The National Health and Nutrition Examination Survey (NHANES) is a nationally representative, cross-sectional survey that is currently conducted every 2 years by the Centers for Disease Control and Prevention's National Center for Health Statistics to examine disease prevalence and trends over time in noninstitutionalized U.S. civilian residents.
The survey consists of a standardized in-home interview and a physical examination with blood and urine collected at a mobile examination center (MEC). Here, we examined data from the 1999-2000, 2001-2002, 2003-2004, 2005-2006, 2007-2008, 2009-2010, 2011-2012, and 2013-2014 NHANES, in addition to data from NHANES III (1988-1994). Estimated glomerular filtration rate (eGFR) was calculated according to the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation for calibrated creatinine (Levey et al., 2009). Serum creatinine was calibrated for 1999-2000 and 2005-2006 participants; no correction was required for calibrated serum creatinine in participants in the 2001-2002, 2003-2004, 2007-2008, 2009-2010, 2011-2012, and 2013-2014 surveys (Selvin et al., 2007). Albuminuria was defined by urinary albumin-to-creatinine ratio ≥30 mg/g; moderate albuminuria ranges between 30 and 299 mg/g and severe albuminuria is ≥300 mg/g; pregnant women were excluded. For comparisons across the 12-year period 1999-2012, albuminuria was corrected in 1999-2006 to account for differences in the instrumentation and method for urine creatinine starting in 2007. Prevalence of CKD is likely overestimated by single measurements of albuminuria and kidney function (eGFR). In clinical practice, CKD is defined by persistent albuminuria or reduced kidney function for ≥3 months.
|Description of Measure||Prevalence of CKD stage 1-4|
|Type of Data Source||Public|
|Health Care System Data||No|
|Regional or National?||National|
|Demographic Group||Non-institutionalized U.S. residents aged 20+ years|
|Numerator||Participants with CKD|
|Denominator||Participants with serum creatinine and urine protein measurements|
|Definition of CKD||Stage 1, eGFR ≥ 90 ml/min/1.73 m² and presence of single albuminuria; Stage 2, eGFR 60-89 ml/min/1.73 m² and presence of single albuminuria; Stage 3, eGFR 30-59 ml/min/1.73 m²; Stage 4, 15-29 ml/min/1.73 m²; Stage 5, excluded|
|Glomerular filtration rate||Estimated using CKD-EPI equation for calibrated creatinine: eGFR=141 x [min(calibrated serum creatinine in mg/dL) /κ, 1)]α x [max(calibrated serum creatinine in mg/dL/κ, 1)]κ x 0.993age x (1.018 if female) x (1.159 if NH Black)|
κ = 0.7 if female, and 0.9 if male
α = -0.329 if female, and -0.411 if male
|Proteinuria||Urinary albumin-to-creatinine ratios of 30-299 mg/g (microalbuminuria) and >300 mg/g (macroalbuminuria); pregnant/menstruating women excluded|
|Primary Data Source Indicator||lbxscr: Serum creatinine|
|Primary Indicator Method of Measurement||Examination/Laboratory|
|Secondary (1) Variable||ridageyr: Age in years|
|Secondary (1) Indicator Method of Measurement||Questionnaire (interviewer-administered)|
|Secondary (2) Variable||ridgendr: Gender|
|Secondary (2) Indicator Method of Measurement||Questionnaire (interviewer-administered)|
|Secondary (3) Variable||ridreth1: Race/ethnicity|
|Secondary (3) Indicator Method of Measurement||Questionnaire (interviewer-administered)|
|Secondary (3) from Medical Record? ||No|
|Secondary (4) Data Source Indicator||urxuma: Urine albumin|
|Secondary (4) Indicator Method of Measurement ||Examination/lab|
|Secondary (5) Data Source Indicator||urxucr: Urine creatinine|
|Secondary (5) Indicator Method of Measurement ||Examination/lab|
|Frequency of Measurement (Primary)||Once (cross-sectional)|
|U.S. Region Covered by Primary Variable||All|
|Period Currently Available||1999–2014|
|Additional Data Items of Interest||Stage of CKD, year, other stratification variables of interest (diabetes by self-report, hypertension by self-report)|
|Limitations of Indicator||Albuminuria and kidney function can only be assessed from a one-time cross-sectional measurement, leading to overestimation of prevalence; second measures of albuminuria are available for only 2009-2010 and were first-morning rather than spot urine samples; no second measures of creatinine|
|Analytic Considerations||Appropriate NHANES survey weights must be used for all analyses; creatinine measurements must be calibrated for NHANES III, 1999-2000 and 2005-2006; many variable names differ across surveys; if SE 30% or more of estimate, must report as “low precision”|
|Age Adjustment||Adjusted for the distribution of age within the sample.|
After age-adjustments, the prevalence of CKD stages 1-4 was approximately 13% to 16%, during the periods 1999 to 2014. Prevalence was higher among females than males, and higher in non-Hispanic blacks and Mexican-Americans than in non-Hispanic whites. Those with diabetes or hypertension had far greater age-adjusted prevalence of CKD than those without these conditions.
Chart Explanation: From 1999 to 2014, the overall age-adjusted prevalence was relatively the save for the 16 years (15.3% in 1999 and 15.2% in 2014). Even with these adjustments, the prevalence of CKD stages 1-4 was still higher in females than in males (17.06% vs. 13.3%). However, the pattern for overall prevalence by race/ethnicity shifted after age adjustments. Non-Hispanic blacks continued to have the highest prevalence throughout the 16 years, but in 2013-2014 they had they highest prevalence after adjustements (17.3%); whereas non-Hispanic whites had the lowest prevalence of 14.9% when compared to their counterparts, while Mexican-Americans had a prevalence of 15.5%. In 2013-2014, those with diabetes (34.5%) or hypertension (20.6%) had higher prevalence of CKD than those without these conditions, as expected, even with adjustment for age. All comparisons within subgroup were statistically significantly different (P<0.001), with age adjustment.
References and Sources:
Levey AS, Stevens LA, Schmid CH, et al. A New Equation to Estimate Glomerular Filtration Rate. Ann Intern Med. 2009;150(9):604-612.
Coresh J, Astor BC, Greene T, Eknoyan G, Levey AS. Prevalence of chronic kidney disease and decreased kidney function in the adult US population: Third National Health and Nutrition Examination Survey. Am. J. Kidney Dis. 2003;41(1):1-12.
Selvin E, Manzi J, Stevens LA, et al. Calibration of serum creatinine in the National Health and Nutrition Examination Surveys (NHANES) 1988-1994, 1999-2004. Am J Kidney Dis. 2007;50(6):918-26.