Applicability of estimated glomerular filtration rate in stratifying chronic kidney disease

Objective. The aim of this audit was to evaluate the degree of glomerular filtration rate (GFR) among inpatients and outpatients in a District General Hospital, with special attention given to laboratory testing and impact on health delivery. Background. UK Chronic Kidney Disease guidelines recommend that investigation of renal function should be accompanied by an estimation of GFR (eGFR) in order to identify and manage patients with chronic kidney disease (CKD). The estimated GFR forms the basis for classification of CKD and appropriate action plans for patient management and follow‐up. Method. A retrospective audit of 8160 results from a predominantly British Caucasian population was carried out; extracting creatinine results from two isolated months in years 2001 and 2004. The estimated GFR (eGFR) was calculated using the MDRD formula. The data were classified according to demography, serum creatinine and eGFR. Patients from the 2001 database were classified according to eGFR and those with a value of <60?mL/min/1.73m² were followed up in 2004. Results. The difference in eGFR between the men and women was significantly different with medians (confidence intervals) of 80.1 (41–109) and 64.4 (30–84.6) (p<0.0001), respectively. There was an inverse association between age and eGFR in both genders (p<0.0001), with a decrease in eGFR of around 7?% for each decade increase in age. 1926 patients (24?%) of results studied had eGFR <60?mL/min, of whom 64?% were females and 36?% males. Follow‐up of patients with eGFR<60?mL/min from 2001 showed that 4?% progressed to stages 4 and 5 CKD. Conclusion. eGFR is inversely associated with increasing age and female gender. MDRD derived eGFR fails to completely compensate for age and gender variations and thus different action limits may be required. Small but significant numbers of patients progressed to stages 4 and 5 CKD. Additional clarity in describing “progressive fall in eGFR” in the guidelines would improve identification of the population most at risk.     

肾小球滤过率评估方程在慢性肾脏病患者中的应用评价

目的:评价11种常用的肾小球滤过率(GFR)评估方程在慢性肾脏病(CKD)患者中的适用性.方法: 选择119例CKD患者,用Coekcroft-Gault(CG)方程、MDRD1方程、MDRD3方程、简化MDRD方程、Jelliffe1973(JE73)方程、Mawer(MA)方程、Hull(HU)方程、Jellife1971(JE71)方程、血肌酐倒数公式、Gate(GA)方程、Bjornsson(BJ)方程,分别预测GFR值,与99mTc DTPA测的GFR(sGFR)进行比较.结果:上述11种方程预测的GFR值和sGFR值比较显示,CG方程、MDRD1方程、JE73方程、MA方程、HU方程、JE71方程、GA方程、BJ方程预测的GFR值和sGFR值的差异没有统计学意义.将患者按CKD的不同分期分组,用配对t检验,分别比较上述8种方程预测的GFB值和sGFR值的差异,结果显示只有JE73方程在CKD各期中预测的GFR值和8GFR值的差异均没有统计学差异.结论:JE73方程可能更适合我国CKD患者.     

血清胱抑素C和MDRD方程在慢性肾脏病诊断中的临床应用

目的探讨血清胱抑素-C（Cys—C）在诊断慢性肾脏病（CKD）的意义,以及Cys-C与MDRD方程估计肾小球滤过率（GFR）的准确性及相关性。方法根据MDRD方程7计算的肾小球滤过率（GFR）将CKD患者分为5期,ELISA法检测CKD患者的Cys—C的水平,观察Cys—C与血肌酐（Scr）、GFR的相关性。结果Cys—C与Scr呈正相关,与GFR呈负相关;在肾功能轻度损伤时,Cys-C反映肾功能恶化程度的敏感度较Scr高。结论ELISA法能够检测Cys—C的水平,Cys—C能够作为反映肾功能的可靠指标,并且是肾功能的早期诊断指标。CKD2-5期,Cys—C与MDRD方程7有良好的相关性;Cys-C与MDRD方程7能够作为CKD2-5期患者估计GFR的指标。     

