Home > DARE Reviews > Ayurvedic and collateral herbal...

PubMed Health. A service of the National Library of Medicine, National Institutes of Health.

Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet]. York (UK): Centre for Reviews and Dissemination (UK); 1995-.

Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet].

Ayurvedic and collateral herbal treatments for hyperlipidemia: a systematic review of randomized controlled trials and quasi-experimental designs

BB Singh, SP Vinjamury, C Der-Martirosian, E Kubic, LC Mishra, NP Shepard, VJ Singh, M Meier, and SG Madhu.

Review published: 2007.

CRD summary

The review concluded that Ayurvedic and commonly used collateral herbs have shown positive results for the treatment of hyperlipidemia, but that the results should be viewed with caution due to the limitations of the quality scores used. The reliability of the authors' cautious conclusions were uncertain due to lack of reporting of review methods and details of individual studies.

Authors' objectives

To evaluate the efficacy and safety of Ayurvedic and commonly used collateral herbals for the treatment of hyperlipidemia.

Searching

PubMed, National Library of Medicine, National Center for Complementary and Alternative Medicine and EBSCO were searched in September 2003, February 2004 and January 2007 for studies published after 1970. Search terms were reported. Only studies in English were eligible for inclusion. Web searches were conducted for relevant articles. Footnotes of selected articles, meta-analyses and systematic reviews were scanned for additional articles. The Indian Pharmacopoeia and several Ayurvedic physicians were consulted for additional articles.

Study selection

Randomised controlled trials (RCTs) and quasi-experimental design (QEDs) trials evaluating the safety and efficacy or effectiveness of Ayurvedic and commonly used collateral herbals available over the counter for the treatment of hyperlipidemia were eligible for inclusion. Studies of herbs used in traditional Chinese medicine (TCM) were excluded. Studies that tested herbals for related conditions (hypertension or diabetes) were included only if the primary outcome measure was serum lipid levels.

Approximately half of the included studies assessed garlic. Other herbal products that were assessed included guggal, arjuna and guar gum.

The authors stated neither how papers were selected for the review nor how many reviewers performed the selection.

Assessment of study quality

Validity was assessed using criteria developed previously by the authors including the Singh RCT Quality Scale, which included the Jadad Scale, (scores 0 to 9 were considered low, 10 to 17 medium and 18 to 26 = high), the Singh QED Quality Review Scale (scores 0 to 5 were low, 6 to 10 medium and 11 to 15 high) and the Safety Assessment Score for Clinical Trials (SAS-CT) (scores 0 to 28 were poor, 29 to 68 medium and 69 to 100 high).

Three reviewers independently assessed validity using the Singh RCT Quality Scale and the Singh QED Quality Review Scale. Disagreements were resolved through discussion or by recourse to a fourth reviewer. Safety was assessed by two reviewers using SAS-CT and checked for consistency by a third reviewer.

Data extraction

The authors stated neither how data were extracted for the review nor how many reviewers performed the data extraction.

Methods of synthesis

The authors evaluated RCTs as positive if there were significant differences between groups for outcomes and evaluated QEDs as positive if study participants improved significantly over the duration of the study. The studies were combined narratively with accompanying tables. Mean safety scores were calculated by study type.

Results of the review

Fifty one studies (n unknown) were included (36 RCTs and 15 QEDs).

Quality

Quality scores for RCTs overall ranged from 11 to 26 points, with most studies achieving high quality scores. One RCT assessing garlic and one RCT assessing guggul had a medium score. Quality scores of RCTs improved by decade (RCTs of Arjuna achieved medium scores during the 1990s and high scores during the 2000s). All QEDs had medium or high quality scores. One QED assessing guar gum and two QEDs assessing miscellaneous herbals had a medium score. The mean overall quality score for QEDs was 11.66.

