title: Impact of asthmatic control status on serum cystatin C concentrations.
abstract: BACKGROUND
  To determine whether cystatin C accurately reflects renal function in asthma, we investigated serum cystatin C concentrations in a large number of asthmatic patients by adjusting for several confounding factors that might affect serum cystatin C concentrations.
  
  
  METHODS
  A total of 126 asthmatic patients and 126 healthy volunteers, matched for age and gender, were studied.
  
  
  RESULTS
  Serum cystatin C concentrations in symptomatic subjects with asthma were significantly higher than in healthy controls (p < 0.001) and asymptomatic subjects with asthma (p = 0.007), whereas no significant difference was observed between healthy controls and asymptomatic subjects. In asthmatic subjects, serum cystatin C concentrations were not influenced by inhaled corticosteroid (ICS). However, serum cystatin C concentrations were significantly higher in subjects who were regularly treated by oral corticosteroid (OCS) (p = 0.001).
  
  
  CONCLUSIONS
  Serum cystatin C concentrations are elevated in asthmatic patients; particularly while symptomatic and/or taking OCS but not ICS. Serum cystatin C concentrations may not accurately reflect renal function in those patients.
authors.affiliation: First Department of Medicine, Hokkaido University School of Medicine, Sapporo, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Shigemura
authors.forename: Satoshi
authors.initials: S
authors.lastname: Konno
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Nasuhara
authors.forename: Chikara
authors.initials: C
authors.lastname: Shimizu
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Matsuno
authors.forename: Masaharu
authors.initials: M
authors.lastname: Nishimura
mesh_terms: D000305:Adrenal Cortex Hormones / Q000097:blood / Q000378:metabolism; D000328:Adult; D000368:Aged; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use*; D001249:Asthma / Q000097:blood* / Q000188:drug therapy* / Q000503:physiopathology; D055316:Cystatin C / Q000097:blood* / Q000378:metabolism; D005260:Female; D006801:Humans; D007677:Kidney Function Tests; D008297:Male; D008875:Middle Aged; D055815:Young Adult
chemical_list: D000305:Adrenal Cortex Hormones; D018927:Anti-Asthmatic Agents; D055316:Cystatin C