Impact of Neighborhood Factors on Exercise Capacity in Children With Hypertrophic Cardiomyopathy.

Background: Restricting certain patients with hypertrophic cardiomyopathy (HCM) from exercise likely has negative cardiovascular effects and has not been shown to reduce the risk of sudden cardiac death. Promoting exercise in children with HCM is complex and requires knowledge of the environmental factors that impact exercise capacity in children with HCM.

Methods: This retrospective, cross-sectional analysis includes children with HCM who underwent exercise stress testing at a single, children's tertiary-care center between 2000 and 2023. Addresses from contemporaneous exercise stress testing were accessed and geocoded to census tracts. The child opportunity index was the primary exposure of interest. Granular neighborhood measures including the walkability index, rural-urban commuting area codes, index of concentration at the extremes, and uniform crime reporting rates were measured. The primary outcome measure was peak oxygen consumption. Linear regression and multivariable analyses were performed.

Results: A total of 155 patients were identified who met inclusion criteria, 23% (n=35) of whom were female. The mean age at the time of exercise stress testing was 15.8±3.1 years. More than half of the included patients were from a high or very high child opportunity index (30%, n=46, and 35%, n=54, respectively). Most patients lived in urban environments (rural-urban commuting area codes score, 1 or 2, 96.7%, n=150). The mean peak oxygen consumption was 2159±906 mm/min, and the adjusted peak oxygen consumption was 35.5±9.3 mL/kg per min. A multivariate model adjusting for disease severity, age at diagnosis of HCM, race, and accounting for collinearity showed that low child opportunity index, higher levels of urbanization, and lower concentration of neighborhood wealth were independently associated with lower peak oxygen consumption.

Conclusions: Our study identified previously unrecognized environmental determinants of exercise capacity in children with HCM, with lower child opportunity index, increased urbanization, and lower neighborhood wealth independently associated with lower exercise performance. Programs designed to increase physical activity levels and exercise performance in children with HCM should account for neighborhood and economic factors.