Abstract: Objective The prevalence of hypertension in children has been increasing over the past years. This study sought to summarize the clinical data of children who were admitted to Beijing Children's Hospital with a diagnosis of hypertension, and try to analyze the discriminating factors between primary hypertension and secondary hypertension. Methods All children with hypertension who were admitted to Beijing Children's Hospital during 2003 through 2007 were enrolled retrospectively. Data of medical history, physical examination and laboratory studies were recorded by a pediatric cardiologist. Hypertension was diagnosed according to the Chinese guideline for childhood hypertension and American national high blood pressure education program working group on high blood pressure in children and adolescents. Hypertension was classified as primary and secondary based on the etiology of hypertension. Data were analyzed by logistic regression with SPSS 11.5 software. Results A total of 304 children who met the inclusion criteria were included. Out of them, 146(48.0%) children were classified as primary hypertension, 158(52.0%) were secondary hypertension. Adolescents dominated as compared to other ages. Renal hypertension was the leading etiology in secondary hypertension, followed by hypertension due to endocrine system diseases, cardiovascular system and central nervous system. Between children with primary and secondary hypertension, time since onset of hypertension, diastolic blood pressure on admission, 24-hour average heart rate, gender, age, family history of hypertension, presences of dizziness, nausea and vomiting, melanin pigmentation, body mass index, serum uric acid, urine protein, ST-T changes on electrocardiogram, urea nitrogen(BUN), creatinine(Cr), standing serum level of renin activity
and adiposis hepatica on ultrasound were significantly different(P<0.05). Binary logistic regression showed positive family history of hypertension(OR=8.897), age over 10 years(OR=10.176) and increased BMI(OR=19.256) were independent risk factors of primary hypertension, while ST-T changes on electrocardiogram(OR=0.0257), standing serum renin >6 μg/(L·h^-1）(OR=0.0593) were risk factors of secondary hypertension. Conclusion Admission for hypertension is more prevalent in adolescents. Secondary hypertension is more common. Family history of hypertension, age above 10 years, increased BMI were risk factors of primary hypertension, while ST-T changes on electrocardiogram, serum renin at standing posture >6 μg/(L·h^-1） were risk factors of secondary hypertension.

Key words: primary hypertension, secondary hypertension, Children, differential diagnosis