Original InvestigationPathogenesis and Treatment of Kidney DiseaseThe Role of Cystatin C in Improving GFR Estimation in the General Population
Section snippets
Participants
RENIS-T6 is a substudy of the sixth Tromsø Study (Tromsø 6). In the main part of Tromsø 6, a representative sample of 12,984 persons of the 65,286 inhabitants of Tromsø municipality in Northern Norway were studied with questionnaires and a wide range of biochemical and other measurements between October 2007 and December 2008. Among those invited to participate in the main part of Tromsø 6 was a random sample of 40% of persons aged 50-59 years and all persons aged 60-62 years; 5,464 persons in
Results
Of 1,632 investigated persons, 5 were excluded because their iohexol-clearance measurements were technical failures, leaving 1,627 persons included in the RENIS-T6 cohort. In the present study, 6 of these were excluded because they used prednisolone. Accordingly, we examined 1,621 persons (Fig 1), whose characteristics are listed in Table 1. A comparison between the 1,627 participants in the RENIS-T6 cohort and all 2,825 eligible persons has been reported previously and showed that the cohort
Discussion
In the middle-aged general population, we found that models with either cystatin C or creatinine level had almost identical fit to GFR measurements. Including both markers in the same model improved fit significantly, but little was gained by including height and body weight or using nonlinear modeling with multivariable fractional polynomials (Table 2).
The internal validation found almost identical precision and accuracy for models with either cystatin C or creatinine level and significant
Acknowledgements
We thank Britt-Ann Winther Eilertsen, Bjørg Skog Høgset, Saskia van Heusden, and the rest of the staff at the Clinical Research Unit (University Hospital of North Norway) for performing the study; Harald Strand and the staff at the Department of Medical Biochemistry (University Hospital of North Norway) for HPLC analyses of iohexol; Inger Sperstad and Ingrid Dorthea Sandstad (Clinical Research Centre, University Hospital of North Norway) for database support; and Tom Wilsgaard, Sriharan
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2014, Kidney InternationalValidation of a new standardized cystatin C turbidimetric assay: Evaluation of the three novel CKD-EPI equations in hypertensive patients
2013, Clinical BiochemistryCitation Excerpt :By contrast, the use of the CKD-EPI combined formula significantly enhanced precision and accuracy (P20) as compared to CKD-EPI creatinine equation (p = 0.003 and p = 0.015 respectively). These results corroborate data obtained by Inker et al. in the initial external validation data set [11] and by Eriksen in a general healthy population [10]. In addition, we observed a significant improvement especially in the sub-group of patients with mGFR > 90 mL/min/1.73 m2.
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2013, American Journal of Kidney DiseasesCitation Excerpt :The finding that the lowest quintiles of serum BTP and B2M are not associated consistently with lowest risk may suggest differences among these markers in non-GFR determinants at higher GFRs and needs to be replicated. Prior work has shown that although GFR estimation equations based on either creatinine or cystatin C level separately perform similarly well, the combination of these 2 markers can lead to more precise and accurate GFR estimates.8,51 Results of our study and others suggest that BTP and B2M levels, in addition to cystatin C level, may be useful as an adjunct to creatinine level for GFR estimation and risk prediction across a broad range of clinical settings.
Originally published online October 17, 2011.