Handgrip Strength, Skeletal Muscle Mass, and the Association With Exercise Capacity and Clinical Outcomes in Children and Adults With Congenital Heart Disease

: Introduction Handgrip strength (HGS) is an understudied assessment of skeletal muscle strength in patients with congenital heart disease (CHD). Our aim is to investigate the relationship between HGS and body composition, diagnostic subtype, cardiopulmonary fitness, and clinical outcomes in patients with CHD. Methods This single-center retrospective study included patients with complex CHD who underwent testing for HGS, body composition, and cardiopulmonary fitness. Z-scores for HGS (HGZS) were calculated using published normative reference data. Mixed-effects regression models were used to account for repeated measurements, and Kaplan–Meier and Cox proportional hazards analyses were performed to evaluate the association between HGS and a composite outcome of nonelective cardiac hospitalization, unplanned cardiac procedure, or death. Results 751 patients were analyzed (mean age 21.7 years-old; 53.8% male; 33.4% < 18 years-old,). Compared with moderate complexity, patients with great complexity had lower HGS (p=0.006), lower skeletal muscle mass (SMM) (p=0.002), lower percent predicted peak oxygen consumption (VO 2 peak; p<0.001) and experienced the composite outcome more (14.0% vs 3.2%; p<0.001). Patients with higher HGS tertile had higher VO 2 peak (p<0.001). On linear mixed-effects modeling, HGZS and SMM were both strong independent predictors of VO 2 peak when adjusted for age and body size (both p<0.001). In Cox proportional hazards models, a higher HGZS was protective of the composite outcome (HR 0.71 per 1-SD, p <0.001), and diagnosis complexity increased the risk (HR 4.98, p<0.001) when adjusting for repeated measures, age, and BMI. Conclusions Patients with CHD and lower HGS tend to have higher complexity disease, low VO 2 peak, low SMM, and are at risk for worse clinical outcomes.