Home > Prevention

Prevention

About kidney diseases

Kidneys are organs (usually two) located in the upper part of the lumbar region, which are vital due to the various functions they perform:

The kidneys play a crucial role in maintaining the body’s fluid balance. They are responsible for controlling the amount of body fluid and regulating blood pressure, ensuring that these vital processes are kept in check.

In addition to fluid and blood pressure regulation, the kidneys perform several essential functions. They regulate blood pH and osmolality, remove toxins and waste products from the blood, and manage the concentration of important salts and electrolytes, including sodium, potassium, calcium, magnesium, and phosphorus.

The kidneys also contribute to the production of key substances necessary for overall health. They produce erythropoietin, which is vital for the formation of red blood cells, and Klotho, a protein that delays biological aging.

Furthermore, the kidneys activate vitamin D, which is essential for maintaining bone health. This activation helps regulate calcium and phosphate levels in the body, contributing to strong and healthy bones.

Chronic kidney disease (CKD) is defined by abnormalities of kidney structure or functions, regardless of the cause, present for more than 3 months, with implications for health.

Causes

There are diverse causes of CKD:

01.

Diabetes mellitus is the most common cause of CKD

02.

Hypertension and cardiovascular diseases

03.

Primary glomerular disease or glomerular disease secondary to systemic diseases

04.

Congenital and hereditary nephropathies

05.

Interstitial nephropathies

06.

Prolonged obstruction of the urinary tract (including lithiasis, tumours, prostate hyperplasia)

07.

Recurrent urinary tract infections

08.

Systemic diseases (lupus, vasculitis, myeloma)

Epidemology

In recent years, CKD has become more and more frequent, and nowadays, it constitutes a serious public health issue.

In 2021, it was estimated to affect 673 million people (> 8% of the population worldwide), this percentage being 20% in people older than 55 years, probably even higher since it is an entity widely underdiagnosed. The problem is even more significant given the increase in morbidity and mortality, especially cardiovascular, related to kidney deterioration. CKD is predicted to be the fifth leading cause of death globally by 2050.

In 2021

>8%

of the population worldwide was affected by CKD

20%

of the affected CKD population was older than 55 years old.

In 2050

CKD probably will be

the 5th leading cause of death globally

Symptoms

Early stage

In the early stages of the disease, CKD is usually silent. Thus, it is typically identified through routine screening with a serum chemistry profile and urine studies or as an incidental finding. Less commonly, patients may present symptoms such as gross haematuria, “foamy urine” (a sign of albuminuria), nocturia, flank pain, or decreased urine output.

Advanced stage

If CKD is advanced, nonspecific symptoms may appear, such as fatigue, poor appetite, nausea, vomiting, metallic taste, unintentional weight loss, pruritus, changes in mental status, dyspnoea, or peripheral edema. By the time these symptoms develop, kidney replacement therapy is already necessary or will be in the short term.

Diagnosis

CKD is usually diagnosed by a blood test (serum creatinine) or a urine test (albuminuria).

Serum creatinine

Serum creatinine is used to estimate kidney function, i.e. the glomerular filtration rate (the volume of blood filtered by the kidneys per minute).

Albuminuria

Albuminuria indicates kidney damage, as do other urine components such as other proteins or red blood cells.

Criteria for CKD diagnosis are either a decrease in glomerular filtration rate <60 ml/min per 1.73 m2 (i.e. below 50% of normal), or markers of kidney damage (usually albuminuria > 30 mg/g urinary creatinine but also other urine abnormalities, electrolyte alterations due to kidney disorders, or structural abnormalities) that persist for longer than 3 months (chronic).

Once a diagnosis of CKD has been made, the next steps are identifying the cause, establishing the risk based on the combination of GFR and urine albumin/creatinine ratio values and initiating cause-specific and non-specific kidney protective therapy.

Prevention and treatment

Several factors can contribute to the onset and progression of CKD.

