Serum cystatin C is not a better marker of creatinine or digoxin clearance than serum creatinine

Content Provider	Scilit
Author	O'Riordan, S. Ouldred, E. Brice, S. Jackson, S. H. D. Swift, C. G.
Copyright Year	2002
Description	Journal: British journal of clinical pharmacology Aims To assess whether cystatin C, a new serum marker of renal function, is a better index of creatinine or digoxin clearance than serum creatinine in older people. Methods Twenty-two volunteers over the age of 65 years (mean 73±5) were recruited from a healthy elderly volunteer database. None of the volunteers was taking digoxin or other medication known to interfere with digoxin kinetics or assay. Digoxin was infused at a dose of 7–10 µg $kg^{−1}$ and blood samples were taken over the following 48 h and assayed for serum digoxin. Serum cystatin C, creatinine and creatinine clearance were measured and a calculated creatinine clearance was estimated using the Cockcroft Gault formula. Digoxin clearance was calculated using a pharmacokinetic software package. All values were log transformed to normalize their distribution. Results Of the 22 volunteers enrolled into the study, 18 completed the study. Serum cystatin C ranged between 0.72 and 1.89 mg $l^{−1}$ and serum creatinine ranged from 69.6 to 153.9 µmol $l^{−1}$. Measured creatinine clearance ranged from 38 to 123 ml $min^{−1}$ and calculated creatinine clearance from 29.5 to 88.0 ml $min^{−1}$. Digoxin clearance ranged from 51.0 to 103.5 ml $min^{−1}$. Cystatin C correlated extremely well with creatinine (r=0.93, P<0.001, 95% CI 0.82, 0.97) and with creatinine clearance (r=0.67, P=0.002, 95% CI 0.3, 0.87). Neither serum cystatin C nor serum creatinine correlated with digoxin clearance (r=0.25, P=0.31, 95% CI −0.25, 0.64 and r=0.44, P=0.068, 95% CI −0.03, 0.75, respectively). Measured creatinine clearance, however, did correlate well with digoxin clearance (r=0.55, P=0.018, 95% CI 0.11, 0.81). Conclusions Serum cystatin C and serum creatinine show very similar correlations with creatinine and digoxin clearances. Serum cystatin C does not offer any advantages in this respect. It remains to be seen whether cystatin C offers any advantage over creatinine in elderly people in other respects.
Related Links	http://europepmc.org/articles/pmc1874275?pdf=render https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1874275/pdf http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2125.2002.01549.x/pdf
Ending Page	402
Page Count	5
Starting Page	398
e-ISSN	13652125
DOI	10.1046/j.1365-2125.2002.01549.x
Journal	British journal of clinical pharmacology
Issue Number	4
Volume Number	53
Language	English
Publisher	Wiley-Blackwell
Publisher Date	2002-04-28
Access Restriction	Open
Subject Keyword	Journal: British journal of clinical pharmacology Medical Laboratory Technology Cystatin C Kidney Function Older People
Content Type	Text
Resource Type	Article