Chinese Herbal Medicine Versus Other Interventions in the Treatment of Type 2 Diabetes: A Systematic Review of Randomized Controlled Trials (2025)

Keywords: Chinese medicine, type 2 diabetes

Description of the Condition

As a group of chronic metabolic diseases, diabetes mellitus was identified in 382 millionpeople in 2013 worldwide and will affect almost 600 million by 2035 based on theprediction from the International Diabetes Foundation.¹ About 5.8% of the world population was diagnosed with diabetes in 2014.² Additionally, 1.5 million deaths were estimated as a direct result of diabetes in 2012,² and this number went up to 4.9 million in 2014 globally.³ The World Health Organization predicts that diabetes will be the seventh leadingcause of death in 2030.⁴

There are 2 main types of diabetes: type 1 diabetes and type 2 diabetes; gestationaldiabetes is a third form of diabetes.⁵ Type 2 diabetes, which is also called non–insulin-dependent or adult-onsetdiabetes, is described as a progressive condition where the body becomes resistant toinsulin and is associated with multiple lifestyle risk factors.⁵

Diabetes, predominantly type 2 diabetes, has been recognized as one of the enormoushealth care challenges for the 21st century.¹ Ninety percent of the people with diabetes are recognized to have type 2 diabetesaround the world.⁶ There is also an increasing prevalence of type 2 diabetes in children, adolescents,and young adults.¹

The economic burden of diabetes is remarkable and estimated as US$376 billion, which was12% of all global health expenditure in 2010.¹ It is predicted to rise to between US$490 and US$893 billion by 2030.¹

China has become the diabetes focus among all nations in the world; there were 98.4million diabetes patients diagnosed in China in 2013 and this number will increase to142.7 million in 2035.¹ A total of 1.3 million Chinese with diabetes died in 2011.⁷ Direct health care expenditure of type 2 diabetes and its complications in Chinawere estimated at US$26 billion in 2007 and is expected to increase to US$47.2 billion by 2030.¹

Description of Intervention

There is no cure for type 2 diabetes and the management is through the control of bloodglucose level by diet and exercise alone or in combination with medications. These includepharmaceuticals that are mainly Western hypoglycemic drugs and complementary therapy.Traditional Chinese medicine (TCM) is becoming increasingly popular in Western countriesas an alternative intervention for type 2 diabetes.⁸

Diabetes mellitus has been recognized since antiquity and TCM herbs have been used totreat diabetes in China for more than 2000 years.⁹ Xiaoke (wasting-thirst) is an ancient term for diabetes, which was first recordedin The Yellow Emperor’s Classic of Internal Medicine.¹⁰ The recorded symptoms describe 3 increases and 1 decrease (polydipsia, polyphagia,polyuria, and weight loss) and probably equates to the term “diabetes” in Western medicine.¹⁰

The treatment of diabetes with Chinese herbs is according to syndrome differentiationbased on Qi (vital energy) and blood, Zang-Fu (5 viscera and 6 bowels), and Yin-Yang(representing 2 opposite principles in the body) theory, which is different from Western medicine.¹¹

The commonly recognized patterns of type 2 diabetes are Qi and Yin (body fluids)deficiency, heat, and stasis based on TCM theory. Qi and Yin deficiency patterns may occurin initial stages and result in the heat of tissues and blood stasis.¹² Alternatively, heat can occur earlier, or Yin deficiency and heat may presentsimultaneously for relatively longer duration, while stasis may happen at any stage.¹³ Thus, frequently used herbal formulae can be categorized into 4 groups: Qiinvigorating, Yin nourishing, heat clearing, and stasis-reducing (improving blood circulation).¹² The most frequently prescribed herbs are Membranous Milkvetch Root (Huang qi),Rehmannia Root (Di huang), Common Anemarrhena Rhizome (Zhi mu), and Danshen Root (Danshen), which respectively belong to the above-mentioned groups.¹²

