Chronic kidney disease

Chronic kidney disease (CKD) is a type of long-term kidney disease, in which either there is a gradual loss of kidney function which occurs over a period of months to years, or an abnormal kidney structure (with normal function). Initially, patients are usually asymptomatic, but later symptoms may include leg swelling, feeling tired, vomiting, loss of appetite, and confusion. Complications can relate to hormonal dysfunction of the kidneys and include (in chronological order) high blood pressure (often related to activation of the renin–angiotensin system), bone disease, and anemia. Additionally CKD patients have markedly increased cardiovascular complications with increased risks of death and hospitalization. CKD can lead to end-stage kidney failure requiring kidney dialysis or kidney transplantation.
Causes of chronic kidney disease include diabetes, high blood pressure, glomerulonephritis, and polycystic kidney disease. Risk factors include a family history of chronic kidney disease. Diagnosis is by blood tests to measure the estimated glomerular filtration rate (eGFR), and a urine test to measure albumin. Ultrasound or kidney biopsy may be performed to determine the underlying cause. Several severity-based staging systems are in use.
Screening at-risk people is recommended. Initial treatments may include medications to lower blood pressure, blood sugar, and cholesterol. Angiotensin converting enzyme inhibitors (ACEIs) or angiotensin II receptor antagonists (ARBs) are generally first-line agents for blood pressure control, as they slow progression of the kidney disease and the risk of heart disease. Loop diuretics may be used to control edema and, if needed, to further lower blood pressure. NSAIDs should be avoided. Other recommended measures include staying active, and "to adopt healthy and diverse diets with a higher consumption of plant-based foods compared to animal-based foods and a lower consumption of ultraprocessed foods." Plant-based diets are feasible and are associated with improved intermediate outcomes and biomarkers. An example of a general, healthy diet, suitable for people with CKD who do not require restrictions, is the Canada Food Guide Diet. People with CKD who require dietary restrictions or who have other specific nutritional problems should be referred to a dietitian. Treatments for anemia and bone disease may also be required. Severe disease requires hemodialysis, peritoneal dialysis, or a kidney transplant for survival.
Chronic kidney disease affected 753 million people globally in 2016 (417 million females and 336 million males.) In 2015, it caused 1.2 million deaths, up from 409,000 in 1990. The causes that contribute to the greatest number of deaths are high blood pressure at 550,000, followed by diabetes at 418,000, and glomerulonephritis at 238,000.
CKD is initially without symptoms and is usually detected on routine screening blood work by either an increase in serum creatinine, or protein in the urine. As the kidney function decreases, more unpleasant symptoms may emerge:
The most common causes of CKD are diabetes mellitus, hypertension, and glomerulonephritis. About one of five adults with hypertension and one of three adults with diabetes have CKD. If the cause is unknown, it is called idiopathic.
Diagnosis of CKD is largely based on history, examination, and urine dipstick combined with the measurement of the serum creatinine level. Differentiating CKD from acute kidney injury (AKI) is important because AKI can be reversible. One diagnostic clue that helps differentiate CKD from AKI is a gradual rise in serum creatinine (over several months or years) as opposed to a sudden increase in the serum creatinine (several days to weeks). In many people with CKD, previous kidney disease or other underlying diseases are already known. A significant number present with CKD of unknown cause.
Screening those who have neither symptoms nor risk factors for CKD is not recommended. Those who should be screened include: those with hypertension or history of cardiovascular disease, those with diabetes or marked obesity, those aged > 60 years, subjects with African American ancestry, those with a history of kidney disease in the past, and subjects who have relatives who had kidney disease requiring dialysis.
Screening should include calculation of the estimated GFR (eGFR) from the serum creatinine level, and measurement of urine albumin-to-creatinine ratio (ACR) in a first-morning urine specimen (this reflects the amount of a protein called albumin in the urine), as well as a urine dipstick screen for hematuria.
The GFR is derived from the serum creatinine and is proportional to 1/creatinine, i.e. it is a reciprocal relationship; the higher the creatinine, the lower the GFR. It reflects one aspect of kidney function, how efficiently the glomeruli – the filtering units – work. The normal GFR is >90 ml/min. The units of creatinine vary from country to country, but since the glomeruli comprise <5% of the mass of the kidney, the GFR does not indicate all aspects of kidney health and function. This can be done by combining the GFR level with the clinical assessment of the person, including fluid status, and measuring the levels of hemoglobin, potassium, phosphate, and parathyroid hormone.
