title: Heart rate variability is a predictor of mortality in chronic kidney disease: a report from the CRIC Study.
abstract: OBJECTIVE
  Low heart rate variability (HRV) is a risk factor for adverse outcomes in the general population. We aimed to determine the factors associated with HRV and evaluate the association between low HRV and clinical outcomes in patients with chronic kidney disease (CKD).
  
  
  METHODS
  A 10-second electrocardiogram was obtained at baseline in the Chronic Renal Insufficiency Cohort (CRIC) Study. HRV was measured by the standard deviation of all R-R intervals (SDNN) and the root mean square of successive differences between R-R intervals (RMSSD).
  
  
  RESULTS
  In 3,245 CRIC participants with available baseline SDNN and RMSSD, lower HRV was associated with older age, lack of exercise, heart failure, elevated phosphorus and hemoglobin A1c, and low estimated glomerular filtration rate. After a median follow-up of 4.2 years, in fully adjusted models, lower HRV was not associated with renal [SDNN: hazard rate, HR = 0.96 (95% confidence interval, CI 0.88-1.05); RMSSD: HR = 0.97 (95% CI 0.88-1.07)] or cardiovascular outcomes [SDNN: HR = 1.02 (95% CI 0.92-1.13); RMSSD: HR = 1.00 (95% CI 0.90-1.10)]. There was a nonlinear relationship between RMSSD and all-cause mortality with increased risk with both low and high RMSSD (p = 0.04).
  
  
  CONCLUSIONS
  In a large cohort of patients with CKD, multiple risk factors for renal and cardiovascular diseases were associated with lower HRV. Lower HRV was not associated with increased risk for renal or cardiovascular outcomes, but both low and high RMSSD were associated with increased risk for all-cause mortality. In conclusion, HRV measured by RMSSD may be a novel and independent risk factor for mortality in CKD patients.
authors.affiliation: Division of Renal Diseases and Hypertension, University of Minnesota, Minneapolis, Minn., USA.
authors.forename: Paul E
authors.initials: PE
authors.lastname: Drawz
authors.forename: Denise C
authors.initials: DC
authors.lastname: Babineau
authors.forename: Carolyn
authors.initials: C
authors.lastname: Brecklin
authors.forename: Jiang
authors.initials: J
authors.lastname: He
authors.forename: Radhakrishna R
authors.initials: RR
authors.lastname: Kallem
authors.forename: Elsayed Z
authors.initials: EZ
authors.lastname: Soliman
authors.forename: Dawei
authors.initials: D
authors.lastname: Xie
authors.forename: Dina
authors.initials: D
authors.lastname: Appleby
authors.forename: Amanda H
authors.initials: AH
authors.lastname: Anderson
authors.forename: Mahboob
authors.initials: M
authors.lastname: Rahman
mesh_terms: D000328:Adult; D000368:Aged; D002318:Cardiovascular Diseases / Q000378:metabolism; D015331:Cohort Studies; D018572:Disease-Free Survival; D004562:Electrocardiography; D015444:Exercise; D005260:Female; D005919:Glomerular Filtration Rate; D006333:Heart Failure; D006339:Heart Rate / Q000502:physiology*; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010758:Phosphorus / Q000378:metabolism; D051437:Renal Insufficiency / Q000503:physiopathology; D051436:Renal Insufficiency, Chronic / Q000503:physiopathology*; D012307:Risk Factors; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D006454:Hemoglobins; D010758:Phosphorus