Pre-chronic kidney disease: Serial creatinine tracks glomerular filtration rate decline above 60 mL/min

OBJECTIVESPrimary care for chronic kidney disease (CKD) stage 1-2 has recently been shown to slow CKD progression. We describe an approach to detect early decline in glomerular filtration rate (GFR) above 60 milliliters per minute (mL/min), before CKD stage 3. METHODSWe re-examined a standard reference that found low tubular secretion of creatinine (TScr) at GFRs above 80 mL/min and suggested "...observation of subtle changes in serum creatinine levels". We explain why that method extends down to 60 mL/min and summarize why estimated GFR (eGFR) is unreliable above 60 mL/min. RESULTSFour patient cases show how serum creatinine (sCr) referenced to an individuals historical maximum suggests increased risk, triggering investigation to separate benign processes that alter sCr from decline in GFR of prechronic kidney disease (preCKD). CONCLUSIONSAt GFRs above 60 mL/min, serial creatinine is more reliable than GFR estimating equations and appears practical for race-free clinical monitoring and early intervention. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=108 SRC="FIGDIR/small/24313678v9_ufig1.gif" ALT="Figure 1"> View larger version (48K): org.highwire.dtl.DTLVardef@1d7e4d6org.highwire.dtl.DTLVardef@f0b51dorg.highwire.dtl.DTLVardef@102a01forg.highwire.dtl.DTLVardef@15e7597_HPS_FORMAT_FIGEXP M_FIG C_FIG STRENGTHS OF THIS STUDYO_LIIncludes serial creatinine proof-of-concept cases that show preCKD C_LIO_LIReviews race-free properties that favor serial creatinine for early kidney disease C_LIO_LIAddresses mathematical limitations of GFR estimating equations C_LIO_LIRe-analyzes a 40-year-old standard reference that still influences research, showing its overlooked importance for CKD stage 1-2 C_LI