Prevalence of CKD in the United States: A Sensitivity Analysis Using the National Health and Nutrition Examination Survey (NHANES) 1999-2004
Received 21 February 2008; accepted 18 July 2008. published online 28 October 2008.
Background
Estimates of chronic kidney disease (CKD) in the United States using the continuous National Health and Nutrition Examination Survey (NHANES) data set 1999-2004 indicate that 13.1% of the population (26.3 million people based on the 2000 census) has CKD stages 1 to 4.
Study Design
We performed sensitivity analyses to highlight assumptions underlying these estimates and illustrate their robustness to varying assumptions.
Setting & Participants
NHANES 1999-2004 was a nationally representative cross-sectional continuous survey of the civilian noninstitutionalized US population. Our sample included participants 20 years and older.
Reference Test
Estimated glomerular filtration rate (GFR) less than 60 mL/min/1.73 m2 defined from the 4-variable Modification of Diet in Renal Disease (MDRD) Study equation; albuminuria defined as persistence of urinary albumin-creatinine ratio greater than 30 mg/g.
Index Tests
We compared prevalence estimates using the MDRD Study equation with 2 other GFR estimating equations (equation 5 by Rule et al from the Mayo Clinic Donors study; Cockcroft-Gault equation adjusted for body surface area and corrected for the bias in the MDRD Study sample), and sex-specific cutoff values to define albuminuria.
Results
We found CKD stages 1 to 4 prevalence estimates ranging from 11.7% to 24.9%, a more than 2-fold difference resulting in population estimates of 25.8 million to 54.0 million people using 2006 population estimates. Considering only stages 3 and 4, which are not affected by the choice of cutoff values to define albuminuria, prevalence estimates ranged from 6.3% to 18.6%, resulting in population estimates of 13.7 million to 40.3 million people, a nearly 3-fold difference.
Limitations
NHANES 1999-2004 is a cross-sectional survey and allows for GFR and albumin-creatinine ratio estimates at 1 point in time. NHANES does not account for seniors in long-term care facilities.
Conclusions
Although CKD prevalence is high regardless of varying modeling assumptions, different assumptions yield large differences in prevalence estimates.
ABSTRACT