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Assessment of Mitochondrial Functions and Cell Viability in Renal Cells Overexpressing Protein Kinase C Isozymes
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Serum cystatin C: a useful marker of kidney function in very old people

Ingela Fehrman-Ekholm1, Astrid Seeberger, Jonas Björk

  • 1Sophiahemmet, 86 Stockholm, Sweden. ingela.fehrman@sophiahemmet.se

Scandinavian Journal of Clinical and Laboratory Investigation
|June 12, 2009
PubMed

Insights

Serum Cystatin C offers a more accurate measure of kidney function in the elderly compared to serum creatinine. This study found Cystatin C-based equations to be highly reliable for estimating glomerular filtration rate (GFR) in older adults.

Area of Science:

  • Gerontology
  • Nephrology
  • Biomarkers

Background:

  • Serum creatinine-based estimates of glomerular filtration rate (GFR) can be inaccurate in elderly individuals.
  • Serum Cystatin C is a potential alternative biomarker for GFR, as it is not influenced by muscle mass.

Purpose of the Study:

  • To evaluate the accuracy of serum Cystatin C in estimating GFR in elderly individuals.
  • To compare Cystatin C-based GFR estimations with creatinine-based equations.

Main Methods:

  • Measured GFR using plasma clearance of iohexol in 50 participants aged over 70.
  • Analyzed serum creatinine, albumin, urea, and Cystatin C.
  • Compared GFR estimates from Cystatin C and creatinine using established equations.

Main Results:

  • Serum Cystatin C and urea levels increased significantly with age, unlike creatinine.
  • All tested equations underestimated GFR, with bias ranging from -2.2% to -31%.
  • The Hoek equation (Cystatin C-based) demonstrated the highest accuracy (98% within 30% of measured GFR).
  • Creatinine-based MDRD Study equations showed 94% accuracy. Gender differences in accuracy were observed, with higher accuracy in males.
  • The Cockcroft Gault equation proved unreliable due to high bias and low accuracy.

Conclusions:

  • Serum Cystatin C is a valuable biomarker for assessing kidney function in the elderly.
  • Both Cystatin C-based equations and MDRD equations appear adequate for estimating GFR in this population.
Abstract

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