title: Obstructive sleep apnea: the most common secondary cause of hypertension associated with resistant hypertension.
abstract: Recognition and treatment of secondary causes of hypertension among patients with resistant hypertension may help to control blood pressure and reduce cardiovascular risk. However, there are no studies systematically evaluating secondary causes of hypertension according to the Seventh Joint National Committee. Consecutive patients with resistant hypertension were investigated for known causes of hypertension irrespective of symptoms and signs, including aortic coarctation, Cushing syndrome, obstructive sleep apnea, drugs, pheochromocytoma, primary aldosteronism, renal parenchymal disease, renovascular hypertension, and thyroid disorders. Among 125 patients (age: 52±1 years, 43% males, systolic and diastolic blood pressure: 176±31 and 107±19 mm Hg, respectively), obstructive sleep apnea (apnea-hypopnea index: >15 events per hour) was the most common condition associated with resistant hypertension (64.0%), followed by primary aldosteronism (5.6%), renal artery stenosis (2.4%), renal parenchymal disease (1.6%), oral contraceptives (1.6%), and thyroid disorders (0.8%). In 34.4%, no secondary cause of hypertension was identified (primary hypertension). Two concomitant secondary causes of hypertension were found in 6.4% of patients. Age >50 years (odds ratio: 5.2 [95% CI: 1.9-14.2]; P<0.01), neck circumference ≥41 cm for women and ≥43 cm for men (odds ratio: 4.7 [95% CI: 1.3-16.9]; P=0.02), and presence of snoring (odds ratio: 3.7 [95% CI: 1.3-11]; P=0.02) were predictors of obstructive sleep apnea. In conclusion, obstructive sleep apnea appears to be the most common condition associated with resistant hypertension. Age >50 years, large neck circumference measurement, and snoring are good predictors of obstructive sleep apnea in this population.
authors.affiliation: Sleep Laboratory, Pulmonary Division, Heart Institute, Av Enéas Carvalho de Aguiar 44, São Paulo, Brazil.
authors.forename: Rodrigo P
authors.initials: RP
authors.lastname: Pedrosa
authors.forename: Luciano F
authors.initials: LF
authors.lastname: Drager
authors.forename: Carolina C
authors.initials: CC
authors.lastname: Gonzaga
authors.forename: Marcio G
authors.initials: MG
authors.lastname: Sousa
authors.forename: Lílian K G
authors.initials: LK
authors.lastname: de Paula
authors.forename: Aline C S
authors.initials: AC
authors.lastname: Amaro
authors.forename: Celso
authors.initials: C
authors.lastname: Amodeo
authors.forename: Luiz A
authors.initials: LA
authors.lastname: Bortolotto
authors.forename: Eduardo M
authors.initials: EM
authors.lastname: Krieger
authors.forename: T Douglas
authors.initials: TD
authors.lastname: Bradley
authors.forename: Geraldo
authors.initials: G
authors.lastname: Lorenzi-Filho
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D000959:Antihypertensive Agents / Q000627:therapeutic use; D001795:Blood Pressure Determination; D001938:Brazil; D015331:Cohort Studies; D004351:Drug Resistance; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006929:Hyperaldosteronism / Q000150:complications / Q000175:diagnosis; D006973:Hypertension / Q000188:drug therapy* / Q000453:epidemiology / Q000209:etiology*; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D017286:Polysomnography / Q000379:methods; D012078:Renal Artery Obstruction / Q000150:complications / Q000175:diagnosis; D012189:Retrospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology
chemical_list: D000959:Antihypertensive Agents