Hyperuricemia: the invisible killer of renal impairment in young people

Author: Wu Hao and Chen Runyao, 910th Hospital of Joint Logistics Support Force

Reviewer: Yan Zhencheng, Chief Physician of Hypertension Endocrinology Department, Army Specialty Medical Center

When it comes to high blood sugar, high blood pressure, and high blood lipids, everyone should be familiar with them, but you may not know that hyperuricemia has become the "fourth high" after the "three highs", and the prevalence rate is extremely high among young people. Hyperuricemia not only causes gout attacks, but is also closely related to kidney damage. This article will take you to understand the basic knowledge of hyperuricemia and let you correctly understand this disease.

1. Definition of hyperuricemia and its incidence in young people

Uric acid is one of the products of purine metabolism in the human body. The production and excretion of uric acid together maintain the balance of uric acid concentration in the blood. When purine metabolism disorders cause excessive uric acid production and/or reduced renal uric acid excretion, the blood uric acid concentration increases. Whether male or female, if the blood uric acid level exceeds 420 μmol/L on two different days, it is called hyperuricemia[1].

As our lifestyle changes, the prevalence of hyperuricemia and related chronic complications has increased year by year, and is showing a trend of younger age, seriously threatening the life and health of Chinese residents and military officers and soldiers. It is reported that the overall prevalence of hyperuricemia in Chinese adult residents is 13.3%, with a higher prevalence in men than in women, higher prevalence in urban areas than in rural areas, and higher prevalence in coastal areas than inland areas. The detection rate of hyperuricemia in the military has also been increasing in recent years. We recently found that the detection rate of hyperuricemia in male soldiers in a coastal city was about 46.3%, and the detection rate of hyperuricemia in young soldiers aged 19-30 was as high as 52.7% [2].

2. Hyperuricemia leads to renal impairment

In addition to causing acute gout, hyperuricemia, as an invisible killer of health, also causes renal damage. In the health check population, higher blood uric acid can predict renal damage, which is manifested in early stages as renal filtration barrier damage and reduced glomerular filtration rate. Studies have found that hyperuricemia is closely related to the onset and progression of kidney disease [3]. For every 59.5 μmol/L (i.e. 1 mg/dL) increase in blood uric acid concentration, the risk of new kidney disease increases by 7%-11% [4]. Lowering blood uric acid can delay the progression of chronic kidney disease and has a protective effect on kidney function. The mechanism by which hyperuricemia causes renal damage includes the deposition of urate crystals in the renal tubules and renal interstitium, causing oxidative stress and inflammatory response, which in turn causes vascular damage; persistent high uric acid leads to abnormal endothelial cell function and activates the renin-angiotensin system, promoting glomerular arteriosclerosis and impaired renal function [5].

3. How to prevent and treat renal damage caused by hyperuricemia

(1) Improve dietary structure and bad living habits

Hyperuricemia is closely related to diet and lifestyle. Especially young people who consume too much meat, sweets, beverages, etc. on a daily basis can easily cause an increase in purine levels in the body, which is the biggest hidden danger leading to gout. A reasonable diet should be matched, and the intake of high-purine foods such as animal offal such as liver, kidney and heart should be reduced, but the purine content of egg protein and milk is low and can be eaten with peace of mind. Although the purine content of soybeans is slightly higher than that of lean meat and fish, the utilization rate of purine in plant foods is low, and soy products can be consumed in moderation. In addition to dietary factors, irregular work and rest is also a major factor. Staying up late and anxiety can easily cause problems with uric acid excretion.

(2) Drink plenty of water and limit alcohol consumption

Drinking water regularly can promote uric acid excretion. When heart and kidney function is normal, you should drink enough water, 2000-3000mL per day is recommended. Try to maintain a daily urine volume of more than 2000mL. White water is preferred, and lemonade, light tea, sugar-free coffee and soda water can also be consumed, but excessive drinking of strong tea, strong coffee, etc. should be avoided, and drinking raw and cold drinks should be avoided. Alcohol metabolism increases uric acid production and reduces uric acid excretion. Alcoholic beverages such as rice wine and beer also contain purine. Therefore, drinking should be limited.

(3) Uric acid lowering drugs

When the blood uric acid concentration is greater than 500 μmol/L, the glomerular filtration rate is significantly reduced. my country's guidelines recommend that patients with chronic kidney disease without gout can use uric acid-lowering drugs under the guidance of a physician if the blood uric acid concentration is still greater than 420 μmol/L after three months of non-drug treatment. The indications for lowering uric acid, the selection of uric acid-lowering drugs, and the target of blood uric acid control are related to whether gout occurs, the primary disease, whether dialysis is required, and whether cardiovascular and cerebrovascular diseases are present.

(4) Exercise moderately and maintain a healthy weight

Overweight and obesity increase the risk of hyperuricemia in the population, and weight loss can significantly reduce blood uric acid levels. Overweight and obese people with hyperuricemia should choose sports that suit them on the basis of meeting their daily nutritional needs, and exercise step by step. The intensity of exercise is mainly low- and medium-intensity aerobic exercise. Aerobic exercise should be performed 4 to 5 times a week for 30 to 60 minutes each time. You can choose jogging, walking, cycling, swimming and other sports that have little or no impact on the joints. During or after exercise, you should replenish water in time. However, exercise should be reduced or avoided during the gouty arthritis period.

(5) Lowering blood lipids

Renal damage caused by hyperuricemia is related to low-density lipoprotein cholesterol (LDL-C), which is also the primary target for dyslipidemia management. Therefore, lowering LDL-C may prevent renal damage caused by hyperuricemia.

4. Conclusion

As the incidence of hyperuricemia increases and the disease is younger, the renal damage caused by it cannot be ignored. However, hyperuricemia is not terrible. As long as we pay attention to it and take reasonable measures in time, we can prevent hyperuricemia and its renal damage and protect our life and health.

References:

[1] Chinese Guidelines for the Diagnosis and Treatment of Hyperuricemia and Gout (2019)[J]. Chinese Journal of Endocrinology and Metabolism, 2020, 36(1): 1-13.

[2] Chen Runyao, Wu Hao, Zhang Liting, et al. Effects of serum uric acid on renal function and factors analysis in male soldiers aged 19 to <30 years[J]. Modern Medicine and Health, 2024, 40(14): 2362-2366

[3] CAO

[4] WEINER DE, TIGHIOUART H, ELSAYED EF, et al. Uric acid and incident kidney disease in the community[J]. J Am Soc Nephrol,2008,19(6):1204-1211.

[5] SHARAF EL DIN UAA, SALEM MM, ABDULAZIM D O. Uric acid in the pathogenesis of metabolic, renal, and cardiovascular diseases: A review[J]. J Adv Res, 2017,8(5):537-548.