In China, government-owned health care delivery facilities are responsible for thetreatment of most of patients and hospital delivery rates averaged 95% in 2011.^14,15 The private sector has grown more quickly than the public sector since themid-1990s, especially in rural areas.¹⁴ Diabetes in China is mainly managed in public health care sectors as inpatient oroutpatient services.¹⁶

How TCM Works

TCM has its own theory for disease mechanism, diagnostic techniques, and therapeuticprinciples. Generally speaking, diseases are considered as interaction between bothinternal and external causes and result in disturbance of Qi and blood, Zang-Fu, andimbalance between Yin and Yang.¹⁷ The diagnostic system in TCM is 4 examinations: inspection, listening/smelling,inquiry, and palpation.¹⁷ Tongue inspection and pulse palpation are 2 unique diagnostic techniques of TCMcompared with Western medicine. The discussion of treatment is based on syndromedifferentiation. Syndrome differentiation is an approach to make a comprehensive analysisof the data collected from the 4 examinations and decide the diagnosis based on TCM theory.¹⁷ The major differentiating methods are developed as follows: 8 guiding principlessyndrome differentiation, disease-cause syndrome differentiation, syndrome differentiationof qi, blood and body fluids, Zang-Fu organ syndrome differentiation, 6-channel syndromedifferentiation, defense-qi-nutrient-blood syndrome differentiation, and triple-burnersyndrome differentiation.¹⁷ The therapeutic philosophy and goals of TCM are focused on the overall functionalstate of the patient, which can differ from those in Western medicine.¹⁸ Acupuncture and moxibustion, Chinese herbal medicine, Chinese dietary therapy,Chinese exercise therapy, and manual therapy are the 5 major branches of TCM treatment methods.¹⁷

TCM usually concentrates on holistic treatment of the patient instead of focusing ontreating a single disease.¹⁸ TCM formulae often contain large numbers of active ingredients that are suitablefor regulating several crucial targets based on individualized treatment.¹⁸ Thus, the action of Chinese herbal medicine is different due to the therapeuticprinciples and goals of TCM differing from those in Western medicine. And the measurementof intended effects of TCM herbs is also complicated compared to Western medicine, whichprimarily consists of single chemical compounds.¹⁸

Although many of the antihyperglycemic components of TCM herbs are unknown, Chang andcolleagues summarized the chemistry and biological action of 40 extracts and compounds ofplant origin.¹⁹ The mechanism of action of these herbal medicines involves improving insulinsensitivity, stimulating insulin secretion, protecting pancreatic islet cells, andinhibiting intake of intestinal carbohydrates.¹²

Adverse Effects of Chinese Herbal Medicine

It has been widely acknowledged that medicinal herbs are normally nontoxic, while theconsumption of herbs still has risk due to incorrect prescribing, over dosage, improperpreparation, erroneous substitution, adulteration with Western medicine, and inherenttoxicity or contaminants.^8,20 The toxicity-related issues of herbal ingredients have been reported earlier.⁸ The most commonly seen TCM-dependent clinical complications are interactionsbetween TCM herbs and conventional drugs taken for diabetes.⁸ Another source of clinical concern is contamination of TCM preparations withimpurities, heavy metals, or bacteria, and heavy metals have been reported before as themain poison associated with the use of TCM products.⁸ Other causes of toxicity also involve intentional adulteration of TCM withbioactive additives such as corticosteroids, hormones, salicylates, or antihistamines.⁸ Improper prescription of herbal formulae and preparation of herbs, which relate tothe regulation of herbal medicine and Chinese herbal medicine practitioners, is a crypticunderlying risk factor. For example, if a doctor prescribed energy invigorating herbsrather than heat clearing herbs to a diabetic patient with body heat pattern, the symptomscould be worse in this patient. Identifying the active ingredients of herbs and theirpharmacological mechanism of actions are both time consuming and financially expensivesince one formula is often formed from many single herbs, and a single herb usually hasmultiple compounds. Besides, the real efficacy and toxicity of herbal agents are difficultto test using the current evaluation paradigm for single chemical compounds.¹⁸

