Detecting Sarcopenic Obesity in Survivors of Pediatric Acute Lymphoblastic Leukemia: An Exploration of Body Mass Index and Triponderal Mass Index as Potential Surrogate Markers

Survivors of pediatric acute lymphoblastic leukemia (ALL) often have altered body composition secondary to treatment effects, including sarcopenic obesity (SO), which increases the risk of both metabolic complications and frailty. SO is difficult to detect without using advanced imaging techniques to which access is often limited. To explore whether common clinical indices can reliably identify the presence of SO in a cohort of long-term survivors of ALL, the discriminatory capacity of body mass index (BMI) or triponderal mass index (TMI, kg/m 3 ) for detecting SO was assessed. Thresholds of BMI and TMI associated with overweight or obesity status had poor sensitivity (<50%) and specificity for detecting SO. Total misclassification rates at these thresholds exceeded 50% and positive likelihood ratios were nonsignificant. Notably, TMI is more strongly correlated with elevated adiposity than is BMI in this survivor population ( R2 =0.73 vs. 0.57), suggesting further exploration is warranted. Our study is limited by the sample size, precluding detailed regression analysis. This study highlights the challenges of identifying SO in survivors of pediatric ALL using common clinical indices. Prospective evaluation of additional potential surrogate markers in survivors, in conjunction with the component features of SO, should be a key focus of future research.