4. Limitations
BLIND
This study has some limitations. First, we are unable to blind all patients. No sham TEAS interventions will be used in the usual care group, which causes this group unable to be blind to their grouping, so there may be some psychological factors that affect the BP of patients in this group. While the objective of this study is to screen for optimal stimulation parameters of TEAS, we can try to ensure that patients in the 2 TEAS intervention groups are blind to the specific stimulation frequency. Besides, BP is measured and recorded using automated equipment to minimize bias in essential results. Second, although 4 weeks is the common clinical treatment period for acupuncture, future studies may require a longer treatment period and follow-up time to investigate the profound effects of TEAS on BP. Finally, further expansion of the sample size in future studies is necessary to confirm the findings of this trials.