title: Diagnostic value of screening instruments for identifying obstructive sleep apnea in kidney failure.
abstract: BACKGROUND
  Patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD) have a high prevalence of obstructive sleep apnea (OSA) that can have significant clinical implications. An accurate clinical screening tool for OSA that identifies patients for further diagnostic testing would assist in the identification of this comorbidity. The Berlin Questionnaire (BQ), Adjusted Neck Circumference (ANC), and STOP-BANG questionnaire are 3 such instruments that have been validated in patients with normal kidney function.
  
  
  OBJECTIVE
  The objective of this study was to determine the validity of these screening instruments in patients with CKD and ESRD, using overnight cardiopulmonary monitoring to diagnose OSA.
  
  
  METHODS
  One hundred seventy-two patients were recruited from nephrology clinics and hemodialysis units (CKD: n = 109; ESRD: n = 63). All patients completed the BQ, ANC, STOP-BANG, and overnight cardiopulmonary monitoring to diagnose OSA (respiratory disturbance index [RDI] ≥ 15). Sensitivity, specificity, positive and negative predictive values, and accuracy were calculated for the BQ, ANC, and STOP-BANG.
  
  
  RESULTS
  Obstructive sleep apnea was present in 41 CKD patients (38%) and 32 ESRD patients (51%). All screening instruments had satisfactory sensitivity (56% to 94%) but poor specificity (29% to 77%) and low accuracy (51% to 69%) in both CKD and ESRD patients with RDI ≥ 15. Using an RDI ≥ 30 yielded similar results.
  
  
  CONCLUSIONS
  Current screening questionnaires do not accurately identify patients at high risk for OSA or rule out the presence of OSA in patients with CKD and ESRD. Consequently, objective monitoring during sleep is required to reliably identify sleep apnea in these patient populations.
authors: Department of Medicine, University of Calgary, Alberta, Canada.
authors: David D M
authors: DD
authors: Nicholl
authors: Sofia B
authors: SB
authors: Ahmed
authors: Andrea H S
authors: AH
authors: Loewen
authors: Brenda R
authors: BR
authors: Hemmelgarn
authors: Darlene Y
authors: DY
authors: Sola
authors: Jaime M
authors: JM
authors: Beecroft
authors: Tanvir C
authors: TC
authors: Turin
authors: Patrick J
authors: PJ
authors: Hanly
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000150:complications; D008297:Male; D017286:Polysomnography; D051437:Renal Insufficiency / Q000150:complications*; D051436:Renal Insufficiency, Chronic / Q000150:complications; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000175:diagnosis*; D011795:Surveys and Questionnaires