Hemodialysis 101 | Avoiding Hyperphosphatemia: Remember the "3D Principle of Phosphate Control"

Hyperphosphatemia is a common complication in chronic kidney disease (CKD), especially in end-stage renal disease (ESRD) patients. What is the relationship between CKD and hyperphosphatemia? What are the dangers of high phosphate levels in the blood? Today, we'll discuss the "past and present" of hyperphosphatemia and how patients can effectively and reasonably control their phosphate intake.

Phosphorus

Phosphorus is one of the essential minerals for the human body, primarily metabolized through the intestines (absorption) and kidneys (excretion). About 70% to 80% of the phosphorus in the body is metabolized by the kidneys and excreted through urine and feces.

Causes of Hyperphosphatemia

1. Kidney Dysfunction

Unlike healthy individuals, CKD patients have shrunken and dysfunctional kidneys, suffering from varying degrees of kidney damage, leading to excretion disorders and decreased regulatory function.

Hemodialysis is a common method to extend the survival and improve the symptoms of ESRD patients. However, hemodialysis cannot completely replace normal kidney function. Dialysis patients experience excretion disorders, leading to calcium-phosphorus metabolism disorders, which worsen with disease progression, gradually increasing blood phosphate levels and inducing hyperphosphatemia.

2. Excessive Phosphorus Intake from Food

Diet is one of the main sources of phosphorus. Excessive intake of phosphorus-rich foods is a significant cause of hyperphosphatemia in maintenance hemodialysis (MHD) patients.

Dangers of Hyperphosphatemia

1. Hyperparathyroidism

Increased blood phosphate levels continuously stimulate the parathyroid gland, leading to hyperparathyroidism, which causes bone tissue to release large amounts of phosphorus, exacerbating hyperphosphatemia and creating a vicious cycle. Research reports that for CKD patients, every 0.32 mmol/L increase in blood phosphorus raises the risk of death by 6%.

2. Aging

High blood phosphate levels cause inflammatory responses and cell apoptosis, leading to widespread tissue damage and accelerating the aging process.

3. Bone Abnormalities

High blood phosphate levels cause soft tissue calcification outside the bones, increasing the risk of osteoporosis and fractures. About 70% to 90% of CKD stage 3-4 patients have varying degrees of bone metabolism abnormalities.

4. Cardiovascular Disease

Excess phosphorus deposits in bones and blood vessels, causing vascular calcification, damaging the cardiovascular system, and inducing cardiovascular disease. Cardiovascular events are one of the leading causes of death in uremic patients, accounting for approximately 50% of deaths in ESRD patients.

Controlling blood phosphate levels is crucial.

How to Prevent Hyperphosphatemia

Currently, the main measures to control blood phosphate include dietary intervention, enhanced dialysis, and the rational use of phosphate binders.

1. Adequate Dialysis

Dialysis is fundamental in treating hyperphosphatemia. After receiving blood purification treatment, ESRD patients experience significant improvements in anemia and calcium-phosphorus metabolism disorders.

2. Maintaining Blood Phosphate Levels

The CKD-MBD diagnosis and treatment guidelines released by the Chinese Society of Nephrology recommend that CKD stage 3-5 patients maintain blood phosphate levels within the normal range; dialysis patients should keep blood phosphate levels between 1.13-1.78 mmol/L.

3. Low-Phosphorus Diet

Reducing the intake of phosphorus-rich foods is the simplest and most convenient treatment method, achievable with patient cooperation.

How to Follow a Low-Phosphorus Diet

A high-protein diet can burden the kidneys, accelerating the progression of kidney disease. Conversely, a low-protein diet can lead to malnutrition. Only by consuming sufficient protein while controlling phosphorus intake can patients improve their blood phosphate levels.

1. High-Quality Protein, Low-Phosphorus Diet

MHD patients are recommended to limit their daily phosphorus intake to 800 mg. They are encouraged to eat low-phosphorus foods such as spinach, tomatoes, and celery, while avoiding cheese, pure milk, and beans. They should control plant protein intake and prioritize high-quality proteins such as fish, lean meat, egg whites, and sea cucumbers.

For patients with decreased appetite, oral special formula dietary supplements such as whey protein and dialysis-specific total nutrients can be considered.

Tip: Kidney friends can download dietary guide apps suitable for their use.

2. Choosing the Right Cooking Methods

Using high temperatures for short periods in the cooking process can reduce the phosphorus-to-protein ratio. Boiling before frying helps retain high-quality protein. For example, blanch vegetables and remove the broth before consuming fish and lean meat.

Summary

To prevent hyperphosphatemia from affecting the quality of life and disease prognosis, kidney friends should remember the "3D Principle of Phosphate Control": Diet, Dialysis, Drug.

References:

1. Cheng Hong, et al. "The Impact of Low-Phosphorus Diet on CKD Stage 3-4 Patients." Modern Clinical Medicine, June 2017, Vol. 43, Issue 3.

2. Lin Xingfang. "The Effect of Low-Phosphorus Diet on Nutritional Status and Calcium-Phosphorus Metabolism in Hemodialysis Patients with Chronic Renal Failure." Clinical Medicine, June 2023, Vol. 43, Issue 6.

3. Su Huiling. "The Impact of Low-Phosphorus Diet Education on Bone Mineral Metabolism in Hemodialysis Patients." Journal of Practical Clinical Nursing, 2018, Vol. 3, Issue 2.

4. Long Youai, et al. "The Impact of High-Protein Low-Phosphorus Diet on Nutritional Status of Dialysis Patients." Nursing Research, May 2017, Vol. 31, Issue 15.

5. Li Shuangshuang, et al. "Summary of Best Evidence for Nutritional Management in Maintenance Hemodialysis Patients." General Nursing, November 2023, Vol. 21, Issue 32.

6. Lu Xiaoyan, et al. "Diet Survey of 75 Maintenance Hemodialysis Patients with Hyperphosphatemia." Chinese Journal of Integrative Medicine Nephrology, September 2021, Vol. 22, Issue 9.

7. Wei Qing, et al. "Progress in the Treatment of Hyperphosphatemia in Patients with Chronic Renal Insufficiency." Journal of Southeast University (Medical Edition), August 14, Vol. 33, Issue 4, pp. 536-540.

8. Tang Yueqiu, et al. "The Effect of High-Flux Dialysis Combined with Hemoperfusion on Nutritional Status and Calcium-Phosphorus Metabolism in Maintenance Hemodialysis Patients." Hebei Medicine, April 2023, Vol. 29, Issue 4.

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