The effectiveness of Dietary Approaches to Stop Hypertension (DASH) counselling on estimated 10-year cardiovascular risk among patients with newly diagnosed grade 1 hypertension: A randomised clinical trial.

BACKGROUND:The Dietary Approaches to Stop Hypertension (DASH) has been shown to lower blood pressure in the West. However, the real-life impact of DASH on reducing cardiovascular (CV) risk in routine clinical setting has not been studied. METHODS:A parallel-group, open-labelled, physician-blinded, randomised controlled trial was conducted in January-June 2013 and followed up for 6- and 12-months in primary care settings in Hong Kong. Patients newly diagnosed with grade 1 hypertension (aged 40-70years) who had no concomitant medical conditions requiring dietary modifications were consecutively recruited. Subjects were randomised to standard education (usual care) (n=275), or usual care plus dietitian-delivered DASH-based dietary counselling in a single one-to-one session (intervention) (n=281). Primary outcomes were the changes in estimated 10-year CV risk. RESULTS:Outcome data were available for 504 (90.6%) and 485 (87.2%) patients at 6 and 12months, respectively. There was no difference in the reduction of 10-year CV risk between the two groups at 6months (-0.13%, 95% confidence interval [95% CI] -0.50% to 0.23%, p=0.477) and 12months (-0.08%, 95% CI -0.33% to 0.18%, p=0.568). Multivariate regression analyses showed that male subjects, younger patients, current smokers, subjects with lower educational level, and those who dined out for main meals for ≥4 times in a typical week were significantly associated with no improvements in CV risk. CONCLUSIONS:The findings may not support automatic referral of newly diagnosed grade 1 hypertensive patients for further one-to-one dietitian counselling on top of primary care physician's usual care. Patients with those risk factors identified should receive more clinical attention to reduce their CV risk. CLINICAL TRIAL REGISTRATION:ChiCTR-TRC-13003014 (http://www.chictr.org.cn/enindex.aspx).