Chinese Herbal Medicine for COVID-19? The evidence remains unconvincing

The Chinese have made several attempts to persuade us that their traditional remedies are effective for COVID-19 infections. Here is yet another one. This review summarised the evidence of the therapeutic effects and safety of Chinese herbal medicine (CHM) used with or without conventional western therapy for COVID-19. All clinical studies of the therapeutic effects and safety of CHM for COVID-19 were included. The authors

• summarized the general characteristics of included studies,
• evaluated the methodological quality of the randomized controlled trials (RCTs) using the Cochrane risk of bias tool,
• analyzed the use of CHM,
• used Revman 5.4 software to present the risk ratio (RR) or mean difference (MD) and their 95% confidence interval (CI) to estimate the therapeutic effects and safety of CHM.

A total of 58 clinical studies were identified including;

• 10 RCTs,
• 1 non-randomized controlled trials,
• 11 retrospective studies with a control group,
• 12 case-series,
• 24 case-reports.

All of the studies had been performed in China. No RCTs of high methodological quality were identified. The most frequently tested oral Chinese patent medicine, Chinese herbal medicine injection, or prescribed herbal decoction were:

• Lianhua Qingwen granule/capsule,
• Xuebijing injection,
• Maxing Shigan Tang.

The pooled analyses showed that there were statistical differences between the intervention group and the comparator group (RR 0.42, 95% CI 0.21 to 0.82, six RCTs; RR 0.38, 95% CI 0.23 to 0.64, five retrospective studies with a control group), indicating that CHM plus conventional western therapy appeared to be better than conventional western therapy alone in reducing aggravation rate.

In addition, compared with conventional western therapy, CHM plus conventional western therapy had the potential advantages in increasing the recovery rate and shortening the duration of fever, cough, and fatigue, improving the negative conversion rate of nucleic acid test, and increasing the improvement rate of chest CT manifestations and shortening the time from receiving the treatment to the beginning of chest CT manifestations improvement.

For adverse events, the pooled data showed that there were no statistical differences between the CHM and the control groups.

The authors concluded that current low certainty evidence suggests that there maybe a tendency that CHM plus conventional western therapy is superior to conventional western therapy alone. The use of CHM did not increase the risk of adverse events.

One of the principles to remember here is this: RUBBISH IN, RUBBISH OUT. If you meta-analyze primary data that are rubbish, your findings can only be rubbish as well.

All one needs to know about the primary data entered into the present analysis is that there were no rigorous RCTs… not one! That means the evidence is, as the authors rightly but modestly conclude of LOW CERTAINTY. My conclusions would have been a little different:

1. In terms of safety, the dataset is too small and unreliable to make any judgment.
2. In terms of efficacy, there is no sound data that CHM has a positive effect.