Severe obstructive sleep apnea increases cystatin C in clinically latent renal dysfunction

Respir Med. 2011 Apr;105(4):643-9. doi: 10.1016/j.rmed.2010.11.024. Epub 2010 Dec 22.


Background: Obstructive sleep apnea (OSA) increases the risk of cardiovascular disease (CVD) and has been reported to be associated with chronic kidney disease (CKD). Recent studies have demonstrated that cystatin C is a prognostic biomarker of the risk of death and CVD even in patients without established CKD.

Methods: In a cross-sectional study, we enrolled 267 consecutive OSA patients without CKD who had an apnea-hypopnea index (AHI) ≥ 5 events per hour in overnight polysomnography. CKD was defined as an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m(2) according to the modification of diet in renal disease (MDRD) equation (modified for Japanese). Serum cystatin C levels were measured in all patients.

Results: Cystatin C was significantly correlated with age (r = 0.37), body mass index (BMI) (r = 0.12), AHI (r = 0.17), C-reactive protein (CRP) (r = 0.12), and Brachial-ankle pulse wave velocity (r = 0.18). Logistic regression analysis demonstrated that severe OSA defined by an AHI ≥ 30 events per hour was an independent variable for the highest quartiles of serum cystatin C levels (≥0.88 mg/L) (OR: 2.04, 95% CI: 1.04-4.01, P = 0.04) even after adjustment for age, BMI ≥ 25, hypertension, and diabetes mellitus.

Conclusions: This study indicates that severe OSA independently increases serum cystatin C levels in patients without CKD. Cystatin C is considered to be a biomarker that reflects both clinically latent renal dysfunction and cardiovascular risk that are influenced by OSA.

MeSH terms

  • Age Factors
  • Biomarkers / blood
  • Body Mass Index
  • Cardiovascular Diseases / etiology
  • Cardiovascular Diseases / metabolism*
  • Cross-Sectional Studies
  • Cystatin C / blood*
  • Female
  • Glomerular Filtration Rate
  • Humans
  • Male
  • Middle Aged
  • Polysomnography
  • Renal Insufficiency, Chronic / complications
  • Renal Insufficiency, Chronic / diagnosis
  • Renal Insufficiency, Chronic / metabolism*
  • Renal Insufficiency, Chronic / physiopathology
  • Risk Factors
  • Sleep Apnea, Obstructive / complications
  • Sleep Apnea, Obstructive / metabolism*


  • Biomarkers
  • Cystatin C