Ayurvedic Interventions for Diabetes Mellitus A Systematic Review

Summary

Evidence Report/Technology Assessment: Number 41

Please Note: The evidence report this summary was derived from has not been updated within the past 5 years and is therefore no longer considered current. It is maintained for archival purposes only.

Under its Evidence-based Practice Program, the Agency for Healthcare Research and Quality (AHRQ) is developing scientific information for other agencies and organizations on which to base clinical guidelines, performance measures, and other quality improvement tools. Contractor institutions review all relevant scientific literature on assigned clinical care topics and produce evidence reports and technology assessments, conduct research on methodologies and the effectiveness of their implementation, and participate in technical assistance activities.

Overview

The objective of this evidence report was to conduct a search of the published literature on the use of Ayurvedic medicine/therapies for the treatment of health conditions and, on the basis of that search, to choose either a condition or a modality for a comprehensive review. A broad search of Ayurvedic medicine/therapies showed that there was sufficient literature to support a systematic review of the use of Ayurvedic therapies for the treatment of diabetes. Diabetes is a common illness, and many traditional medical systems have developed strategies to treat this condition. The Ayurvedic therapy most commonly used to treat diabetes was herbal therapy, which therefore became the primary focus of this review. A small number of studies looking at diet therapy were also found.

Empirical evidence of efficacy for the Ayurvedic treatment of diabetes would be helpful to health care providers managing diabetic patients and would be useful in identifying areas for future research. The specific questions addressed in this project were:

1. What Ayurvedic therapies have been reported in the literature, for which conditions/body systems, and using what kinds of research designs?
2. What is the efficacy of Ayurvedic medicine/therapies for the treatment of diabetes?

Reporting the Evidence

An initial broad search of the literature found 2,565 titles, of which 1,214 were judged to represent Ayurvedic therapies that were neither veterinary nor agricultural in nature and thus potentially relevant to our review. To answer our first research question, these 1,214 titles were screened for subject, language, body system/disease state, study population, and study design. To answer our second research question, we further assessed the potentially relevant articles, including literature received from India. Fifty-four articles containing the results of 62 human clinical studies using Ayurvedic therapy for diabetes were identified. These studies were analyzed in detail to determine if evidence existed regarding the efficacy of Ayurvedic therapy for diabetes.

Methodology

A panel of technical experts representing diverse disciplines was established to advise us throughout the course of our research. A number of databases were searched: MEDLINE®, HealthSTAR, EMBASE®, Allied and Complementary Medicine™, MANTIS™, BIOSIS Previews®, CAB HEALTH, and CINAHL®. We used the MeSH terms "Ayurveda" or "Ayurvedic" combined with the botanical names of 16 herbs commonly used in Ayurvedic treatment. In addition, a strategy was developed to identify and retrieve literature from India. This involved using an abstracting service in India to identify potentially relevant literature.

There was no language restriction in the Western literature search. The Indian search was limited to studies published in English because we could not read studies in other languages and did not have the resources to have them translated. Additional articles were identified from supplemental searches that focused on the Ayurvedic herbs most often used for diabetes, on review articles, and on citations of articles. All titles, abstracts, and articles were reviewed by two reviewers, and all disagreements were resolved by consensus.

Data were collected using screening forms that we developed for this purpose. We analyzed the data regarding the general characteristics of the Ayurveda literature and used this information to select a topic for a focused review.

We then conducted a focused literature review using the articles we had identified from the Western literature and abstracts of articles published in India. We selected all articles identified as studying Ayurvedic therapies for diabetes in either the initial or the focused search. We identified 54 articles containing the results of 62 studies in this manner. Because of the heterogeneity of these studies, a meta-analysis was not possible. Approximately one-third of the studies were subjected to further analysis in which we calculated a common effect statistic. We also conducted a qualitative analysis on these studies.

Findings

• The most common conditions or body systems for which studies of Ayurvedic therapies have been published are:
  • Diabetes mellitus.
  • Liver/hepatitis.
  • Infectious diseases.
  • Hypercholesterolemia.
  • Central nervous system disorders (dementia/depression).
  • Cardiovascular diseases.
• The Ayurvedic therapy that was the most common subject of published studies was herbal therapy. Almost no studies were found on any other Ayurvedic modalities.
• No studies were found that tested Ayurveda as a whole system or that tested multiple modalities for the same disease state at the same time.
• A significant body of literature in English exists in India; it can be identified, and a large portion of the studies can be obtained with effort. However, even after extensive efforts, a handful of English-language studies in India could not be found. Studies in non-English languages also exist but were not reviewed.
• Significant heterogeneity exists in the studies identified. More than 45 single herbs or combination herbal therapies were tested. The study designs likewise were varied. The 54 articles reported the results of 62 studies. Of these, 7 were randomized controlled trials (RCTs), and 10 were controlled clinical trials (CCTs). There were 38 case series, the most frequently used clinical design, and 7 cohort studies.
• The most common single herbs studied were Gymnema sylvestre, Coccinia indica, fenugreek (Trigonella foenum-graecum), and Eugenia jambolana. A number of herbal formulas were tested, but Ayush-82 and D-400 were the two most often studied.
• There is evidence to suggest that the single herbs Coccinia indica, holy basil, fenugreek, and Gymnema sylvestre and the herbal formulas Ayush-82 and D-400 have a glucose-lowering effect and deserve further study. Evidence of effectiveness of several other herbs is less extensive (C. tamala, Eugenia jambolana, and Momordica charantia).

Future Research

Our review has identified a number of interesting areas for future research. Basic scientific studies of Ayurvedic medicine have not been rigorously pursued. There are currently few RCTs and CCTs in the literature, which hinders the assessment of efficacy. Future trials need to enroll an adequate number of subjects. Interventions should be compared to placebo preparations, and care should be taken to construct placebos that cannot be distinguished from the trial drug.

The clinical trials of Ayurvedic therapies for diabetes need to be better reported. The method of patient selection and assignment to arms needs to be better described, and the reporting of results should follow good statistical practice. In addition, the trials need to be of sufficient length to determine a relevant clinical effect.

It would also be useful to investigate the efficacy of single-herb therapies versus the relatively complex Ayurvedic formulas used. It is not clear from the currently available literature if the formulas provide any additional benefit over single-herb therapies.

Field studies to determine how Ayurvedic medicine is used in real-life clinical practice should be conducted. The interaction between botanicals and other Ayurvedic modalities (yoga, for example) on diabetes could be assessed. The relationship between Ayurvedic diagnosis and Western diagnosis needs to be established.

Furthermore, trials incorporating more sophisticated diabetes research should be conducted. Studies evaluating the impact of Ayurveda using more current methods of assessing diabetes are also needed.

Availability of the Full Report

The full evidence report from which this summary was taken was prepared for the Agency for Healthcare Research and Quality by the Southern California Evidence-based Practice Center under contract No. 290-97-0001. Print copies may be obtained free of charge from the AHRQ Publications Clearinghouse by calling 1-800-358-9295. Requesters should ask for Evidence Report/Technology Assessment No. 41, Ayurvedic Interventions for Diabetes Mellitus: A Systematic Review (AHRQ Publication No. 01-E040).

The Evidence Report is also online at the National Library of Medicine Bookshelf.

AHRQ Publication Number 01-E039
Current as of June 2001

Internet Citation:

Ayurvedic Interventions for Diabetes Mellitus: A Systematic Review. Summary, Evidence Report/Technology Assessment: Number 41. AHRQ Publication No. 01-E039, June 2001. Agency for Healthcare Research and Quality, Rockville, MD. http://www.ahrq.gov/clinic/epcsums/ayurvsum.htm