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 / Reporting the Evidence / Methodology / Findings / Future Research / Availability of the Full Report
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:
- What Ayurvedic therapies have been reported
in the literature, for which conditions/body
systems, and using what kinds of research
designs?
- What is the efficacy of Ayurvedic
medicine/therapies for the treatment of
diabetes?
Return to Contents
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.
Return to Contents
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.
Return to Contents
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).
Return to Contents
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.
Return to Contents
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.
Return to Contents
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