BLOOD PRESSURE LOWERING EFFECT OF A TRADITIONAL CHINESE HERBAL FORMULA IN PATIENTS WITH STAGE-1 HYPERTENSION: A MULTI-CENTRE, RANDOMISED, DOUBLE-BLIND, PLACEBO-CONTROLLED TRIAL

Objective: Gastrodia and Uncaria Granule (GUG) is a classic herbal formula of traditional Chinese medicine (TCM) which has been applied in clinical practice for many years to relieve hypertension-related symptoms. However, the blood pressure (BP) lowering effect of GUG remains to be evaluated with standard clinical trials. Design and method: We conducted a multicentre, randomised, double-blind, placebo-controlled trial in 23 hospitals in China (NCT04035824). Outpatients aged 18-80 years, drug naïve or on stable antihypertensive medications for >2 weeks, with an office systolic/diastolic BP of 140-159/<100 mmHg at both screening visits, and with a 24-hour ambulatory systolic BP of >=130 mmHg were included. After stratified randomisation by centre, sex, and the TCM syndrome (liver yang hyperreactive syndrome [LYHS] or non-LYHS), participants were allocated to receive orally administered GUG or placebo, ten grams twice daily. Primary outcome was the change in 24-hour systolic BP at eight weeks. Intention-to-treat and safety analyses were conducted in all randomised participants and all participants who received at least one dose of study drug, respectively. Results: From October 8, 2019 to Jan 24, 2024, a total of 605 patients were randomised to receive GUG (n=309, 46.6% women, 57.3% with LYHS) or placebo (n=296, 48.3% women, 58.8% with LYHS). At eight weeks, change in 24-hour systolic BP was -3.32 mmHg in GUG group and -2.47 mmHg in placebo group, with a between-group difference of -0.85 mmHg (95% confidence interval: -2.09 to 0.39 mmHg, p=0.18). In pre-specified analyses by the TCM syndrome, GUG lowered 24-hour systolic BP more than placebo only in participants with LYHS (difference: -2.45 mmHg, -4.06 to -0.85 mmHg, p=0.0030). For secondary outcomes in all participants, GUG also lowered office and home systolic BP more than placebo (differences: -2.30 [-3.97 to -0.63] mmHg, p=0.0070 and -1.02 [-1.99 to -0.06] mmHg, p=0.038). No significant between-group difference in adverse events (GUG: 3.9%; placebo: 1.7%, p=0.14) was observed. Conclusions: GUG has a mild blood pressure lowering effect in patients with stage-1 hypertension and LYHS. These findings support the use of GUG in the treatment of mild hypertension with the differentiation of TCM syndromes.