A Foot Ergometer for Graded Muscular Exercise

Objective: In 2002, a uniform definition of chronic kidney disease (CKD) became widely accepted. The level of glomerular filtration rate (GFR) is the pivot for staging the disease. Because GFR is not readily measured in routine clinical practice, statistical models such as the Modification of Diet in Renal Disease (MDRD) equation have been proposed for estimating GFR. The MDRD equation is gaining worldwide acceptance in assisting the diagnosis and staging of CKD. Material and methods: We use theoretical and experimental considerations based on serum creatinine (Scr) measurements obtained with an enzymatic IDMS-traceable assay and compare CKD classifications based on Scr alone with classifications based on the eGFR-MDRD and eGFR-Mayo Clinic equations. Results: Based on recently published reference intervals for enzymatically determined Scr, we show that eGFR-MDRD<60 mL/min/1.73m² corresponds extremely well with Scr>upper reference limit. The different CKD stages III, IV and V can be redefined using Scr alone, resulting in 97.5% agreement. Conclusion: We show that neither the MDRD study equation nor the Mayo Clinic equation add extra value to the information already contained in Scr itself. Because of the limited applicability of the eGFR equations, Scr has even more potential to assist in the diagnosis and classification of CKD than eGFR-MDRD.     

Applicability of estimated glomerular filtration rate in stratifying chronic kidney disease

OBJECTIVE: The aim of this audit was to evaluate the degree of glomerular filtration rate (GFR) among inpatients and outpatients in a District General Hospital, with special attention given to laboratory testing and impact on health delivery. BACKGROUND: UK Chronic Kidney Disease guidelines recommend that investigation of renal function should be accompanied by an estimation of GFR (eGFR) in order to identify and manage patients with chronic kidney disease (CKD). The estimated GFR forms the basis for classification of CKD and appropriate action plans for patient management and follow-up. METHOD: A retrospective audit of 8160 results from a predominantly British Caucasian population was carried out; extracting creatinine results from two isolated months in years 2001 and 2004. The estimated GFR (eGFR) was calculated using the MDRD formula. The data were classified according to demography, serum creatinine and eGFR. Patients from the 2001 database were classified according to eGFR and those with a value of <60 mL/min/1.73 m(2) were followed up in 2004. RESULTS: The difference in eGFR between the men and women was significantly different with medians (confidence intervals) of 80.1 (41-109) and 64.4 (30-84.6) (p<0.0001), respectively. There was an inverse association between age and eGFR in both genders (p<0.0001), with a decrease in eGFR of around 7 % for each decade increase in age. 1926 patients (24 %) of results studied had eGFR <60 mL/min, of whom 64 % were females and 36 % males. Follow-up of patients with eGFR<60 mL/min from 2001 showed that 4 % progressed to stages 4 and 5 CKD. CONCLUSION: eGFR is inversely associated with increasing age and female gender. MDRD derived eGFR fails to completely compensate for age and gender variations and thus different action limits may be required. Small but significant numbers of patients progressed to stages 4 and 5 CKD. Additional clarity in describing "progressive fall in eGFR" in the guidelines would improve identification of the population most at risk.     

4种估算肾小球滤过率公式在体检人群中的应用评价

目的评价4种基于血清肌酐(Cr)或基于血清半胱氨酸蛋白酶抑制剂C(Cys C)的估算肾小球滤过率公式在体检人群中的适用性。方法随机取出2 032例体检健康者,分别检测血清Cr、Cys C、尿清蛋白和肌酐比值(ACR),通过4种公式,即同位素稀释质谱法-肾脏病膳食改善公式(IDMS-MDRD)、慢性肾脏病流行病合作组(CKD-EPI)公式(EPI-Cr、EPI-Cys C和EPI-CrCys C),分别计算其估算的肾小球滤过率(e GFR)并进行比较。结果 2 032例体检健康者血清Cr为(65.4±14.3)μmol/L,血清Cys C为(0.77±0.19)mg/L,ACR中位数为3.1 mg/g。将4种公式计算的e GFR值按照60 m L/min/1.73 m~2、60~89m L/min/1.73 m~2、≥90 m L/min/1.73 m~2分为3组,3组分布差异均有统计学意义(P0.05)。联合4种公式计算的e GFR和ACR对CKD预后分为低危、中危、高危和极高危4期,各期分布差异无统计学意义(P均0.05)。在2 032例健康人群中,以EPI-Cr公式计算的e GFR值在45~60 m L/min/1.73 m~2之间的例数为44例(2.2%),以IDMS-MDRD公式计算的e GFR值在45~60 m L/min/1.73 m~2之间的例数为58例(2.9%),该58例人群的ACR结果有45例30 mg/g,以EPI-Cr-Cys公式计算该45例人群的e GFR值,有40例60 m L/min/1.73 m~2。结论联合e GFR和ACR对CKD预后进行分期,4种公式的一致性高。对于选用基于血清Cr的IDMS-MDRD公式计算的e GFR值,如果在45~60 m L/min/1.73 m~2之间,建议检测Cys C,并且采用血清Cr和Cys C联合公式计算e GFR,以减少对患者GFR的误判。     

