[Kidney Disease Special Topic]Preserve residual renal function to reduce medical burden…

Report◇Compiled by Yang Qianni◇Liang Yingxiu

(Kuala Lumpur News) In clinical practice, creatinine clearance (CrCI) is mainly used to calculate the estimated glomerular filtration rate (eGFR), thereby classifying chronic kidney disease into five stages.

When the eGFR is lower than 15mL/min/1.73m2, it is classified as end-stage renal disease, and the patient needs to prepare and receive dialysis treatment (kidney dialysis) or kidney transplantation.

In addition to using eGFR as the standard for dialysis treatment, it is also necessary to take into account the patient’s clinical symptoms, such as severe water retention that cannot be controlled by drugs, causing pulmonary hydrops or hydropericardium, or uremic neuropathy and pericardial and pulmonary pleurisy. Or severe metabolic acidosis, high blood potassium levels, etc.

Patient RRF decreases year by year

Dr. Chiew Yeong Woei, consultant in the Department of Nephrology, pointed out that when kidney patients develop any of the above serious complications, eGFR and clinical manifestations need to be comprehensively considered to decide whether to initiate dialysis treatment.

Basically, some patients still retain residual renal function (Residual Renal Function, RRF) when they start dialysis treatment (commonly known as kidney dialysis).

However, usually within one or two years, the RRF of most patients will gradually decrease, and the frequency and volume of urination will also decrease until they almost no longer urinate, and it can be speculated that the RRF is close to zero.

“As far as current dialysis technology is concerned, the most commonly mentioned RRF is peritoneal dialysis treatment. Although we often say that hemodialysis and peritoneal dialysis are equally effective, in theory the toxin removal rate of peritoneal dialysis is still slightly worse. Therefore, patients are still very dependent on RRF.”

Several large studies have shown that the higher a patient’s RRF when starting peritoneal dialysis, the lower their risk of heart disease, stroke, toxin buildup, and water retention in the first few years. When their RRF decreases year by year, it will directly affect the survival rate of peritoneal dialysis.

Although hemodialysis is relatively less dependent on RRF, there have been some discussions in the medical community in recent years—whether RRF is of substantial help to hemodialysis patients? There is also evidence that RRF can indeed bring benefits to hemodialysis patients, including reducing cardiovascular disease risk, increasing toxin removal efficiency, and reducing water retention.

He pointed out that incremental dialysis treatment (incremental dialysis) proposed by the medical community in recent years, that is, gradually adjusting the dialysis prescription as the patient’s RRF decreases, can preserve and extend more RRF while avoiding complications.

Normally, home peritoneal dialysis is performed 4 times a day, 20 to 40 minutes each time. The progressive approach starts with 3 times a day. Standard hemodialysis is 3 times a week, with an average of 4 hours each time. It starts from 2 times a week.

In fact, the original intention of proposing progressive dialysis treatment is not only to delay the decline of RRF, but also to consider multiple aspects, especially reducing medical burden and expenses and the psychological pressure of patients. This is why everyone focuses more on progressive hemodialysis. .

Recommended for new patients

For patients who have just entered the kidney dialysis stage, they do not have to “check in” three times a week right away. This will reduce the pressure on patients and caregivers in terms of life and time. For example, patients do not have to travel to and from the dialysis center frequently, and the fear of injections is reduced, which can alleviate negative emotions to some extent.

Furthermore, since the frequency of dialysis is fewer and the nutrients removed are relatively small, the nutritional status of patients with progressive dialysis may be better. The reduced number of dialysis sessions is aided by RRF. Also because the RRF is preserved and the kidneys still have a certain ability to secrete the hematopoietic hormone EPO, the patient’s anemia will be alleviated.

“For patients with end-stage renal disease whose RRF is still relatively high (close to 15mL/min/1.73m2), if there are no symptoms such as uremia or other complications, clinical practice is still to follow the principle of low-protein diet and strengthen the control of diabetes and hypertension as much as possible. It is possible to preserve the original kidney function and delay the time to enter kidney dialysis.”

When these methods fail, patients may need help with dialysis. Taking kidney dialysis as an example, the past practice was that once a patient meets the conditions for dialysis, he or she would start dialysis three times a week. At this time, protein intake would no longer be restricted. Progressive dialysis will now be considered for some new patients who are in better condition.

