Kidney Disease and Treatment

Kidney Disease and Treatment

Chronic kidney disease (CKD) is common not only in the United States, but also around the world in both developed and developing countries. An estimated 37 million American adults (15 percent of the adult U.S. population) have CKD as defined by the Kidney Disease Outcomes Quality Initiative (KDOQI) and Kidney Disease: Improving Global Outcomes (KDIGO) guidelines—an abnormal estimating glomerular filtration rate (eGFR) and/or urine albumin loss (albuminuria) for at least three months.1-4 The leading cause of CKD in the U.S. is diabetes mellitus (DM), but other risk factors for CKD include hypertension, cardiovascular disease, a family history of CKD, and advanced age (>60 years).2

The Centers for Disease Control and Prevention (CDC) recommends kidney disease screening for all people at risk for CKD. Kidney disease screening includes a simple blood test (serum creatinine) and a urinalysis to assess the presence of blood or protein in the urine. The serum creatinine is used to calculate the estimated glomerular filtration rate (eGFR), which is an estimate of kidney function indicating how well the kidneys are cleaning the blood. People with advanced kidney disease can make a normal volume of urine, so daily urine volume is not an indicator of CKD. Anyone with an abnormal CKD screening test needs repeat testing to confirm the abnormal findings over time.

There are many causes of CKD. Diabetes mellitus, hypertension, and cardiovascular disease are systemic diseases that impact kidney function by damaging the large and small blood vessels that are critical to normal kidney function. Some autoimmune diseases, such as systemic lupus erythematosus (SLE), can cause chronic inflammation and kidney damage in the same way inflammation affects other body organs. Glomerular diseases such as focal segmental glomerular sclerosis (FSGS) and IgA nephropathy only affect the kidneys and can cause kidney failure. Inherited diseases such as polycystic kidney disease (PKD) and Fabry's disease as well as congenital kidney abnormalities are also well-known causes of CKD. The evaluation of abnormal kidney function may include renal ultrasound, CT, or MRI to look at the anatomical structure of the kidneys. A renal biopsy may be done to examine the filtering units of the kidney under the microscope.

Measures of kidney function based on the eGFR and the presence of protein in the urine are used to determine kidney disease stage.4 A minor decrease in eGFR with no or little urine protein is consistent with CKD stage 1 as shown in the chart below. CKD stages 2 and 3 represent more significant kidney injury and dysfunction. CKD stages 4 and 5 are considered late-stage CKD consistent with severe kidney damage. People with late-stage CKD often have symptoms of renal failure and should receive nephrology care if they have not been referred to nephrology earlier in CKD care.

CKD staging helps people and care providers estimate the severity of kidney disease and begin treatments to slow CKD progression. CKD is a silent disease without symptoms until very late in the disease course, which is often too late to start treatments that improve patient outcomes and slow CKD progression, so measuring kidney function is critical. Protecting the kidneys includes healthy lifestyle habits such as eating a well-balanced diet low in saturated fats and salt, maintaining an ideal body weight, and exercising regularly.2 Smoking and exposure to secondhand smoke in the home or workplace are associated with the development of CKD and with CKD progression.5,6 If you have CKD, it is important to avoid some over-the-counter medications such as nonsteroidal anti-inflammatory drugs that can worsen kidney function.2 The Medical Education Institute also has some good information about slowing kidney disease.

Research data suggests that some medications slow CKD progression and may prevent patients with CKD from advancing to end stage renal disease (ESRD). Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin-receptor blockers (ARBs) are commonly used, if tolerated, to provide kidney protection from CKD progression.7 Recent research suggests that the SGLT-2 inhibitor canagliflozin—used to treat type 2 DM—may decrease CKD progression and provide some cardiac protection.

Typically, patients do not have symptoms related to CKD until the eGFR falls below 30 ml/min/1.73 m2—consistent with CKD stage 4. Late-stage CKD symptoms include:

• Lower extremity swelling or facial puffiness
• High blood pressure related to fluid retention
• Anemia, which causes fatigue
• Decreased appetite and nausea

Blood measurements of calcium, phosphorus, bicarbonate, and potassium are also abnormal in late-stage CKD and may require treatment intervention.2

People with advanced CKD (typically eGFR <20 ml/min/1.73 m2) should be partnered with a multidisciplinary nephrology team including a nephrologist to consider treatment options. Treatment with a kidney transplant from either a deceased or living donor involves surgical placement of a functioning kidney into a patient with end stage kidney disease (ESKD) or ESRD. A successfully transplanted kidney cleans the blood, effectively restoring adequate kidney function to make people feel well. Kidney transplant is a very effective treatment option that restores excellent quality of life to advanced CKD patients, but it is not a cure for kidney disease. Transplant recipients remain on immunosuppressive therapy that increases infection risk and has medication side effects.

If a kidney transplant is not an immediate possibility for an ESRD patient, dialysis treatment options will be considered. Home dialysis therapies, which provide patient empowerment, choice, and flexibility, should be considered as a first dialysis treatment option.8-10 Starting dialysis with peritoneal dialysis (PD) may be associated with preservation of residual renal function and improvement in early dialysis outcomes.8 While home dialysis options should be considered for every new dialysis patient, some patients will start with in-center hemodialysis (ICHD) as a treatment for ESRD. Treatment choices should be made in collaboration with a nephrologist and the multidisciplinary nephrology team. Some patients, particularly those with advanced age or significant comorbid conditions, may opt for supportive or conservative treatment for advanced CKD that does not include a kidney transplant or dialysis therapy.

