Lowering blood pressure in primary care in Vienna (LOW-BP-VIENNA) : A cluster-randomized trial

Abstract

Background: In Austria only 41% of patients with treated hypertension (HTN) have their blood pressure (BP) controlled. This study investigated a strategy to improve BP control in primary care.

Methods: General practitioners (GPs) were randomized to interventional care vs. standard care and included patients with uncontrolled office BP > 140/90 mm Hg. In interventional care, antihypertensive therapy was up-titrated using a single pill combination (olmesartan, amlodipine and/or hydrochlorothiazde) in 4‑week intervals. In standard care, physicians were encouraged to treat according to the 2013 European Society of Cardiology guidelines for the management of arterial hypertension. The primary endpoint was the proportion of patients with controlled office BP < 140/90 mm Hg at 6 months. The main secondary endpoint was the improvement in 24 h ambulatory BP (ABPM, Clinicaltrials.gov NCT02377661).

Results: Between 2015-2017, 20 GPs contributed to patient recruitment. The trial was discontinued due to slow recruitment after inclusion of 139 eligible patients, 54 of whom were included in the interventional group. A significantly larger proportion of patients in interventional vs. standard care achieved the office BP target (67% ± 26% vs. 39% ± 29%, respectively, mean difference -27.9%, 95% confidence interval CI -54.0%; -1.7%, p = 0.038). The proportion of patients with controlled 24 h ABPM (<130/80 mm Hg) was similar between groups (49% ± 33% vs. 40% ± 34%, respectively, mean difference -8.8%, 95% CI -40.7%; 23.1%, p = 0.57). At baseline, pretreated patients received an average of 1.5 ± 0.8 vs. 1.7 ± 0.9 antihypertensive prescriptions. At 6 months, the respective BP reductions were achieved with 1.2 ± 0.5 prescriptions in interventional vs. 2.0 ± 1.0 in standard care (p < 0.01).

Conclusion: In both groups statistically and clinically significant BP reductions were observed after 6 months. In the interventional care group, a larger proportion of patients achieved the office BP target compared to standard care. The 24 h ambulatory blood pressure levels were controlled in 44% of patients at 6 months, without significant differences between groups. The respective BP reductions were achieved with a significantly lower medication burden in interventional care.

Keywords: Ambulatory blood pressure measurement; Arterial hypertension; Disease management programs; Hypertension control; Single pill combination drugs.

Fig. 1

Prespecified titration regimen with the single pill combination drug in the interventional care group. BP blood pressure, HCT hydrochlorothiazide

Fig. 2

Flow diagram showing the study design, the number of sites and the number of participants in each trial arm. BP blood pressure, ABPM ambulatory blood pressure measurement

Fig. 3

Graph showing the proportion of patients with controlled office blood pressure and ambulatory blood pressure levels at 6 months of follow-up. p-values are reported for differences between standard and interventional care. Additional data for control rates according to systolic and diastolic ambulatory blood pressure levels are presented in Supplementary Table 1. BP blood pressure, SBP systolic blood pressure, DBP diastolic blood pressure, ABPM ambulatory blood pressure measurement

Fig. 4

Mean office and ambulatory blood pressure reductions in standard and interventional care after 6 months of follow-up. P-values are reported for between-group differences. SBP systolic blood pressure, DBP diastolic blood pressure