Safety

Twenty one (58 per cent) RCTs had a high score for safety and tolerance assessed using the SAS-CT scale; 42 per cent of RCTs had poor safety scores. The mean score for safety and tolerance overall was 58.61 points (Arjuna=20.17, garlic=62.71, guggul=71). Most of the Arjuna studies failed to report adverse events. Safety scores did not improve by decade of publication.

Eight (57 per cent) of QEDs had high scores for safety and tolerance, six (43 per cent) had low safety scores. The mean score overall for safety and tolerance was 54 (garlic= 43.8, guggal=66.67 and guar gum=96).

Of the 28 studies that reported adverse events and tolerance, seven (25 per cent) reported no adverse events. Reported adverse events were largely gastrointestinal and transient in nature, including belching, bloating, flatulence, cramping, nausea, upset stomach and diarrhoea. Symptoms were reported for both placebo and intervention groups. Other adverse events included headaches, weakness and rashes. Few adverse events required withdrawal from the study (data not reported).

Efficacy/Effectiveness

The majority of RCTs reported that treatment of hyperlipidemia with herbals was effective with 71 per cent overall reported as positive (Arjuna 100 per cent, garlic 53 per cent and guggul 86 per cent). Most QEDs reported that treatment of hyperlipidemia with herbals was effective, with 93 per cent reported as positive (garlic, guggul and guar gum reported as 100 per cent). One study evaluating silymarin had a negative outcome.

Authors' conclusions

Herbals showed positive results through clinical trials for the treatment of hyperlipidemia, but the results should be viewed with caution due to the limitations of the quality scores used.

CRD commentary

Inclusion criteria were clearly defined in terms of interventions and study designs, but not defined in terms of participants or outcomes. Several relevant sources were searched, but restriction to English-language studies may have resulted in the loss of some relevant data. Methods were used to minimise reviewer errors and bias in the assessment of validity, but it was not clear whether similar steps were taken in study selection and data extraction. Validity was assessed using specified criteria and results of the assessment were reported. However, quality assessment for individual studies were reported only for RCTs, making it difficult for the reader to judge the study validity for themselves. The method used to calculate overall mean safety scores was not provided. Pooling the results in this way seemed inappropriate given the apparent differences between studies. The narrative synthesis adopted for quality and efficacy/effectiveness was appropriate. Results for individual studies were reported without supporting data or levels of statistical significance, which meant that the findings reported in the review could not be verified. Issues of safety and tolerance reported may not be comparable to standards used in conventional medicine. No details were reported for the number or characteristics of study participants, whether controls were placebo or standard allopathic ingredients. The reliability of the authors' cautious conclusions was uncertain due to lack of reporting of review methods and details of individual studies.

Implications of the review for practice and research

Practice: The authors stated that physicians should consider Ayurvedic herbs for the management of hyperlipidemia.

Research: The authors stated a need for further studies utilising sample size calculation, compliance reporting, dropout appraisal and structural design bias conducted in all languages. Future research also needed to evaluate tolerance and safety.

Funding

Not stated.

Bibliographic details

Singh B B, Vinjamury S P, Der-Martirosian C, Kubic E, Mishra L C, Shepard N P, Singh V J, Meier M, Madhu S G. Ayurvedic and collateral herbal treatments for hyperlipidemia: a systematic review of randomized controlled trials and quasi-experimental designs. Alternative Therapies in Health and Medicine 2007; 13(4): 22-28. [PubMed: 17658119]

Indexing Status

Subject indexing assigned by NLM

MeSH

Evidence-Based Medicine; Female; Humans; Hyperlipidemias /drug therapy /therapy; Male; Medicine, Ayurvedic; Phytotherapy; Plants, Medicinal; Quality Control; Randomized Controlled Trials as Topic; Research Design; Treatment Outcome

AccessionNumber

12007009189

Database entry date

15/07/2009

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.

CRD has determined that this article meets the DARE scientific quality criteria for a systematic review.

Copyright © 2014 University of York.

PMID: 17658119

PubMed Health Blog...

read all...

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...