title: Cystatin C, vascular biomarkers and measured glomerular filtration rate in patients with unresponsive hypertensive phenotype: a pilot study.
abstract: BACKGROUND
  Biomarkers are commonly used to estimate the presence of subclinical cardiovascular disease (CVD) in patients with essential arterial hypertension (HT). In addition to known association between cystatin C and glomerular filtration rate (GFR), elucidating the association between cystatin C and vascular biomarkers (intima-media thickness of common carotid arteries (CCIMT), carotid plaque and renal artery resistance index (RRI)) in patients with unresponsive hypertensive phenotype could be of significant clinical interest.
  
  
  METHODS
  Participants (n = 200, median age 58 (52-64) years, 49% female) under treatment with antihypertensive drugs were stratified into two subgroups based on their blood pressure level as having responsive hypertension (RHT - compliant and responsive to treatment, n = 100), or nonresponsive (URHT - compliant but nonresponsive to treatment, n = 100). GFR was measured by isotopic (slope-intercept) method (99m Tc diethylene triamine penta-acetic acid - mGFR).
  
  
  RESULTS
  The URHT group had significantly higher median cystatin C serum concentration (p = 0.02) and CCIMT (p = 0.00) compared to the RHT group, with no significant difference in RRI (p = 0.51) and mGFR among subgroups [69.9 ± 28.2 vs 76.74 ± 23.61 ml/min/1.73m2, p = 0.27]. In the URHT group, cystatin C was found to be associated with CCIMT (p = 0.02), hsCRP (p = 0.01) and duration of HT (p = 0.02), independently of mGFR and age. Independent predictors of URHT phenotype were CCIMT (p= 0.02) and hsCRP (p= 0.04).
  
  
  CONCLUSIONS
  In addition to GFR, cystatin C serum concentration is positively and independently associated with CCIMT in patient with URHT phenotype and subclinical CVD. Prospective larger studies should further investigate the clinical importance of this relationship.
authors.affiliation: a Clinical Center of Vojvodina , Faculty of Medicine, University of Novi Sad , Novi Sad , Serbia.
authors.forename: Velibor
authors.initials: V
authors.lastname: Čabarkapa
authors.affiliation: a Clinical Center of Vojvodina , Faculty of Medicine, University of Novi Sad , Novi Sad , Serbia.
authors.forename: Branislava
authors.initials: B
authors.lastname: Ilinčić
authors.affiliation: a Clinical Center of Vojvodina , Faculty of Medicine, University of Novi Sad , Novi Sad , Serbia.
authors.forename: Mirjana
authors.initials: M
authors.lastname: Đerić
authors.affiliation: a Clinical Center of Vojvodina , Faculty of Medicine, University of Novi Sad , Novi Sad , Serbia.
authors.forename: Viktorija
authors.initials: V
authors.lastname: Vučaj Ćirilović
authors.affiliation: b Department of Mathematics and Informatics, Faculty of Sciences , University of Novi Sad , Novi Sad , Serbia.
authors.forename: Milena
authors.initials: M
authors.lastname: Kresoja
authors.affiliation: a Clinical Center of Vojvodina , Faculty of Medicine, University of Novi Sad , Novi Sad , Serbia.
authors.forename: Radmila
authors.initials: R
authors.lastname: Žeravica
authors.affiliation: a Clinical Center of Vojvodina , Faculty of Medicine, University of Novi Sad , Novi Sad , Serbia.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Sakač
mesh_terms: D015415:Biomarkers / Q000097:blood; D059168:Carotid Intima-Media Thickness; D003404:Creatinine / Q000097:blood*; D003430:Cross-Sectional Studies; D055316:Cystatin C / Q000097:blood*; D000075222:Essential Hypertension; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D006973:Hypertension / Q000175:diagnosis* / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D010865:Pilot Projects; D012044:Regression Analysis; D055771:Serbia
chemical_list: D015415:Biomarkers; D055316:Cystatin C; D003404:Creatinine
keywords: Biomarkers; cardiovascular risk; cystatin C; essential hypertension; glomerular filtration rate; subclinical tissue organ damage