Evidence-based clinical guidelines.
KDIGO 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease
“The Kidney Disease: Improving Global Outcomes (KDIGO) 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease (CKD) serves to update the 2002 KDOQI™ Clinical Practice Guidelines for Chronic Kidney Disease: Evaluation, Classification, and Stratification following a decade of focused research and clinical practice in CKD. The document aims to provide state-of-the-art guidance on the evaluation, management and treatment for all patients with CKD. Specifically, the guideline retains the definition of CKD but presents an enhanced classification framework for CKD; elaborates on the identification and prognosis of CKD; discusses the management of progression and complications of CKD; and expands on the continuum of CKD care: timing of specialist referral, ongoing management of people with progressive CKD, timing of the initiation of dialysis, and finally the implementation of a treatment program which includes comprehensive conservative management. The development of the guideline followed an explicit process of evidence review and appraisal. Treatment approaches are addressed in each chapter and guideline recommendations are based on systematic reviews of relevant trials. Practical comments or statements which serve as educational purposes are ungraded, but included as important information for the readership. Appraisal of the quality of the evidence and the strength of recommendations followed the GRADE approach. Ongoing areas of controversies, limitations of the evidence, and international relevance are discussed and additional suggestions are provided for future research.”
The guideline recommends using serum creatinine and a GFR estimating equation for initial assessment of CKD. It suggests using additional tests (such as cystatin C or a clearance measurement) for confirmatory testing in specific circumstances when eGFR based on serum creatinine is less accurate. Confirmation of a decreased eGFR is warranted in specific circumstances where decisions depend on more accurate knowledge of the GFR, such as confirming a diagnosis of CKD, determining eligibility for kidney donation, or adjusting the dosage of toxic drugs that are excreted by the kidneys. It also suggests measuring cystatin C in adults with eGFRcreat 45–59 ml/min/1.73 m2 who do not have markers of kidney damage if confirmation of CKD is required. Another suggestion is measuring GFR using an exogenous filtration marker under circumstances where more accurate ascertainment of GFR will impact on treatment decisions.
KDOQI™ US Commentary on the 2012 KDIGO Clinical Practice Guideline for the Evaluation and Management of CKD
“The National Kidney Foundation–Kidney Disease Outcomes Quality Initiative (NKF-KDOQI™) guideline for evaluation, classification, and stratification of chronic kidney disease (CKD) was published in 2002. The KDOQI™ guideline was well accepted by the medical and public health communities, but concerns and criticisms arose as new evidence became available since the publication of the original guidelines. KDIGO (Kidney Disease: Improving Global Outcomes) recently published an updated guideline to clarify the definition and classification of CKD and to update recommendations for the evaluation and management of individuals with CKD based on new evidence published since 2002. The primary recommendations were to retain the current definition of CKD based on decreased glomerular filtration rate or markers of kidney damage for 3 months or more and to include the cause of kidney disease and level of albuminuria, as well as level of glomerular filtration rate, for CKD classification. NKF-KDOQI™ convened a work group to write a commentary on the KDIGO guideline in order to assist US practitioners in interpreting the KDIGO guideline and determining its applicability within their own practices. Overall, the commentary work group agreed with most of the recommendations contained in the KDIGO guidelines, particularly the recommendations regarding the definition and classification of CKD. However, there were some concerns about incorporating the cause of disease into CKD classification, in addition to certain recommendations for evaluation and management.”
The guideline states estimation of GFR from serum creatinine remains the clinical standard worldwide. It also recognizes the limitations of creatinine and recommends additional confirmatory tests, such as measurement of cystatin C or clearance, in situations when estimates of GFR from serum creatinine are less accurate. For the purposes of estimation of measured GFR, the combination of both markers (cystatin C and creatinine) provides a more precise estimate. The guideline agrees that GFR estimation using cystatin C alone or in combination with creatinine is useful as a confirmatory test of eGFR from creatinine, and that it improves risk stratification.
National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines: Emerging Biomarkers for Primary Prevention of Cardiovascular Disease
The guidelines state cystatin C may be a more powerful predictor of cardiovascular events than eGFR calculation based on creatinine and recommends additional research to determine if interventions based on cystatin C measurements for risk stratification will provide added clinical benefit. Also, the guidelines state cystatin C has been proposed and investigated as an improved marker of renal function, a potential alternative to serum creatinine based estimated GFR, and the results of a meta-analysis support serum cystatin C as a promising, easily measured marker for detecting early kidney function impairment.
2010 ACCF/AHA Guideline for Assessment of Cardiovascular Risk in Asymptomatic Adults: Executive Summary
The American College of Cardiology Foundation (ACCF) and the American Heart Association (AHA) state “Global risk scores (such as the Framingham Risk Score [FRS]) that use multiple traditional cardiovascular risk factors should be obtained for risk assessment in all asymptomatic adults without a clinical history of coronary heart disease. These scores are useful for combining individual risk factor measurements into a single quantitative estimate of risk that can be used to target preventive interventions.”
Cystatin C is not referenced in the guideline. Therefore, there are no recommendations for cystatin C testing for cardiovascular risk assessment.
2013 ACC/AHA Cardiovascular Risk Assessment Guideline
Members of the American College of Cardiology (ACC) and the American Heart Association (AHA) Work Group proposed an initial list of novel risk markers for inclusion in critical question 1 (CQ1), which was then prioritized during several rounds of discussion. In selecting the final list, the Work Group gave priority to factors that have engendered substantial discussion in the scientific community and that could be reasonably considered as potentially feasible for widespread population use by primary care providers in routine clinical settings in the United States. In these deliberations, the Work Group considered availability, cost, assay reliability, and risks of the test or downstream testing. The final list of new risk markers to be evaluated included several blood and urine biomarkers (hs-CRP [high-sensitivity C-reactive protein], ApoB [Apolipoprotein B], creatinine [or eGFR], and microalbuminuria), several measures of subclinical cardiovascular disease (CAC [coronary artery calcium], CIMT [carotid intima-media thickness], and ABI [ankle brachial index]), family history, and cardiorespiratory fitness. It was noted that measurement of ApoB, albuminuria, GFR, or cardiorespiratory fitness is of uncertain value. The contribution of ApoB, CKD, albuminuria, and cardiorespiratory fitness to risk assessment for a first atherosclerotic cardiovascular disease (ASCVD) event is uncertain at present.
Cystatin C is not referenced in the guideline. Therefore, there are no recommendations for cystatin C testing for cardiovascular risk assessment.
