The Time Blood Pressure Is in Therapeutic Range Predicts Cardiovascular and All-Cause Mortality in Hypertension

Objective: To study how regular control of systolic blood pressure (BP), assessed as time in therapeutic range (TTR), is associated to mortality in treated hypertensive patients attending primary care. Design and method: Electronic health record data from SPCCD on treated hypertensive patients in a Swedish primary care cohort at any time during 2001–08 were assessed. All recorded BP values 2001–08 (and time between each recorded value) were used to calculate time weighted mean systolic BP and TTR. All-cause mortality in 2013 was obtained from the Swedish Cause of Death Register. Results: We identified 50 393 patients, 30 227 (60%) women, with no concomitant cardiovascular disease or diabetes. Mean age was 65(women) and 62,(men) (range 30–102) years, median number of measured BP 8 (IQ 4–14), and follow-up was 5–13 years. Mortality according to a single last recorded systolic BP < 120,<130,<140,<150,<160, and >160 mm Hg was 24,13,15,18,22, and 27% in women, and 27,16,15,18,22, and 27% in men, respectively. For weighted mean SBP mortality was 19,11,11,16,22 and 31% in women and 23,14,15,17,23 and 30% in men, respectively. The proportions for 0–25,26–50,51–75, and 76–100% of TTR for systolic BP <140 mmHg during 2001–08 were 55,19,13, and 13% in women, and 52,19,14, and 14% in men, respectively. Mortality for TTR 0–25,26–50,51–75, and 76–100% and systolic BP <140 mmHg were 23,17,13, and 9% in women, and 22,18,17,11% in men, respectively. Similar relations with TTR were seen for cardiovascular mortality (representing 39% of all-cause mortality). Findings were consistent over age groups. Conclusions: Systolic BP in hypertensive patients without cardiovascular disease or diabetes treated in primary care has a U-shaped relation to mortality risk, with an apparent optimal systolic BP of 121–140 mmHg. A weighted mean systolic BP provides a stronger risk prediction than the last recorded BP. A lower TTR relates to increased mortality, but a majority of patients achieve only 0–25% TTR for a systolic BP < 140 mm Hg. The association to mortality is stronger for TTR than for weighed mean systolic BP and for the last recorded systolic BP. Thus, consistency of BP control is a determinant of mortality in hypertension.