不同方程估算的肾小球滤过率在人群肾功能评价中的差异比较

目的比较3种肾小球滤过率(GFR)估算方程估算的GFR(eGFR)对人群肾功能评估的结果差异。方法本研究回顾性分析了门诊和住院患者中同时进行血清肌酐和胱抑素C检测者,共65 856例,以3个估算方程分别计算eGFR,并比较整体及不同肾功能分组人群eGFR结果的差异。以3个方程得到的eGFR对个体肾功能重新分期,比较肾功能各分期例数分布的差异。结果与肌酐方程估算eGFR比较,另两个方程估算eGFR的相关系数分别为0.81、0.90(均P0.05)。一致性分析GFR均值差值分别为6.19、1.79mL/(min×1.73m2),差异有统计学意义(P0.01),应用肌酐方程估算eGFR时,明显高估了个体的肾功能分期。结论 3种方程估算GFR有相关性但存在明显差异,在评估不同人群肾功能时应选择合适的估算方程。     

CKD-EPI 开发方程在评价慢性肾脏病患者病情中的作用

目的：分析评价美国慢性肾脏病（CKD）流行病合作工作组（CKD‐EPI）开发方程在 CKD 患者病情评估中的作用。方法2012年1月至2014年4月湖北省中医院肾病门诊260例 CKD 患者,用 CKD‐EPI 开发方程计算肾小球滤过率（GFR）（EPI‐GFR）,同 CKD 患者血肌酐（Cr）、尿酸（UA）、清蛋白（ALB）、钙（Ca）、磷（P）、胱抑素 C（CysC）、24 h 尿蛋白（UP）、血红蛋白（Hb）等生化指标比较,并与简化肾脏病饮食改良（MDRD）方差计算的 eGFR（简化‐GFR）和中国人校正的 MDRD 方程计算的 eGFR（校正‐GFR）进行比较。结果 EPI‐GFR 与 Cr 、UA 、CysC 、P 及24 h UP 呈显著负相关（P ＜0．05）,与 Hb 差异有统计学意义（P＜0．05）,呈显著正相关,随着病程进展,GFR 逐渐下降,患者贫血也逐渐加重,ALB 、Ca 出现不同程度的下降。简化‐GFR 和校正‐GFR 与 EPI‐GFR 的相关性均较好（r 分别为0．997和0．995,P ＜0．05）。 EPI‐GFR 比简化‐GFR 平均值高约0．49 mL／（min ×1．73 m2）,比校正‐GFR 平均值低约0．81 mL ／（min ×1．73 m2）。结论以 CKD‐EPI 开发方程计算 GFR ,对 CKD 患者肾功能的损伤评价有较好相关性及较好的预测能力,测定简便易行,可弥补其他评估方程导致的过度治疗或降低分级诊断的缺陷,为 CKD分期提供了极大便利,可在临床常规肾功能检测中推广使用。     

Comparing different estimated glomerular filtration rate equations in assessing glomerular function in children based on creatinine and cystatin C

Background

Glomerular filtration rate (GFR) is the best marker used to assess renal function. Estimated GFR (eGFR) equations have been developed, and the ideal formula is still under discussion. We wanted to find the most practical and reliable GFR in eGFR formulas. We compared serum creatinine (Scr)‐ and cystatin C (cysC)‐based eGFR formulas in the literature. We also aimed to determine the suitability and the reliability of cysC for practical use in determining GFR in children.

Methods

We have enrolled 238 children in the study. Measurement of 24‐hour creatinine clearance was compared with eGFR equations which are based on Scr, cysC, and creatinine plus cysC.

