Race and Sex Differences Seen in ICD Use for Hypertrophic Cardiomyopathy

Among patients hospitalized with hypertrophic cardiomyopathy (HCM), implantable cardioverter-defibrillator (ICD) devices are underused in women and racial minorities, regardless of demographics, hospital characteristics, and comorbidities, according to research published in Mayo Clinic Proceedings. 

Individuals with HCM can be at an increased risk of sudden cardiac death (SCD), while use of ICDs can help alleviate this risk, authors explained. “Implantation of an ICD for primary prevention of SCD in HCM patients is based on risk stratification using various clinical parameters, and the current HCM guidelines recommend ICD implantation in individuals with recognized risk markers or modifiers for SCD,” they added.

However, few data exist on the demographic trends in ICD use for this population across the United States, and past studies have revealed racial and sex disparities in ICD use in patients with heart failure.

To address this knowledge gap, the researchers assessed data from the National Inpatient Sample, a large, representative, all payer-administrative database. Data represent a 20% stratified sample of inpatient hospitalizations, and all individuals with a primary diagnosis of HCM recorded between January 2003 and December 2014 were included in the current analysis.

Within the study window, 23,535 adults were hospitalized with HCM, while 3954 (16.8%) underwent ICD implantations; the authors found an overall increasing trend in ICD use (11.6% in 2003 to 17% in 2014; P<.001).

Analyses revealed:

• Compared with admissions not receiving an ICD, those receiving an ICD had shorter median lengths of in-hospital stay but higher hospitalization costs (P<.001)
• Compared with men and White race, female sex (odds ratio [OR], 0.72; 95% CI, 0.66-0.78; P<.001) and being a racial minority (OR, 0.87; 95% CI, 0.79-0.96; P<.001) were associated with lower adjusted odds of receiving an ICD
• Women and racial minority hospitalizations had higher rates of device-related complications, longer lengths of in-hospital stay, and higher hospitalization costs compared with men and White race, respectively (all P<.01)

In this cohort, racial minority individuals exhibited a higher prevalence of hypertension, renal disease, and atrial fibrillation, while presence of any comorbidity or a higher comorbidity index score were linked with lower rates of ICD use.

Furthermore, “compared with hospitals in the Northeast, HCM admissions receiving care in the Midwest, South, and West were less likely to receive an ICD during hospitalization,” the researchers wrote.

When it comes to the sex differences observed in the current study, the authors hypothesized they could be a result of the fact that women often present with more advanced disease at older ages than men. The disparity could also be due to patient preference or additional socioeconomic or clinical factors.

With regard to race, previous research has shown younger Black individuals have increased rates of HCM-related SCD, largely attributable to underdiagnosis of HCM in this population and underreferral for effective therapies. Differential access to care and potential provider bias could also impact this finding.

In the current study “race-specific differences were not observed in ICD use for secondary prevention potentially due to adherence to guideline recommendations for managing patients with ventricular arrhythmias,” the authors added.

Potential device-related complications also need to be taken into account when weighing ICD use, as nearly 15% of patients who undergo the procedure have complications.

Results observed in the current study could have been impacted by residual confounders, marking a limitation.

“We believe this study provides important insights into the nonuniform use of ICD among HCM hospitalizations and can serve as a step for further investigations using robust clinical data,” the researchers concluded.

Reference

Patlolla SH, Schaff HV, Nishimura RA, Geske JB, Dunlay SM, Ommen SR. Sex and race disparities in hypertrophic cardiomyopathy. Mayo Clin Proc. Published online December 7, 2021. doi:10.1016/j.mayocp.2021.07.022