title: Estimation of the glomerular filtration rate in NIDDM patients from plasma creatinine concentration after cimetidine administration.
abstract: OBJECTIVE
  Glomerular filtration rate (GFR) can be estimated in patients with renal disease from plasma creatinine concentration, age, sex, and body weight according to the formula of Cockcroft and Gault. The hypothesis that this method can be improved when tubular secretion of creatinine is inhibited by cimetidine was studied in NIDDM patients.
  
  
  METHODS
  In 30 outpatients with NIDDM and normo- (n = 10), micro- (n = 9), or macroalbuminuria (n = 11), GFR was measured as the urinary clearance during continuous infusion of 125I-labeled iothalamate. Plasma creatinine concentration was analyzed with an enzymatic assay before and after 800 mg t.i.d. oral cimetidine was given during a 24-h period.
  
  
  RESULTS
  Plasma creatinine rose in all patients after cimetidine administration and, as a consequence, the clearance calculated with the Cockcroft-Gault formula fell. The ratio of this formula and GFR decreased from 1.16 +/- 0.20 to 0.97 +/- 0.16 (means +/- SD). This ratio tended to be smaller in the normo- (0.93) than in the micro- (0.98) and macroalbuminuric (1.00) groups. Also, 20 patients with a BMI < 30 kg/m2 had a smaller ratio than those with a BMI > 30 kg/m2 (0.92 vs. 1.07; P < 0.05). Bland and Altman analysis showed a difference of the Cockcroft-Gault formula and GFR of 12.0 +/- 17.4 ml.min-1 (1.73 m2)-1, which decreased to -3.8 +/- 14.8 ml.min-1.(1.73 m2)-1. The same analysis of 24-h creatinine clearance with urine collection and GFR showed larger standard deviations.
  
  
  CONCLUSIONS
  GFR can be estimated in an acceptable way from plasma creatinine concentration after cimetidine administration in outpatients with NIDDM. Despite a nonsignificant underestimation in normoalbuminuric and overestimation in overweighted patients, this method is superior to 24-h creatinine clearance with outpatient urine collection.
authors.affiliation: Department of Internal Medicine, University of Amsterdam, The Netherlands. m.a.zeeman@amc.uva.nl
authors.forename: F A
authors.initials: FA
authors.lastname: Kemperman
authors.forename: J
authors.initials: J
authors.lastname: Silberbusch
authors.forename: E H
authors.initials: EH
authors.lastname: Slaats
authors.forename: A M
authors.initials: AM
authors.lastname: Prins
authors.forename: J A
authors.initials: JA
authors.lastname: Weber
authors.forename: R T
authors.initials: RT
authors.lastname: Krediet
authors.forename: L
authors.initials: L
authors.lastname: Arisz
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000419:Albuminuria / Q000097:blood / Q000503:physiopathology / Q000652:urine; D002927:Cimetidine / Q000008:administration & dosage / Q000494:pharmacology*; D015331:Cohort Studies; D003404:Creatinine / Q000097:blood* / Q000652:urine; D003627:Data Interpretation, Statistical; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000503:physiopathology* / Q000652:urine; D005260:Female; D005919:Glomerular Filtration Rate / Q000187:drug effects*; D006635:Histamine H2 Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D007457:Iodine Radioisotopes; D007483:Iothalamic Acid; D008297:Male; D008875:Middle Aged
chemical_list: D006635:Histamine H2 Antagonists; D007457:Iodine Radioisotopes; D007483:Iothalamic Acid; D002927:Cimetidine; D003404:Creatinine