–Tantalizing suggestion of benefit but evidence is weak and sparse.
Traditional Chinese medicine (TCM) is used by hundreds of millions of Chinese people and increasing numbers of people in developed countries.
A new state-of-the-art review published in the Journal of the American College of Cardiology suggests that some TCM products may be helpful in different cardiovascular conditions, but the larger message is that there is a tremendous gap in knowledge about these drugs.
“In China, home to a fifth of the world’s population, the use of TCM for cardiovascular disease, including intravenous use in AMI, is quite common – and yet the evidence base is incredibly weak,” said Harlan Krumholz (Yale University), who has been working in recent years to help China develop its research infrastructure. “There is an imperative there to determine if these medications provide any benefit – and, if so, how to optimize them.”
Researchers in China analyzed randomized, controlled trials (RCTs) with at least 50 patients and with a followup period of at least 4 weeks. They found 56 studies published between 2006 and 2016 in hypertension, dyslipidemia, diabetes, atherosclerotic cardiovascular disease (ASCVD), and heart failure. They concluded that “some TCM medications might be used as a complementary and alternative approach for primary and secondary prevention of cardiovascular disease. However, further rigorously designed RCTs are warranted to evaluate the effect of TCM on total mortality or major adverse cardiovascular events in patients with cardiovascular disease.”
One of the largest and highest quality RCTs was the Chinese Coronary Secondary Prevention Study, which compared the effect of Xuezhikang, a form of red yeast rice, to placebo on lipid levels and CV endpoints in 4,870 patients with a previous MI. After 4.5 years, the rate of CV events was significantly reduced from 10.4% in the placebo group to 5.7% in the Xuezhikang group. Xuezhikang treatment also led to a significant reduction in LDL and triglycerides and an increase in HDL.
Another RCT performed at 6 centers in China compared Tiankuijiangya to placebo in patients with hypertension. After 8 weeks Tiankuijiangya resulted in a significant reduction from baseline of 17.64 mm Hg systolic and a 11.85 mm Hg diastolic. The rate of adverse effects was 3.13% (5 of 160) in the Tiankuijiangya group and 2.5% (2 of 80) in the placebo group, the authors reported.
The authors noted that many TCM products consist of “dozens of ingredients with innumerous chemical molecules, making it difficult, if not impossible, to elucidate the therapeutic mechanism of TCM” and that these products are not subject to rigorous regulatory review. Further, most TCM studies are performed in China by TCM physicians. For these reasons, the authors write, “most TCM studies are of poor quality, and the conclusions drawn are not accepted by Western society.”
Another key point is that the studies may reflect a significant publication bias, since nearly all the studies identified by the authors were broadly positive.
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