High Blood Pressure and Cognitive Decline
According to National Health and Nutrition Examination Survey (NHANES) data, the prevalence of hypertension increases dramatically with age. While 28.6% of Americans have hypertension, the incidence increases to 66.7% in those ages 60 and older.1 The prevalence of resistant hypertension (ie, uncontrolled blood pressure [BP] with three anti-hypertensive medications, controlled BP with ≥4 anti-hypertensive medications) is rising at a faster rate than hypertension itself. A time-sequence comparison of NHANES data indicated that the rate of resistant hypertension has reached 20.7% (2005-2008) due to an aging population and increasing rate of obesity.2 Those with resistant hypertension face an increased risk of cardiovascular and microvascular events, as well as greater medical expenditures, versus those with controlled BP.3
Cognitive performance in response to BP treatment has also been a focus of study. The Observational Study on Cognitive Function And SBP Reduction (OSCAR) open-label trial, with an intent-to-treat cohort of 25,745 patients ages 50 and older with hypertension treated with eprosartan-based treatment regimens, found that following a six-month treatment period, lowering systolic BP (SBP) correlated with greater cognitive function.4
To follow up, Petrella and colleagues from the OSCAR group conducted a retrospective subgroup analysis of OSCAR study data to determine whether patients with difficult-to-treat hypertension (DTTH, defined as SBP/diastolic BP [DBP] ≥140/90 in spite of three anti-hypertensive medications within the past month) would demonstrate improved cognitive performance with eprosartan-based treatment (EBT).4 The study authors theorized that sustained hypertension despite treatment efforts might increase the risk for long-term adverse effects such as cognitive decline, as hypertension impairs cerebrovascular circulation through arterial stiffness.
The study authors examined data on 4,649 patients with DTTH at baseline who received 600mg/day of EBT as part of OSCAR. These patients had significantly higher SBP at baseline than the non-DTTH group (P<0.001). At six months, mean SBP and DBP for DTTH patients decreased significantly from baseline (SBP, 164.8 versus 138.8 mm Hg, P<0.001; DBP, 93.3 versus 81.9 mm Hg, mean reduction -11.4±9.8). The mean reduction in SBP (-26.0±15.7 mm Hg) was similar to that of the non-DTTH group (-25.8±13.9 mm Hg; P<0.001 for both groups).4 However, for BP normalization (SBP >140 mm Hg/DBP >90 mm Hg), a lower percentage of DTTH patients (48.4 percent) than non-DTTH patients (61.3%; P<0.001 by c2 test) achieved normalization.