Measurement error as alternative explanation for the observation that CrCl/GFR ratio is higher at lower GFR

Xuehan Zhang, Charles E. McCulloch, Feng Lin, Yen Chung Lin, Isabel Elaine Allen, Nisha Bansal, Alan S. Go, Chi Yuan Hsu

研究成果: 雜誌貢獻文章同行評審

5 引文 斯高帕斯(Scopus)

摘要

Background and objectives Overestimation of GFR by urinary creatinine clearance (CrCl) at lower levels of GFR has long been attributed to enhanced creatinine secretion. However, this does not take into consideration the contribution of errors in measured GFR (and CrCl) due to short-term biologic variability or test imprecision. Design, setting, participants, & measurements: We analyzed cross-sectional data among 1342 participants from theChronicRenal InsufficiencyCohort studywith baseline measurement ofGFR by iothalamate clearance (iGFR) and CrCl by 24-hour urine collection. We examined the CrCl/iGFR ratio classified by categories of iGFR and also by categories of CrCl. Results: Overall, mean CrCl/iGFR ratio was 1.13. CrCl/iGFR ratio was higher at lower iGFR categories. In contrast, this ratio was lower at lower CrCl levels. We hypothesize these relationships could be due to measurement error,which is bolstered by replicating these trends in a simulation andmodeling exercise inwhich there was no variation in the ratio of CrCl/iGFR with true kidney function but taking into account the effect of measurement error in both CrCl and iGFR (of magnitudes previously described in the literature). In our simulated data, the observed CrCl/iGFR ratio was higher at lower observed iGFR levels when patients were classified by categories of observed iGFR. When the same patientswere classified by categories of observed CrCl, the observed CrCl/iGFR ratio was lower at lower observed CrCl levels. Conclusions: The combined empirical and modeling results suggest that measurement errors (in both CrCl and iGFR) should be considered as an alternative explanation for the longstanding observation that the ratio of CrCl to iGFR gets larger as iGFR decreases.
原文英語
頁(從 - 到)1574-1581
頁數8
期刊Clinical Journal of the American Society of Nephrology
11
發行號9
DOIs
出版狀態已發佈 - 2016

ASJC Scopus subject areas

  • Epidemiology
  • Critical Care and Intensive Care Medicine
  • Nephrology
  • Transplantation

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