Transcatheter aortic valve replacement (TAVR) emerged as alternative to surgical replacement for patients with severe aortic stenosis [1,2,3]. However, little is known about ethnic and gender disparities for TAVR procedures in the United States. This study aimed to evaluate the temporal changes in the uptake of TAVR procedures among the major ethnic groups.

Using the Nationwide Inpatient Sample (NIS) database years 2011–2014, we identified patients who underwent TAVR procedures using International Classification of Diseases procedure code-9; (trans-femoral 35.05 and trans-apical 35.06). Using linear logistic regression analysis, we described the temporal trends in number of TAVR procedures and mortality among various ethnicities and genders. Effect sizes were expressed using co-efficient of regression. Multivariable regression analysis was conducted to compare in-hospital mortality among different study groups. The model included the following variables: age, hypertension, diabetes mellitus, congestive heart failure, chronic lung disease, chronic kidney disease (CKD), obesity, anemia, hypothyroidism, liver disease, fluid/electrolytes abnormalities, peripheral vascular disease, pulmonary circulation disorders, smokers, history of PCI, history of coronary artery bypass grafting, prior MI, and access route for TAVR.

From 2011 to 2014, 42,189 records underwent TAVR. After excluding records with missing data regarding ethnicity (2936), the final cohort included 39,253 records; 20,497 (52.2%) were men and 18,756 (47.8%) were women. Among all TAVRs, 34,229 (87.2%) were Caucasians, 1527 (3.9%) were African Americans (AA), 1471 (3.7%) were Hispanics and 2027 (5.2%) were of other ethnicities. Among Caucasians, 18,023 (52.7%) were men and 16,206 (47.3%) were women, among AA ethnicity 589 (38.6%) were men and 937 (61.4%) were women, while among Hispanics 825 (56.1%) were men and 646 (43.9%) were women. Baseline characteristics for different study groups are outlined in Table 1.

Table 1 Baseline characteristics among different study groups
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From 2011 to 2014, there was an increase in TAVRs in Caucasian men from 493 in the 2011 quarter (q)4 to 2470 in 2014-q4 with a significant change of trend (coefficient = 0.946, p < 0.001), and in Caucasian women from 381 in 2011-q4 to 2280 in 2014-q4 (coefficient = 0.985, p < 0.001). Among AA men, TAVRs increased from 11 in 2011-q4 to 85 in 2014-q4 (coefficient = 0.940, p < 0.001), and in AA women TAVRs increased from 37 in 2011-q4 to 140 in 2014-q4 (coefficient = 0.864, p < 0.001). In Hispanic men, there was an increase in TAVRs from 11 in 2011-q4 to 100 in 2014-q4 (coefficient = 0.812, p = 0.001), while in Hispanic women, TAVRs increased from 11 in 2011-q4 to 90 in 2014-q4 (coefficient = 0.845, p < 0.001) (Fig. 1). Hence, the uptrend was most significant among Caucasian women, and relatively least significant among Hispanic men.

Fig. 1
figure 1

Trends in number of TAVR procedures and the rate of in-hospital mortality among Caucasians, African Americans, and Hispanics

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Multivariate regression analysis was conducted to evaluate in-hospital mortality among different groups after adjusting for demographics and baseline characteristics. Overall, the in-hospital mortality per 100 TAVRs was highest among Hispanic men 5.5% (45/825), followed by Caucasian women 5.0% (804/15,402), Hispanic women 4.6% (30/646), AA women 3.7% (35/937), AA men 3.40% (20/589), and Caucasian men 3.38% (610/18,023) (adjusted p value = 0.004). Temporal changes in the in-hospital mortality among different groups are outlined in Fig. 1. Overall, there was no significant change in the trends, despite some numerical differences along the years.

In this observational study, we demonstrated that there is evidence of ethnic and gender differences in the overall uptake of TAVRs in the US. According to the United States Census Bureau, AA and Hispanics represent 13% and 17.1% of the general population, respectively [5]. However, in our study, they only represented 3.9% and 3.7% of the TAVR procedures, respectively. We have demonstrated a significant uptrend in the number of TAVRs in all groups, which was most significant in Caucasian women, and least in Hispanic men. Data from the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy (TVT) have reported ethnic differences in the uptake of TAVRs in the United States [4]. In their report including 26,378 TAVRs from 2012 to 2014, the majority were Caucasians (93.8%) and AA represented only 3.8% of all TAVRs [4]. The present study extends our knowledge by examining other ethnicities and evaluating gender differences as well. Further, we demonstrated ethnic and gender disparities in the adjusted in-hospital mortality rate, which was highest among Hispanic men followed by Caucasian women.

The background for ethnic disparities in the uptake of TAVR is multi-factorial. Socio-economic status and insurance coverage play important roles in preventing certain groups from receiving TAVRs. Reports from the United States Census Bureau suggested higher rates of non-insurance among minorities; reaching 10.5% in AA and 16% among Hispanics compared with 6.3% among Caucasians [5]. Cultural differences may also play a role, with reports of higher propensities to refuse invasive treatments among some minorities compared to Caucasians [6]. Importantly, minorities have been underrepresented in major clinical trials and specifically for TAVR [1].

This analysis is limited by the data source, which is an administrative database, and liable to documentation errors. Also, the NIS provides only data related to the index hospitalization, with no available long-term data. Being an observation study, there is always potential for selection bias. However, we attempted to reduce allocation bias by conducting multivariable regression analyses. Useful information, such as medications, laboratory data, as well as type of TAVR valves, was unavailable through this database. Further studies are encouraged to identify barriers for uptake of TAVR by minorities, as well as to better specify ethnic and gender differences in outcomes of TAVR procedures.