Kidney ultrasonography is useful for diagnostic and prognostic purposes in chronic kidney disease. Whether the underlying pathologic change is glomerular sclerosis, tubular atrophy, interstitial fibrosis, or inflammation, the result is often increased echogenicity of the cortex. The echogenicity of the kidney should be related to the echogenicity of the liver or the spleen. Moreover, decreased kidney size and cortical thinning are often seen especially when the disease progresses. However, kidney size correlates to height, and short persons tend to have small kidneys; thus, kidney size as the only parameter is unreliable.
Additional tests may include nuclear medicine MAG3 scan to confirm blood flow and establish the differential function between the two kidneys. Dimercaptosuccinic acid (DMSA) scans are also used in kidney imaging; with both MAG3 and DMSA being used chelated with the radioactive element technetium-99.
A glomerular filtration rate (GFR) ≥ 60 mL/min/1.73 m is considered normal without chronic kidney disease if there is no kidney damage present.
Kidney damage is defined as signs of damage seen in blood, urine, or imaging studies which include lab albumin/creatinine ratio (ACR) ≥ 30. All people with a GFR <60 mL/min/1.73 m for 3 months are defined as having chronic kidney disease.
Protein in the urine is regarded as an independent marker for the worsening of kidney function and cardiovascular disease. Hence, British guidelines append the letter "P" to the stage of chronic kidney disease if protein loss is significant.
The term "non-dialysis-dependent chronic kidney disease" (NDD-CKD) is a designation used to encompass the status of those persons with an established CKD who do not yet require the life-supporting treatments for kidney failure known as kidney replacement therapy (RRT, including maintenance dialysis or kidney transplantation). The condition of individuals with CKD, who require either of the two types of kidney replacement therapy (dialysis or transplant), is referred to as end-stage kidney disease (ESKD). Hence, the start of the ESKD is practically the irreversible conclusion of the NDD-CKD. Even though the NDD-CKD status refers to the status of persons with earlier stages of CKD (stages 1 to 4), people with advanced stages of CKD (stage 5), who have not yet started kidney replacement therapy, are also referred to as NDD-CKD.
Chronic kidney disease (CKD) is a serious condition often linked to diabetes and high blood pressure. There is no cure, but a combination of lifestyle changes and medications can help slow its progression. This might include a plant-dominant diet with less protein and salt, medications to control blood pressure and sugar, and potentially newer anti-inflammatory drugs. Doctors may also focus on managing heart disease risk, preventing infections, and avoiding further kidney damage. While dialysis may eventually be needed, a gradual transition can help preserve remaining kidney function. More research is ongoing to improve CKD management and patient outcomes.
Angiotensin converting enzyme inhibitors (ACEIs) or angiotensin II receptor antagonists (ARBs) are recommended as first-line agents since they have been found to slow the decline of kidney function, relative to a more rapid decline in those not on one of these agents. They have also been found to reduce the risk of major cardiovascular events such as myocardial infarction, stroke, heart failure, and death from cardiovascular disease when compared to placebo in individuals with CKD. ACEIs may be superior to ARBs for protection against progression to kidney failure and death from any cause in those with CKD. Aggressive blood pressure lowering decreases people's risk of death.
Obesity may have a negative impact in CKD, increasing the risk of disease progression to ESKD or kidney failure compared to controls with healthy weight, and when in advanced stages also may hinder people's eligibility to kidney transplantation. For example, the consumption of high calorie and high fructose beverages can make an individual "60% more likely to develop CKD".
Weight management interventions in overweight and obese adults with CKD include lifestyle interventions (dietary changes, physical activity/exercise, or behavioural strategies), pharmacological (used to reduce absorption or suppress appetite) and surgical interventions. Any of these can help people with CKD lose weight, however, it is not known if they can also prevent death or cardiovascular events like heart complications or stroke. It is recommended that weight management interventions should be individualised, according to a thorough patients' assessment regarding clinical condition, motivations, and preferences.
High dietary sodium intake may increase the risk of hypertension and cardiovascular disease. The effect of dietary restriction of salt in foods has been investigated in people with chronic kidney disease. For people with CKD, including those on dialysis, reduced salt intake may help to lower both systolic and diastolic blood pressure, as well as albuminuria. Some people may experience low blood pressure and associated symptoms, such as dizziness, with lower salt intake. The effect of salt restriction on extracellular fluid, oedema, and total body weight reduction is unknown.
EHealth interventions may improve dietary sodium intake and fluid management for people with CKD.
In people with CKD who require hemodialysis, there is a risk that vascular blockage due to clotting, may prevent dialysis therapy from being possible. Even though Omega-3 fatty acids contribute to the production of eicosanoid molecules that reduce clotting, it does not have any impact on the prevention of vascular blockage in people with CKD.
Regular consumption of oral protein-based nutritional supplements may increase serum albumin levels slightly in people with CKD, especially among those requiring hemodialysis or who are malnourished. Prealbumin level and mid-arm muscle circumference may also be increased following supplementation. Despite possible improvement in these indicators of nutritional status, it is not certain that protein supplements affect the quality of life, life expectancy, inflammation, or body composition.
