventions within 1 year of diagnosis (surgical or transcatheter aortic valve replacement [SAVR/TAVR]), and outcomes of AS management (number of all-cause hospitalizations, heart failure hospitalizations, and mortality within 1 year of diagnosis).

Poisson regression models were used to test prevalence and incidence trends, examine the risks of prevalence and incidence for race groups, and, individually, to test trends by race group and provide incidence rate ratios for the evaluated outcomes.

In the overall group, both the incidence and prevalence of AS increased from 13.5 to 17.0 per 1,000 beneficiaries and 33.5 to 40.0 per 1,000 beneficiaries, respectively, between 2010 and 2018 (both P < .001). Throughout the study period, racial and ethnic minorities had lower AS incidence and prevalence/diagnosis rates compared with White patients, and this persisted after adjusting for age and sex. Adjusted incidence rate ratios (aIRR) for AS prevalence were between 0.62 (95% CI, 0.60-0.63) to 0.66 (95% CI, 0.65-0.68) for Black patients, 0.71 (95% CI, 0.67-0.74) to 0.67 (95% CI, 0.64-0.70) for Hispanic patients, and 0.73 (95% CI, 0.71-0.76) to 0.75 (95% CI, 0.73-0.77) for Asian and North American Native patients (all P < .001).

After an AS diagnosis, cardiologist visits were comparable across all groups, except for Asian and North American Native patients (aIRR, 0.91; 95% CI, 0.88-0.93; P < .0001). However, Black, Hispanic, and Asian/North American Native patients populations experienced lower rates of evaluation by a cardiothoracic surgeon (aIRR, respectively: 1.00 [0.98, 1.02], P = 0.9; 1.18 [1.14, 1.23], P < .0001; and 1.02 (0.99, 1.04), P = .21). Rates were also lower for SAVR and TAVR for these patient populations (Black patients: aIRR, 0.62; 95% CI, 0.59-0.66; P < .0001 and 0.64; 95% CI, 0.58-0.72; P < .0001; Hispanic patients: aIRR, 0.85; 95% CI, 0.76-0.95; P = .0051 and 0.62; 0.51-0.77; P < .0001; Asian/North American Native patients: aIRR, 0.64; 95% CI, 0.59-0.69; P < .0001 and 0.71; 95% CI, 0.63-0.8; P < .0001).

Regarding outcomes, all-cause hospitalizations, HF hospitalizations, and 1-year mortality were higher for Black patients as compared with White patients (IRR, respectively, 1.19 [95% CI, 1.17-1.21]; P < .0001; 1.32 [95% CI, 1.29-1.35]. P < .0001; and 1.06 [95% CI, 1.03-1.08], P < .0001).

Investigators concluded that although the etiology of these findings is not certain, there is still a clear need to evaluate the driving factors that are leading to these differences in diagnosis, management, and outcomes in order to adequately and equitably address AS across all demographics.

CARDIAC INTERVENTIONS TODAY ASKS…

We spoke with Dr. Michael P. Thompson of University of Michigan in Ann Arbor, Michigan, to provide further context to this study and insight into possible next steps to addressing these disparities.

Your study confirmed that there was a lower share of AS diagnoses among racial/ethnic minorities. How would you summarize what we do and don’t know regarding the reasons for this finding?

The results of our study reveal that racial/ethnic minorities exhibit lower rates of documented diagnoses for AS, a crucial factor in managing and referring patients for advanced therapies. This discrepancy in documented diagnoses places minority patients at risk of treatment delays or even denial—a disparity not experienced by White patients. What remains uncertain is whether minority patients genuinely have lower disease rates or if the findings stem from systemic challenges in diagnosing minority individuals. Nevertheless, the extensive body of literature showcasing racial/ethnic disparities in health care access across various clinical contexts strongly suggests that systemic barriers likely account for this disparity.

An important component of the evaluation was the number of E&M visits, broken down by cardiology, interventional cardiology, and cardiothoracic surgery. How does the number of visits relate to treatment/outcomes, and what are the factors that determine whether the patient is seen by a specialist and who they visit?

In our study, we discovered that Black and White patients diagnosed with AS had similar rates of evaluation by cardiologists and interventional cardiologists. However, we did observe a notable difference: Black patients were less likely to be evaluated by a cardiothoracic surgeon, which is a critical step in the process of receiving an aortic valve replacement. This discrepancy could be due to several factors, such as Black patients having a lower prevalence of symptomatic AS or encountering systemic barriers that hinder their access to care, similar to those faced by other racial/ethnic minorities.

Combining the study’s findings regarding the lower AS diagnosis rates among racial/ethnic minorities and their decreased likelihood of being evaluated by a cardiothoracic surgeon, it appears that these individuals may face a “double-hit” when it comes to receiving life-altering valve replacement procedures. This hypothesis gains strength from our data, which indicate that SAVR/TAVR is far less common among racial/ethnic minority patients.

What is your prediction for why all-cause and heart failure hospitalizations were higher for certain populations?

The reasons behind the poorer outcomes observed among racial/ethnic minority patients are likely multifaceted. Based on our study findings, the most apparent explanation would be that these patients may have a higher likelihood of experiencing persistent AS symptoms without receiving the necessary corrective therapy. Additionally, it is probable that racial/ethnic minorities encounter other challenges not faced by their White counterparts. Our study revealed that racial/ethnic minority patients had higher rates of comorbidities associated with AS, as well as broader health issues. These factors may contribute to an increased risk of hospitalization and death. Furthermore, they may face social determinants that adversely affect their overall health that were not accounted for in our study. Overall, it is evident that various factors, including delayed or inadequate therapy for AS symptoms, a higher burden of comorbidities, or social determinants of health could contribute to the worse outcomes experienced by racial/ethnic minority patients.

What are the next steps required to address the identified disparities? How does the approach to AS need to change, for minorities and for all patients?

Our study highlights the numerous challenges faced by racial/ethnic minority patients with AS. It is evident that concerted efforts are necessary to address these challenges and ensure appropriate diagnosis and care for these individuals, particularly in the context of procedural therapies. Implementing implicit bias training could serve as a valuable tool in mitigating the barriers encountered by racial/ethnic minority patients within the health care system.

Furthermore, further research is essential to gain a deeper understanding of the underlying factors contributing to the observed disparities in the diagnosis and management of AS. This additional research will provide valuable insights and inform targeted strategies to reduce these disparities and improve the overall healthcare outcomes for racial/ethnic minority patients with AS.

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