Prevalence of CKD in diagnosed hypertension remained relatively the same 1999-2004 (37%) to 2011-2014 (36%), yet exhibited a statistically significant increasing trend (p<0.001). During this time period, the prevalence significantly decreased among undiagnosed (27% to 20%) adults.
Chart Explanation: During the period 1999-2004 to 2011-2014, prevalence of CKD varied based on hypertension status. Among adults with diagnosed hypertension, there was a statistically significant increasing trend (p<0.001), despite the prevalence showing little change from 36.5% in 1999-2004 to 35.8% in 2011-2014. Prevalence among undiagnosed hypertensive adults significantly decreased from 26.9% to 20.4 (p<0.001). Among those found to have pre-hypertension, the prevalence significantly decreased (p=0.02) from 14.3% in 1999-2004 to 2011-2014.
The NHANES surveys are currently conducted every 2 years by the CDC's National Center for Health Statistics to examine disease prevalence and trends over time in different cross-sectional representative samples of 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, and 2013-2014 NHANES. CKD was diagnosed by laboratory testing and defined as an eGFR of ≥60 ml/min/1.73 m2 and the presence of albuminuria (first single measurement of albumin:creatinine ratio from random spot urine) or by eGFR alone for CKD stage 3 or 4 (stage 5 was excluded).
Hypertension is the second leading cause of CKD. Hypertensive disease accounts for 28% of incident ESRD in the United States (United States Renal Data System, 2011). Hypertension is associated with higher risk of cardiovascular outcomes in those with CKD. Additionally, treatment of hypertension in CKD, particularly by ACE inhibitors, has been shown to decrease proteinuria and disease progression (Sarafidis et al., 2008). Thus, assessing the prevalence of this risk factor and its control is essential to CKD surveillance. Self-reported hypertension was defined by answer of “yes” to the question “have you ever been told by a doctor or other health professional that you have hypertension, or high blood pressure?” Blood pressure measurements were taken by standardized protocol during the MEC and the average value (up to four measurements) was used. Hypertension medications were recorded from prescription bottles during the interview.
|Description of Measure||Prevalence of CKD in the diagnosed, undiagnosed, and pre-hypertension adult population|
|Type of Data Source||Public|
|Health Care System Data||No|
|Regional or National?||National|
|Demographic Group||Noninstitutionalized U.S. residents aged 20+ years|
|Numerator||Non-pregnant participants with CKD|
|Denominator||Non-pregnant participants with response to self-reported hypertension questionnaire, complete blood pressure measurements, and hypertension drug use.|
|Definition of CKD||Presence of single albuminuria or eGFR <60 ml/min/1,73 m2|
|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||bpq020: "Have you ever been told by a doctor or health professional that you have high blood pressure?" yes/no|
|Primary Indicator Method of Measurement||Questionnaire (interviewer-administered); ages 16+|
|Secondary (1) Variable||bpxsy1-bpxsy4: Up to four blood pressure measurements|
|Secondary (1) Indicator Method of Measurement||Examination/Laboratory|
|Secondary (2) Variable||nhcod/rxddrgid; generic drug codes|
|Secondary (2) Indicator Method of Measurement||Questionnaire (interviewer-administered), with recording of medications from Rx bottles|
|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, stratification variables of interest (age, gender, race/ethnicity, BMI, diabetes by self-report)|
|Limitations of Indicator||Albuminuria and kindey 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 1999-2000 and 2005-2006; many variable names differ across surveys; if SE 30% or more of estimate, must report as "low precision"|