An Introduction to Kidney Disease in African-Americans

black doctor looking at xrayChronic Kidney Disease (CKD) is defined as a decrease in the function of the basic unit of the kidney (called the glomerulus) and /or an anatomic disorder of the organ.    In 2003, 20 million people were estimated to have CKD in the United States.  This equates to one (1) in nine (9) adults in the population.  20 million more Americans are at risk for this condition.  CKD is broken down into 5 stages.  Stage 1 is mild kidney disease and has 5.9 million people.  Stage 2 has 5.3 million people; stage 3 has 7.6 million people; stage 4 has 500,000.  Stage 5 is termed End Stage Renal Disease (ESRD); this stage has 406,000 people.  ESRD is expected to grow to 650,000 people by 2010.

Chronic Kidney Disease affects other systems including the skeletal system, the immune system, the hematopoietic system (which is responsible for blood cell production) and several body regulatory systems.  Most importantly, there is a direct correlation with increased rates of cardiovascular disease as kidney function declines.     The epidemic of Kidney Disease affects minority populations at an increased rate; this is particularly true for the African-American population.

Chronic Kidney Disease incidence according to the second National Health and Nutrition Survey Mortality Study (NHANES II) is about 2.7 times higher for African-Americans than their White counterparts.  A study published in the Journal of the American Society of Nephrology (JASN) in 2002 revealed that African-Americans with CKD progress to ESRD 8.9 times more than Whites.  It is interesting that the two major causes of CKD, diabetes and hypertension, affect African-Americans more than Whites.  Also, these diseases tend to manifest much earlier and more severely in Blacks.  In fact, for both hypertension and diabetes, the rates of developing kidney disease in the Black population are much higher.   However, it is unclear why the rates are so different.  In fact, the study in JASN suggested that “nearly one half of the excess risk of CKD among African-American adults can be explained by potentially modifiable risk factors…much of the excess risk remains unexplained.”

The impact of kidney disease on the Black population has important ramifications given the body systems that it affects.  Cardiovascular Disease produces an increased morbidity and mortality in the Black population.  The extent to which kidney disease directly affects these rates is not known.  However, we do know that, in general, people with CKD have a decreased life expectancy, which is mostly related to cardiovascular events.  For instance, for a 49 year old with ESRD, the life expectancy is 7.1 years.  This is compared to colon cancer (8.6 years), prostate cancer (12.8 years) and the general population (29.8 years).

Three interrelated ideas suggest a link between CKD and increased general morbidity and mortality in Blacks as it relates to cardiovascular disease. First, Cardiovascular events occur at higher rates in the Black population without kidney disease.  Second, CKD disproportionately affects more African-Americans than White Americans.  Third, CKD increases the rates of cardiovascular events in the general population.  It stands to reason that African-Americans with CKD experience higher rates of cardiovascular events than their white counterparts.  Do we need to examine the data more carefully to study the impact of these statistics on the Black population?  The author believes the answer to the question is, unequivocally, yes!

This brief introduction kidney disease in African-Americans has provided a definition and broad scope of the CKD epidemic in this group.  Kidney Disease affects many body systems leading to increased morbidity and mortality in this (and the general) population.  Over the next 5 to 10 years, it is predicted that there will be exponential growth in the rates of CKD in the U.S. population.  If similar rates continue, minority populations will continue to be disproportionately affected resulting in increased loss of life and increased healthcare expenditure.  While, an absolute cure for kidney disease remains elusive, treatments for CKD are improving as technology advances.  Some causes of CKD are preventable; by controlling risk factors it is hoped that we can slow the development of CKD and decrease the rates of both CKD and ESRD in the Black population.

What can I do to lower my risk of developing kidney disease?  What kinds of things can I do to slow the progression of my Chronic Kidney disease?  What are the real risks and benefits of the treatment options for Chronic Kidney Disease and End Stage Renal Disease?  What are some of the major causes of Kidney Disease and can I learn more about