Serum cystatin C: A useful marker of kidney function in very old people

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Abstract

Background: Serum creatinine-based estimates of GFR may be inaccurate in the elderly and there is need for improvement. Serum Cystatin C, not being influenced by muscle volume, may be more accurate. Material and methods: GFR was measured with plasma clearance of iohexol in 50 elderly persons aged >70 years. Blood tests were drawn for analysis of creatinine, albumin and urea. Cystatin C was analysed on frozen specimens using the Dade Behring method. GFR estimates based on cystatin C were compared to estimates based on serum creatinine, using earlier published equations. Results: Significant increase with age was found with cystatin C (rs = 0.62, p < 0.0001) and urea (rs = 0.43, p = 0.0018) but no correlation with creatinine (rs = 0.05, p = 0.7502). All equations underestimated GFR with a bias ranging from -2.2 to -31%. The equation with the greatest accuracy was the Hoek equation (Cystatin C based) with 98% of estimates within 30% of mGFR and confidence interval 89-100%. Estimated GFR using the MDRD Study equations (creatinine based) showed accuracy of 94% with 4 or 6 factors used. There was a gender difference with an accuracy higher among males (p < 0.002). The Cockcroft Gault equation was not found useful with high bias and a low accuracy. Conclusion: S-cystatin C seems a useful marker for kidney function in the elderly. Two equations based on serum cystatin C as well as the two MDRD equations seem adequate for estimating kidney function.

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Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Clinical Medicine
  • Environmental Health and Occupational Health

Keywords

  • eGFR, estimation GFR, ageing, cystatin C, age dependence, serum urea, filtration rate), GFR (glomerular, serum creatinine, Renal function, iohexol clearance, equations, gender, MDRD, measured GFR, mGFR
Original languageEnglish
Pages (from-to)606-611
JournalScandinavian Journal of Clinical & Laboratory Investigation
Volume69
Issue number5
Publication statusPublished - 2009
Publication categoryResearch
Peer-reviewedYes

Bibliographic note

The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Division of Occupational and Environmental Medicine (013078001), Emergency medicine/Medicine/Surgery (013240200)