Dataset Information

Conversion of Urine Protein-Creatinine Ratio or Urine Dipstick Protein to Urine Albumin-Creatinine Ratio for Use in Chronic Kidney Disease Screening and Prognosis : An Individual Participant-Based Meta-analysis.

ABSTRACT:

Background

Although measuring albuminuria is the preferred method for defining and staging chronic kidney disease (CKD), total urine protein or dipstick protein is often measured instead.

Objective

To 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.

Design

Individual participant-based meta-analysis.

Setting

12 research and 21 clinical cohorts.

Participants

919 383 adults with same-day measures of ACR and PCR or dipstick protein.

Measurements

Equations 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).

Results

Median 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.

Limitation

Diverse methods of ACR and PCR quantification were used; measurements were not always performed in the same urine sample.

Conclusion

Urine 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 source

National Institute of Diabetes and Digestive and Kidney Diseases and National Kidney Foundation.

SUBMITTER: Sumida K

PROVIDER: S-EPMC7780415 | biostudies-literature | 2020 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Conversion of Urine Protein-Creatinine Ratio or Urine Dipstick Protein to Urine Albumin-Creatinine Ratio for Use in Chronic Kidney Disease Screening and Prognosis : An Individual Participant-Based Meta-analysis.

Sumida Keiichi K Nadkarni Girish N GN Grams Morgan E ME Sang Yingying Y Ballew Shoshana H SH Coresh Josef J Matsushita Kunihiro K Surapaneni Aditya A Brunskill Nigel N Chadban Steve J SJ Chang Alex R AR Cirillo Massimo M Daratha Kenn B KB Gansevoort Ron T RT Garg Amit X AX Iacoviello Licia L Kayama Takamasa T Konta Tsuneo T Kovesdy Csaba P CP Lash James J Lee Brian J BJ Major Rupert W RW Metzger Marie M Miura Katsuyuki K Naimark David M J DMJ Nelson Robert G RG Sawhney Simon S Stempniewicz Nikita N Tang Mila M Townsend Raymond R RR Traynor Jamie P JP Valdivielso José M JM Wetzels Jack J Polkinghorne Kevan R KR Heerspink Hiddo J L HJL

Annals of internal medicine 20200714 6

<h4>Background</h4>Although measuring albuminuria is the preferred method for defining and staging chronic kidney disease (CKD), total urine protein or dipstick protein is often measured instead.<h4>Objective</h4>To 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.<h4>Design</h4>Individual participant-based meta-analysis.<h4>Setting</h4>12 research ...[more]

PMID: 32658569

Similar Datasets

Project description:BackgroundUrine albumin-creatinine ratio (ACR) and protein-creatinine ratio (PCR) are important markers of kidney damage and are used for prognosis in persons with chronic kidney disease (CKD). Despite how commonly these measurements are done in clinical practice, relatively few studies have directly compared the performance of these 2 measures with regard to associations with clinical outcomes, which may inform clinicians about which measure of urinary protein excretion is best. We studied the association of ACR and PCR with common complications of CKD.Study designCross-sectional study.Setting & participants3,481 participants with CKD in the Chronic Renal Insufficiency Cohort (CRIC) Study.PredictorsACR and PCR.OutcomesWe examined the association between ACR and PCR with measures of common CKD complications: serum hemoglobin, bicarbonate, parathyroid hormone, phosphorus, potassium, and albumin.MeasurementsRestricted cubic spline analyses adjusted for estimated glomerular filtration rate (eGFR; calculated by the MDRD [Modification of Diet in Renal Disease] Study equation) were performed to study the continuous association with our predictors with each outcome.ResultsMean eGFR was 43±13 (SD)mL/min/1.73 m2 and median values for PCR and ACR were 140 and 46 mg/g, respectively. In continuous analyses adjusted for eGFR, higher ACRs and PCRs were similar and both were associated with lower serum hemoglobin, bicarbonate, and albumin levels and higher parathyroid hormone, phosphorus, and potassium levels. Across all outcomes, the associations of ACR and PCR were similar, with only small absolute differences in the outcome measure. Similar associations were seen in patients with diabetes mellitus.LimitationsParticipants largely had moderate CKD with low values for ACR and PCR, so results may not be generalizable to all CKD populations.ConclusionsIn persons with CKD, ACR and PCR are relatively similar in their associations with common complications of CKD. Thus, routine measurement of PCR may provide similar information as ACR in managing immediate complications of CKD.

Project description:Background and objectivesBecause there is substantial biologic intraindividual variation in albumin excretion, randomized trials of albuminuria-reducing therapies may need multiple urine samples to estimate daily urinary albumin excretion. Mailing spot urine samples could offer a convenient and cost-effective method to collect multiple samples, but urine albumin-to-creatinine ratio stability in samples stored at ambient temperatures for several days is unknown.Design, setting, participants, & measurementsPatients with kidney disease provided fresh urine samples in two tubes (with and without boric acid preservative). Reference aliquots from each participant were analyzed immediately, whereas remaining aliquots were subject to different handling/storage conditions before analysis, including delayed processing for up to 7 days at three different storage temperatures (4°C, 18°C, and 30°C), multiple freeze-thaw cycles, and long-term frozen storage at -80°C, -40°C, and -20°C. We calculated the mean percentage change in urine albumin-to-creatinine ratio for each condition, and we considered samples stable if the 95% confidence interval was within a ±5% threshold.ResultsNinety-three patients provided samples with detectable albuminuria in the reference aliquot. Median (interquartile range) urine albumin-to-creatinine ratio was 87 (20-499) mg/g. The inclusion of preservative had minimal effect on fresh urine albumin-to-creatinine ratio measurements but reduced the changes in albumin and creatinine in samples subject to processing delay and storage conditions. The urine albumin-to-creatinine ratio was stable for 7 days in samples containing preservative at 4°C and 18°C and 2 days when stored at 30°C. It was also stable in samples with preservative after three freeze-thaw cycles and in frozen storage for 6 months at -80°C or -40°C but not at -20°C.ConclusionsMailed urine samples collected with preservative and received within 7 days if ambient temperature is ≤18°C, or within 2 days if the temperature is higher but does not exceed 30°C, are suitable for the measurement of urine albumin-to-creatinine ratio in randomized trials. Preserved samples frozen to -40°C or -80°C for 6 months before analysis also seem suitable.

