Reported awareness of disease, among those with greater than 15% risk of kidney failure at 5 years, was 49% in 2011-2016.
From 1999-2016, no distinct increasing or decreasing trends have been noted.
Reported awareness of CKD for stage 3 and 4 was 12.4% in 2013-2014. Across all survey periods, no clear trend was observed between 1999-2004 and 2011-2016. Participants with higher kidney failure risk (≥15% 5-year risk) were consistently more likely to be aware (50.6% in 1999-2004 to 49.0% in 2011-2016) compared to lower risk groups (6.3% to 9.6% among participants with <2% 5-year risk, and 14.6% to 22.6% among participants with 2% to <5% 5-year risk).
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 and blood and urine collection 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, 2013-2014, and 2015-2016 NHANES. Awareness of CKD was defined as a “yes” response to the question “Have you ever been told by a health care provider you have weak or failing kidneys (excluding kidney stones, bladder infections, or incontinence)?” during the interview. CKD was diagnosed by laboratory testing and defined as an eGFR of <60 ml/min/1.73 m2. The 5-year kidney failure risk was estimated using the 4-variable Kidney Failure Risk Equation (Tangri et al, 2011).
Awareness of CKD among those with kidney disease diagnosed by laboratory testing, by risk of kidney failure
Noninstitutionalized U.S. residents aged 20+ years
Participants with CKD who have been told they have weak or failing kidneys
Participants with CKD Stage 3 or 4 (eGFR 15-59 ml/min/1.73 m2)
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
Estimate 5-year risk of kidney failure using the 4-variable Kidney Failure Risk Equation:
5-year kidney failure risk = 1 - 0.9240^[exp(-0.2201*(age/10 - 7.036) + 0.2467 * (male - 0.5642) - 0.5567 * (eGFR/5 - 7.222) + 0.4510 * (ln(UACR) - 5.137))]
Age = age in years
Male = 1 if male and 0 if female
eGFR = estimated glomerular filtration rate in ml/min/1.73 m2
UACR = urine albumin/creatinine ratio in mg/g
kiq022/kiq010: “Have you ever been told by a doctor or health professional that you have weak or failing kidneys (excluding kidney stones, bladder infections, or incontinence)?” yes/no
lbxscr: Serum creatinine
ridageyr: Age in years
urxuma: Urine albumin
urxucr: Urine creatinine
Imperfect sensitivity of “weak or failing kidneys” question to ascertain CKD awareness
Appropriate NHANES survey weights must be used for all analyses; creatinine measurements must be calibrated for NHANES years 1999-2000 and 2005-2006; if 2007-2008 data are combined with 1999-2006 data, the earlier data on urinary creatinine must be corrected; many variable names differ across surveys; if SE 30% or more of estimate, must suppress estimates and report as “low precision”
Tangri N, Grams ME, Levey AS, et al. Multinational assessment of accuracy of equations for predicting risk of kidney failure: a meta-analysis. JAMA. 2016;315(2):164-174.