The Tribune

Dr ADRIAN SAWYER

Last Thursday was observed as World Kidney Day. The theme for this year’s theme, “Kidney Health for Everyone Everywhere”, calls for universal health coverage for prevention and early treatment of kidney disease. Nephrology is the study of kidneys and its diseases, and comes from the Greek word “Nephros” (kidney). The mission objective this year is to raise awareness of the importance of our kidneys to overall health and reduce the frequency and impact of kidney disease and its associated health problems world-wide. Included in the mission for 2019 are the following objectives:

• Improve awareness of the importance of kidney function

• Highlight the overwhelming impact of diabetes and hypertension (high blood pressure) contributing to chronic kidney disease (CKD)

• Encourage the systematic screening of all patients with diabetes and hypertension for CKD

• Encourage preventive behaviours

• Educate all medical professionals about their important role in detecting and reducing the risk of CKD in high risk populations

• Stress the role of local and national health authorities in managing and controlling the emerging CKD epidemic

• Educate health authorities of the high disproportionate costs associated with treating people with CKD and encourage these entities to take action and invest in further kidney screening.

Background

The United States Renal Data System (USRDS) annually compiles statistics on the incidence (number of new cases per year), prevalence (total number of current cases); population demographics among ethnic and racial groups, and more. It also calculates the total economic costs for treatment and management of CKD and end stage renal disease (ESRD). Canada and Europe have similar data systems. The important data-driven information from these data banks indicate the following:

1 Diabetes is far and away the single largest cause of CKD and ESRD; accounting for approximately 45 percent of ESRD in the United States; the figure is closer to the mid-30s in Europe.

2 Hypertension (high blood pressure) follows in second place as the single largest cause of CKD/ESRD.

3 Inflammatory diseases such as systemic lupus erythematosus (SLE) kidney disease, other inflammatory glomerunonephritides such as IgA disease; membranous nephropathy and other immune-related diseases. For the regional and local population, SLE is of importance due to the disproportionately high incidence of Lupus kidney disease in black women of African ancestry along with a pattern of more severe disease burden overall in this population.

4 Hereditary cystic kidney diseases, such as autosomal dominant polycystic kidney disease (ADPKD) accounts for somewhat less than 10 percent of causes of ESRD. In the Bahamas, there are families from the south-eastern islands with this disease entity burden.

5 Black populations have a uniquely disproportionately high incidence of CKD/ESRD related to HIV infections (AIDS). Recently there has emerged evidence indicating that a genetic mutation (change in gene composition) in people of west and central African ancestry predisposed them to more severe kidney disease related to hypertension, HIV and non-HIV collapsing glomerular disease, SLE and possibly other kidney disease entities.

The genetic change seems to have evolved to protect these populations from a fatal African sleeping sickness (trypanosomiasis), transmitted by an airborne vector to humans. This mutated gene while protecting from fatal African sleeping sickness, made the affected populations more susceptible to non-diabetic kidney diseases noted above. This is an ongoing area of research that has recently included some of the regional Caribbean countries; the Bahamas has not been a participant. The parallel with sickle cell anaemia theory of evolution in protecting susceptible persons from malaria is evident.

6 In the United States Renal Data System, African Americans have a 3.5 to 4.5-fold higher incidence of diabetic and non-diabetic kidney diseases contributing to end stage kidney disease (ESRD). They account for some 12 to 14 percent of the population, but account for 20 to 25 percent of the ESRD population.

The demographics of the Bahamas with a population of approximately 400,000 persons of which 85 percent are of African ancestry and the remainder classified as Caucasian/mixed, the USRDS data bank is the most relevant for analysis and projection of expected kidney disease burden and cost nationally.

• See next week’s Health section for part two.