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M-03: Systematic Evaluation of Randomized Controlled Trials on Nutraceuticals Containing Chinese Medicines for Diabetes Management

Poster Presenter

Junnan Shi

Student
University of Macau
Macao

Objectives

Nutraceuticals containing Chinese medicines have been used to manage diabetes but the efficacy remains questionable. The study aimed to evaluate the quality of evidence from literature in randomized controlled trials on nutraceuticals containing Chinese medicines for diabetes management.

Method

Literature from 4 databases (PubMed, Scopus, CINAHL and Web of Science) was searched following PRISMA guidelines to yield RCT publications on nutraceutical for diabetes management dated since 2009 till now. The quality of reporting was assessed using the CONSORT 2010 checklist statement.

Results

A total of 1,978 records were identified from initial search, 24 of which were included in this study for being randomized, double/triple-blinded, controlled trials which investigated the effect of nutraceuticals containing Chinese medicines on diabetes management. Seventeen Chinese medicines were involved including cinnamon (n=4), ginger (n=2), circuminoids (n=2), Silybum marianum (n=2), propolis (n=2), Andrographis paniculata (n=1), garlic (n=1), ginseng (n=1), Ginkgo biloba (n=1), Glycyrrhiza glabra L. (n=1), Morus alba (n=1), Nigella sative (n=1), Flaxseed (n=1), Daidzein (n=1), Albe vera (n=1), Psyllium (n=1), Cornus mas (n=1). The study targets were either diabetes patients (n=16), pre-diabetic patients (n=3) or people with predisposing factors of diabetes (n=5). The study sample size ranged between 23-117 for 2 arms, or 99-165 for 3 arms. Comparisons were made against placebo (n=22), conventional medicine (n=1) and regular diet (n=1). Duration of studies ranged from 4 to 24 weeks. Among the 24 studies, 23 tested the effect on fasting blood glucose level as the primary outcome with only 16 of them showed reduction with statistical difference. Out of the 7 studies which did not have marked effect on fasting blood glucose level; 2 showed significant reduction in HbA1c; 1 showed significant reduction in both postprandial blood glucose and postprandial insulin; and 4 showed no effect on primary outcome nor secondary outcomes. The remaining study investigated the effect on insulin resistance and showed no significant influence. Evaluation of the studies showed none of them fully complied with the Consort guideline. Major discrepancies identified were a lack of explanation about how the sample size was determined, how randomization was performed, and what interventions were in place to ensure blinding; a lack of ancillary analyses to explore other influential factors; and a lack of reporting about possible harms associated with the use of the nutraceuticals.

Conclusion

This study shows there is some clinical evidence for the beneficial effects of nutraceutical containing Chinese medicines on diabetes management, but the overall quality of reporting randomized controlled trials appears to be weak. The sample size in most of the randomized controlled trials was relatively small and random errors may occur affecting the validity of the clinical trial results. While the short-term trial design was sufficient to demonstrate some immediate effects of the nutraceuticals on reducing blood glucose level, the long-term effects such as sustainable efficacy on the overall management of diabetes or even the overall mortality, and the safety profile are not fully investigated. The positive results about the beneficial effects were further complicated by the obvious lack of reporting on randomization and blinding measures. More rigorous long-term clinical trials to investigate both safety and efficacy are warranted. Until then, the claims about the beneficial effects of nutraceuticals containing Chinese medicines on diabetes management should be treated with cautions.