Therefore, to prevent its development and progression, the following general measures are recommended:

Eat a varied diet rich in vegetables. Avoid processed foods (eat a market diet, not a supermarket diet) and excess protein, especially in the advanced stages of the disease.
Reduce salt intake.
Avoid toxic substances such as tobacco, alcohol, or other drugs.
Perform physical exercise daily and avoid being overweight.
Adequate hydration.
Avoid nephrotoxic drugs, such as non-steroidal anti-inflammatory drugs, herbal products, or protein supplements.
Control blood pressure.

In addition to the above, there are drugs for high blood pressure or diabetes, which reduce the loss of albumin in urine and slow the progression of the disease. Some antidiabetic drugs (example. SGLT2 inhibitors or gliflozins) protect the kidneys more than other antidiabetic drugs.

Evolution

The evolution of kidney disease is usually slow and progressive. It does not cause symptoms until the most advanced phases when the kidneys have established damage and little chance of recovery.

Early detection and treatment are therefore crucial.

Progressive CKD is associated with adverse clinical outcomes, including kidney failure (also termed end-stage kidney disease, ESKD), cardiovascular disease, and increased mortality.

Despite all efforts to optimize the management of CKD, many patients reach ESKD, in which kidneys are no longer able to perform their functions, life-threatening complications appear, and kidney function should be replaced.

Therapeutic options to replace kidney function are:

Hemodialysis

An extracorporeal blood purification technique using a machine that replaces some kidney functions (elimination of toxins, balance of electrolytes, and pH and water regulation).

The rest of the functions will have to be supplemented with drugs or remain unreplaced (e.g. production of the antiaging protein Klotho). Vascular access is needed to perform haemodialysis, such as an arteriovenous fistula (union of artery and vein, usually in the arm) or a catheter. This access allows blood to flow outside the body (extracorporeal) where it’s filtered through a special membrane called a dialyzer. Haemodialysis is generally done in hospital or at a dialysis centre about three days a week, for approximately 4 hours each session. In some cases, it is possible to do it at home. However, the appropriate material and learning of the technique are required.

Peritoneal dialysis

The peritoneum (a membrane that lines the inside of the abdominal cavity) is used as a dialyzing membrane.

To perform the technique, a peritoneal catheter must be implanted (in the abdomen), through which dialysis fluid will be inserted and removed after a few hours. This procedure is usually performed at home, requiring all the necessary materials and knowledge of the technique. It does not replace all kidney functions, so it will be essential to replace some of them with drugs.

Kidney transplant

A transplant can come from a living or a deceased donor. It is the ideal option since it replaces all kidney functions, usually offering a better quality of life and greater survival than dialysis.

However, it carries the risks of surgery and immunosuppressive medication to prevent organ rejection, which can increase the risk of infections and tumours. Therefore, it is not possible to do it in all patients. Very recently, kidneys from genetically modified pigs have been successfully transplanted in humans.

Comprehensive conservative care

Planned and holistic care for patients with ESKD that does not include dialysis or kidney transplant because of frailty or comorbidity, which decreases the benefit obtained from kidney replacement therapy.

This approach includes interventions to delay CKD progression and minimise the risk of adverse events or complications. It emphasises shared decision-making and detailed communication (including advance care planning), and it focuses on active symptom management and psychological, social, family, cultural, and spiritual support.

None of these alternatives is a perfect solution since life expectancy is shorter than for the general population of the same age.

In Europe, it is estimated that kidney transplant patients may live up to 20 years less than their healthy peers, and those on dialysis up to 40 years less (these differences vary depending on age).

Thus, the best approach is to prevent CKD and, if this is not possible, to diagnose it early (when it is still silent) and treat it early.