Intravenous (IV) iron therapy may help more than oral iron supplements in reaching target hemoglobin levels. However, allergic reactions may also be more likely following IV-iron therapy.
Individuals with CKD have an increased prevalence of sleep apnea compared to the general population (both OSA and central sleep apnea). The presence of sleep apnea in CKD has been associated with an increased risk of cardiovascular events and mortality.
People with CKD also experience sleep disorders, thus unable to get quality sleep. There are several strategies that could help, such as relaxation techniques, exercise, and medication. Exercise may be helpful with sleep regulation and may decrease fatigue and depression in people with CKD. However, none of these options have been proven to be effective in the treatment of sleep disorders. This means that it is unknown what is the best guidance to improve sleep quality in this population.
Guidelines for referral to a nephrologist vary between countries. Most agree that nephrology referral is required by Stage 4 CKD (when eGFR/1.73m is less than 30 mL/min; or decreasing by more than 3 mL/min/year).
It may also be useful at an earlier stage (e.g. CKD3) when urine albumin-to-creatinine ratio is more than 30 mg/mmol, when blood pressure is difficult to control, or when hematuria or other findings suggest either a primarily glomerular disorder or secondary disease amenable to a specific treatment. Other benefits of early nephrology referral include proper education regarding options for kidney replacement therapy as well as pre-emptive transplantation, and timely workup and placement of an arteriovenous fistula in those people with chronic kidney disease opting for future hemodialysis.
At stage 5 CKD, kidney replacement therapy is usually required, in the form of either dialysis or a kidney transplant.
In CKD numerous uremic toxins accumulate in the blood. Even when ESKD (largely synonymous with CKD5) is treated with dialysis, the toxin levels do not go back to normal as dialysis is not that efficient. Similarly, after a kidney transplant, the levels may not go back to normal as the transplanted kidney may not work 100%. If it does, the creatinine level is often normal. The toxins show various cytotoxic activities in the serum and have different molecular weights, and some of them are bound to other proteins, primarily to albumin. Uremic toxins are classified into three groups as small water-soluble solutes, middle molecular-weight solutes, and protein-bound solutes. Hemodialysis with high-flux dialysis membrane, long or frequent treatment, and increased blood/dialysate flow has improved removal of water-soluble small molecular weight uremic toxins. Middle molecular weight molecules are removed more effectively with hemodialysis using a high-flux membrane, hemodiafiltration, and hemofiltration. However, conventional dialysis treatment is limited in its ability to remove protein-bound uremic toxins.
CKD increases the risk of cardiovascular disease, and people with CKD often have other risk factors for heart disease, such as high blood lipids. The most common cause of death in people with CKD is cardiovascular disease rather than kidney failure.
Chronic kidney disease results in worse all-cause mortality (the overall death rate) which increases as kidney function decreases. The leading cause of death in chronic kidney disease is cardiovascular disease, regardless of whether there is progression to stage 5.
While kidney replacement therapies can maintain people indefinitely and prolong life, the quality of life is negatively affected. Kidney transplantation increases the survival of people with stage 5 CKD when compared to other options; however, it is associated with an increased short-term mortality due to complications of the surgery. Transplantation aside, high-intensity home hemodialysis appears to be associated with improved survival and a greater quality of life, when compared to the conventional three-times-a-week hemodialysis and peritoneal dialysis.
People with ESKD are at increased overall risk for cancer. This risk is particularly high in younger people and gradually diminishes with age. Medical specialty professional organizations recommend that physicians do not perform routine cancer screening in people with limited life expectancies due to ESKD because the evidence does not show that such tests lead to improved outcomes.
In children, growth failure is a common complication of CKD. Children with CKD will be shorter than 97% of children the same age and sex. This can be treated with additional nutritional support or medication such as growth hormone.
Survival rates of CKD are generally longer with dialysis than without (having only conservative kidney management). However, from the age of 80 and in elderly patients with comorbidities there is no difference in survival between the two groups. Quality of life might be better for people without dialysis.
People who had decided against dialysis treatment when reaching end-stage chronic kidney disease could survive several years and experience improvements in their mental well-being in addition to sustained physical well-being and overall quality of life until late in their illness course. However, use of acute care services in these cases is common, and the intensity of end-of-life care is highly variable among people opting out of dialysis.
About one in ten people have chronic kidney disease. In Canada 1.9 to 2.3 million people were estimated to have CKD in 2008. CKD affected an estimated 13.9% of U.S. adults aged 18 years and older in the period from 2017 to 2020. In 2007 8.8% of the population of Great Britain and Northern Ireland had symptomatic CKD.
