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Impact of reporting estimated glomerular filtration rate: it's not just about us

2009; Elsevier BV; Volume: 76; Issue: 3 Linguagem: Inglês

10.1038/ki.2009.143

1523-1755

Lesley A. Stevens, Andrew S. Levey,

Liver Disease Diagnosis and Treatment

The reporting of estimated glomerular filtration rate (eGFR) is a key component of a public-health strategy for chronic kidney disease (CKD). Jain and colleagues show that eGFR reporting in Ontario increased referrals to nephrologists by 23 consults per year, equivalent to 2.9 additional consults per 100,000 population. In our view, a complete assessment requires a broader perspective. Most patients with CKD do not require referral to a nephrologist. Improving outcomes requires coordinated efforts of all physicians. The reporting of estimated glomerular filtration rate (eGFR) is a key component of a public-health strategy for chronic kidney disease (CKD). Jain and colleagues show that eGFR reporting in Ontario increased referrals to nephrologists by 23 consults per year, equivalent to 2.9 additional consults per 100,000 population. In our view, a complete assessment requires a broader perspective. Most patients with CKD do not require referral to a nephrologist. Improving outcomes requires coordinated efforts of all physicians. Clinical assessment of kidney function is central to the practice of medicine. Glomerular filtration rate (GFR) is considered to be the best index of overall kidney function in health and disease. Accurate assessment of GFR levels is important for detection, evaluation of the severity and progression, and initiation of appropriate management for both acute and chronic kidney disease. Recent estimates in the United States suggest a prevalence of chronic kidney disease (CKD) among adults of 13.1%, and up to 45% in those age 70 or above.1.Coresh J. Selvin E. Stevens L.A. et al.Prevalence of chronic kidney disease in the United States.JAMA. 2007; 298: 2038-2047Crossref PubMed Scopus (3662) Google Scholar Outcomes of CKD include not only kidney failure but also complications of decreased GFR and increased risk for cardiovascular disease. Advanced CKD is often complicated by anemia or mineral and bone disorders, but earlier stages are associated with an increased risk for acute kidney injury and side effects of medications and procedures. As nephrologists, we are appropriately most concerned with the small fraction of patients with advanced kidney disease and kidney failure (less than 1% of US adults). However, improving outcomes for all patients with CKD requires the coordinated efforts of nephrologists, other specialists, and primary-care physicians. Indeed, because of its high prevalence, poor outcomes, and high cost, CKD has now been recognized as a public-health problem, requiring cooperation among federal, state, and local governmental and private organizations, in addition to physicians.2.Levey A.S. Schoolwerth A.C. Burrows N.R. et al.Comprehensive public health strategies for preventing the development, progression, and complications of CKD: report of an expert panel convened by the Centers for Disease Control and Prevention.Am J Kidney Dis. 2009; 53: 522-535Abstract Full Text Full Text PDF PubMed Scopus (154) Google Scholar The reporting of estimated GFR (eGFR) was identified as a key component of a public-health strategy for CKD in the first clinical practice guidelines for CKD and has since been endorsed by national and international groups. In the United States, recent reports show that more than 75% of laboratories now report eGFR.3.Miller W.G. Reporting estimated GFR: a laboratory perspective.Am J Kidney Dis. 2008; 52: 645-648Abstract Full Text Full Text PDF PubMed Scopus (60) Google Scholar In other countries with greater coordination of clinical laboratory systems, these figures are even higher. Focusing on eGFR enables public-health campaigns with simple messages such as ‘Know your number’ and ‘Save your kidney function.’ These messages are analogous to those used for hypertension, diabetes, or hyperlipidemia, which are easily understood by all clinicians, patients, and the public. As with other public-health initiatives, randomized trials were not available before implementation of eGFR reporting. Therefore, studies of the impact of eGFR reporting on clinical practice, patient care, and public health are important and informative. Jain and colleagues4.Jain A.K. McLeod I. Huo C. et al.When laboratories report estimated glomerular filtration rates in addition to serum creatinines, nephrology consults increase.Kidney Int. 2009; 76: 318-323Abstract Full Text Full Text PDF PubMed Scopus (87) Google Scholar (this issue) focus on the impact of eGFR reporting on nephrology referrals in Ontario, Canada, from January 1999 to