In order to promote progressive kidney dialysis, end-stage renal disease is clinically subdivided into two categories: early stage and late stage. If the patient’s eGRF is less than 5 to 7mL/min/1.73m2 when entering kidney dialysis, he or she is in an advanced stage and progressive kidney dialysis is not recommended.

Prevent malnutrition in patients

Low protein diet with keto acids

Progressive dialysis is more suitable for patients with a slow progression of the disease (RRF decreases slowly), and can start from twice a week (there are currently a few studies trying once a week), but because the toxin clearance rate will be limited, patients still need to follow a low-protein diet , supplement nutrition, inject EPO (blood replenishment) and continue to take specific medications.

Qiu Yongwei pointed out that for patients undergoing progressive dialysis, doctors need to spend more time adjusting their dialysis prescriptions and monitoring their condition, especially frequent RRF measurements and close observation for uremia complications.

“Although the frequency of kidney dialysis has been reduced, some nutrients will still be removed, and patients with kidney disease cannot absorb too much protein, so controlling the nutritional status of such patients will face greater challenges.”

Take according to the patient’s health condition

He pointed out that in order to maintain the required nutritional status, progressive dialysis patients will need to supplement ketoanalogue while practicing a low-protein diet to maintain normal amino acid intake to help regenerate protein.

This is because the protein in daily food contains nitrogen (nitrogen), which will be converted into urea and excreted from the body after being absorbed by the body. If kidney function has declined, the burden on the kidneys in eliminating these nitrogen-containing metabolic wastes will increase.

As for ketoacids, they are nitrogen-free amino acids that can reuse nitrogen-containing metabolites and convert them into essential amino acids, thereby reducing the accumulation of toxins and improving uremia symptoms. This will have the effect of reducing the burden on the kidneys.

He said that whether for patients with CKD or progressive dialysis, a low-protein diet combined with ketoacid therapy can bring many benefits, especially in preventing malnutrition. This is a nutritional suggestion rather than a rigid rule. Patients are mainly encouraged to take it based on their respective physical health conditions and financial considerations.

Although there are no standard official guidelines for progressive kidney dialysis in Malaysia, it is not new to us and many nephrologists have flexibly used it in daily clinical practice.

Step-by-step starting from two hours

“Generally speaking, for older patients with end-stage renal disease who have already developed uremia symptoms, I will not let them receive dialysis treatment for 4 hours each time immediately. Instead, I will gradually start from two hours and slowly increase the time each time. . The patient’s uremia will gradually improve and his appetite will increase, without increasing the patient’s physical load as much as possible. This is actually a type of progressive kidney dialysis.”

Another situation is related to the fistula required for kidney dialysis. Some patients have poor maturity of the fistula, thin skin or poor hemostatic function, and cannot withstand injections three times a week. This approach is adjusted according to individual conditions. If the patient’s vaginal canal naturally heals slowly after being punctured by a needle, has poor hemostasis, or has blood stasis around it, it is recommended to first reduce the number of weekly dialysis sessions until the patient’s vaginal canal is mature and the skin is strong. Some, then consider the standard practice of dialysis.

“In short, doctors will use progressive dialysis treatment flexibly based on experience, provided that the patient meets the conditions, including urine output and urea clearance. This is also in line with the concept of precision medicine that is valued today. Each patient is an individual and should receive appropriate treatment.”

There needs to be a balance between RRF retention and renal dialysis

Question 1: How does kidney dialysis affect residual renal function?

Answer 1: Currently there is no conclusive theory in medicine that can determine what factors are causing it. First, during kidney dialysis, the patient’s blood needs to be pumped out and fed into a machine to filter out metabolites and remove water from the blood. This process often affects the patient’s blood pressure. If the patient has a weak heart, is malnourished, or is anemic, this can lower blood pressure and reduce the amount of blood circulating in the kidneys, which will accelerate the deterioration of kidney function.

The second speculation is related to the biocompatibility of kidney dialysis equipment and tubing. Some patients may have allergic or inflammatory reactions to different materials of kidney dialysis equipment, causing the kidneys to be in a state of chronic inflammation and leading to renal failure. Continue to degrade.

Next, patients generally need to take anticoagulants to prevent small blood clots from blocking blood vessels due to incompatible equipment or chronic inflammation of the body during kidney dialysis. However, drugs cannot 100% prevent the formation of blood clots. Some tiny blood clots may flow through the blood circulation into other organs, including the kidneys themselves, causing microvascular obstruction. This will also affect the remaining function of the kidneys.