Results

Of the patients (n = 238), 117 were males (49.2%), and 121 (50.8%) were females with a median age of 9.0 years. The areas under the ROC curves of Counahan‐Barratt and Bedside Schwartz were equal and 0.89 (with a 95% CI 0.80‐0.97). The areas under the ROC curves were not significantly different in all cystatin C‐based eGFR equations. The highest AUC values for differentiating normal vs abnormal renal functions according to CrCl₂₄ were for the CKiD‐cysC and CKiD‐Scr‐cysC equations.

Conclusions

In our study, compared with creatinine‐based ones, the cystatin C‐based formulas did not show much superiority in predicting eGFR. Still, we think Bedside Schwartz is a good formula to provide ease of use because, in this equation, the constant k is same for all age groups. However, the most valuable equations in determining chronic kidney disease are the CKiD‐cysC and CKiD‐Scr‐cysC equations.

     

CystatinC在评价CKD患者肾小球滤过功能中的作用

目的比较血清胱抑素c（CystatfnC）、血清肌酐（Scr）、肌酐清除率（Ccr）在慢性肾病（CKD）患者各期与简化MDRD方程估算的肾小球滤过率（eGFR）的符合率。方法血清胱抑索c采用免疫透射比浊法测定,scr和尿肌酐采用酶法测定。估算的eGFR采用简化MDRD方程进行计算。CKD患者临床分期采用美国NFK—K／DOQI指南分期。结果109例CKD患者各期CystatinC、Scr随eGFR的降低而逐渐升高,Ccr随eGFR的降低而逐渐降低,三者在各期间水平的差异均有统计学意义（P〈0．05）。当eGFR≤29ml／min时。CystatinC、Scr、Ccr均为100％的异常,CystatinC、Scr平均水平是参考范围上限的5倍左右,ccr下降4—6倍,三者呈平行性改变;在eGFR30—59ml／min组,CystatinC、Scr、Ccr的平均水平分别为2．54mg／L、144．6gmol／L和50．6ml／min,异常率分别为95％、83％和85％,三者之间异常率的差异无统计学意义（P〉0．05）;在eGFR60．89ml／min组,cvs—tatinC、Ccr异常率为84％和63％,Scr异常率为5．9％,三者之间异常率的差异具有统计学意义（P〈0．05）;在eGFR≥90m1／min组,CystatinC、Ccr异常率为5l％和40％,Scr异常率为l％。结论eGFR〈59ml／min时,CystatlnC、scr、Ccr的结果一致好,与诂算的结果符合率高,基本可以诊断肾小球滤过功能中度下降;当eGFR在60。89ml／min时,CystatinC、Ccr可以检出2／3患者肾小球滤过率的异常,且CystatinC更敏感,而scr不能反应肾小球滤过功能的下降;当eGFR≥90ml／min时,MDRD方程过高估计eGFR值,需检测CystafinC和Ccr以及时发现eGFR的下降。     

不同肾小球滤过率预估公式的评价

目的 将四个研究团队(Macisaac、Perkins、Rule、Stevens)的Cys C为变量估算肾小球滤过率(eGFR)公式,与以肌酐为变量之一的简化肾脏病膳食改善方程(MDRD)比较,在2型糖尿病人群肾脏损害各个阶段中,单独或联合应用,是否更能改进eGFR的准确性.方法 检测213例2型糖尿病患者的血清肌酐和Cys C,并运用六个不同的公式作eGFR.结果 六个预估公式均呈正态分布;在GFR的五个临床分期中,均数间多重比较,1、2、3期差异有统计学意义(P＜0.01);以MDRD方程为基准,比较以Cys C为变量的五个估算公式,1、2期Perkins和Macisaac的预估公式值大于MDRD值,3期中Steven的2个估算公式值接近.结论 2型糖尿病人群不同GFR临床分期,基于Cys C和Cr所作预估公式间有不同变化,相同趋势,两者可以互相参考和补充;在1、2期中,Cys C预估公式可能优于Cr.建议在标准化Cys C检测的基础上,扩大研究人群,建立全段和各个分期内eGFR的预估公式.     