Why It Is Important to Conduct This Review

An increasing number of type 2 diabetes patients choose to manage their condition withTCM without consideration of the potential toxic effects of medicinal herbs.⁸ There are limited studies in the English literature discussing both effectivenessand adverse effects of Chinese herbs used to treat type 2 diabetes. This review evaluatedthe evidence for effectiveness, explored adverse effects, and quality control according tothe Cochrane Handbook for Systematic Reviews of Interventions, and alsoprovides an English literature review of type 2 diabetes treatments with Chinese herbalmedicines versus other interventions based on the original Chinese literature. Inpractice, it should also provide valuable information of study designs for future researchinto diabetes treatment with TCM herbal medicines.

Criteria for Considering Studies for This Review

We did a systematic review and assessed the primary outcomes according to theCochrane Handbook for Systematic Review of Interventions.

Types of Studies

Randomized controlled clinical trials with a minimum treatment period of 8 weeks wereincluded in this review. Only studies in the English and Chinese literature were used inthis review.

Types of Participants

Adults diagnosed with type 2 diabetes mellitus based on documented diagnostic criteriawere included. WHO 1999, WHO 2007, ADA 1999, ADA 2003, China 1994, China 2007 and China2012 were used as the benchmark for type 2 diabetes in the inclusion criterion. Onlystudies of type 2 diabetes with Chinese herbal medicine treatment were studied. The reviewincluded studies only if participants’ intervention duration was 8 weeks or more. Trialsinvolving type 2 diabetes treatment with acupuncture or other TCM modalities (alone orcombined with Chinese herbal medicine) were excluded.

Types of Interventions

Chinese herbal medicines including a compounded herbal formula or individualizedprescriptions by Chinese medicine practitioner(s), patent herbs, single herb, Chineseherbal medicines combined with pharmacological intervention, and other interventionincluding diet control, exercise therapy, and diabetes education, regardless of the dose,method of dosing, or duration of administration were compared with other treatments(mainly pharmacological intervention). The following comparisons were included:

1. Chinese herbal medicines combined with other pharmaceuticals versus otherpharmaceuticals (mainly Western medicines)

2. Chinese herbal medicines alone versus other pharmaceuticals (mainly Westernmedicines)

3. Chinese herbal medicines (alone or combined with other interventions or otherpharmaceuticals) versus placebo

4. Chinese herbal medicines combined with other pharmaceuticals versus Chinese herbalmedicines versus pharmaceuticals alone

5. Chinese herbal medicines alone versus pharmaceuticals versus other interventions(including diabetes education, diet control, and exercise therapy)

Types of Outcome Measures

Timing of Outcome Assessment

Studies with possible effective treatment duration from 8 weeks to 1 year were includedfor analysis.

Search Methods for Identification of Studies

The following resources were searched to identify trials:

• The Cochrane Library (Wiley Online Library)

• Web of Science

• PubMed

• Google Scholar

• The University of Adelaide Library Research

• China Academic Journals Full-text Database (Basic Search)

• China Dissertation Database

• China Knowledge Resource Integrated (CNKI) Database

• Baker Heart and Diabetes Institute

We conducted extensive and ongoing electronic searches in the above-described databasesfrom 2004 until April 2016. All authors screened search results and identified the fulltexts of all relevant trials reports. We also detected additional keywords of relevanceduring any of electronic or other searches by modifying the search strategies toincorporate the search terms. Studies published in English and Chinese were included. Wesearched other resources as well, such as reference lists of relevant trials and reviewsfrom published studies and used personal communication from the National Resource Centrefor Chinese Materia Medica for identification of additional relevant studies. We did notsearch unpublished literature (the studies that have not been published due to negativeresults and the studies that were not peer reviewed).

Data Collection and Analysis

Data Extraction and Management

For studies that fulfilled the inclusion criteria, data of the relevant population,intervention, and outcome characteristics were abstracted by using standard dataextraction templates (for details, see “Table 2: Characteristics of Included Studies,”available as supplemental material in the online version of the article); any questionswere resolved by discussion between the authors, referring back to the original article.When necessary, additional information was sought from the authors of the primarystudies.