Project description:Rationale & objectiveTest the feasibility of replacing 24-hour urine collection with a single voided urinary protein-creatinine ratio (UPCR) in patients with amyloid light-chain (AL) amyloidosis.Study designRetrospective study examining the correlation between a 24-hour urine measurement and UPCR at various proteinuria levels using a linear regression analysis with Pearson's correlation coefficient (r). We assessed how using these 2 different measurements would alter the diagnosis, staging, and kidney response assessment in patients with AL amyloidosis.Setting & participantsWe included 265 patients with systemic AL amyloidosis who visited the Amyloidosis Center at Boston University between July 2018-January 2020 and had proteinuria measurement by both methods on the same day.Tests compared24-hour urine collection for protein versus UPCR.ResultsThe correlation between 24-hour urine and UPCR was moderate in patients with proteinuria levels of 500-3,000 mg/day and >3,000 mg/day, with r values of 0.57 and 0.62, respectively. Replacing the 24-hour urine collection with UPCR changed kidney staging in 10% of the patients: 77% were reclassified to a worse kidney stage and 23% to a more favorable stage. The majority of changes (85%) in kidney staging occurred in the >3,000 mg/day cohort. There were 35 patients whose kidney response was assessed by concomitant 24-hour urine collection and UPCR with visits at least 6 months apart. Of these patients, 20% had discordance between the 24-hour urine collection and UPCR that changed their definition of organ response.LimitationsGiven the rarity of AL amyloidosis, our sample size is small and from a single referral center.ConclusionsAlthough the 24-hour urine collection is cumbersome, we continue to recommend it in patients with AL amyloidosis because replacing the 24-hour urine collection with UPCR would change kidney staging and organ response in 10%-20% of patients. In addition, the correlation between the 2 modalities was moderate at best in patients with nephrotic-range proteinuria.

Project description:BackgroundThe utility of dipstick proteinuria for predicting microalbuminuria in non-diabetic lifestyle-related diseases compared with the urine protein-to-creatinine ratio (uPCR) and the effect of dipstick proteinuria on the cut-off value (CO) and accuracy of uPCR are unclear.MethodsThe subjects included Japanese patients ≥ 18 years old with lifestyle-related diseases who had an estimated glomerular filtration rate of ≥ 15 ml/min/1.73 m2 and uPCR of < 0.5 g/gCr at initiation. Urine dipstick, uPCR and urine albumin-to-creatinine ratio (uACR) were measured three times per case. Microalbuminuria was defined as uACR of 30-299 mg/gCr for at least 2 of 3 measurements. Youden's Index was used as the optimal CO. Factors associated with microalbuminuria were analyzed using a logistic regression model.ResultsIn 313 non-diabetic cases (median 70.8 years old), 3 dipstick proteinuria measurements were independently useful for detecting microalbuminuria, and the CO was set when a trace finding was obtained at least 1 of 3 times (sensitivity 0.56, specificity 0.80, positive predictive value [PPV] 0.73, negative predictive value [NPV] 0.65). A single uPCR measurement was more useful than 3 dipstick measurements, and was useful for detecting microalbuminuria even in cases with three consecutive negative proteinuria findings, indicating that the CO of the second uPCR with G1-3a (n = 136) was 0.06 g/gCr (sensitivity 0.76, specificity 0.84. PPV 0.68, NPV 0.89), while that with G3-b4 (n = 59) was 0.10 g/gCr (sensitivity 0.56, specificity 0.91. PPV 0.83, NPV 0.71). The sum of 3 uPCRs was useful for detecting microalbuminuria in cases with G1-3a (sensitivity 0.67, specificity 0.94, PPV 0.82, NPV 0.86) and G3b-4 (sensitivity 0.78, specificity 0.94, PPV 0.91 NPV 0.83), with both COs being 0.23 g/gCr. These COs of microalbuminuria did not change when trace or more proteinuria was included, although the sensitivity increased. A high uPCR and low urine specific gravity or creatinine level were independent factors for uACR ≥ 30 mg/gCr in cases with negative proteinuria, although the uPCR was a major predictive factor of a uACR ≥ 30 mg/gCr.ConclusionsThe uPCR (preferably determined using early-morning urine), including in dipstick-negative proteinuria cases with non-diabetic lifestyle-related diseases, can aid in the early detection of microalbuminuria.Trial registrationRetrospectively registered.

Dataset Information

Conversion of Urine Protein-Creatinine Ratio or Urine Dipstick Protein to Urine Albumin-Creatinine Ratio for Use in Chronic Kidney Disease Screening and Prognosis : An Individual Participant-Based Meta-analysis.

Background

Objective

Design

Setting

Participants

Measurements

Results

Limitation

Conclusion

Primary funding source

Publications

Conversion of Urine Protein-Creatinine Ratio or Urine Dipstick Protein to Urine Albumin-Creatinine Ratio for Use in Chronic Kidney Disease Screening and Prognosis : An Individual Participant-Based Meta-analysis.

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