From 1999 to 2016, the percentage of U.S. adults with chronic kidney disease (CKD) remained relatively stable overall. Whether or not this was true for individual demographics, however, was unknown. To fill in this knowledge gap, Priya Vart, PhD, of Radboud University Medical Center in the Netherlands, led a team of investigators to identify recent CKD prevalence trends across all major sociodemographic groups.*

What they did

Using National Health and Nutrition Examination Surveys (NHANES) for 54,554 U.S. adults with a minimum age of 20 and an average age of 46.2, the team analyzed CKD prevalence data from 1988 through 1994, as well as data from every two years from 1999 through 2016. 

Demographics of interest included:

• Race and ethnicity, divided into Non-Hispanic Caucasian, Non-Hispanic Black, Mexican American, and Other
• Socioeconomic status (SES), using educational level attained (<high school being low; >high school being high) and poverty income ratio (total household income divided by federal poverty income threshold, corrected for household size and inflation)

For the study, CKD was defined as an estimated glomerular filtration rate (eGFR) of 15 to 59, reflecting the percentage of kidney function remaining.

What they found

Race and ethnicity

After being adjusted for age, sex, and race/ethnicity, the overall prevalence of CKD stages 3 and 4 (out of 5 stages, with stage 5 being kidney failure) increased from 3.9% in 1988-1994 to 5.2% in 2003-2004 and then stabilized.

Specific racial and ethnic disparities included the following:

• From 1988-1994, prevalence was highest for Non-Hispanic Blacks (4.4%) and lowest for Mexican Americans (2.3%).
• Rates increased for Non-Hispanic Caucasians and Non-Hispanic Blacks between the 1988-1994 period and the 2003-2004 period. After 2004, they remained stable.
• Between the 1988-1994 period and the 2003-2004 period, Mexican Americans had lower rates than any other racial or ethnic group.
• The rate nearly doubled for Mexican Americans between 2004 and the 2015-2016 period, putting it on par with the CKD prevalence for Non-Hispanic Blacks (5.7%).

Socioeconomic status

From 1988 to 1994, rates of CKD were higher among groups with lower education and income levels—specifically 5.8% (lower education level) vs 4.3% (higher education level) and 4.3% (lower income) vs 3.1% (higher income). A higher prevalence of CKD among people with lower education levels and lower income levels persisted throughout the study period, regardless of race and ethnicity.

What it means

The authors of the study suggest that further research is needed to determine the causes of the discouraging health inequities they found, despite the encouraging overall trend, and find solutions to them. 

“Gaps in CKD prevalence across racial/ethnic groups and levels of socioeconomic status largely persisted over 28 years,” as stated in the study. “There is a need to identify and address causes of increasing CKD prevalence among Mexican American persons and a need to renew efforts to effectively mitigate persistent disparities in CKD prevalence.”

*Vart, P., Powe, N. R., McCulloch, C. E., Saran, R., et. al. (2020, July 16). National Trends in the Prevalence of Chronic Kidney Disease Among Racial/Ethnic and Socioeconomic Status Groups, 1988-2016. JAMA Network Open. https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2768339