Dietary counselling has no effect on cardiovascular risk factors among Chinese Grade 1 hypertensive patients: a randomized controlled trial

Aims To evaluate the effectiveness of Dietary Approaches to Stop Hypertension (DASH) by one-off dietary counselling on reducing cardiovascular risk factors among Chinese Grade 1 hypertensive patients in primary care. Methods and results A parallel-group, randomized controlled trial (ChiCTR-TRC-13003014) was conducted among patients (40-70 years old) newly diagnosed with Grade 1 hypertension in primary care settings in Hong Kong. Subjects were randomized to usual care (standard education, control) (n = 275), or usual care plus DASH-based dietary counselling (intervention) (n = 281). The study endpoints included blood pressure (BP), lipid profile, and body mass index (BMI) at 6- and 12-months. Outcome data were available for 504 (90.6%) and 485 (87.2%) patients at 6 and 12 months, respectively. Blood pressure levels reduced in both groups at follow-ups. However, the intervention group did not show a significantly greater reduction in either systolic BP (-0.7 mmHg, 95% CI -3.0-1.5 at 6-month; -0.1 mmHg, 95% CI -2.4-2.2 at 12-month) or diastolic BP (-1.0 mmHg, 95% CI -2.7-0.7 at 6-month; -1.1 mmHg, 95% CI -2.9-0.6 at 12-month), when compared with the control group. The improvements in lipid profile and BMI were observed among all subjects, yet no significant differences were detected between intervention and control groups. Conclusion The DASH diet by one-off dietitian counselling which resembled the common primary care practice might confer no added long-term benefits on top of physician's usual care in optimizing cardiovascular risk factors. Physicians may still practice standard usual care, yet further explorations on different DASH delivery models are warranted to inform best clinical practice.