In addition, current kidney dialysis technology cannot “screen” or filter only bad substances, so some important proteins, nutrients and vitamins that are beneficial to patients (such as vitamin B3, which is considered to repair kidney function) will also be included in the kidney dialysis process. drain. When these nutrients used by the body to repair the organs are filtered out, the patient may be in a state of poor nutrition, the kidney’s own repair ability will become worse and its function will continue to decrease.

However, patients cannot avoid dialysis in order to preserve RRF, so it is important to strike a balance between the two.

Patients must meet 2 important conditions

Question 2: Which patients are suitable for progressive kidney dialysis?

Answer 2: Malaysia has not set standards, but according to the Kidney Disease Patient Quality of Life (KDOQI) guidelines developed with the assistance of the American Kidney Foundation, in order to achieve better progressive dialysis effects without causing too many side effects (the number of dialysis The patient must meet the two most important conditions, namely, maintaining the urea clearance rate above 3 ml per minute and urinating at least 500 to 600 ml per day.

Some other strings attached include:

◆Have a relatively healthy heart and cannot suffer from severe heart failure or frequent cardiopulmonary hydrops.

◆No severe anemia

◆Serum potassium is properly controlled

◆Proper control of blood phosphorus

◆Relatively healthy physical condition, with good nutrition and metabolism.

Renal drainage capacity varies with disease

Question 3: Because the amount of drinking water is restricted,

Do kidney dialysis patients urinate less?

Answer 3: This is incorrect. First of all, the main functions of the kidneys are to detoxify and remove water, and these functions will decline as the disease progresses. As a simple analogy, if an average person drinks 3 liters of water, the body will use and process these 3 liters of water so that there will be no accumulation of excess water in the body. When a patient’s kidney function remains at 50%, if he drinks 3 liters of water, only 1.5 liters of water may be excreted. Then the remaining 1.5 liters will remain in the body.

It is even more dangerous if the kidney function is only 10%, which means that after drinking 3 liters of water, only 300 ml of urine can be excreted, and more than 2 liters of water will remain in the body, causing edema of the lower limbs, hydrops in the heart and lungs, etc. Of course, each person’s actual residual renal function drainage capacity varies from person to person and from disease to disease, and cannot be easily converted as described above.

Therefore, I often tell patients that the amount of water they can drink is determined by their urine output.

He can excrete 1.5 liters of urine and drink 1.5 liters of water. Everything is based on his urinary capacity (kidney function). It is not the doctor who specifically limits the patient’s water intake.

How long it lasts depends on the patient’s condition

Question 4: How long can progressive kidney dialysis last?

Answer 4: Frankly speaking, there is no definite answer. It depends on the individual circumstances. Some patients can still urinate two to three hundred milliliters a day after receiving standard kidney dialysis for two or three years. The RRF declines slowly. However, through progressive kidney dialysis, the RRF can be preserved for a longer period of time.

However, some patients’ RRF is initially high but worsens rapidly within a month or two after starting dialysis.

Therefore, the progressive kidney dialysis method adopted by these patients may only last for one or two months.

Need to measure urine output more frequently

Question 5: What are the difficulties with progressive kidney dialysis?

A5: For patients, they need to collect and measure urine volume more frequently, usually with 24-hour urine collection on non-dialysis days. This is to measure RRF, however many patients will refuse due to busyness or trouble, however it is necessary.

Dialysis can be reduced for long-term patients

Question 6: If you have been on kidney dialysis for a long time, what should you do?

Is it possible to reduce the frequency of dialysis?

Answer 6: Yes, it depends on the patient’s condition and needs.

There was an 84-year-old female patient who had poor appetite and reduced food intake, possibly due to the natural degeneration of her organs and the slowdown of her digestive system. Therefore, her family proposed the idea of ​​reducing the number of dialysis sessions. Considering that her food intake and weight gain were not much, and there were not so many toxins in her body, she needed kidney dialysis three times a week. After evaluation, it was reduced to twice a week.

Another more significant case is a patient with laryngeal cancer. Due to the combination of end-stage renal disease and heart disease, her family did not intend for her to undergo major surgery to remove the tumor, but chose milder palliative care.

As the tumor in the throat grows larger, the patient’s food intake is directly affected. At first, we asked the patient to change her dialysis from three times a week to twice a week. In the later stage, she could hardly eat, so we did not force her to come for dialysis regularly.

However, I also reminded the child to observe whether the mother has symptoms of uremia or signs of water accumulation, and only send her to dialysis if so.

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