CARDIOVASCULAR RISK IN TREATED HYPERTENSIVE PATIENTS WITH ISOLATED DIASTOLIC HYPERTENSION AND ISOLATED LOW DIASTOLIC BLOOD PRESSURE

Abstract

Objective: Antihypertensive therapy in the elderly often targets at systolic blood pressure (SBP) and excessive lowering of diastolic blood pressure (DBP) may occur. Evidence on the cardiovascular risk of isolated diastolic hypertension (IDH) is inconsistent. This study investigated whether IDH and isolated low diastolic blood pressure (ILDBP) were associated with major adverse cardiovascular events (MACE) in patients who were receiving antihypertensive therapy and had normalized SBP. Design and method: A total of 7582 hypertensive patients aged > = 50 years and with on-treatment SBP <130 mmHg from the Systolic Blood Pressure Intervention Trial (SPRINT) were analyzed. Average DBP of 60 mmHg during follow-up visits was determined as the lower boundary by a multivariate adaptive regression spline analysis for MACE. According to the on-treatment DBP, patients were divided into <60 mmHg (ILDBP, n = 1031), 60–79 mmHg (n = 5432), and > = 80 mmHg (IDH, n = 1119). Time-varying Cox proportional hazards model was used to estimate the MACE risk, comparing IDH or ILDBP with DBP 60–79 mmHg. External validation was carried out with a two-stage meta-analysis of individual participant data (IPD) for 3560 individuals from six cohorts. Results: The SPRINT participants had a median age of 68.2 years, and 64.9% of whom were men. During a median follow-up of 3.5 years, 512 patients had MACE. Incidence of MACE per 100 person-years was 3.9 case for ILDBP, 1.9 cases for DBP 60 – 79 mmHg, and 1.8 cases for IDH. Compared with DBP 60 – 79 mmHg, ILDBP was associated with a 1.32-fold increased MACE risk (95% CI: 1.05 – 1.66), but IDH was not (hazard ratio: 1.18, 95% CI: 0.87 – 1.59). Among the 50 – 64 years subgroup, IDH was associated with a 1.59-fold increased MACE risk (95% CI: 1.01 – 2.49), with effect modification by age (P for interaction 0.005). The IPD meta-analysis also suggested a significantly higher risk for MACE among patients with ILDBP (hazard ratio: 1.22, 95% CI: 1.03 – 1.46), compared to patients with DBP 60 – 79 mmHg. Conclusions: Among patients on antihypertensive medications with normalized SBP, excessively low DBP increased the MACE risk but IDH did not. More research is needed to develop appropriate treatment strategies for ILDBP.