Our intent was to explore the predictive value of body mass index (BMI) in differentiating between vasovagal syncope (VVS) and postural tachycardia syndrome (POTS) in children and adolescents. A total of 111 children and adolescents with POTS and 154 children and adolescents with VVS were included in our study. The control group included 82 healthy children and adolescents. Height and weight were measured in all participants. The headup tilt test was performed in participants in all groups (POTS, VVS, and control). BMI was significantly lower in children and adolescents with POTS (18.3±3.4) than in children and adolescents with VVS (20.3±4.2) and the control group (20.5±2.9). The receiver operating characteristic curve was performed to determine the predictive value of BMI differentiation between POTS and VVS and showed that a BMI of 19.30 was the cutoff value for the probability of distinction. However, the results (BMI of 19.30) produced unsatisfactory sensitivity (57.1%) and specificity (28.8%) rates of correctly discriminating between patients with POTS and patients with VVS. Children and adolescents with POTS have a lower BMI compared with healthy peers or children and adolescents with VVS.

Keywords: body mass index, differential diagnosis, postural tachycardia syndrome, vasovagal syncope