Other insights

References

Rennke H, Denker BM. Renal pathophysiology: The essentials. 6a ed. Baltimore, MD, United States of America: Wolters Kluwer Health; 2024.
Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group. KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int. 2024;105(4S):S117-S314. doi:10.1016/j.kint.2023.10.018, available at https://www.kidney-international.org/article/S0085-2538(23)00766-4/fulltext.
Lucas B, Taal MW. Epidemiology and causes of chronic kidney disease. Medicine. 2023;51(3):165–9. Available at: http://dx.doi.org/10.1016/j.mpmed.2022.12.003
GBD Results [Internet]. Institute for Health Metrics and Evaluation. [citado el 15 de abril de 2024]. Available at: https://vizhub.healthdata.org/gbd-results/
GBD 2013 Mortality and Causes of Death Collaborators. Global, regional, and national age-sex specific all-cause and cause-specific mortality for 240 causes of death, 1990-2013: a systematic analysis for the Global Burden of Disease Study 2013. Lancet. 2015;385(9963):117–71. Available at: http://dx.doi.org/10.1016/S0140-6736(14)61682-2
Chen TK, Knicely DH, Grams ME. Chronic kidney disease diagnosis and management: A review: A review. JAMA. 2019;322(13):1294–304. Available at: http://dx.doi.org/10.1001/jama.2019.14745
Cheung KL, Crews DC, Cushman M, Yuan Y, Wilkinson K, Long DL, et al. Risk factors for incident CKD in Black and White Americans: The REGARDS study. Am J Kidney Dis. 2023;82(1):11-21.e1. Available at: http://dx.doi.org/10.1053/j.ajkd.2022.11.015
Chertow GM, Correa-Rotter R, Vart P, Jongs N, McMurray JJV, Rossing P, et al. Effects of dapagliflozin in Chronic Kidney Disease, with and without other cardiovascular medications: DAPA-CKD trial. J Am Heart Assoc. 2023;12(9):e028739. Available at: http://dx.doi.org/10.1161/JAHA.122.028739
EMPA-KIDNEY Collaborative Group. Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial. Lancet Diabetes Endocrinol. 2024;12(1):51–60. Available at: http://dx.doi.org/10.1016/S2213-8587(23)00322-4
Yi TW, Smyth B, Di Tanna GL, Arnott C, Cardoza K, Kang A, et al. Kidney and cardiovascular effects of canagliflozin according to age and sex: A post hoc analysis of the CREDENCE randomized clinical trial. Am J Kidney Dis. 2023;82(1):84-96.e1. Available at: http://dx.doi.org/10.1053/j.ajkd.2022.12.015
Perez-Gomez MV, Bartsch LA, Castillo-Rodriguez E, et al. Clarifying the concept of chronic kidney disease for non-nephrologists. Clin Kidney J. 2019;12(2):258-261. Published 2019 Feb 14. http://doi:10.1093/ckj/sfz007
Fernández-Fernandez B, Sarafidis P, Soler MJ, Ortiz A. EMPA-KIDNEY: expanding the range of kidney protection by SGLT2 inhibitors. Clin Kidney J. 2023;16(8):1187-1198. Published 2023 Jun 16. http://doi:10.1093/ckj/sfad082
Lewis EJ, Hunsicker LG, Clarke WR, Berl T, Pohl MA, Lewis JB, et al. Renoprotective effect of the angiotensin-receptor antagonist irbesartan in patients with nephropathy due to type 2 diabetes. N Engl J Med 2001;345(12):851–60. Available at: http://dx.doi.org/10.1056/NEJMoa011303
Hou FF, Zhang X, Zhang GH, Xie D, Chen PY, Zhang WR, et al. Efficacy and safety of benazepril for advanced chronic renal insufficiency. N Engl J Med 2006;354(2):131–40. Available at: http://dx.doi.org/10.1056/NEJMoa053107
Himmelfarb J, Ikizler TA. Hemodialysis. N Engl J Med 2010;363(19):1833–45. Available at: http://dx.doi.org/10.1056/NEJMra0902710
Teitelbaum I. Peritoneal dialysis. N Engl J Med. 2021;385(19):1786–95. Available at: http://dx.doi.org/10.1056/nejmra2100152
Danovitch GM. Manual de trasplante renal. 6a ed. la Ciudad Condal, España: Lippincott Williams & Wilkins; 2018.
Hamroun A, Glowacki F, Frimat L. Comprehensive conservative care: what doctors say, what patients hear. Nephrol Dial Transplant. 2023;38(11):2428–43. Available at: http://dx.doi.org/10.1093/ndt/gfad088
Boerstra BA, Boenink R, Astley ME, Bonthuis M, ElHafeez SA, Monzón FA, et al. The ERA Registry Annual Report 2021: a summary. Clin Kidney J 2023; Available at: http://dx.doi.org/10.1093/ckj/sfad281