BACKGROUND: We examined cardiorespiratory fitness and physical performance in long-term survivors of paediatric haematopoietic stem cell transplantation (HSCT) and explored how these are associated with the presence of metabolic syndrome (MetS).

PROCEDURE: We included 90 survivors of paediatric HSCT (median age, 30.3 years; range, 19.6-53.0; median follow-up time, 20.2 years) and 32 healthy controls. Cardiorespiratory fitness was evaluated by cardiopulmonary exercise tests, and physical performance was assessed through sit-to-stand, handgrip strength, timed-up-and-go, walking pace and six-minute walk tests. We assessed for components of MetS (blood pressure, waist circumference, plasma lipids, and glucose). For comparison of physical capacity between survivors and controls and survivors with or without the presence of MetS, a multiple linear regression analysis corrected for age and sex was applied.

RESULTS: Survivors demonstrated lower cardiorespiratory fitness compared with controls (mean ± SD VO₂ peak 29.3 ± 7.0 mL/kg/min vs. 44.3 ± 6.8 mL/kg/min, p < 0.0001) and impairment in all physical performance outcomes, where the most prominent differences compared with controls were seen in the sit-to-stand test (33% reduction). Twenty-eight percent of survivors fulfilled the criteria for MetS. The presence of MetS associated with lower VO₂ peak (p = 0.03), poorer outcomes in the six-minute walk test (p = 0.02), walking pace (p = 0.03) and the timed-up-and-go test (p = 0.003).

CONCLUSIONS: Young adult survivors of paediatric HSCT are at risk of markedly reduced physical capacity compared with age- and sex-matched controls, and the high incidence of MetS observed among survivors was associated with this impairment. Overall, these data underline the importance of monitoring physical capacity in survivors of paediatric HSCT.