The last two decades have seen enormous advances in understanding and ability to treat many types of kidney disease. Simultaneously, the global rise of noncommunicable diseases and other chronic kidney disease (CKD) risk factors have drastically increased the number living with or at risk for CKD.
As of 2015 it was estimated that 10% of the global population is living with CKD. Within low-income nations primarily in Africa and Asia common causes of CKD include glomerulonephritis and interstitial nephritis (due to high levels of infection). Despite prevalence of known causes of CKD such as streptococcal infection, hepatitis B and C, and HIV, the particular causes of CKD within many low-income nations is still unknown.
Within higher income nations the leading causes of CKD are more clear. In the United States a majority of adults currently have CKD or are at risk for CKD.
CKD Risk Factor (percentage of American adults)
A selection of these conditions feed into actual causes of CKD (or are the causes themselves). These include:
CKD Cause (percentage of American adults)
While CKD can be managed medically and through lifestyle changes, one of the largest issues with renal health outcomes in America is the lack of knowledge about personal renal health. Of American adults with CKD, 9 out of 10 don’t know they have it. 
Now that we’ve outlined the huge number of global adults at risk or currently living with CKD, let’s follow the trajectory of the disease and different potential outcomes.
What is CKD?
Put simply, CKD is a process by which one gradually loses kidney function. Kidneys are responsible for filtering excess waste and fluid from your blood. When kidneys aren’t functioning optimally (or at all) dangerous levels of waste, fluids, and electrolytes can build in your blood. This stage of the process, known as end-stage kidney failure (or end-stage renal disease) can be fatal and lead to many other serious health complications if untreated.
CKD is most commonly treated by lifestyle changes and medical treatment for underlying causes (listed in the last section). Many of these conditions are serious on their own. But when coupled with CKD can alter health outcomes and life expectancy even more. For this reason, it’s important to be tested for CKD if you have any of the conditions above (or you exhibit other symptoms of kidney stress or dysfunction).
Additionally, CKD has been shown to increase morbidity and premature death independently of comorbidities .
Most Typical Causes of CKD
As outlined above, the most typical causes of CKD vary by region of the world. Within low-income nations the prevalence of infection, hepatitis, and HIV are thought -- though often aren’t proven in individuals -- to contribute to CKD.
Within higher income nations, by far the largest causes of CKD include diabetes, and high blood pressure. A host of risk factors for these precipitating causes as well as CKD itself are also more common than not.
Roughly 1 in 2 American adults have CKD or are at risk for CKD due to one of these causes or risk factors.
CKD By Physical Trauma or Infection
Within low income nations, untreated tropical infections including malaria and streptococcal infection are some of the largest risk factors for CKD. Sepsis is also much more common within low income nations , and can lead to CKD or renal failure.
Worldwide, blunt and penetrative physical trauma such as from a fall, a car accident, or other form of accident are among leading causes of CKD. Though a much smaller percentage of the overall population experience kidney dysfunction due to physical trauma than due to infections or noncommunicable diseases.
Among high income nations drug overdose and poisoning are more common forms of acute trauma that can lead to CKD or renal failure. Close to 70,000 Americans died in 2018 due to drug overdose or complications.
One distinguishing factor between causes of CKD in this factor and others is that acute injuries are likely to lead to significant impairment in kidney function rapidly. Meanwhile, more common causes of CKD typically exhibit a gradual decline in function.
While a much smaller portion than common causes of CKD outlined in the last section, physical trauma, infection, and drug overdose are a noteworthy cause of CKD or kidney failure globally.
CKD By Cancer
CKD has a complicated and troublesome relationship with a number of cancers. While some cancers are known to commonly cause CKD, CKD can also cause a number of cancers.
As individuals progress to end-stage renal disease the likelihood that CKD can precipitate cancer increases.
Studies have shown that between 10% and 80% of individuals who have used dialysis have significantly higher risks for cancer . Individuals who have received kidney transplants have been found to have a 2-4x chance of developing over 20 cancer types .
Emerging research is showing increased cancer risks for individuals with early CKD as well .
The most common cancers known to increase the risk of CKD include:
The most common cancers more common among CKD patients include:
While CKD by cancer is less common than the most common causes such as high blood pressure, cardiovascular disease, and diabetes, the range of cancers that can lead to CKD risk is alarming. Additionally, the complex relationship between CKD and having cancer in the future leads to increased mortality among those presently with CKD.
CKD by Polycystic Kidney Disease
Around .3% (or roughly 600,000) American adults presently have Polycystic Kidney Disease. This genetic disease causes cysts to grow inside the kidney, increasing the size of the organ and reducing the function of the organ.
While not exceedingly common, polycystic kidney disease is a noteworthy cause of eventual kidney failure. Around 2% of annual kidney failures occur due to polycystic kidney disease .
What is End-Stage Renal Disease?
Individuals whose CKD continues to progress (or who suffer an acute injury to the kidneys) often enter what is known as end-stage renal disease (or end-stage kidney failure). At this stage of kidney dysfunction, individuals are at high risk of death without dialysis or a kidney transplant.
End-stage renal disease is typically diagnosed when kidneys are performing at 10% or less of a typical functional unit.
Even among individuals on dialysis or who do gain a kidney transplant, life expectancy is often dramatically shortened. The only true “cure” for end-stage renal disease is cutting off the progression of CKD before kidney failure becomes extreme.
With this said, individuals lucky enough to find a kidney transplant that is compatible with their body can often expect substantially longer life expectancies than those on dialysis