GFR Estimation Using a Panel of Filtration Markers in Shanghai and Beijing.

Rationale & Objectives: Estimated glomerular filtration rate (eGFR) using creatinine and cystatin C (eGFR) may be less accurate compared to measured GFR (mGFR) in China than in North America, Europe, and Australia due to variation across regions in their non-GFR determinants. The non-GFR determinants of β-microglobulin (B2M) and β-trace protein (BTP) differ from those of creatinine and cystatin C. Thus, the average eGFR using all 4 markers (eGFR) could be more accurate than eGFR in China.

Non-GFR Determinants of Low-Molecular-Weight Serum Protein Filtration Markers in the Elderly: AGES-Kidney and MESA-Kidney.

Background: Studies in chronic kidney disease populations suggest that the non-glomerular filtration rate (GFR) determinants of serum levels of the low-molecular-weight protein filtration markers cystatin C, β-microglobulin (B2M), and beta-trace protein (BTP) are less affected by age, sex, and ethnicity than those of creatinine.

Study Design: Cross-sectional study.

Setting & Participants: Predominantly elderly participants selected from the Age, Gene/Environment Susceptibility Kidney Study (AGES-Kidney; N=683; mean [SD] age, 79 [4] years; GFR, 62 [17]mL/min/1.

Performance of glomerular filtration rate estimating equations in a community-based sample of Blacks and Whites: the multiethnic study of atherosclerosis.

Background: The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations are recommended for glomerular filtration rate (GFR) estimation in the general population. They have not been evaluated in community-based populations, including Blacks at higher levels of GFR, but are commonly applied in such populations.

Methods: In an ancillary study of Multi-Ethnic Study of Atherosclerosis conducted at one site, we evaluated the performance of the CKD-EPI equations for creatinine (eGFRcr), cystatin C (eGFRcys) or the combination (eGFRcr-cys) compared with GFR measured as plasma clearance of iohexol.

Effects of Race and Sex on Measured GFR: The Multi-Ethnic Study of Atherosclerosis.

Background: Kidney failure disproportionately affects older blacks versus whites. The reasons are unknown and may be related to lower measured glomerular filtration rate (GFR) and higher levels of albuminuria in community-based population samples.

Study Design: Cross-sectional analysis of a substudy of a prospective cohort.

Prevalence and complications of chronic kidney disease in a representative elderly population in Iceland.

Background: Chronic kidney disease (CKD) is common in the elderly, but data are limited on the distribution of glomerular filtration rate (GFR) and albuminuria and the prevalence of CKD and related complications in this population.

Methods: A cross-sectional study of 3173 older Icelandic adults [42% men; mean (standard deviation, SD) age of 80 (5) years] was performed to examine the distribution of estimated glomerular filtration rate (eGFR) from creatinine and cystatin C, the albumin-to-creatinine ratio (ACR), and CKD-related metabolic complications (hyperparathyroidism, anemia, hypoalbuminemia, increased anion gap, acidosis, hyperphosphatemia and hyperkalemia).

Results: There was substantial variability in eGFR [mean (SD) 64 (18) mL/min/1.

Midlife Blood Pressure and Late-Life GFR and Albuminuria: An Elderly General Population Cohort.

Background: Chronic kidney disease (CKD) is common in the elderly, but the cause is often not identifiable. Some posit that age-related reductions in glomerular filtration rate (GFR) and increases in albuminuria are normal, whereas others suggest that they are a consequence of vascular disease.

Study Design: Cross-sectional analysis of a substudy of a prospective cohort.

Early change in proteinuria as a surrogate end point for kidney disease progression: an individual patient meta-analysis.

Background: It is controversial whether proteinuria is a valid surrogate end point for randomized trials in chronic kidney disease.

Study Design: Meta-analysis of individual patient-level data.

Setting & Population: Individual patient data for 9,008 patients from 32 randomized trials evaluating 5 intervention types.

Use of glomerular filtration rate estimating equations for drug dosing in HIV-positive patients.

Background: Current HIV treatment guidelines recommend using the Cockcroft-Gault equation for drug dosing adjustments. The use of newer glomerular filtration rate (GFR) estimating equations for drug dosing and the appropriateness of physician antiretroviral dosing based on estimated kidney function have not been studied in an HIV-positive population.

Methods: We evaluated concordance between measured and estimated GFR for the assignment of kidney function categories designated by the US Food and Drug Administration (FDA) Guidance for industry for pharmacokinetic studies, and appropriateness of physician antiretroviral drug dosing for level of kidney function in 200 HIV-positive patients on stable antiretroviral therapy.

Performance of creatinine and cystatin C GFR estimating equations in an HIV-positive population on antiretrovirals.

Objective: To evaluate the performance of Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) creatinine, cystatin C, and creatinine-cystatin C estimating equations in HIV-positive patients.

Methods: We evaluated the performance of the Modification of Diet in Renal Disease (MDRD) Study and CKD-EPI creatinine 2009, CKD-EPI cystatin C 2012, and CKD-EPI creatinine-cystatin C 2012 glomerular filtration rate (GFR) estimating equations compared with GFR measured using plasma clearance of iohexol in 200 HIV-positive patients on stable antiretroviral therapy. Creatinine and cystatin C assays were standardized to certified reference materials.

Cystatin C as a marker of glomerular filtration rate: prospects and limitations.

Purpose Of Review: There is much interest in cystatin C to replace or supplement serum creatinine to estimate the glomerular filtration rate (GFR). Here we review the performance of cystatin C and combined creatinine-cystatin C estimating equations compared to creatinine-based estimating equations in chronic and acute kidney disease.

Recent Findings: Drift in the cystatin C assay has had a large effect on the results reported using cystatin C, but these issues are not routinely considered in evaluation of GFR-estimating equations.

Early change in proteinuria as a surrogate outcome in kidney disease progression: a systematic review of previous analyses and creation of a patient-level pooled dataset.

Background: Proteinuria is a candidate surrogate end point for randomized controlled trials (RCTs) in chronic kidney disease (CKD). There is a reasonably sound biological basis for this hypothesis, but only preliminary empirical evidence currently exists.

Methods: A systematic review and creation of a patient-level dataset of randomized controlled trials (RCTs) in CKD that reported changes in proteinuria and assessed progression of kidney disease as defined by dialysis, transplantation, death, or changes in GFR or creatinine were performed.

Comparison of drug dosing recommendations based on measured GFR and kidney function estimating equations.

Background: Kidney disease alters the pharmacokinetic disposition of many medications, requiring dosage adjustment to maintain therapeutic serum concentrations. The Cockcroft-Gault (CG) equation is used for pharmacokinetic studies and drug dosage adjustments, but the Modification of Diet in Renal Disease (MDRD) Study equation is more accurate and more often reported by clinical laboratories than the CG equation.

Study Design: Diagnostic test study.

Tai Chi for treating knee osteoarthritis: designing a long-term follow up randomized controlled trial.

Background: Knee Osteoarthritis (KOA) is a major cause of pain and functional impairment among elders. Currently, there are neither feasible preventive intervention strategies nor effective medical remedies for the management of KOA. Tai Chi, an ancient Chinese mind-body exercise that is reported to enhance muscle function, balance and flexibility, and to reduce pain, depression and anxiety, may safely and effectively be used to treat KOA.