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.”