September 2007. The design and analysis were rigorous. The authors used the Ontario provincial health administrative database, which allows for complete ascertainment with little concern for disenrollment. They used seasonal time series modeling to examine changes over time. Based on their report, the following details emerge. eGFR reporting was implemented in all outpatient clinical laboratories in January 2006, affecting the reporting of approximately 4.8 million serum creatinine results per year for an adult population of 8.9 million served by approximately 135–140 non-salaried nephrologists. The initiative was not accompanied by a province-wide educational program, but laboratory reports did include prompts to relate levels of eGFR to CKD. After implementation, non-urgent nephrology referrals increased from 18,372 (134 per nephrologist) per year to 21,805 (156 per nephrologist) per year. The 23 additional consults per nephrologist per year translate to an increase in the rate of referral by 2.9 consults per 100,000 population, with a greater increase in women and the elderly. The authors describe their findings as consistent with other reports in the literature and conclude that eGFR reporting likely caused the increase in nephrology referrals. Limitations of the analysis are that the authors were not able to determine the clinical characteristics of the patients referred, the clinical care provided by the nephrologists, nor the patient outcomes. Physician awareness of CKD is low,5.Plantinga L.C. Boulware L.E. Coresh J. et al.Patient awareness of chronic kidney disease: trends and predictors.Arch Intern Med. 2008; 168: 2268-2275Crossref PubMed Scopus (203) Google Scholar and in the United States a substantial minority of patients do not see a nephrologist until just before the initiation of dialysis for chronic kidney failure. Studies have documented the association of referral to nephrologists with improved outcomes.6.Levinsky N.G. Specialist evaluation in chronic kidney disease: too little, too late.Ann Intern Med. 2002; 137: 542-543Crossref PubMed Scopus (42) Google Scholar,7.Tseng C.L. Kern E.F. Miller D.R. et al.Survival benefit of nephrologic care in patients with diabetes mellitus and chronic kidney disease.Arch Intern Med. 2008; 168: 55-62Crossref PubMed Scopus (87) Google Scholar Earlier detection and earlier referral are certainly important and worthwhile outcomes. However, the number of people with earlier stages of CKD far outweighs the number with kidney failure, so it is not feasible for nephrologists to care for all patients with CKD. Thus, Jain and colleagues4.Jain A.K. McLeod I. Huo C. et al.When laboratories report estimated glomerular filtration rates in addition to serum creatinines, nephrology consults increase.Kidney Int. 2009; 76: 318-323Abstract Full Text Full Text PDF PubMed Scopus (87) Google Scholar speculate about the appropriateness of the additional referrals. However, in our view, before we can question the appropriateness of referrals, we first must develop consensus on a care model for CKD that describes the role of nephrologists, other specialists, and primary-care physicians and indications for referral to nephrologists. This task is hampered by the absence of a widely used prediction score for progression to kidney failure. A strategy of delaying referral until patients have further decline in kidney function is not appropriate, as it risks losing the opportunity gained from early detection. Finally, we must acknowledge that nephrologists have a role in the management of patients, even those who do not progress. Other studies have assessed the appropriateness of referral following implementation of eGFR reporting. A report from Australia by Noble and colleagues suggested that the number of appropriate and inappropriate referrals to nephrologists increased after eGFR reporting.8.Noble E. Johnson D.W. Gray N. et al.The impact of automated eGFR reporting and education on nephrology service referrals.Nephrol Dial Transplant. 2008; 23: 3845-3850Crossref PubMed Scopus (61) Google Scholar Similar results were observed by Richards and colleagues in the United Kingdom.9.Richards N. Harris K. Whitfield M. et al.Primary care-based disease management of chronic kidney disease (CKD), based on estimated glomerular filtration rate (eGFR) reporting, improves patient outcomes.Nephrol Dial Transplant. 