Treatment options for ESRD include:

• Renal transplant including surgical placement of a functioning kidney from a living or deceased donor. Immunosuppressive medications are required to prevent rejection of the transplanted kidney. If a kidney transplant fails, patients may start a dialysis therapy or receive another renal transplant. Immunosuppressive medications have side effects, but a transplanted kidney generally results in very good kidney function that makes people feel well.
• Home dialysis therapies include peritoneal dialysis and home hemodialysis. Peritoneal dialysis (PD) involves use of a catheter into the abdominal cavity to inflow dialysis fluid. As the fluid dwells in the abdomen, waste products and extra water move across the peritoneal membrane and are removed when the dialysate fluid is drained several hours later. PD is a continuous, gentle therapy that has the advantage of being performed at home on a flexible schedule. PD patients enjoy a less-restricted diet since the treatment is continuous.
• Home hemodialysis (HHD) involves accessing the bloodstream to allow the blood to flow across a dialysis membrane for a treatment time that typically lasts three to six hours. Hemodialysis in the home setting provides flexibility and control for people and eliminates the need to travel to a hemodialysis in-center clinic three times per week. HHD patients often benefit from slow, longer and/or more frequent dialysis treatments that have been associated with improved quality of life and clinical outcomes.11,12 HHD requires a vascular access and often the use of needles to cannulate the access for treatment.
• In-center hemodialysis (ICHD) is hemodialysis or dialysis involving the bloodstream that occurs at an in-center treatment facility. ICHD patients typically dialyze on a Monday, Wednesday, Friday or Tuesday, Thursday, Saturday schedule based on clinic schedules and patient assignments. ICHD treatments average about four hours and are monitored by the clinical staff in the dialysis facility.

Healthy lifestyle choices are important in preventing the onset of CKD and slowing CKD progression. People with DM can also decrease the risk of CKD by using lifestyle and medications to optimize blood glucose control.2 For people with CKD, managing high blood pressure to achieve a goal of <130/80 mm Hg is recommended to improve outcomes.13 Daily exercise and healthy eating decrease the risk of cardiovascular disease, which is a common cause and complication of CKD.14 The nephrology care team is a key resource for medical interventions that can protect your kidneys.

References

1. United States Renal Data System. 2017 USRDS annual data report: Epidemiology of kidney disease in the United States. 2017 [cited 2017 March 6]; Available from: https://www.usrds.org/2017/view/v2_03.aspx.
2. National Chronic Kidney Disease Fact Sheet. 2017 [cited 2018 March 6]; Available from: https://www.cdc.gov/kidneydisease/pdf/kidney_factsheet.pdf.
3. KDOQI Clinical Practice Guidelines for Chronic Kidney Disease: Evaluation, Classification, and Stratification. PART 7. STRATIFICATION OF RISK FOR PROGRESSION OF KIDNEY DISEASE AND DEVELOPMENT OF CARDIOVASCULAR DISEASE GUIDELINE 15. ASSOCIATION OF CHRONIC KIDNEY DISEASE WITH CARDIOVASCULAR DISEASE. 2002 November 30, 2016]; Available from: http://www2.kidney.org/professionals/kdoqi/guidelines_ckd/p7_risk_g15.htm.
4. Chapter 1: Definition and classification of CKD. Kidney Int Suppl (2011), 2013. 3(1): p. 19-62.
5. Leonberg-Yoo, A.K. and M.R. Rudnick, Tobacco Use: A Chronic Kidney Disease Accelerant. Am J Nephrol, 2017. 46(4): p. 257-259.
6. Jhee, J.H., et al., Secondhand Smoke and CKD. Clin J Am Soc Nephrol, 2019. 14(4): p. 515-522.
7. Bakris, G.L., Slowing nephropathy progression: focus on proteinuria reduction. Clin J Am Soc Nephrol, 2008. 3 Suppl 1: p. S3-10.
8. François, K. and J.M. Bargman, Evaluating the benefits of home-based peritoneal dialysis. Int J Nephrol Renovasc Dis, 2014. 7: p. 447-55.
9. Kerr, P.G. and J.W. Agar, Keeping Home Dialysis Patients at Home. Am J Kidney Dis, 2016. 67(4): p. 542-4.
10. Young, B.A., et al., How to overcome barriers and establish a successful home HD program. Clin J Am Soc Nephrol, 2012. 7(12): p. 2023-32.
11. Hajj, J.J. and K. Laudanski, Home Hemodialysis (HHD) Treatment as Effective yet Underutilized Treatment Modality in the United States. Healthcare (Basel), 2017. 5(4).
12. Miller, B.W., et al., Choosing Home Hemodialysis: A Critical Review of Patient Outcomes. Blood Purif, 2018. 45(1-3): p. 224-229.
13. Chang, A.R., et al., Blood Pressure Goals in Patients with CKD: A Review of Evidence and Guidelines. Clin J Am Soc Nephrol, 2019. 14(1): p. 161-169.
14. Howden, E.J., et al., Effects of exercise and lifestyle intervention on cardiovascular function in CKD. Clin J Am Soc Nephrol, 2013. 8(9): p. 1494-501.