Demographic features of vasovagal syncope subtypes identified by head-up tilt testing: a 10-year cross-sectional study of 3084 cases

The head-up tilt test (HUTT) is an effective tool for the diagnosis and management of patients with vasovagal syncope (VVS). The aim of this study was to evaluate the impact of age and gender on positive responses across the three hemodynamic types of VVS on HUTT in a large sample. In this study, we retrospectively reviewed data from 3084 consecutive Chinese patients with suspected reflex syncope who had undergone HUTT following the Italian protocol at Yantai Yuhuangding Hospital. Significant differences in the distribution of the three VVS subtypes were observed across the four age groups ( P < 0.001). The gender ratio also differed significantly between the passive phase and the TNG-enhanced phase for all subtypes ( P < 0.001). Only 10% of HUTT‑positive VVS cases were induced during the passive phase. In the passive phase, restricted cubic spline (RCS) analysis, after adjusting for hypertension, revealed a nonlinear association between age and the risk of mixed and cardioinhibitory subtypes, with the mixed subtype exhibiting a "J"‑shaped pattern and a higher risk in females (aOR = 2.44), whereas the vasodepressor subtype showed a linear relationship. During the TNG-enhanced phase, all three subtypes displayed nonlinear age‑risk associations: both mixed and cardioinhibitory subtypes followed a "J"‑shaped pattern (female aOR = 2.265 and 2.557, respectively), while the vasodepressor subtype exhibited a "U"‑shaped distribution. Logistic regression showed that hypertension was significantly negatively associated with all VVS subtypes in the TNG-enhanced phase (mixed: aOR = 0.420; cardioinhibitory: aOR = 0.502; vasodepressor: aOR = 0.326). Furthermore, significant interactions between hypertension and age were found for the mixed and cardioinhibitory subtypes (P for interaction < 0.05). This study unveiled the non-linear risk patterns of VVS subtypes in relation to age, gender, and hypertension. Young females are at the highest risk of the cardioinhibitory subtype, and the protective effect of hypertension changes with age. Therefore, subtype-based stratified assessment is recommended for personalized prevention and intervention.