Hypertension Severity as Quantified by Hypertension Daily Dose and Blood Pressure With Risk of Stroke in REGARDS

Background: It is unknown how blood pressure (BP) relates to stroke risk across levels of hypertension daily dose (HDD)-quantified antihypertensive medication intensity. Methods and Results: The REGARDS (Reasons for Geographic and Racial Differences in Stroke) study enrolled 30 239 participants from the 48 contiguous US states in 2003 to 2007 with in-person follow-up in 2013 to 2016 (Visit 2). We included those without prior stroke at Visit 2, treating this visit as T0. Biannual phone calls and medical record review ascertained incident stroke events. Cox proportional hazard models estimated the hazard ratio (HR) of incident stroke by treatment intensity defined by systolic BP stages and HDD groupings. There were 344 stroke events over a median 5.5 years. Relative to systolic BP <120 mm Hg and no antihypertensive medications, the stroke HR was 2.86 (95% CI, 1.68-4.85) for systolic BP 140 to 159 mm Hg and HDD tertile 2, 2.33 (1.37-3.97) for systolic BP 140 to 159 mm Hg and HDD tertile 3, 3.08 (1.20-7.88) for systolic BP >= 160 mm Hg and HDD tertile 2, and 3.66 (1.61-8.30) for systolic BP >= 160 mm Hg and HDD tertile 3. Stroke risk was similar across HDD levels for people with systolic BP <140 mm Hg. Conclusions: Among adults without prior stroke, systolic BP >= 140 mm Hg and HDD tertile >= 2 was associated with greater stroke risk. For adults with BP <140 mm Hg, stroke risk was similar despite cumulative dose of antihypertensive medications used. These findings support the practice of BP-lowering medications to mitigate stroke risk.