Assessment of Risk of Bias in Included Studies

We assessed the risk of bias for each included study based on the criteria outlined inthe Cochrane Handbook for Systematic Review of Interventions. Anyuncertainty was resolved by discussion between the 3 authors. The details of risk of biasare listed in “Table 2: Characteristics of Included Studies” (available in the onlineversion of the article).

Description of Studies

558 clinical trials of type 2 diabetes with Chinese herbal medicine treatment wereidentified, and 165 full-text articles were eligible for detailed review. 58 studies wereincluded and 107 studies excluded based on the above-mentioned criteria.

Results of the Search

A total of 558 references were identified by initial database searching up to April 8,2016. 382 potentially eligible studies were kept for further assessment after duplicateswere removed. 217 studies were excluded because they clearly did not fulfil the inclusioncriteria. Full-text articles were explored for clarification if the title and abstract didnot provide clear information. 165 full-text articles were assessed for eligibility. 58full-text articles were included in our qualitative synthesis, and 107 full-text articleswere excluded. The reasons for exclusion are listed in Figure 1 and “Table 3: Characteristics of ExcludedStudies” (available in the online version of the article). Further investigation of thefull articles retrieved included 5 studies that were initially excluded, and 9 studieswere excluded that were initially included. An adapted PRISMA (Preferred Reporting Itemsfor Systematic Reviews and Meta-Analysis) flowchart of study selections is shown in Figure 1.

Included Studies

58 trials were included for effectiveness and safety assessment and risk of biasanalysis. For more information, see “Table 2: Characteristics of Included Studies”(available in the online version of the artilce).

Study Design

All the included studies stated they were randomized controlled clinical trials, but only13 trials reported the details of randomization methods, and 3 trials (Ji 2013; Chao 2009;Tong 2013) provided very detailed information of the randomization methods. 1 trial (Ji2013) had 4 arms (see Supplemental Materials for details of the studies).

Participants

All the study participants were hospital patients diagnosed with type 2 diabetes mellitusthat were either receiving or not receiving treatment before the study commenced. 55studies were carried out in a single study center, mainly different provincial andmunicipal hospitals of main cities in mainland China. 3 trials (Chao 2009; Tong 2013; Ji2013) were carried out in multiple study centers, with 2 studies using 2 and 10 centers,respectively, in China, and the other study using 20 centers (19 participant centers inChina and 1 participant center in Queensland, Australia). See Supplemental Materials fordetails of the studies.

Diagnosis

The diagnostic criteria for type 2 diabetes mellitus were mainly based on WHO criteria(43 trials by criteria in 1999, 1 trial by 2007, 2 trials without specification), and 3trials used the criteria of ADA (1 trial by 1999, 1 trial by 2003, and 1 trial withoutspecification). 4 trials used their diagnostic criteria based on textbook criteria, and 5trials had no specification.

Interventions and Comparisons

42 trials compared combined Chinese herbal medicines and other pharmaceuticals with otherpharmaceutical. Ten trials compared Chinese herbal medicines with other pharmaceuticals. 4trials compared Chinese herbal medicines with placebo; 2 trials compared 3 groups (onecompared Chinese herbal medicines combined with pharmaceuticals to other pharmaceuticalsor to Chinese herbal medicines; the other compared Chinese herbal medicines topharmaceuticals or to other interventions). Only 1 trial was a multiple-armed study thatcompared Chinese herbal medicines combined with pharmaceuticals to other pharmaceuticalbetween a drug naïve group and drug group. Most trials tested various Chinese herbalmedicines including individual prescriptions modified from classical formulae. 3 trialsonly tested a single Chinese herb: Huanglian (Coptidis Rhizoma) or Wuweizi (FructusSchisandrae).