老年患者慢性肾脏病诊断率的调查研究

目的回顾性研究老年住院患者慢性肾脏病(CKD)的诊断情况,探讨引起老年CKD诊断率差异的因素。方法以1 042例具有3个月以上完整病历资料的内科老年住院患者为研究对象,并以病历首页资料齐全的4 984例内科老年住院患者的首页内科诊断目录进行对比分析。采集尿常规、尿白蛋白、尿肌酐、血肌酐、尿素氮、肾脏B超检查结果,用CKD-EPI公式估算肾小球滤过率(eGFR)。结果 1肾病科医师依据2012年KDIGO-CKD诊断标准进行诊断,CKD诊断率为33.49%;内科医师以"慢性肾小球肾炎、肾小管间质疾病、继发性肾脏疾病、慢性肾功能不全"作为CKD诊断依据,CKD诊断率为10.67%,差异有显著统计学意义(P0.01);218.33%的老年住院患者被漏诊,CKD G2期和G3a期患者是被漏诊的主要人群;3随年龄增加,CKD诊断率增加,差异有显著统计学意义(P0.01)。结论医师认知不同、加上肾功能随增龄的变化,是老年患者CKD诊断率差异的主要因素。提高医师对老年CKD的认知,能及时、准确诊断老年CKD。     

三种CKD-EPI公式在女性慢性肾病人群中估算肾小球滤过率的比较

目的评价在我国女性慢性肾病(CKD)患者人群中3种CKD-EPI公式计算肾小球滤过率估算值(eGFR)的性能。方法将2010年1月至2015年1月在江苏省中医院肾内科住院的女性CKD患者75例纳入本研究,收集患者的一般资料、血清肌酐(Cr)水平、血清胱抑素C(CycC)水平和99 mTc-DTPA肾动态显像资料。以99 mTc-DTPA肾动态显像法所测肾小球滤过率(GFR)为金标准,用3种CKD-EPI公式(EPI_(Scr)、EPI_(CysC)和EPI_(Scr-CysC))估算eGFR,比较3种公式的偏倚、准确性和95%一致性范围。结果整体公式性能比较,偏倚方面三种公式绝对偏倚比较差异无统计学意义(P0.05);准确度方面:相对偏倚在±30%范围内百分率,CKD-EPICysC与CKD-EPI_(Scr)公式间比较差异有统计学意义(66.67%vs.56.00%,P0.05);一致性方面:BlandAltman散点图显示,CKD-EPI_(Scr-CysC)、CKD-EPI_(Scr)、CKD-EPI_(CysC)公式的95%一致性范围分别为(-33.0%,36.1%)、(-38.4%,35.7%)和(-33.7%,36.6%)。CKD早期,偏倚和准确度方面三个公式比较差异无统计学意义(P0.05),一致性方面:CKDEPI_(Scr-CysC)、CKD-EPI_(Scr)和CKD-EPI_(CysC)公式的95%一致性范围分别为(-33.5%,36.9%)、(-39.0%,36.4%)和(-34.3%,37.5%)。结论尽管CKD-EPI_(Scr-CysC)公式在评估中表现最为优秀,但三种CKD-EPI公式性能差异并不十分明显,在临床实际中仍需综合考虑。     

血清肌酐和半胱氨酸蛋白酶抑制剂C及估算的肾小球滤过率在评价慢性肾病患者肾小球滤过功能中的比较研究

目的比较血清肌酐（Scr）、肌酐清除率（Ccr）、半胱氨酸蛋白酶抑制剂C（CystatinC）及估算的肾小球滤过率（eGFR）在慢性肾病（CKD）患者各期中的符合率。方法Scr和尿肌酐采用苦味酸动力学法测定，血清CystatinC采用颗粒增强免疫散射比浊法测定，主要基于Scr估计的eC．FR采用简化的肾病膳食改良试验（MDRD）方程进行计算，CKD患者根据1999年美国肾病基金会（NKF）公布的“改善肾病预后及生活质量的倡议”（KidneyDiseaseOutcomeQualityInitiative，K／DOQI）所制定的指南，按照eGFR分为5期。结果228例CKD患者，各期Scr、CystatinC随eGFR的降低而逐渐升高，Ccr随eGFR的降低而逐渐降低，三者在各期间水平的差异均有统计学意义（P〈0．05）。当eGFR≤29ml／min时，Scr、Ccr及CystatinC的异常率均为100％，Scr、CystatinC平均水平是正常参考值上限的4—6倍和3．5—5．5倍，Ccr下降3．8—7．3倍，三者呈平行性改变；在eGFR30—59ml／min组，Scr、Ccr和CystatinC的平均水平分别为129．2μmol／L、44．3ml／min和2．16mg／L，异常率分别为84％、91％和98％，三者间异常率的差异无统计学意义（P〉0．05）；在eGFR60—89ml／min组，血清肌酐的平均水平为83．3μmol／L，异常率仅为6．8％，对于GFR下降的检出不敏感，Ccr、CystatinC分别呈边缘性下降和上升，异常率为70％和86％，三者问异常率的差异有统计学意义（P〈0．05）；在eGFR≥90ml／min组，血清肌酐的异常率为0，Ccr、CystatinC的异常率仍高达44％和59％。结论eGFR〈60ml／min时，与Scr、Ccr及CystatinC的总符合率高，此时可以基本诊断肾小球滤过功能中度下降；60ml／min≤eGFR≤89ml／min时，Scr不能反映肾脏滤过功能的下降，但CystatinC和Ccr至少能检出2／3患者GFR的异常，CystatinC较Ccr更敏感；在eGFR≥90ml／min时，MDRD方程高估了实际GFR，对于Scr水平正常，特别是老年CKD患者，MDRD方程不适用，需联合检测Ccr和CystatinC，以及时发现GFR的下降。     

