OBJECTIVETo analyze the etiology of 628 patients with refractory hypertension and to observe the disease distribution with respect to gender and different age groups.

METHODSIn 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, primary 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).

CONCLUSIONOur 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 aldosteronism was the commonest reason of endocrine hypertension in youth and middle-aged patients with refractory hypertension.