The formulae of Chinese herbal medicines were different in each study. All recordedformulae, individual formulae, and patent herbal formulae were included in the studies andthe basic composition consisted of the 132 common Chinese herbal medicines; for moredetails, see “Table 4: List of Chinese Herbal Medicines Used as Treatment for Type 2Diabetes” (available in the online version of the article). Pharmaceuticals includedcommonly used hypoglycemic Western medicines such as metformin, sulfonylureas(glibenclamide, glimepiride, and glipizide), α-glucosidase inhibitor (acarbose),thiazolidinediones (rosiglitazone), and insulin. Other interventions mainly included dietcontrol, exercise therapy, diabetes health education, and other lifestyle changes.

Follow-up

All of the 58 included trials followed-up the participants until the end of thetreatment. 24 trials studied and/or reported the adverse effects of the intervention.

Publication Details

See “Table 2: Characteristics of Included Studies” for detailed information (available inthe online version of the article).

Risk of Bias in Included Studies

Most participants in included studies were mainly Chinese recruited from TCM hospitals,which led to selection bias because the results might not be applicable to the generalpopulation. A general conclusion cannot be drawn because the sample might not berepresentative of the whole population.

In addition, there was insufficient information to make a formal assessment; mostincluded studies were at an unclear risk of bias for nearly all of the “Risk of Bias”domains apart from attrition bias. See “Table 2: Characteristics of Included Studies” formore information.

Allocation

42 included studies reported that the participants were randomly divided into 2 groupsfor respective treatments without giving further details. 11 included studies reported afurther randomization method: “By using random number table method.” Moreover, 2 trialsmention “by random file number method.” Only 3 trials reported a detailed randomizationmethod, “Statistics Analysis System software was used to randomly divide the subjects,”²¹ or “randomization was performed centrally and was concealed and stratified inblocks of four,”²² or “randomization and blinding were conducted by personnel who did not participatein data acquisition and evaluation. A computer program was used to generate the subjectassignment; each subject was given a unique number and this number was used throughout the trial.”²³ In addition, all 16 of these trials were assessed as having a low risk of selectionbias.

Blinding

53 studies were assessed as unclear for performance bias and detection bias because noinformation on blinding of participants and personnel or outcome assessors was provided inthe trial reports. Only 5 studies reported detailed information of blinding methods:“double-blinded and placebo-controlled” or “All investigators were blinded from the studydrug assignment, in which only a randomization code was disclosed. Unblinding wasconducted only after all study data were collected.” Moreover, all 5 of these trials wereassessed as having a low risk of performance bias and detection bias.

Incomplete Outcome Data

All 58 studies were assessed as having a low risk of attrition bias. After checking thetotal number of participants and the patients included in each intervention group, therewere no missing data in 53 studies. There were exclusions or losses to follow-up reportedin 5 included studies. 1 trial lost follow-up in both groups before the start of thestudy. 2 trials had missing outcome data balanced in numbers and with similar reasons formissing data across groups. Another trial had missing outcome data balanced in numbersacross groups for no reported reason. The last one had missing outcome data balanced innumbers across intervention groups, and the proportion of missing data compared with theobserved event risk was not enough to have a clinically relevant impact on theintervention effect estimate.²⁴

Selective Reporting

54 studies were assessed as having an unclear risk of reporting bias since theirprotocols were not available. 4 had clear protocols and were assessed as having a low riskof reporting bias.

Other Potential Sources of Bias

All 58 studies were assessed as unclear risk of other potential bias. All includedstudies followed-up the participants until the end of treatment. Most of studies reportedthat there was no significant difference among the groups before the interventions, andwere considered to have good baseline similarity. However, other aspects of bias werestill unclear, as most studies did not clearly report how diabetes had been controlled,and for how long, before the studies.

Effects of Interventions

58 studies with 6637 patients diagnosed with type 2 diabetes were included in the review.All included studies compared Chinese herbal medicine with other interventions(pharmaceuticals, diet control, and exercise therapy and health education). 5 comparisonsand summary of findings are available in Supplemental Table 1 (available in the onlineversion of the article).

