Uncontrolled and Apparent Treatment Resistant Hypertension in the United States, 1988 to 2008

Abstract

Despite progress, many hypertensive patients remain uncontrolled. Defining characteristics of uncontrolled hypertensives may facilitate efforts to improve blood pressure control. Subjects included 13,375 hypertensive adults from National Health and Nutrition Examination Surveys (NHANESs) subdivided into 1988 to 1994, 1999 to 2004, and 2005 to 2008. Uncontrolled hypertension was defined as blood pressure ≥140/≥90 mm Hg and apparent treatment-resistant hypertension (aTRH) when subjects reported taking ≥3 antihypertensive medications. Framingham 10-year coronary risk was calculated. Multivariable logistic regression was used to identify clinical characteristics associated with untreated, treated uncontrolled on 1 to 2 blood pressure medications, and aTRH across all 3 survey periods. More than half of uncontrolled hypertensives were untreated across surveys, including 52.2% in 2005 to 2008. Clinical factors linked with untreated hypertension included male sex, infrequent healthcare visits (0 to 1 per year), body mass index <25 kg/m2, absence of chronic kidney disease, and Framingham 10-year coronary risk <10% (P<0.01). Most treated uncontrolled patients reported taking 1 to 2 blood pressure medications, a proxy for therapeutic inertia. This group was older, had higher Framingham 10-year coronary risk than patients controlled on 1 to 2 medications (P<0.01), and comprised 34.4% of all uncontrolled and 72.0% of treated uncontrolled patients in 2005 to 2008. We found that aTRH increased from 15.9% (1998-2004) to 28.0% (2005-2008) of treated patients (P<0.001). Clinical characteristics associated with aTRH included ≥4 visits per year, obesity, chronic kidney disease, and Framingham 10-year coronary risk >20% (P<0.01). Untreated, undertreated, and aTRH patients have consistent characteristics that could inform strategies to improve blood pressure control by decreasing untreated hypertension, reducing therapeutic inertia in undertreated patients, and enhancing therapeutic efficiency in aTRH.