2008; 23: 549-555Crossref PubMed Scopus (82) Google Scholar In the latter study, the authors were also able to demonstrate a decreased mortality of referred patients with CKD stage 4. In both analyses, there was no concern that the observed higher referral rate would exceed nephrology capacity in their respective countries. Figure 1 suggests possible indications for referral to nephrologists.10.K'DOQI clinical practice guidelines on hypertension and antihypertensive agents in chronic kidney disease Kidney Disease Outcomes Quality Initiative (K'DOQI).Am J Kidney Dis. 2004; 43: S1-S290PubMed Google Scholar Importantly, one indication is that all patients with an eGFR less than 30 ml/min per 1.73 m2 (CKD stage 4) should be referred. A recent analysis of data from the National Health and Nutrition Examination Survey (NHANES) suggests that approximately 18.6% of people with CKD stage 3 would also meet these criteria.11.Castro A.F. Coresh J. CKD surveillance using laboratory data from the population-based National Health and Nutrition Examination Survey (NHANES).Am J Kidney Dis. 2009; 53: S46-S55Abstract Full Text Full Text PDF PubMed Scopus (77) Google Scholar These data provide a useful starting point for developing care models for CKD. The article by Jain and colleagues4.Jain A.K. McLeod I. Huo C. et al.When laboratories report estimated glomerular filtration rates in addition to serum creatinines, nephrology consults increase.Kidney Int. 2009; 76: 318-323Abstract Full Text Full Text PDF PubMed Scopus (87) Google Scholar represents an excellent first step in the evaluation of this large-scale initiative. However, for a more complete assessment we need data on awareness of CKD by primary-care physicians and other specialists, and appropriate evaluation and management of patients with CKD by nephrologists and other health-care providers. In one large clinical population, the average age of patients with CKD was approximately 70 years, and death was approximately 25 times more common than progression to kidney failure.12.Keith D.S. Nichols G.A. Gullion C.M. et al.Longitudinal follow-up and outcomes among a population with chronic kidney disease in a large managed care organization.Arch Intern Med. 2004; 164: 659-663Crossref PubMed Scopus (1283) Google Scholar Even among patients with CKD stage 4, death was three times more common than initiation of dialysis. The recent publication of clinical practice guidelines for many of the conditions affecting patients with early stages of CKD should enable primary-care physicians and other specialists to deal with many of the routine problems. In our view, most patients with CKD do not need to be referred to a nephrologist. This is similar to other common chronic conditions affecting older adults. Not all patients with type 2 diabetes are referred to an endocrinologist, and not all patients with cardiovascular disease are referred to a cardiologist. Thus, we need to know whether eGFR reporting has led to greater adherence by all physicians to these guidelines, such as lower blood pressure targets in people with CKD, use of medications that block the renin–angiotensin system in patients with high blood pressure and proteinuria, evaluation of complications of CKD in patients with CKD stage 3 or higher, and appropriate decisions for medication selection and imaging procedures as well as dose adjustments. Wyatt and colleagues performed such a study at the Veterans Affairs center in the Bronx, New York, and demonstrated that despite increased recognition of CKD with eGFR reporting, the care provided did not improve; they concluded that greater education coincident with eGFR reporting is required for improvement in care.13.Wyatt C. Konduri V. Eng J. et al.Reporting of estimated GFR in the primary care clinic.Am J Kidney Dis. 2007; 49: 634-641Abstract Full Text Full Text PDF PubMed Scopus (54) Google Scholar We need to know whether eGFR reporting has consequences for outcomes of diseases other than CKD, such as detection of acute kidney injury, medication dose adjustment, and monitoring of toxicities following initiation of medications. We also need data on the impact of eGFR reporting on patient and public awareness of CKD and its risk factors, antecedents, and outcomes. Management of chronic diseases requires patient participation to improve outcomes. It is likely that the full benefit of eGFR will require educational efforts for clinicians, patients, and the public. Ongoing initiatives will allow for further assessment of this and other public-health initiatives to improve the care and outcomes of people with CKD.2.Levey A.S. Schoolwerth A.C. Burrows N.R. et al.Comprehensive public health strategies for preventing the development, progression, and complications of CKD: report of an expert panel convened by the Centers for Disease Control and Prevention.Am J Kidney Dis. 2009; 53: 522-535Abstract Full Text Full Text PDF PubMed Scopus (154) Google Scholar A complete assessment of eGFR reporting requires a broader perspective on CKD than its impact on nephrology referral. CKD is no longer just about kidney failure, nor is it just about us, nephrologists, but includes all health-care professionals and the public. The authors declared no competing interests.