Carolyn Bauer

Staging of Chronic Kidney Disease: Time for a Course Correction

Awareness of chronic kidney disease (CKD) has increased in part because of the definitions and treatment guidelines set out by Kidney Disease Outcomes Quality Initiative (KDOQI); however, the staging system set forth by these guidelines has led to several problems and unforeseen consequences. Stages 1 and 2 CKD are difficult to determine using the standard Modification of Diet in Renal Disease (MDRD) estimation of GFR, and their clinical significance in the absence of other risk factors is unclear. Just because microalbuminuria in people without diabetes is a cardiovascular risk factor does not make it kidney disease. Most patients who receive a diagnosis of stage 3 CKD (GFR between 30 and 59 ml/min) are elderly people, and the vast majority of these patients will die before they reach ESRD. The staging system needs to be modified to reflect the severity and complications of CKD. It is suggested that stages 1 and 2 be eliminated and stages 3, 4, and 5, be simply termed moderate impairment, severe impairment, and kidney failure, respectively. In addition, age should be a modifying factor, especially in moderate kidney impairment. These changes would allow identification and treatment of clinically relevant disease and avoidance of what can seem exaggerated prevalence estimates.

Treatment of chronic kidney disease

Treatment of chronic kidney disease (CKD) can slow its progression to end-stage renal disease (ESRD). However, the therapies remain limited. Blood pressure control using angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs) has the greatest weight of evidence. Glycemic control in diabetes seems likely to retard progression. Several metabolic disturbances of CKD may prove to be useful therapeutic targets but have been insufficiently tested. These include acidosis, hyperphosphatemia, and vitamin D deficiency. Drugs aimed at other potentially damaging systems and processes, including endothelin, fibrosis, oxidation, and advanced glycation end products, are at various stages of development. In addition to the paucity of proven effective therapies, the incomplete application of existing treatments, the education of patients about their disease, and the transition to ESRD care remain major practical barriers to better outcomes.

Effects of Oral Sodium Bicarbonate in Patients with CKD

BACKGROUND AND OBJECTIVES Metabolic acidosis contributes to muscle breakdown in patients with CKD, but whether its treatment improves functional outcomes is unknown. The choice of dose and tolerability of high doses remain unclear. In CKD patients with mild acidosis, this study evaluated the dose-response relationship of alkali with serum bicarbonate, its side effect profile, and its effect on muscle strength. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS In this single-blinded pilot study from March of 2009 to August of 2010, 20 adults with estimated GFR 15-45 ml/min per 1.73 m(2) and serum bicarbonate 20-24 mEq/L were treated during successive 2-week periods with placebo followed by escalating oral NaHCO3 doses (0.3, 0.6, and 1.0 mEq/kg per day). At each visit, handgrip strength and time required to complete 5 and 10 repetitions of a sit-to-stand test were measured. RESULTS Each 0.1 mEq/kg per day increase in dose produced a 0.33 mEq/L (95% confidence interval=0.23-0.43 mEq/L) higher serum bicarbonate. Sit-to-stand time improved after 6 weeks of oral NaHCO3 (23.8±1.4 versus 22.2±1.6 seconds for 10 repetitions, P=0.002), and urinary nitrogen excretion decreased (-0.70 g/g creatinine [95% confidence interval=-1.11 to -0.30] per 0.1 mEq/kg per day higher dose). No statistically significant change was seen in handgrip strength (29.5±9.6 versus 28.4±9.4 kg, P=0.12). Higher NaHCO3 doses were not associated with increased BP or greater edema. CONCLUSIONS NaHCO3 supplementation produces a dose-dependent increase in serum bicarbonate and improves lower extremity muscle strength after a short-term intervention in CKD patients with mild acidosis. Long-term studies are needed to determine if this finding translates into improved functional status.

eGFR: Is It Ready for Early Identification of CKD?

Reporting estimated glomerular filtration rate (eGFR) with serum creatinine simply provides the information for which the serum creatinine was ordered in the first place. Mass or universal screening is not the purpose of eGFR reporting. Furthermore, such mass screening does not seem justified. Rather, testing of high-risk groups with eGFR and urinary albumin is useful. Population estimates of the prevalence of chronic kidney disease in the United States that use the Kidney Disease Outcomes Quality Initiative staging system lead to disturbingly high estimates. Many of these people are elderly with marginally depressed GFRs and for whom there are no known therapeutic implications. However, an even more disturbing fraction of people with serious and progressive renal disease are not diagnosed, counseled, or treated. Reporting of eGFR is only one tool in attempting to rectify this latter problem. Nephrologists need to educate patients and their primary care colleagues in the use of this tool.

Interdisciplinary care clinics in chronic kidney disease

The burden of chronic kidney disease (CKD) is substantial, and is associated with high hospitalization rates, premature deaths, and considerable health care costs. These factors provide strong rationale for quality improvement initiatives in CKD care. The interdisciplinary care clinic (IDC) has emerged as one solution to improving CKD care. The IDC team may include other physicians, advanced practice providers, nurses, dietitians, pharmacists, and social workers—all working together to provide effective care to patients with chronic kidney disease. Studies suggest that IDCs may improve patient education and preparedness prior to kidney failure, both of which have been associated with improved health outcomes. Interdisciplinary care may also delay the progression to end-stage renal disease and reduce mortality. While most studies suggest that IDC services are likely cost-effective, financing IDCs is challenging and many insurance providers do not pay for all of the services. There are also no robust long-term studies demonstrating the cost-effectiveness of IDCs. This review discusses IDC models and its potential impact on CKD care as well as some of the challenges that may be associated with implementing these clinics.

The Interdisciplinary Chronic Kidney Disease Clinic

The CKD clinic has emerged as an interdisciplinary care (IDC) model that encompasses patient education, medical management of CKD complications and progression risk factors and quality improvement. The CKD clinic team may include physicians, advanced practice providers, nurses, dietitians, pharmacists and social workers. Team structure and clinic goals should be tailored to local practice needs. Common goals include CKD education, RRT planning and treatment of complications of CKD based on national/international guidelines. Data suggest that CKD clinics improve CKD and RRT education and lead to greater rates of home dialysis and permanent access placement. Long-term studies are needed to determine if CKD clinics provide a beneficial effect on preserving kidney function. Financing CKD clinics remains problematic as many insurers do not pay for IDC services. The long-term viability of the CKD clinic model may ultimately depend on demonstrating effectiveness and a reduction in overall patient care costs.

Chronic kidney disease: Is angiotensin system blockade indicated in the elderly?

Evidence supporting the renal benefits of angiotensin-converting-enzyme inhibitors and angiotensin II receptor blockers in elderly patients without proteinuria is lacking. However, until such data are available, if tolerated, these medications should continue to be used in this patient population because of their potent effect on blood pressure.

Is angiotensin system blockade indicated in the elderly

Evidence supporting the renal benefits of angiotensin-converting-enzyme inhibitors and angiotensin II receptor blockers in elderly patients without proteinuria is lacking. However, until such data are available, if tolerated, these medications should continue to be used in this patient population because of their potent effect on blood pressure.

Is angiotensin system blockade indicated in the elderly?: Chronic kidney disease

Evidence supporting the renal benefits of angiotensin-converting-enzyme inhibitors and angiotensin II receptor blockers in elderly patients without proteinuria is lacking. However, until such data are available, if tolerated, these medications should continue to be used in this patient population because of their potent effect on blood pressure.