计算法测定肾小球滤过率的临床对比研究

目的 探讨计算法测定肾小球滤过率（GFR）的临床应用价值。方法 采用^99mTc—DTPA清除率准确测定106例不同疾病住院患者GFR（Tc—GFR），并测血清肌酐及尿素氮，同时以WCP公式、Robert公式计算GFR（WCP—GFR、Robert—GFR），以Cockcroft／Gault公式计算内生肌酐清除率（CG—CCr），所得数据进行对比研究及相关分析。结果WCP—GFR、Robert—GFR、CG—CCr均能在一定程度上准确反映GFR，而以wCP—GFR更准确，可代替Tc—GFR应用于临床。结论 WCP—GFR是一种准确、简便、快速、安全而廉价测定GFR的方法，值得临床推广应用。     

Glycated albumin is independently associated with estimated glomerular filtration rate in nondiabetic patients with chronic kidney disease

BackgroundGlycated albumin (GA) may contribute to diabetic nephropathy, but the clinical significance of GA in patients with chronic kidney disease (CKD) is unknown.MethodsPatients were classified with the NKF/DOQI classification system as mild (stage I, II), moderate (stage III), or advanced CKD (stage IV). Those undergoing dialysis or with CKD stage V were excluded. GA was measured using the Lucica TM GA-L assay kit. The relationship between GA and renal dysfunction was analyzed in patients with or without diabetes.ResultsA total of 187 subjects were enrolled. GA values in those with normal, mild, moderate and advanced CKD were 18.4 ± 1.4%, 18.4 ± 3.1%, 19.0 ± 3.8%, 20.4 ± 6.4%, respectively, in diabetic patients (N = 67, p = 0.5), and were 14.1 ± 1.9%, 14.2 ± 2.2%, 15.9 ± 1.9%, 15.0 ± 1.7%, respectively, in nondiabetic patients (N = 120, p = 0.004). GA value was negatively correlated to eGFR in nondiabetic patients (r = ?0.35, p < 0.001) but not in diabetic patients (r = ?0.11, p = 0.39). In the adjusted model, GA is independently correlated to eGFR only in nondiabetic subjects.ConclusionsIncreased GA concentrations are independently associated with renal dysfunction in nondiabetic patients with CKD.     

Chronic kidney disease and risk of mortality,cardiovascular events or end-stage renal disease in older patients with hypertension

Older individuals with a diagnosis of chronic kidney disease are at higher risk of all-cause mortality, cardiovascular (CV) events and end-stage renal disease. In such patients, the glomerular filtration rate may be estimated with different formulas, including the Modification of Diet in Renal Disease and the Chronic Kidney Disease Epidemiology Collaboration equations. The recently published post-hoc analysis of the long-term CV and renal outcomes of the ALLHAT trial that enrolled older patients with hypertension and high CV risk, but very low risk of renal disease progression, clearly highlights the interpretative pitfalls associated with this approach. Until future studies better establish the boundaries of ‘normal’ glomerular filtration rate in older people, physicians should not underestimate the importance of proteinuria and accurate glomerular filtration rate measurement in choosing the most appropriate antihypertensive combination in daily clinical practice, particularly in patients at high risk of progression to end-stage renal disease.