title: [Renal function in hypertensive patients with obstructive sleep apnea].
abstract: BACKGROUND
  Patients with hypertension often suffer from obstructive sleep apnea (OSA). In addition to hypertension several other risk factors (hypoxemia, hyperlipidemia, and increased sympathic nerve activity) may contribute to progressive renal dysfunction in OSA patients. The aim of this study was to compare renal function in OSA-patients with and without hypertension.
  
  
  METHODS
  81 consecutive patients (50 males, 31 females) were screened for sleep apnea. Parameters of renal function (serum creatinine, creatinine clearance, microalbuminuria), and of lipid and glucose metabolism were correlated to polysomnographic results.
  
  
  RESULTS
  OSA (apnea/hypopnea index [AHI] > or = 5) was found in 57 of 81 patients. Mean AHI was 26.7 +/- 26.1. Hypertension (blood pressure > or = 140/90 mmHg or use of antihypertensive drugs) occurred in 63 of 81 patients. Serum creatinine in OSA patients was significantly higher than in patients without OSA (1.11 +/- 0.15 vs. 0.91 +/- 0.12 mg/dl, p < 0.001). Serum creatinine correlated significantly with AHI. Creatinine clearance was associated with age (r = -0.314; p = 0.014) and presence of OSA (r = 0.265; p = 0.093). No correlation was shown between hypertension and serum creatinine or creatinine clearance. Microalbuminuria was not associated with OSA.
  
  
  CONCLUSIONS
  Our results suggest an independent association between OSA and impaired renal function. Further prospective studies will have to be done to elucidate the pathophysiological mechanisms.
authors.affiliation: Medizinische Klinik I am Marienhospital Herne, Klinikum der Ruhr-Universität Bochum. nikolaus.buechner@ruhr-uni-bochum.de
authors.forename: N J
authors.initials: NJ
authors.lastname: Büchner
authors.forename: B F
authors.initials: BF
authors.lastname: Henning
authors.forename: K F
authors.initials: KF
authors.lastname: Hägele
authors.forename: I A
authors.initials: IA
authors.lastname: Quack
authors.forename: L C
authors.initials: LC
authors.lastname: Rump
mesh_terms: D000328:Adult; D000368:Aged; D000419:Albuminuria / Q000175:diagnosis; D003404:Creatinine / Q000097:blood / Q000652:urine; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000503:physiopathology*; D007668:Kidney / Q000503:physiopathology*; D007677:Kidney Function Tests; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012307:Risk Factors; D020181:Sleep Apnea, Obstructive / Q000097:blood / Q000150:complications / Q000503:physiopathology*
chemical_list: D003404:Creatinine