An Overview of Chronic Kidney Disease

So what will we be covering?

§         What is chronic kidney disease?

§         What happens to people with chronic kidney disease?

§         What are management issues of people with chronic kidney disease?

§         What are treatments for people with end stage renal disease?

So what are the stages of chronic kidney disease or chronic renal failure (all of these stages require the signs to be going on for more than 3 months)?

§         Stage 1-Signs of kidney damage (protinuria or hematuria) with a normal or increased Glomerular Filtration Rate.  This is commonly seen in the early stages of diabetic nephropathy where you get hyperfiltration and microalbuminuria

§         Stage 2-Signs of kidney damage with mild decrease in Glomerular Filtration Rate (60-89)

§         Stage 3-Signs of kidney damage with a moderate decrease in Glomerular Filtration Rate (30-59)

§         Stage 4-Signs of kidney damage with a severe decrease in Glomerular Filtration Rate (29-15)

§         Stage 5-Kidney failure or a patient that is on dialysis (Glomerular Filtration Rate 15 or less)

So how can we measure Glomerular Filtration Rate?

§         One was is to measure an isotope clearance. 

§         A very common thing to use is inulin, since it is only filtered at the glomerulus and then excreted but neither absorbed nor secreted from the kidney tubules. 

§         However, inulin is expensive so it is rarely done.

§         Another way is an old equation, the Cockcroft-Gault equation, but it is not used anymore.

§         A third way is to do a 24 hour urine creatinine clearance test. 

§         This is where you collect all of the urine for 24 hours and then measure the amount of creatinine in the urine. 

§         But it is only an estimation since creatinine is secreted and absorbed in the tubules a bit.  It is also very hard to do collect a 24 hour urine sample.

§         Sometimes preferred is the MDRD Glomerular Filtration Rate clearance equation. 

§         It uses age, race, BUN, creatinine and albumin to calculate the Glomerular Filtration Rate.  It is generally more accurate than a 24 hour urine sample and there are plans to possibly make it a mandatory piece of data reported by labs on patients.
 

So why do we care about Glomerular Filtration Rate?

1.       It helps us recognize kidney disease.  Creatinine can be normal, but a Glomerular Filtration Rate can be low, and that will be a problem.

2.       It also allows propre dosing of drugs, so you do not give a drug that is cleared by the kidneys to someone with no kidney function.

The next few paragraphs are merely for enjoyment and “flavor”. 

§         The numbers of people with high blood pressure and diabetes and patients with high blood pressure alone is going up. 

§         The number of older people with end stage renal disease is shooting up and every age group except for 19 and under have had an increase in the number people with end stage kidney disease.  This is probably due to the fact that we are keeping people alive much longer after other medical conditions, like cancer and heart attacks so that they get kidney end stage kidney disease.

§         Every racial group except for Native Americans have had an increase in end stage kidney disease.

§         Diabetes and hypertension have increased significantly as the primary diagnosis to explain the end stage kidney disease.  However, hypertension is the diagnosis given for when people do not know what caused the kidney disease, so it is not a very good category to analyze.  It also includes nondiagnosed kidney problems.

§         More people are getting kidney dialysis and transplants.

§         People with chronic kidney disease do not do well.  There are double the amount of people admitted to the hospital with heart disease and chronic kidney than just heart disease alone.  This is because chronic kidney disease leads to heart disease due to increased rate of atherosclerosis.  The rate of admission for pneumonia with chronic kidney disease is also doubled compared to pneumonia patients without chronic kidney disease.

§         People with chronic kidney disease who get a heart attack are more likely to die than people who get a heart attack without chronic kidney disease.

§         Every single diagnosis is more prevalent with chronic kidney disease and percent mortaility is higher with chronic kidney disease.

§         Spending on chronic kidney disease is shooting up too.

§         People die pretty quickly with chronic kidney disease.  There is a 40% 5 year survival rate on dialysis.  This is actually worse than some cancer prognosis.  But a kidney transplant clearly shows a better 5-year survival rate than dialysis.

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