Dataset Information

New combined serum creatinine and cystatin C quadratic formula for GFR assessment in children.

ABSTRACT:

Background and objectives

The estimated GFR (eGFR) is important in clinical practice. To find the best formula for eGFR, this study assessed the best model of correlation between sinistrin clearance (iGFR) and the solely or combined cystatin C (CysC)- and serum creatinine (SCreat)-derived models. It also evaluated the accuracy of the combined Schwartz formula across all GFR levels.

Design, setting, participants, & measurements

Two hundred thirty-eight iGFRs performed between January 2012 and April 2013 for 238 children were analyzed. Regression techniques were used to fit the different equations used for eGFR (i.e., logarithmic, inverse, linear, and quadratic). The performance of each model was evaluated using the Cohen ? correlation coefficient and the percentage reaching 30% accuracy was calculated.

Results

The best model of correlation between iGFRs and CysC is linear; however, it presents a low ? coefficient (0.24) and is far below the Kidney Disease Outcomes Quality Initiative targets to be validated, with only 84% of eGFRs reaching accuracy of 30%. SCreat and iGFRs showed the best correlation in a fitted quadratic model with a ? coefficient of 0.53 and 93% accuracy. Adding CysC significantly (P<0.001) increased the ? coefficient to 0.56 and the quadratic model accuracy to 97%. Therefore, a combined SCreat and CysC quadratic formula was derived and internally validated using the cross-validation technique. This quadratic formula significantly outperformed the combined Schwartz formula, which was biased for an iGFR?91 ml/min per 1.73 m(2).

Conclusions

This study allowed deriving a new combined SCreat and CysC quadratic formula that could replace the combined Schwartz formula, which is accurate only for children with moderate chronic kidney disease.

SUBMITTER: Chehade H

PROVIDER: S-EPMC3878689 | biostudies-literature | 2014 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

New combined serum creatinine and cystatin C quadratic formula for GFR assessment in children.

Chehade Hassib H Cachat Francois F Jannot Anne-Sophie AS Meyrat Blaise-Julien BJ Mosig Dolores D Bardy Daniel D Parvex Paloma P Girardin Eric E

Clinical journal of the American Society of Nephrology : CJASN 20131107 1

<h4>Background and objectives</h4>The estimated GFR (eGFR) is important in clinical practice. To find the best formula for eGFR, this study assessed the best model of correlation between sinistrin clearance (iGFR) and the solely or combined cystatin C (CysC)- and serum creatinine (SCreat)-derived models. It also evaluated the accuracy of the combined Schwartz formula across all GFR levels.<h4>Design, setting, participants, & measurements</h4>Two hundred thirty-eight iGFRs performed between Janua ...[more]

PMID: 24202134

Similar Datasets

Project description:Background and objectiveseGFR equations have been evaluated in kidney transplant recipients with variable performance. We assessed the performance of the Modification of Diet in Renal Disease equation and the Chronic Kidney Disease Epidemiology Collaboration equations on the basis of creatinine, cystatin C, and both (eGFR creatinine-cystatin C) compared with measured GFR by iothalamate clearance and evaluated their non-GFR determinants and associations across 15 cardiovascular risk factors.Design, setting, participants, & measurementsA cross-sectional cohort of 1139 kidney transplant recipients >1 year after transplant was analyzed. eGFR bias, precision, and accuracy (percentage of estimates within 30% of measured GFR) were assessed. Interaction of each cardiovascular risk factor with eGFR relative to measured GFR was determined.ResultsMedian measured GFR was 55.0 ml/min per 1.73 m(2). eGFR creatinine overestimated measured GFR by 3.1% (percentage of estimates within 30% of measured GFR of 80.4%), and eGFR Modification of Diet in Renal Disease underestimated measured GFR by 2.2% (percentage of estimates within 30% of measured GFR of 80.4%). eGFR cystatin C underestimated measured GFR by -13.7% (percentage of estimates within 30% of measured GFR of 77.1%), and eGFR creatinine-cystatin C underestimated measured GFR by -8.1% (percentage of estimates within 30% of measured GFR of 86.5%). Lower measured GFR associated with older age, women, obesity, longer time after transplant, lower HDL, lower hemoglobin, lower albumin, higher triglycerides, higher proteinuria, and an elevated cardiac troponin T level but did not associate with diabetes, smoking, cardiovascular events, pretransplant dialysis, or hemoglobin A1c. These risk factor associations differed for five risk factors with eGFR creatinine, six risk factors for eGFR Modification of Diet in Renal Disease, ten risk factors for eGFR cystatin C, and four risk factors for eGFR creatinine-cystatin C.ConclusionsThus, eGFR creatinine and eGFR creatinine-cystatin C are preferred over eGFR cystatin C in kidney transplant recipients because they are less biased, more accurate, and more consistently reflect the same risk factor associations seen with measured GFR.

