Considerations in Chronic Kidney Disease and Transplantation

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Despite advances in the management of hypertension and diabetes—the two risk factors accounting for over 70% of all cases of chronic kidney disease (CKD)—the prevalence of CKD in the general population has risen from about 10% two decades ago to 14.8% in 2017, surpassing that of diabetes (9.4%) (1) and making it a major public health problem in the United States.

Minority populations disproportionately have hypertension and diabetes and consequently bear a disproportionate burden of CKD (2). This trajectory is unacceptable and requires heightened awareness, particularly among primary care providers and nephrologists, with the goal of reducing these disparities and the associated morbidity, mortality, and economic costs. Here, we outline the health disparities considerations in addressing patients with CKD and CKD risk factors.

Disparities in the burden of CKD

The National Kidney Foundation of the United States is credited for defining CKD as kidney damage lasting over 3 months with or without decreased estimated GFR (eGFR), evidenced by pathologic abnormalities, or an absolute eGFR less than 60 mL/min per 1.73 m2 lasting over 3 months (3, 4). On the basis of this definition, guidelines were developed in 2002 that classify CKD into five stages, from kidney disease with preserved GFR to end-stage kidney failure. In stage 1, there is evidence of kidney damage, but GFR is preserved (>90 mL/min). Stage 2 is mild kidney damage with GFR 60 to 90 mL/min, stage 3 is moderate kidney damage with GFR 30 to 59 mL/min, stage 4 is severe kidney damage with GFR 15 to 29 mL/min, and stage 5 is end-stage kidney damage with GFR <15 mL/min. Patients in stage 5 are often treated with dialysis or kidney transplantation.

CKD is a public health problem (5). In the United States alone, 14.8% of the population, or over 48 million people, are afflicted with CKD. Yet, many patients do not know they have CKD. According to data from the Behavioral Risk Factors Surveillance System, the prevalence of self-reported CKD is very low in the U.S. general population. Reports range from 1.8% in Virginia to 4.0% in Arizona. Given the overall prevalence of CKD in the U.S. population of about 14.8%, these numbers mean that most patients with CKD are not aware they actually have it. Furthermore, data from the National Health and Nutrition Examination Survey show that the prevalence of CKD is highest in African Americans (16.9%), although they make up only 12% of the U.S. population, followed by non-Hispanic white (15.2%) and Hispanic (12.8%) individuals (6).

Cardiovascular disease is the leading cause of death in this population, and most patients die during the course of CKD before dialysis is indicated. In a study by Keith et al. (7), the 5-year mortality rates for CKD stages 2, 3, and 4 were 19.5%, 24.3%, and 45.7%, respectively, whereas the corresponding rates in patients in these stages who progressed to ESRD were much lower at 1.1%, 1.3%, and 19.9%. Cardiovascular events such as ischemic heart disease, heart failure, stroke, and peripheral arterial disease have also been demonstrated to increase with decreasing eGFR (811), calling into action greater awareness of the impact of CKD on cardiovascular disease morbidity and mortality.

The healthcare expenditure associated with CKD is enormous. In 2015, Medicare spent 11%, or $64 billion, for CKD, and 5.8%, or $34 billion, for ESRD, for a total of $98 billion. This does not include spending in the public sector, nor spending attributable to lost productivity. Spending for CKD patients 65 years old and older exceeded $55 billion, representing 20% of all Medicare spending in this age group, with over half of these expenses being devoted to patients with diabetes mellitus or heart failure. African Americans with CKD account for higher spending in all disease categories than do other racial groups (12). This disparity in spending also needs to be addressed. Opportunities for cost containment could be achieved through screening and early detection that particularly targets African Americans to modify risk factors, retard disease progression, and manage comorbidities (13).

Acknowledgment: This work is supported by the National Institute of Minority Health and Health Disparities (NIMHD) Grant # S21 MD012474 to the Brooklyn Health Disparities Center.

January 2019 (Vol. 11, Number 1)

References

1. American Diabetes Association. Statistics about diabetes. Available at: http://www.diabetes.org/diabetes-basics/statistics/.

2. Kissmeyer L, et al. Community nephrology: Audit of screening for renal insufficiency in a high risk population. Nephrol Dial Transplant 1999; 14:2150–2155.

3. National Kidney Foundation. K/DOQI clinical practice guidelines for chronic kidney disease: Evaluation, classification, and stratification. Am J Kidney Dis 2002; 39:S1–S266.

4. Levey AS, et al. National Kidney Foundation practice guidelines for chronic kidney disease: evaluation, classification, and stratification. Ann Intern Med 2003; 139:137–147.

5. Levey AS, et al. Chronic kidney disease as a global public health problem: approaches and initiatives: A position statement from Kidney Disease Improving Global Outcomes. Kidney Int 2007; 72:247–259.

6. US Renal Data System. 2016 USRDS Annual Data Report: Epidemiology of Kidney Disease in the United States. Bethesda, MD: National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases; 2016. https://www.usrds.org/2017/download/v1_c01_GenPop_17.pdf.

7. Keith DS, et al. Longitudinal follow-up and outcomes among a population with chronic kidney disease in a large managed care organization. Arch Intern Med 2004; 164:659–663.

8. Go AS, et al. Chronic kidney disease and the risks of death, cardiovascular events, and hospitalization. N Engl J Med 2004; 351:1296–1305.

9. Hui X, et al. CKD and cardiovascular disease in the Atherosclerosis Risk in Communities (ARIC) study: Interactions with age, sex, and race. Am J Kidney Dis 2013; 62:691–702.

10. Chronic Kidney Disease Prognosis Consortium, Matsushita K, et al. Association of estimated glomerular filtration rate and albuminuria with all-cause and cardiovascular mortality in general population cohorts: A collaborative meta-analysis. Lancet 2010; 375:2073–2081.

11. Bansal N Evolution of cardiovascular disease during the transition to end-stage renal disease. Semin Nephrol 2017; 37:120–131.

12. US Renal Data System. 2016 USRDS Annual Data Report: Epidemiology of Kidney Disease in the United States. Bethesda, MD: National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases; 2016. https://www.usrds.org/2017/view/v1_06.aspx.

13. Harding K, et al. Current state and future trends to optimize the care of chronic kidney disease in African Americans. Am J Nephrol 2017; 46:176–186.