Summary of Main Results

Quality of Methodology

The general methodological quality of all selected trials was unsatisfactory based oninternational standards for a well-conducted randomized controlled trial. All selectedtrials reported important demographic information and mentioned that no significantdifference was found between intervention groups on baseline data at recruitment. Moststudies provided detailed information with baseline data before the recruitment of thestudy. However, in terms of randomization, allocation, and concealment methods, only 3studies provided sufficient details. 13 trials reported limited details of randomizationand allocation concealment method. The remaining 42 trials only generally mentioned thatrandomization applied in their studies without details of the randomization, allocation,and concealment methods. Only 5 studies reported detailed information of blinding methods.However, blinding is difficult with respect to Chinese medicine due to its taste.Furthermore, most studies that did not mention blinding might have avoided blindingbecause the patients were expected to receive only Chinese herbal treatment rather thanWestern medicines or placebo since they had decided to see a traditional Chinese medicinepractitioner.

Study Design

Most of the included studies provided information regarding the hypothesis to be tested,the baseline information of participants, their recruitment criteria, WHO diagnosiscriteria of type 2 diabetes mellitus, and diagnosis criteria by Chinese medicine theory,clear information on study and control groups, the details of intervention medicines andtreatment methods, the duration of intervention, and the proper outcome measurements.However, only 22 clinical trials out of 58 reported adverse effects, with 19 trialsreporting the examination details for adverse effects. Most trials did not reportpotential side effects as a study outcome. Adverse effects of Chinese herbal medicines mayhave been neglected in most clinical studies due to various reasons mentioned above.Meta-analysis could not performed due to the limited information with respect to studymedicines and the different Chinese herbs used in each study. Furthermore, there were only4 placebo-controlled trials, which were insufficient to draw any conclusion with respectto the effectiveness and safety of Chinese herbal medicine for treating type 2 diabetesmellitus.

Result Report and Analysis

No exclusion or losses were reported in most of the included trials, but the number ofparticipants remained the same at the beginning and the endpoint of studies. So apart from5 trials that reported lost follow-up data, all remaining 53 trials were assumed to havehad no dropouts by checking the numbers of participants from the beginning and the end ofthe study. The 5 studies that reported the incomplete data were assessed as low risk basedon the Cochrane Collaboration’s tool for assessing risk of bias.²⁴ The protocol of most included studies was not described in sufficient detail, so itwas not possible to carry out a meta-analysis.

Conclusions of the Included Studies

All studies reported the therapeutic effects of the interventions, but only 2 studiespublished outside of China recorded their limitations in the discussion section of thetrial report. The approach to treating type 2 diabetes may differ according to TCMsyndrome differentiation. Many herbal formulae were slightly modified compared to theclassical prescription depending on individual clinical presentation. Most studiesdescribed formulae with multiple herbs and only 3 studies reported single herb usage.Therefore, the conclusion with respect to effectiveness in this review is only in generalterms but not for specific formulae or individual Chinese herbal medicines.

All selected studies were eligible for this review but the overall quality of themethodology was inconclusive and unsatisfactory. The evidence of included studies wasinsufficient, so the risk of bias of included studies was unclear. In addition, theevidence of safety of Chinese herbal medicines as a treatment for type 2 diabetes wasinadequate due to the variation in studies and methodology. Well-designed clinical trialswith standard criteria are required for the study of safety of Chinese herbalmedicines.

Potential Biases in the Review Process

We tried to include all relevant studies on type 2 diabetes treatment with Chinese herbalmedicine. Most full-text articles were in Chinese with only English abstracts. However,not all literature are in all database. Some database could not be accessed due tolocation and language limitation, as some Chinese databases are not accessible fromAustralia. It is also impossible to avoid publication bias, as negative studies were notreported. Alternatively, some articles were published but not peer reviewed. Meta-analysiscould not be conducted due to the reason mentioned above.

Systematic bias could be possible since most of the included studies did not providedetailed protocol of administration of treatment and assessment of outcomes but onlysimply reported that randomization was performed for allocation of intervention groups.Selection bias could not be avoided since most study participants were Chinese recruitedfrom TCM hospitals. Blinding of participants and personnel processes were described withdetailed information in most included studies.

