title: Cystatin C as predictor of microalbuminuria in the early stage of hypertension.
abstract: OBJECTIVE
  Predictors of microalbuminuria in the early stage of hypertension are not well known. We did a prospective study to investigate whether glomerular hyperfiltration assessed from serum cystatin C predicts development of microalbuminuria in hypertension.
  
  
  METHODS
  We assessed 101 treatment-naive subjects screened for stage 1 hypertension and followed-up for a median 3.1 years. Cystatin C was measured at entry and glomerular filtration rate was estimated using the Hoek formula (CystGFR). Urinary albumin and ambulatory blood pressure were measured at entry and during the follow-up.
  
  
  RESULTS
  Subjects in the top CystGFR tertile (>115 ml/min/1.73 m(2)) were leaner (p = 0.002) and developed microalbuminuria more frequently (p = 0.02) than the rest of the group. In univariate Cox regression, CystGFR was associated with future microalbuminuria (hazard ratio, 1.06, 95% confidence interval (CI), 1.02-1.10, p = 0.001). After controlling for baseline albumin excretion rate and several confounders, CystGFR remained a significant predictor of microalbuminuria development (hazard ratio, 1.19, 95% CI, 1.03-1.37, p = 0.019). The association between future microalbuminuria and creatinine clearance or glomerular filtration rate estimated with the Cockroft-Gault or the Modification of Diet in Renal Disease formula did not attain the level of statistical significance in this sample.
  
  
  CONCLUSIONS
  The present findings indicate that CystGFR is more sensitive than creatinine clearance or estimated glomerular filtration rate for predicting microalbuminuria development in the early stage of hypertension and confirm that hyperfiltration precedes microalbuminuria in this clinical entity.
authors.affiliation: Department of Clinical and Experimental Medicine, University of Padova, Padova, Italy. palatini@unipd.it
authors.forename: Paolo
authors.initials: P
authors.lastname: Palatini
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Benetti
authors.forename: Ada
authors.initials: A
authors.lastname: Zanier
authors.forename: Massimo
authors.initials: M
authors.lastname: Santonastaso
authors.forename: Adriano
authors.initials: A
authors.lastname: Mazzer
authors.forename: Susanna
authors.initials: S
authors.lastname: Cozzio
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Zanata
authors.forename: Renzo
authors.initials: R
authors.lastname: De Toni
authors.forename: Martina
authors.initials: M
authors.lastname: Zaninotto
mesh_terms: D000419:Albuminuria / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology*; D015415:Biomarkers / Q000097:blood; D015897:Comorbidity; D055316:Cystatin C / Q000097:blood*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology*; D015994:Incidence; D007558:Italy / Q000453:epidemiology; D008297:Male; D016016:Proportional Hazards Models; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D055316:Cystatin C