The NHANES (National Health and Nutrition Examination Survey) 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, 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 (U.S. 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.