Chronic kidney disease was the cause of 956,000 deaths globally in 2013, up from 409,000 deaths in 1990.
The cause of chronic kidney disease is sometimes unknown; it is referred to as chronic kidney disease of unknown aetiology (CKDu). As of 2020 a rapidly progressive chronic kidney disease, unexplained by diabetes and hypertension, had increased dramatically in prevalence over a few decades in several regions in Central America and Mexico, a CKDu referred to as the Mesoamerican nephropathy (MeN). It was estimated in 2013 that at least 20,000 men had died prematurely, some in their 20s and 30s; a figure of 40,000 per year was estimated in 2020. In some affected areas CKD mortality was five times the national rate. MeN primarily affects men working as sugarcane labourers. The cause is unknown, but in 2020 the science found a clearer connection between heavy labour in high temperatures and incidence of CKDu; improvements such as regular access to water, rest and shade, can significantly decrease the potential CKDu incidence. CKDu also affects people in Sri Lanka where it is the eighth largest cause of in-hospital mortality.
African, Hispanic, and South Asian (particularly those from Pakistan, Sri Lanka, Bangladesh, and India) populations are at high risk of developing CKD. Africans are at greater risk due to the number of people affected with hypertension among them. As an example, 37% of ESKD cases in African Americans can be attributed to high blood pressure, compared with 19% among Caucasians. Treatment efficacy also differs between racial groups. Administration of antihypertensive drugs generally halts disease progression in white populations but has little effect in slowing kidney disease among black people, and additional treatment such as bicarbonate therapy is often required. While lower socioeconomic status contributes to the number of people affected with CKD, differences in the number of people affected by CKD are still evident between Africans and Whites when controlling for environmental factors.
Although CKD of unknown etiology was first documented among sugar cane workers in Costa Rica in the 1970s, it may well have affected plantation laborers since the introduction of sugar cane farming to the Caribbean in the 1600s. In colonial times the death records of slaves on sugar plantations were much higher than for slaves forced into other labor.
Denial of care in chronic kidney disease treatment and management is a significant issue for minority populations. This can be due to healthcare provider prejudice, structural barriers, and health insurance coverage disparities. Healthcare provider biases can lead to under-treatment, misdiagnosis, or delayed diagnosis. Structural barriers, such as lack of insurance and limited healthcare facilities, hinder access to timely care. Furthermore, health insurance coverage disparities, with minority populations lacking adequate coverage, contribute to these disparities. Denial of care worsens health outcomes and perpetuates existing health inequities.
Race-based kidney function metrics, particularly normalizing creatinine, pose ethical challenges in diagnosing and managing chronic kidney disease (CKD). While certain racial and ethnic groups are at higher risk, using race as a reference range may reinforce stereotypes and perpetuate health disparities. This approach fails to account for the complex interplay of genetic, environmental, and social factors influencing kidney function. Depending solely on race-based metrics may lead to misdiagnosis or underdiagnosis in minority populations. Alternative approaches that consider socioeconomic status, environmental exposures, and genetic vulnerability, are needed to accurately assess kidney function and address CKD care disparities.
The International Society of Nephrology is an international body representing specialists in kidney diseases.
It was said to be costing the National Health Service about £1.5 billion a year in 2020.
Kidney Care UK and The UK National Kidney Federation represent people with chronic kidney disease. The Renal Association represents Kidney physicians and works closely with the National Service Framework for kidney disease.
Kidney Health Australia serves that country.
The incidence rate of CKD in dogs was 15.8 cases per 10,000 dog years at risk. The mortality rate of CKD was 9.7 deaths per 10,000 dog years at risk. (Rates developed from a population of 600,000 insured Swedish dogs; one dog year at risk is one dog at risk for one year). The breeds with the highest rates were the Bernese mountain dog, miniature schnauzer, and boxer. The Swedish elkhound, Siberian husky and Finnish spitz were the breeds with the lowest rates.
Cats with chronic kidney disease may have a buildup of waste products usually removed by the kidneys. They may appear lethargic, unkempt, and lose weight, and may have hypertension. The disease can prevent appropriate concentration of urine, causing cats to urinate in greater volumes and drink more water to compensate. Loss of important proteins and vitamins through urine may cause abnormal metabolism and loss of appetite. The buildup of acids within the blood can result in acidosis, which can lead to anemia (which can sometimes be indicated by pink or whitish gums, but by no means does the presence of normal colored gums guarantee that anemia is not present or developing), and lethargy.
As of 2019 several compounds are in development for the treatment of CKD. These include the angiotensin receptor blocker (ARB) olmesartan medoxomil; and sulodexide, a mixture of low molecular weight heparin and dermatan sulfate.