From hypertension control to global cardiovascular risk management: an educational intervention in a cluster-randomised controlled trial

BACKGROUND: Guidelines on hypertension management recommend adjusting therapeutic efforts in accordance with global cardiovascular risk (CVR) rather than by blood pressure levels alone. However, this paradigm change has not yet arrived in German General Practice. We have evaluated the effect of an educational outreach visit with general practitioners (GPs), encouraging them to consider CVR in treatment decisions for patients with hypertension. METHODS: Prospective cluster-randomised trial comprising 3443 patients with known hypertension treated by 87 GPs. Practices were randomly assigned to complex (A) or simple (B) intervention. Both groups received a guideline by mail; group A also received complex peer intervention promoting the concept of global CVR. Clinical data were collected at baseline and 6-9 months after intervention. Main outcome was improvement of calculated CVR in the predefined subpopulation of patients with a high CVR (10-year mortality ≥5%), but no manifest cardiovascular disease. RESULTS: Adjusted for baseline the follow-up CVR were 13.1% (95% CI 12.6%-13.6%) (A) and 12.6% (95% CI 12.2%-13.1%) (B) with a group difference (A vs. B) of 0.5% (-0.2%-1.1%), p = 0.179. The group difference was -0.05% in patients of GPs familiar with global CVR and 1.1% in patients of GPs not familiar with with global CVR. However, this effect modification was not significant (p = 0.165). Pooled over groups, the absolute CVR reduction from baseline was 1.0%, p < 0.001. The ICC was 0.026 (p = 0.002). Hypertension control (BP <140/90 mmHg) improved in the same subpopulation from 38.1 to 45.9% in the complex intervention group, and from 35.6 to 46.5% in the simple intervention group, with adjusted follow-up control rates of 46.7% (95% CI 40.4%-53.1%) (A) and 46.9% (95% CI 40.3%-53.5% (B) and an adjusted odds ratio (A vs B) of 0.99 (95% CI 0.68-1.45), p = 0.966. CONCLUSIONS: Our complex educational intervention, including a clinical outreach visit, had no significant effect on CVR of patients with known hypertension at high risk compared to a simple postal intervention. TRIAL REGISTRATION: ISRCTN44478543.