Health Disparities in Exercise Performance in Patients with Repaired Tetralogy of Fallot

Abstract

Black patients with tetralogy of Fallot (TOF) have higher mortality than White patients. Health disparities related to other patient-important outcomes, such as exercise performance, have not been studied in this population. We aimed to determine if there are racial disparities related to exercise performance in patients with TOF and to investigate possible mediators of those disparities. We conducted a retrospective single center study of patients aged 8-25 years with repaired TOF who completed maximal cardiorespiratory exercise tests between 2007 and 2020. The primary outcome was percent predicted oxygen consumption at peak exercise. We used linear regression to determine if race was associated with exercise performance. We used mediation analysis to investigate insurance coverage and neighborhood Child Opportunity Index as possible mediators of this relationship. The study cohort included 163 patients with TOF (136 non-Hispanic/Latinx White and 27 non-Hispanic/Latinx Black). In multivariable analysis, Black patients had a lower percent predicted peak oxygen consumption than White patients by 6.71 percentage points (95% CI - 12.71, - 0.70; p = 0.029). Mediation analysis revealed that the indirect effect of race through insurance coverage accounted for 34.1% of the decrease in exercise performance. Child Opportunity Index was not a statistically significant mediator. Black patients with TOF had worse exercise performance than White patients. Differences in insurance coverage accounted for a significant portion of this difference. Exercise performance is an important outcome for patients with TOF, and further investigation is needed to better understand this disparity and develop interventions to address it.

Keywords: Cardiopulmonary exercise testing; Child opportunity index; Congenital heart disease; Pediatric cardiology; Social determinants of health; Tetralogy of Fallot.

Fig. 1

Conceptual model of causal pathways between membership in a marginalized racial group (i.e., Black) and exercise performance. Historical and ongoing structural and institutional racism, in addition to personally mediated racism, contribute to current socioeconomic disparities. Socioeconomic disparities, in turn contribute to health outcomes such as exercise performance through pathways including access to healthcare and differential adverse social and environmental exposures. This is consistent with existing health disparities models, which view social and environmental factors, including differential health coverage, as playing a role in racial health disparities

Fig. 2

Conceptual model of mediation analysis. Mediation analysis decomposes the total effect of a predictor (independent variable) on the outcome (dependent variable) into the direct effect and an indirect effect through a mediator. We hypothesized that race is associated with exercise performance in patients with repaired TOF and SES mediates this association

Fig. 3

Mediation results. Total, direct, and indirect effect of non-Hispanic/Latinx Black race vs. non-Hispanic/Latinx White race on percent predicted VO₂ at peak exercise with insurance coverage as a mediator. As a mediator, insurance coverage accounts for 34.1% of the total effect of race on percent predicted peak VO₂ (p = 0.035)