Nephrology care in Canada
=========================

* Keevin Bernstein
* Claudio Rigatto

Caroline Stigant and associates1 raise several controversial issues in their article on caring for adults with chronic kidney disease. How these issues are resolved could have major implications for the delivery and cost of nephrology care in Canada.

First, the authors do not clearly address the question of who should be tested for kidney disease. People with hypertension, diabetes, cardiovascular disease and autoimmune disease (the risk factors listed in Box 4 of the article) are at high risk and should be screened by urinalysis and by testing for serum creatinine. Conversely, the utility of unselected population screening for renal disease (e.g., by dipstick) is very low,2,3 and should not be recommended.

The authors suggest that estimating equations be used to identify patients with low glomerular filtration rate (GFR) (e.g., their Table 2). Arguments both for4 and against5 this strategy have been published. Stigant and associates1 argue the pro position, but the con argument is also compelling. Applying estimating equations universally will lead to the “labelling” and referral of many patients who would not otherwise have been identified as having renal failure. These patients will have different demographic characteristics (older age, more women, higher proportion with nonproteinuric renal disease) and probably a lower risk of progression than those identified on the basis of serum creatinine level.4,5 The benefits of nephrological intervention in such patients is unclear. Moreover, current nephrology resources could not possibly handle the potential referrals indicated in Table 1 in Stigant and associates' article.1 A clinical trial is urgently needed to address whether referral triggered by identification of low estimated GFR leads to cost-effective therapy. In the absence of clear evidence of benefit, it may be premature to advocate a strategy with such major resource implications.

The management of chronic kidney disease depends on the stage of the disease. A simple, unambiguous staging system that reflects key changes in management is the cornerstone of clinical decision-making. Such a scheme must also serve the needs of nonphysician health care providers, a group that increasingly helps to shoulder the burden of renal disease. Although the US National Kidney Foundation staging system, presented in Box 1 of Stigant and associates' article,1 is useful for nephrologists and researchers, we think it is unnecessarily complicated for nonspecialists. For years we have used a simpler, 4-level scheme, which we refer to as the “ABCs of chronic kidney disease” (Fig. 1), to teach generalists, students and nurses. 

![Figure1](http://www.cmaj.ca/https://www.cmaj.ca/content/cmaj/169/10/1006.2/F1.medium.gif)

[Figure1](http://www.cmaj.ca/content/169/10/1006.2/F1)

**Fig. 1: Simplified staging system for kidney disease.** 

Each stage is highlighted by a change in therapeutic focus. The major task in stage A is establishing the diagnosis and prognosis. Identification of high-risk patients and prevention of disease progression are emphasized, which leads naturally to a discussion among learners of approaches to proteinuria and hematuria.

The major task in stage B (roughly stages 3 and 4 of the National Kidney Foundation) is slowing progression of renal disease and minimizing concomitant renal and cardiovascular conditions. This entails modification of cardiorenal risk factors and management of early comorbidities in chronic kidney disease, including slowing the rate of GFR decline. Every year that a prospective dialysis patient remains off dialysis saves the Canadian health care system $50 000 to $75 000.6,7

By the time the patient reaches stage C, it is generally too late to decrease the rate of progression. At this stage the focus is on treatment of advanced cardiorenal comorbidities and preparation for timely initiation of renal replacement therapy.

Stage D is the point at which renal replacement therapy is initiated, generally when the patient has a GFR of 6 mL/min (0.1 mL/s), as recommended by the Canadian Society of Nephrology.8 The US National Kidney Foundation defines its final stage as GFR less than 15 mL/min (0.25 mL/s).9 We estimate that, in Manitoba, initiating dialysis at the latter level would increase the cost to an already stressed renal program budget by 20% without proven benefit to the patient.

**Keevin Bernstein** **Claudio Rigatto** Section of Nephrology University of Manitoba Winnipeg, Man.

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