Project description:Rationale & objectiveUse of cystatin C in addition to creatinine to estimate glomerular filtration rate (estimated glomerular filtration rate based on cystatin C [eGFRcys] and estimated glomerular filtration rate based on creatinine [eGFRcr], respectively) is increasing. When eGFRcr and eGFRcys are discordant, it is not known which is more accurate, leading to uncertainty in clinical decision making.Study designCross-sectional analysis.Setting & participantsFour thousand fifty participants with measured glomerular filtration rate (mGFR) from 12 studies in North America and Europe.ExposuresSerum creatinine and serum cystatin C.OutcomesPerformance of creatinine-based and cystatin C-based glomerular filtration rate estimating equations compared to mGFR.Analytical approachWe evaluated the accuracy of eGFRcr, eGFRcys, and the combination (eGFRcr-cys) compared to mGFR according to the magnitude of the difference between eGFRcr and eGFRcys (eGFRdiff). We used CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equations to estimate glomerular filtration rate. eGFRdiff was defined as eGFRcys minus eGFRcr and categorized as less than -15, -15 to <15, and ≥15 mL/min/1.73 m2 (negative, concordant, and positive groups, respectively). We compared bias (median of mGFR minus eGFR) and the percentage of eGFR within 30% of mGFR.ResultsThirty percent of participants had discordant eGFRdiff (21.0% and 9.6% negative and positive eGFRdiffs, respectively). In the concordant eGFRdiff group, all equations displayed similar accuracy. In the negative eGFRdiff groups, eGFRcr had a large overestimation of mGFR (-13.4 [-14.5 to -12.2] mL/min/1.73 m2) and eGFRcys had a large underestimation (9.9 [9.1-11.2] mL/min/1.73m2), with opposite results in the positive eGFRdiff group. In both negative and positive eGFRdiff groups, eGFRcr-cys was more accurate than either eGFRcr or eGFRcys. These results were largely consistent across age, sex, race, and body mass index.LimitationsFew participants with major comorbid conditions.ConclusionsDiscordant eGFRcr and eGFRcys are common. eGFR using the combination of creatinine and cystatin C provides the most accurate estimates among persons with discordant eGFRcr or eGFRcys.

Project description:Rationale & objectiveRecent reassessment of the use of race in estimated glomerular filtration rate (eGFR) in adults has instigated questions about the role of race in eGFR expressions for children. Little research has examined the associations of self-reported race with measured GFR (mGFR) adjusting for serum creatinine or cystatin C in children and young adults with chronic kidney disease (CKD). This study examined these associations and evaluated the performance of the previously published "U25" (under the age of 25 years) eGFR equations in a large cohort of children and young adults with CKD.Study designObservational cohort study.Setting & participantsParticipants in the Chronic Kidney Disease in Children (CKiD) study including 190 Black and 675 non-Black participants contributing 473 and 1,897 annual person-visits, respectively.ExposureSelf- or parental-reported race (Black, non-Black). Adjustment for serum creatinine or cystatin C, body size, and socioeconomic status.OutcomemGFR based on iohexol clearance.Analytical approachLinear regression with generalized estimating equations, stratified by age (<6, 6-12, 12-18, and ≥18 years) incorporating serum creatinine or serum cystatin C. Contrasting performance in different self-reported racial groups of the U25 eGFR equations.ResultsSelf-reported Black race was significantly associated with 12.8% higher mGFR among children in regression models including serum creatinine. Self-reported Black race was significantly associated with 3.5% lower mGFR after adjustment for cystatin C overall but was not significant for those over 12 years. The results were similar after adjustment for body size and socioeconomic factors. The average of creatinine- and cystatin C-based U25 equations was unbiased by self-reported race groups.LimitationsSmall number of children < 6 years; lean body mass was estimated.ConclusionsDifferences in the creatinine-mGFR relationship by self-reported race were observed in children and young adults with CKD and were consistent with findings in adults. Smaller and opposite differences were observed for the cystatin C-mGFR relationship, especially in the younger age group. We recommend inclusion of children for future investigations of biomarkers to estimate GFR. Importantly, for GFR estimation among those under 25 years of age, the average of the new U25 creatinine and cystatin C equations without race coefficients yields unbiased estimates of mGFR.

