title: Increased dietary sodium is related to severity of obstructive sleep apnea in patients with resistant hypertension and hyperaldosteronism.
abstract: BACKGROUND
  Obstructive sleep apnea (OSA) is a strong and independent risk factor for the development of hypertension, particularly resistant hypertension, and cardiovascular diseases. Patients with resistant hypertension have a high prevalence of OSA in association with elevated aldosterone levels, high salt intake, and salt-sensitive BP. The objective of this study was to determine whether dietary salt and aldosterone are associated with severity of OSA in patients with resistant hypertension.
  
  
  METHODS
  Ninety-seven patients with resistant hypertension were prospectively evaluated by overnight polysomnography and 24-h urinary sodium and aldosterone levels while maintaining their usual diet. Hyperaldosteronism was defined as a plasma renin activity of &lt; 1 ng/mL/h and urinary aldosterone level of ≥ 12 μg/24 h.
  
  
  RESULTS
  Overall, patients' mean clinic BP was 156.3 ± 22.4/88.9 ± 13.3 mm Hg while taking an average of 4.3 ± 1.1 antihypertensive medications. Prevalence of OSA was 77.3%. Twenty-eight (28.9%) patients had hyperaldosteronism. Urinary sodium level was an independent predictor of severity of OSA only in patients with hyperaldosteronism.
  
  
  CONCLUSIONS
  The findings suggest that dietary salt is related to the severity of OSA in patients with resistant hypertension and hyperaldosteronism. The results support dietary salt restriction as a treatment strategy for reduction of OSA severity in these patients.
authors.affiliation: Endocrine Hypertension Research Centre and Clinical Centre of Research Excellence in Cardiovascular Disease and Metabolic Disorders, The School of Medicine, The University of Queensland, Princess Alexandra and Greenslopes Private Hospitals, Brisbane, QLD, Australia; Dante Pazzanese Institute of Cardiology, São Paulo, Brazil.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Pimenta
authors.affiliation: Endocrine Hypertension Research Centre and Clinical Centre of Research Excellence in Cardiovascular Disease and Metabolic Disorders, The School of Medicine, The University of Queensland, Princess Alexandra and Greenslopes Private Hospitals, Brisbane, QLD, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Stowasser
authors.affiliation: Endocrine Hypertension Research Centre and Clinical Centre of Research Excellence in Cardiovascular Disease and Metabolic Disorders, The School of Medicine, The University of Queensland, Princess Alexandra and Greenslopes Private Hospitals, Brisbane, QLD, Australia.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Gordon
authors.affiliation: Sleep/Wake Disorders Center, Division of Pulmonary, Allergy and Critical Care Medicine, Birmingham, AL.
authors.forename: Susan M
authors.initials: SM
authors.lastname: Harding
authors.affiliation: Dante Pazzanese Institute of Cardiology, São Paulo, Brazil.
authors.forename: Michel
authors.initials: M
authors.lastname: Batlouni
authors.affiliation: Division of Biostatistics and Epidemiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH.
authors.forename: Bin
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Vascular Biology and Hypertension Program, The University of Alabama at Birmingham, Birmingham, AL.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Oparil
authors.affiliation: Sleep/Wake Disorders Center, Division of Pulmonary, Allergy and Critical Care Medicine, Birmingham, AL; Vascular Biology and Hypertension Program, The University of Alabama at Birmingham, Birmingham, AL. Electronic address: dcalhoun@uab.edu.
authors.forename: David A
authors.initials: DA
authors.lastname: Calhoun
mesh_terms: D000450:Aldosterone / Q000652:urine; D001794:Blood Pressure / Q000502:physiology; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D006929:Hyperaldosteronism / Q000453:epidemiology* / Q000652:urine; D006973:Hypertension / Q000453:epidemiology* / Q000652:urine; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D015995:Prevalence; D011446:Prospective Studies; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000453:epidemiology* / Q000652:urine; D012964:Sodium / Q000652:urine; D012982:Sodium, Dietary / Q000009:adverse effects*
chemical_list: D012982:Sodium, Dietary; D000450:Aldosterone; D012964:Sodium