In terms of duration of intervention, only 2 studies lasted 4 months, 5 studies lasted 6months, 1 study 48 weeks, and 1 study 1 year. Most trials reported end-of-treatmentoutcomes ranging from 8 to 12 weeks, which was too short to address long-termeffectiveness and toxicity of the herbs. In particular, for Chinese herbal medicine, thereis a lack of information about the half-life of plant secondary metabolites to testlong-term effectiveness and adverse effects, making it problematic to determine if Chineseherbal medicine could be an effective and safe treatment for type 2 diabetes.Effectiveness and safety issues should be a future research emphasis for Chinese herbalmedicine used to treat chronic diseases such as type 2 diabetes.

Agreements and Disagreements With Other Studies or Reviews

The findings in this review related to effectiveness of Chinese herbal medicines to treattype 2 diabetes are similar to the conclusion of previous systematic reviews. The onlyprevious Cochrane systematic review on Chinese herbal medicine to treat type 2 diabeteswas in 2004 by Liu and others.¹¹ Liu and colleagues analyzed the effects of 66 randomized trials of 69 herbsinvolving 8302 patients with type 2 diabetes. The conclusion was that herbal medicineswere effective on blood glucose control in people with type 2 diabetes mellitus.Nevertheless, there was no mention of any adverse effects related to type 2 diabetes withChinese herbal medicine treatment.

Implications for Practice

A combination of Chinese herbal medicine and other pharmaceuticals (mainly Westernhypoglycemic agents) might be more effective than pharmaceuticals in terms of glycatedhemoglobin, glycemia, and control of insulin resistance level in type 2 diabetes mellitus.However, there was limited evidence to assess the effectiveness of Chinese herbal medicinealone for treating type 2 diabetes (only 10 trials with small sample size). The quality ofevidence (data of study duration and outcome) is insufficient to fully evaluate theeffectiveness and adverse effects of the intervention.

Implications for Research

Long-term well-designed studies are required to compare Chinese herbal medicines alonewith pharmaceutical alone or placebo before drawing any conclusion about the effectivenessand safety of type 2 diabetes treatment with Chinese herbal medicine. We suggestundertaking high-quality clinical trials with multiple centers (large samples) andpublication in English as a way to rectify this. Adequate randomization methods need to beapplied and clearly reported. Clear information should be provided about the managementmethods and their duration before the study, along with other baseline characteristics forthe recruitment of patients. Evaluation of effectiveness must be more clearly specifiedand focused on glycated hemoglobin and glycemic control.

We suggest standardization and quality controls to assess effectiveness and safety ofChinese herbal medicine for type 2 diabetes treatment. Future studies should addresssafety issues by not only reporting adverse effects but also supplying details of toxicitytests for type 2 diabetes patients. With respect to TCM assessment and treatment variationbased on syndrome differentiation, we suggest recruiting the same category of type 2diabetes patients and treatment with similar Chinese herbal medicines in future studies inorder to reduce the information bias of studies as much as possible. We recommendmultiple-center trials with type 2 diabetes patients recruited from different sources(such as patients outside hospitals, patients outside China, etc) in order to avoidselection bias.

Supplementary_Table - Chinese Herbal Medicine Versus Other Interventions in theTreatment of Type 2 Diabetes: A Systematic Review of Randomized ControlledTrials

Supplementary_Table for Chinese Herbal Medicine Versus Other Interventions in theTreatment of Type 2 Diabetes: A Systematic Review of Randomized Controlled Trials by AoYu, David Adelson, and David Mills in Journal of Evidence-Based Integrative Medicine

Supplemental_Material_2 - Chinese Herbal Medicine Versus Other Interventions in theTreatment of Type 2 Diabetes: A Systematic Review of Randomized ControlledTrials

Supplemental_Material_2 for Chinese Herbal Medicine Versus Other Interventions in theTreatment of Type 2 Diabetes: A Systematic Review of Randomized Controlled Trials by AoYu, David Adelson, and David Mills in Journal of Evidence-Based Integrative Medicine

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Supplementary Materials