How is kidney disease treated in people with diabetes?

You have read information previously about the association of kidney disease and diabetes. In addition, you have learned about the importance of slowing the progression of kidney disease by following the advice from your diabetes team. This includes managing blood sugar control and heart disease risk factors, such as being a non-smoker and treating hypertension, as well as possibly taking certain medications.

Angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) are the two main medications that have been the standard of care for the past 20 years to manage and slow kidney disease. However, recent studies have shown promise for newer medications that may help people with diabetes and kidney disease, specifically those who also have heart disease.

Once kidney disease is established, how is it treated?

If you have significant kidney disease and, depending on other factors, you will likely be referred to a kidney team in addition to your diabetes management team. Specialist referrals are often recommended for people with diabetes who:

1. Have chronic, progressive loss of kidney function
2. Have a urine albumin to creatinine ratio persistently >60 mg/mmol
3. Have an estimated glomerular filtration rate (eGFR) <30 mL/min
4. Are unable to keep taking ACE inhibitors or ARBs due to side effects
5. Are unable to achieve target blood pressure

Referral to a kidney team is often needed because management of kidney disease can be complex when accompanied by other health issues, such as diabetes or heart disease. As well, this team may need to make decisions about end stage kidney disease management such as transplant and dialysis.

What to expect as kidney disease progresses?

Monitoring

It is important to have regular blood and urine tests to follow kidney function. These tests are done usually every 6 months once kidney disease is present, but more often if there is an intercurrent illness or medications are added. In addition to tests to follow kidney function, potassium may also be monitored. This is because potassium can reach dangerously high levels as kidney function declines; certain medications can also increase potassium levels.

Other tests are also done, including those to monitor bone health and hemoglobin in the blood. The kidneys produce a substance that helps us make red blood cells (hemoglobin), so when a person has kidney disease they may not make as many red blood cells and therefore become anemic. This has particular implications for people with diabetes, as the test to look at average blood glucose, the A1C, is based on a normal hemoglobin and a red blood cell that lasts 3 months. In kidney disease, this is sometimes not the case. That is, the red blood cell may last for a shorter period than 3 months, so the A1C is artificially lower than your actual average blood sugar. The point of this is that it is even more important to measure blood sugars with your home device as directed by your healthcare team if you have kidney disease, to see what your blood sugar numbers are, since the A1C may not tell the whole story as eGFR declines.

Another function of the kidneys is to maintain bone health. They do this by balancing minerals in the blood, such as calcium and phosphorus. As kidney function declines, the balance of these minerals can be altered. Phosphorus can build up in the blood, which can lead to thinning of the bones (osteoporosis). As phosphorus levels go up and blood vitamin D levels go down, your body makes too much parathyroid hormone (PTH). High PTH levels cause calcium to move from your bones into your blood. Kidneys also change vitamin D from sunlight and the foods you eat into active vitamin D that your body can use. So you may have tests to check your blood levels of calcium, phosphorus, PTH and vitamin D.

Diet

As noted above, potassium levels can rise in people with advancing kidney disease. Potassium is found in many foods, so people with kidney disease may have to limit their potassium intake by changing their diet. This can be tricky on top of a diet that is recommended for people with diabetes or also on top of a heart-healthy diet. For example, fresh fruit and vegetables are generally recommended for people with diabetes and heart disease as part of a healthy diet but some of them have high levels of potassium So, it is important to see a registered dietitian who has experience with diets for people with diabetes and kidney disease.

Another mineral, phosphorus, needs to be balanced as well, and this is also found in some foods. Finally, fluid intake and vitamins, especially those that are good for bone health, will be discussed with the team.

Sick day management

For people with any degree of kidney disease, being aware of how to manage sick days is important. As kidney function declines, certain situations that arise from sick days can tip a person who has chronic kidney issues into a more acute phase of kidney disease. It is critical to prevent this from happening.

Sick days that cause a person to be dehydrated, such as vomiting, diarrhea or high fevers, can be especially dangerous. A plan for sick days should be discussed with your kidney and diabetes team. Knowing which medications to temporarily discontinue or reduce when you are sick, understanding how and what fluids to take to keep you hydrated, as well as maintaining blood sugars in an ideal range and knowing when to go to hospital, should all be part of the plan.

Some medications last longer in your system if kidney function is reduced due to dehydration (such as metformin or glyburide), while others may reduce blood pressure further which then reduces kidney function (such as ACE inhibitors, ARBs, water pills or sodium-glucose transporter-2 inhibitors). Some medications are just not good for kidneys at the best of times (such as non-steroidal anti-inflammatory drugs) but can be particularly harmful during times that the kidneys are stressed.

For more information on managing diabetes when you are sick, click here.

Dialysis

The job of the kidneys is so critical that life is not possible without them, unless the cleaning of blood and balancing of fluid is artificially done by kidney dialysis.

The point at which a person requires dialysis can vary, but usually happens when the eGFR gets very low (usually less than 15 ml/min). This is called end stage renal disease. At this point, there is a choice of methods of dialysis; hemodialysis and peritoneal dialysis.

In peritoneal dialysis, the lining of the abdominal wall is used as a filter to clean the blood. To get access, a catheter or tube is inserted near the navel and remains in place as long as you’re on peritoneal dialysis. Waste and excess fluid in your blood pass from the blood through the lining of your abdominal wall and into the dialysis fluid. The fluid is then drained and discarded, and the abdomen is refilled. This process happens several times a day; often 4 times a day for 20 to 40 minutes at a time. It can be done at home and even during the night (nightly for 8 to 10 hours).

Hemodialysis usually requires 4 to 5 hours, 3 times a week. The blood is run through a machine and cleaned, and fluids balanced. An access is required, called a fistula, to reach the blood stream. Hemodialysis can be done in the hospital or at home. If done at home, several weeks of education are required beforehand.

Having diabetes and being on dialysis can be complex. Blood glucose levels and medications can be affected by dialysis.

Slowing the progress of kidney disease is the goal for people who develop it, so that hopefully end stage renal disease and dialysis can be avoided. If, however, people living with diabetes develop end stage renal disease, dialysis is an option that prolongs life and may be used as well while waiting for a kidney transplant.

Kidney transplant

Whether a person with diabetes is a good candidate for a transplant, and which type of transplant they should have, depends on a number of factors. These include general health, heart disease, obesity, other chronic disease such as cancer, ability to follow a treatment plan, and type of diabetes.

There are two types of transplant: one from a deceased person (this is usually from someone who has suffered a head injury and has died suddenly) or one from a living donor. A living donor kidney may last longer as it may be in a better condition when transplanted and the person receiving the donated kidney would do so at an optimal time for them, as the surgery would be scheduled electively and as such they would be in optimal health.

If someone you know is willing to donate a kidney but isn’t a match for you, they may be able to take part in what is called a ‘paired donation.’ In this case, their kidney would go to another kidney transplant patient, and that person’s living donor would donate their kidney to you. The national Kidney Paired Donation Program is operated by Canadian Blood Services.

For people with type 1 diabetes and end stage renal disease, simultaneous pancreas-kidney transplantation can improve kidney survival and result in prolonged insulin independence.

People who have had a kidney transplant need to take anti-rejection medication for the rest of their lives and closely follow a treatment plan.

This article was sponsored by Janssen Inc.