Objective To analyze the etiology of 628 patients with refractory hypertension and to observe the disease distribution with respect to gender and different age groups. Methods In this study,clinical data of 628 refractory hypertensives who hospitalized in our hospital from September 1997 to December 2005 were retrospectively analyzed. Results (1) There were 80.1% (503/628) patients with essential hypertension, 18. 9% (119/628) with secondary hypertension (SH) while diagnosis was not clear in 1.0% (6/628) patients. Renovascular hypertension (33.6%) and obstructive sleep apnea syndrome (23.5%) were the major causes of SH. The highest prevalence rate of endocrine hypertension was primary aldosteronism (13.5%). (2) There were significantly more male patients than female patients with essential hypertension, SH, renal hypertension, obstructive sleep apnea syndrome, rimary aldosteronism while the incidence of pheochromocytoma in female was significantly higher than that in male patients (all P < 0.05).The incidence of renovascular hypertension was similar between male and female patients. (3) SH occurred more often in young patients (33.1%) than in aged patients (13.8%, P < 0.05). Conclusion Our data from this patient cohort showed that SH, especially renovascular hypertension and obstructive sleep apnea syndrome are major causes for refractory hypertension in young patients and primary aldosteromsm was the commonest reason of endocrine hypertension in youth and middle-aged patients with refractory hypertension.

Objective To analyze etiology of hospitalized hypertensive patients in the department of hypertension from 1999 to 2008. Methods This retrospective study was performed to analyze the etiology of hospitalized hypertensive patients in department of hypertension and to show the distribution change of hypertension from 1999 to 2008. Results ( 1 ) There were 5867 ( 75. 1% ) patients with essential hypertension and 1942 (24. 9% ) patients with secondary hypertension (SH). (2) The prevalence rate of SH increased significantly during the 10 years (χ2 = 387.621 ,P ＜ 0.001 ) and was higher in 2008 than in 1999 (39. 3% vs. 9. 5% , P ＜ 0. 05 ). The prevalence of obstructive sleep apnea syndrome (OSAS) and primary aldosteronism (PA) in 2008 increased 38.3 and 1.8 times respectively than in 1999 (χ2 =304. 025 ,P ＜0. 001; χ2 =42. 845 ,P ＜0. 001 ) and other SH remained unchanged. ( 3 ) The prevalence of PA complicated with OSAS increased significantly in recent five years ( χ2 = 26.376, P ＜0. 001 ). Incidence of OSAS was 23.9% in PA patients and incidence of PA was 6. 7% in OSAS patients. Conclusions With the insights gained on hypertension mechanism and the development of new diagnostic technology, percent of diagnosed SH increased remarkably in recent years in hospitalized hypertensive patients in our department of hypertension. OSAS and PA are the leading causes of SH.