title: Short-term reproducibility of ambulatory blood pressure monitoring in autosomal dominant polycystic kidney disease.
abstract: OBJECTIVE
  Nondipping, defined as a less than 10% decline in Night:Day (N:D) ratio of blood pressure using 24 h ambulatory blood pressure monitoring, is associated with poor cardiovascular outcomes. However, its reproducibility has been questioned in autosomal dominant polycystic kidney disease.
  
  
  METHODS
  Twenty-five of 29 recruited hypertensive or prehypertensive patients with autosomal dominant polycystic kidney disease completed ambulatory blood pressure monitoring on two occasions, 7-15 days apart, on a stable antihypertensive regimen. Daytime and night-time were defined as 6:00-21:59 h and 22:00-5:59 h, respectively. Correlation and concordance coefficients for systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate were determined based on N:D and Asleep:Awake (A:A) ratios. Consistency of dipping was assessed by using Cohen's Kappa statistics.
  
  
  RESULTS
  Mean (±standard deviation) for age, estimated glomerular filtration rate, differences in daytime and night-time SBP and DBP were 43.12 years (8.55 years), 63.1 ml/min (20.5 ml/min), 11.74 mmHg (8.2 mmHg), and 10.82 mmHg (6.4 mmHg), respectively. Seventeen of 25 (68%) and 18 of 25 (72%) participants maintained the same dipping category based on D:N or A:A separation. Cohen's Kappa was 0.34 for D:N ratio and 0.38 for A:A ratio. Correlation and concordance coefficients were 0.89 and 0.88 for daytime SBP, 0.91 and 0.91 for daytime DBP, 0.79 and 0.78 for night-time SBP, 0.81 and 0.80 for night-time DBP, 0.58 and 0.56 for N:D ratio of SBP, and 0.56 and 0.53 for N:D ratio of DBP. Coefficients for A:A ratio were almost identical to N:D values except for A:A ratios of SBP (0.69 and 0.67) and DBP (0.48 and 0.45).
  
  
  CONCLUSIONS
  Repeated measures of SBP and DBP, 7-15 days apart, are highly correlative and concordant in the studied population, but nondipping, even though predominant, was found to be modestly reproducible.
authors.affiliation: Renal Division, Department of Medicine, Emory University School of Medicine Atlanta, Georgia 30322, USA. frahbar@emory.edu
authors.forename: Frederic F
authors.initials: FF
authors.lastname: Rahbari-Oskoui
authors.forename: Dana C
authors.initials: DC
authors.lastname: Miskulin
authors.forename: Marie C
authors.initials: MC
authors.lastname: Hogan
authors.forename: Odicie
authors.initials: O
authors.lastname: Fielder
authors.forename: Vicente E
authors.initials: VE
authors.lastname: Torres
authors.forename: James E
authors.initials: JE
authors.lastname: Bost
authors.forename: Arlene Beth
authors.initials: AB
authors.lastname: Chapman
mesh_terms: D000328:Adult; D001794:Blood Pressure; D018660:Blood Pressure Monitoring, Ambulatory / Q000379:methods*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D016891:Polycystic Kidney, Autosomal Dominant / Q000150:complications / Q000503:physiopathology*; D015203:Reproducibility of Results; D055815:Young Adult