Project description:Estimates of glomerular filtration rate (GFR) that are based on serum creatinine are routinely used; however, they are imprecise, potentially leading to the overdiagnosis of chronic kidney disease. Cystatin C is an alternative filtration marker for estimating GFR.Using cross-sectional analyses, we developed estimating equations based on cystatin C alone and in combination with creatinine in diverse populations totaling 5352 participants from 13 studies. These equations were then validated in 1119 participants from 5 different studies in which GFR had been measured. Cystatin and creatinine assays were traceable to primary reference materials.Mean measured GFRs were 68 and 70 ml per minute per 1.73 m(2) of body-surface area in the development and validation data sets, respectively. In the validation data set, the creatinine-cystatin C equation performed better than equations that used creatinine or cystatin C alone. Bias was similar among the three equations, with a median difference between measured and estimated GFR of 3.9 ml per minute per 1.73 m(2) with the combined equation, as compared with 3.7 and 3.4 ml per minute per 1.73 m(2) with the creatinine equation and the cystatin C equation (P=0.07 and P=0.05), respectively. Precision was improved with the combined equation (interquartile range of the difference, 13.4 vs. 15.4 and 16.4 ml per minute per 1.73 m(2), respectively [P=0.001 and P<0.001]), and the results were more accurate (percentage of estimates that were >30% of measured GFR, 8.5 vs. 12.8 and 14.1, respectively [P<0.001 for both comparisons]). In participants whose estimated GFR based on creatinine was 45 to 74 ml per minute per 1.73 m(2), the combined equation improved the classification of measured GFR as either less than 60 ml per minute per 1.73 m(2) or greater than or equal to 60 ml per minute per 1.73 m(2) (net reclassification index, 19.4% [P<0.001]) and correctly reclassified 16.9% of those with an estimated GFR of 45 to 59 ml per minute per 1.73 m(2) as having a GFR of 60 ml or higher per minute per 1.73 m(2).The combined creatinine-cystatin C equation performed better than equations based on either of these markers alone and may be useful as a confirmatory test for chronic kidney disease. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases.).

Project description:BACKGROUND:Higher serum cystatin C level is associated with an increased risk of hip fracture in postmenopausal white women, but there is a paucity of data for men. Whether estimated glomerular filtration rate (eGFR) based on cystatin C (eGFRcys) is superior in predicting hip fracture risk to eGFR based on creatinine (eGFRcr) or the combination (eGFR(cr-cys)) also is uncertain. STUDY DESIGN:Nested case-cohort. SETTING & PARTICIPANTS:Participants enrolled in the Osteoporotic Fractures in Men (MrOS) Study (5,994 men aged ? 65 years from 6 US centers) including a random subcohort of 1,602 men and 168 men with incident hip fractures (51 of whom were in the subcohort). PREDICTOR:eGFR(cys), eGFR(cr), and eGFR(cr-cys) computed using the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equations and expressed in categories of <60, 60-74, and ? 75 mL/min/1.73 m(2) (referent group). OUTCOME:Incident hip fracture ascertained by participant contacts every 4 months and confirmed with radiographic reports. RESULTS:Median eGFR(cys) was 72.9 (IQR, 60.5-85.7) mL/min/1.73 m(2). In unadjusted models, all measures of eGFR were associated with increased hip fracture risk. However, after adjustment for age, race, site, and body mass index, the association of lower eGFR(cys) (but not lower eGFR(cr) or lower eGFR(cr-cys)) with higher hip fracture risk remained: for <60 versus ? 75 mL/min/1.73 m(2), HRs were 1.96 [95% CI, 1.25-3.09], 0.84 [95% CI, 0.52-1.37], and 1.08 [95% CI, 0.66-1.77] for eGFR(cys), eGFR(cr), and eGFR(cr-cys), respectively. Similarly, after adjustment for age, race, site, and body mass index, eGFR < 60 mL/min/1.73 m(2) defined by eGFR(cys), but not eGFR(cr) or eGFR(cr-cys), was associated with higher hip fracture risk. The association between eGFR(cys) and hip fracture was not explained by levels of calciotropic hormones or inflammatory markers, but the relationship was attenuated and no longer reached significance (for <60 vs ? 75 mL/min/1.73 m(2): HR, 1.43; 95% CI, 0.88-2.34) after consideration of additional clinical risk factors and bone mineral density. LIMITATIONS:Findings not generalizable to other populations; residual confounding may exist. CONCLUSIONS:Older community-dwelling men with lower eGFR(cys) have an increased risk of hip fracture that is explained in large part by greater burden of risk factors among men with lower eGFR(cys). In contrast, lower eGFR(cr) or lower eGFR(cr-cys) was not associated with a higher age-adjusted hip fracture risk.

Dataset Information

New combined serum creatinine and cystatin C quadratic formula for GFR assessment in children.

Background and objectives

Design, setting, participants, & measurements

Results

Conclusions

Publications

New combined serum creatinine and cystatin C quadratic formula for GFR assessment in children.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets