The predictive value of low urine specific gravity in the diagnosis of vasovagal syncope in children and adolescents

Abstract

Background Vasovagal syncope (VVS) is a kind of common neurogenic syncope in children and adolescents. Decreased blood volume is one of the pathogenesis of VVS. The study will explore the predictive value of low urine specific gravity (USG) in the diagnosis of VVS in children and adolescents. Methods 97 cases, 43 males and 54 females, aged 4 to 16 years old, with an average age of 10.91 ± 2.18 years old, due to unexplained premonitory syncope or syncope were selected. They were diagnosed with VVS through head-up tilt table test. During the same period, 91 cases of children and adolescents, including 45 males and 46 females, aged from 5 to 15 years old, who underwent a healthy examination were matched as a control (control group). USG was measured in both groups. Results The USG of VVS group was significantly lower than that of the control group (P < 0.01). The sensitivity and specificity of USG prediction in the diagnosis of VVS were evaluated by ROC curve. The area under the ROC curve was 0.751, standard error was 0.035, and 95% CI (0.683, 0.819) suggested that USG was of moderate predictive value in the diagnosis of VVS. Setting USG as < 1.0185, the sensitivity and specificity and diagnostic coincidence rate of VVS were 74.39%, 66.04% and 69.68%, respectively. Conclusion Low USG has predictive value in the diagnosis of VVS in children and adolescents.