• Keiichi Sumida, Girish N Nadkarni, Morgan E Grams, Yingying Sang, Shoshana H Ballew, Josef Coresh, Kunihiro Matsushita, Aditya Surapaneni, Nigel Brunskill, Steve J Chadban, Alex R Chang, Massimo Cirillo, Kenn B Daratha, Ron T Gansevoort, Amit X Garg, Licia Iacoviello, Takamasa Kayama, Tsuneo Konta, Csaba P Kovesdy, James Lash, Brian J Lee, Rupert W Major, Marie Metzger, Katsuyuki Miura, NaimarkDavid M JDMJ0000-0002-0621-0637Sunnybrook Hospital, University of Toronto, Toronto, Ontario, Canada (D.M.N.)., Robert G Nelson, Simon Sawhney, Nikita Stempniewicz, Mila Tang, Raymond R Townsend, Jamie P Traynor, José M Valdivielso, Jack Wetzels, Kevan R Polkinghorne, Hiddo J L Heerspink, and Chronic Kidney Disease Prognosis Consortium.
• University of Tennessee Health Science Center, Memphis, Tennessee (K.S.).
• Ann. Intern. Med. 2020 Sep 15; 173 (6): 426-435.

BackgroundAlthough measuring albuminuria is the preferred method for defining and staging chronic kidney disease (CKD), total urine protein or dipstick protein is often measured instead.ObjectiveTo develop equations for converting urine protein-creatinine ratio (PCR) and dipstick protein to urine albumin-creatinine ratio (ACR) and to test their diagnostic accuracy in CKD screening and staging.DesignIndividual participant-based meta-analysis.Setting12 research and 21 clinical cohorts.Participants919 383 adults with same-day measures of ACR and PCR or dipstick protein.MeasurementsEquations to convert urine PCR and dipstick protein to ACR were developed and tested for purposes of CKD screening (ACR ≥30 mg/g) and staging (stage A2: ACR of 30 to 299 mg/g; stage A3: ACR ≥300 mg/g).ResultsMedian ACR was 14 mg/g (25th to 75th percentile of cohorts, 5 to 25 mg/g). The association between PCR and ACR was inconsistent for PCR values less than 50 mg/g. For higher PCR values, the PCR conversion equations demonstrated moderate sensitivity (91%, 75%, and 87%) and specificity (87%, 89%, and 98%) for screening (ACR >30 mg/g) and classification into stages A2 and A3, respectively. Urine dipstick categories of trace or greater, trace to +, and ++ for screening for ACR values greater than 30 mg/g and classification into stages A2 and A3, respectively, had moderate sensitivity (62%, 36%, and 78%) and high specificity (88%, 88%, and 98%). For individual risk prediction, the estimated 2-year 4-variable kidney failure risk equation using predicted ACR from PCR had discrimination similar to that of using observed ACR.LimitationDiverse methods of ACR and PCR quantification were used; measurements were not always performed in the same urine sample.ConclusionUrine ACR is the preferred measure of albuminuria; however, if ACR is not available, predicted ACR from PCR or urine dipstick protein may help in CKD screening, staging, and prognosis.Primary Funding SourceNational Institute of Diabetes and Digestive and Kidney Diseases and National Kidney Foundation.

24 keywords...

hide…