Diabetes significantly increases the risk of developing chronic kidney disease. The AI/AN population used to have the highest incidence rate of end-stage renal disease (ESRD) among patients with diabetes. While still higher than for several other groups, the rate has decreased significantly in recent years, due at least in part to good clinical care of patients with diabetes. To continue this trend toward lower rates of ESRD, emphasis on improving CKD prevention, screening, monitoring, and treatment is as important as ever in AI/AN people with diabetes.
Clinical Practice Recommendations
Recommendations for Kidney Disease
Order serum creatinine/estimated glomerular filtration rate (eGFR) and urine albumin-to-creatinine ratio (UACR) at diabetes diagnosis and then at least annually thereafter.
Consider nephrology consultation if the etiology of the chronic kidney disease (CKD) is unclear, if CKD is progressing rapidly, if there is any difficulty managing CKD complications, and if eGFR is < 30 mL/min/1.73 m2.
Set and achieve individualized blood pressure targets (e.g., < 130/80 mmHg, < 140/90 mmHg, etc.) for all patients with diabetes:
Prescribe an ACE inhibitor or ARB for all patients with diabetes and hypertension, unless contraindicated.
Begin laboratory testing, monitoring, and treatment of CKD complications such as anemia and metabolic bone disease when patients’ eGFR < 60 mL/min/1.73 m2.
Screening and Monitoring to Assess Kidney Status: eGFR and UACR
Screening includes an assessment of eGFR and a measurement of urinary protein excretion – the spot UACR. These tests should be done at diabetes diagnosis and repeated at least annually – more often, if results are changing rapidly or to assess the effectiveness of interventions.
Use the eGFR and UACR to screen for, diagnose, and monitor the progression of CKD, and to assess the effectiveness of interventions. These tests are continued for the life of the patient, regardless of the stage of kidney disease or types of treatment provided. However, once a patient is on dialysis, these tests no longer are indicated.
Estimated Glomerular Filtration Rate (eGFR)
The eGFR is an estimation of the kidneys’ ability to filter blood and is based on a calculation that includes serum creatinine, body weight, and age. Equations used to calculate eGFR include the Modification of Diet in Renal Disease Study Group (MDRD)
and Cockcroft-Gault equations. While the Cockcroft-Gault equation may still be used for medication dosing, the MDRD is the preferred equation for CKD assessment for adults with diabetes. For youth < 18 years of age, a different equation, the Bedside Schwartz equation
should be used.
The Resource and Patient Management System (RPMS) calculates the eGFR automatically using the MDRD equation when a serum creatinine test is ordered. Because the MDRD equation estimates do not produce reliable results when > 60 mL/min/1.73m2, these results are reported simply as “above 60.” Thus, it is not possible to distinguish clinically between Stages 1 and 2 of CKD.
Urine Albumin-to-Creatinine Ratio (UACR)
The UACR is the test recommended to assess urine albumin excretion and is reported as the ratio of milligrams of albumin to grams of creatinine (mg/g). The UACR is a quantitative test, performed using a single spot urine specimen. Twenty-four hour urine collections are no longer needed nor recommended for routine diabetes nephropathy screening. Also, semi-quantitative “test strips” for urine protein are not sufficiently accurate for CKD diagnosis and monitoring.
The definitions of normal and abnormal albumin excretion on a UACR test are:
Normoalbuminuria < 30 mg/g
Albuminuria ≥ 30 mg/g:
Microalbuminuria 30-300 mg/g
Macroalbuminuria > 300 mg/g.
Because of variability in urinary albumin excretion, at least 2 specimens (preferably first morning void) collected within a 3- to 6-month period should be abnormal before considering a patient to have crossed one of these diagnostic thresholds. Factors that may elevate urinary albumin over baseline values include exercise within 24 hours, infection, fever, congestive heart failure, marked hyperglycemia, pregnancy, marked hypertension, urinary tract infection, and hematuria.
Chronic kidney disease (CKD) is defined as ≥ 3 months duration of either:
Decreased kidney function: eGFR < 60 mL/min/1.73 m2, or
Evidence of kidney damage: albuminuria (e.g., UACR ≥ 30 mg/g) or abnormalities on kidney blood tests, imaging, or biopsy.
Stages of Chronic Kidney Disease (CKD)
Stages of CKD
* Distinguishing Stage 1 from Stage 2 CKD is not possible in clinical settings.
In adults with diabetes, the most likely cause of CKD is the diabetes itself. However, not all CKD in patients with diabetes is due to diabetic nephropathy and it is important to look out for patients whose CKD pattern (e.g., significant albuminuria early in the course of diabetes, a rapid rise in urine albumin excretion) suggests another etiology. These patients should be referred to a nephrologist for further testing (e.g., kidney biopsy) for a definitive diagnosis and treatment plan.
Monitoring and Treatment of Chronic Kidney Disease
Once CKD and its cause(s) are established, there are effective treatments that can delay progression to ESRD and improve quality of life. CKD further increases CVD risk in patients with diabetes. Therefore, modification of CVD risk factors, including tobacco cessation, lipid control, and blood pressure control, is essential.
Treatment of blood pressure requires diligent efforts to achieve targets. For those patients who can achieve a target of < 130/80 mmHg without adverse symptoms, this target may be selected. For other patients, a target of < 140/90 mmHg (or higher if symptoms and comorbidities dictate) should be selected.
The use of ACE inhibitors or ARBs should be considered for all patients with diabetes and hypertension, and/or albuminuria. In addition to lowering blood pressure, these medications also decrease the rate of urinary albumin excretion. Monitoring patients’ serial UACR results will help assess the effectiveness of interventions, and also is prognostic as to the rate of kidney decline. Laboratory testing, monitoring, and treatment of CKD complications such as anemia and metabolic bone disease become important in patients with eGFR < 60 mL/min/1.73 m2.
CKD and Nutrition.
Website designed for general practice registered dietitians (RDs) to provide effective medical nutrition therapy to CKD patients who are not yet on dialysis, includes an overview guide for RDs, tools for assessment and education of test results with patients, and nutrition handouts for people with CKD.